[ltt-dev] [PATCH RFC urcu 0/2] v2 allow multiple URCU flavors in one executable

[ltt-dev] [PATCH RFC urcu 0/2] v2 allow multiple URCU flavors in one executable

[Paul E. McKenney]

Hello!

The following set of patches permits a single executable to use
multiple flavors of URCU without resorting to linker tricks.  The
approach is to map each flavor to a different namespace.  The patches
are as follows:

1.	Provide pthread_atfork-friendly interfaces.
2.	Map symbols to allow multiple flavors of URCU to be mixed.
3.	Apply feedback from v1 review.
4.	Extend symbol mapping to include defer_rcu().

This does not yet centralize pthread_atfork() handling, nor does it
combine all the binaries into a single dynamic library.  This latter
is enabled by the name mapping.

Further thoughts?

							Thanx, Paul


 Makefile.am            |    4 
 README                 |   20 -
 a/urcu-call-rcu.c      |  620 -------------------------------------------------
 b/Makefile.am          |    3 
 b/README               |    4 
 b/tests/Makefile.am    |   33 +-
 b/tests/rcutorture.h   |    1 
 b/tests/urcutorture.c  |   13 -
 b/urcu-bp-map.h        |   61 ++++
 b/urcu-bp.c            |    4 
 b/urcu-bp.h            |    8 
 b/urcu-call-rcu-impl.h |  618 ++++++++++++++++++++++++++++++++++++++++++++++++
 b/urcu-call-rcu.c      |   29 ++
 b/urcu-defer-impl.h    |  450 +++++++++++++++++++++++++++++++++++
 b/urcu-map.h           |  117 +++++++++
 b/urcu-qsbr-map.h      |   63 ++++
 b/urcu-qsbr.c          |   36 +-
 b/urcu-qsbr.h          |   18 -
 b/urcu.c               |    5 
 b/urcu.h               |   20 +
 tests/Makefile.am      |    2 
 urcu-bp-map.h          |    6 
 urcu-bp.c              |    1 
 urcu-bp.h              |    5 
 urcu-defer-static.h    |  108 --------
 urcu-defer.c           |  385 ------------------------------
 urcu-map.h             |   26 ++
 urcu-qsbr-map.h        |    6 
 urcu-qsbr.c            |    1 
 urcu-qsbr.h            |   11 
 urcu.c                 |    1 
 urcu.h                 |   13 -
 32 files changed, 1497 insertions(+), 1195 deletions(-)

[ltt-dev] [PATCH RFC urcu 1/4] Provide pthread_atfork-friendly interfaces

[Paul E. McKenney]

Provides call_rcu_before_fork() and call_rcu_after_fork_parent() to
go with the existing call_rcu_after_fork_child().

Signed-off-by: Paul E. McKenney <paulmck at linux.vnet.ibm.com>
---
 README          |    4 ++++
 urcu-call-rcu.c |   29 ++++++++++++++++++++++++++++-
 2 files changed, 32 insertions(+), 1 deletions(-)

diff --git a/README b/README
index f7f0dec..56e98d7 100644
--- a/README
+++ b/README
@@ -204,3 +204,7 @@ Interaction with fork()
 	liburcu-bp, which is designed to handle fork() by calling
 	rcu_bp_before_fork, rcu_bp_after_fork_parent and
 	rcu_bp_after_fork_child.
+
+	Applications that use call_rcu() are required to invoke
+	call_rcu_after_fork_child() from the child process after a
+	successful fork() system call that is not followed by exec().
diff --git a/urcu-call-rcu.c b/urcu-call-rcu.c
index bb56dbb..665f20c 100644
--- a/urcu-call-rcu.c
+++ b/urcu-call-rcu.c
@@ -566,13 +566,40 @@ void free_all_cpu_call_rcu_data(void)
 }
 
 /*
+ * Acquire the call_rcu_mutex in order to ensure that the child sees
+ * all of the call_rcu() data structures in a consistent state.
+ * Suitable for pthread_atfork() and friends.
+ */
+void call_rcu_before_fork(void)
+{
+	call_rcu_lock(&call_rcu_mutex);
+}
+
+/*
+ * Clean up call_rcu data structures in the parent of a successful fork()
+ * that is not followed by exec() in the child.  Suitable for
+ * pthread_atfork() and friends.
+ */
+void call_rcu_after_fork_parent(void)
+{
+	call_rcu_unlock(&call_rcu_mutex);
+}
+
+/*
  * Clean up call_rcu data structures in the child of a successful fork()
- * that is not followed by exec().
+ * that is not followed by exec().  Suitable for pthread_atfork() and
+ * friends.
  */
 void call_rcu_after_fork_child(void)
 {
 	struct call_rcu_data *crdp;
 
+	/* Re-initialize the mutex. */
+	if (pthread_mutex_init(&call_rcu_mutex, NULL) != 0) {
+		perror("pthread_mutex_init");
+		exit(-1);
+	}
+
 	/*
 	 * Allocate a new default call_rcu_data structure in order
 	 * to get a working call_rcu thread to go with it.
-- 
1.7.3.2

[ltt-dev] [PATCH RFC urcu 2/4] Map symbols to allow multiple RCU flavors to be used in one binary

[Paul E. McKenney]

Probably need similar mapping for rcu_defer().  Definitely need
backwards-compatibility mapping for programs compiled against
old versions of the library.

Signed-off-by: Paul E. McKenney <paulmck at linux.vnet.ibm.com>
---
 Makefile.am          |    3 +-
 tests/Makefile.am    |   33 ++--
 tests/rcutorture.h   |    1 -
 tests/urcutorture.c  |   13 +-
 urcu-bp-map.h        |   61 +++++
 urcu-bp.c            |    4 +
 urcu-bp.h            |    8 +-
 urcu-call-rcu-impl.h |  618 +++++++++++++++++++++++++++++++++++++++++++++++++
 urcu-call-rcu.c      |  620 --------------------------------------------------
 urcu-map.h           |  117 ++++++++++
 urcu-qsbr-map.h      |   63 +++++
 urcu-qsbr.c          |   36 ++--
 urcu-qsbr.h          |   18 +-
 urcu.c               |    5 +
 urcu.h               |   20 ++-
 15 files changed, 945 insertions(+), 675 deletions(-)
 create mode 100644 urcu-bp-map.h
 create mode 100644 urcu-call-rcu-impl.h
 delete mode 100644 urcu-call-rcu.c
 create mode 100644 urcu-map.h
 create mode 100644 urcu-qsbr-map.h

diff --git a/Makefile.am b/Makefile.am
index 7956e7e..ef3bfef 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -30,7 +30,7 @@ COMPAT+=compat_futex.c
 endif
 
 lib_LTLIBRARIES = liburcu.la liburcu-qsbr.la liburcu-mb.la liburcu-signal.la \
-		  liburcu-bp.la liburcu-defer.la liburcu-call.la \
+		  liburcu-bp.la liburcu-defer.la \
 		  libwfqueue.la libwfstack.la librculfqueue.la librculfstack.la
 
 liburcu_la_SOURCES = urcu.c urcu-pointer.c $(COMPAT)
@@ -45,7 +45,6 @@ liburcu_signal_la_CFLAGS = -DRCU_SIGNAL
 
 liburcu_bp_la_SOURCES = urcu-bp.c urcu-pointer.c $(COMPAT)
 
-liburcu_call_la_SOURCES = urcu-call-rcu.c $(COMPAT)
 liburcu_defer_la_SOURCES = urcu-defer.c $(COMPAT)
 
 libwfqueue_la_SOURCES = wfqueue.c $(COMPAT)
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 3c025a4..8dacb11 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -28,21 +28,20 @@ if COMPAT_FUTEX
 COMPAT+=$(top_srcdir)/compat_futex.c
 endif
 
-URCU=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT)
-URCU_QSBR=$(top_srcdir)/urcu-qsbr.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT)
+URCU=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
+URCU_QSBR=$(top_srcdir)/urcu-qsbr.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
 # URCU_MB uses urcu.c but -DRCU_MB must be defined
-URCU_MB=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT)
+URCU_MB=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
 # URCU_SIGNAL uses urcu.c but -DRCU_SIGNAL must be defined
-URCU_SIGNAL=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT)
-URCU_BP=$(top_srcdir)/urcu-bp.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT)
-URCU_DEFER=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-defer.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT)
+URCU_SIGNAL=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
+URCU_BP=$(top_srcdir)/urcu-bp.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
+URCU_DEFER=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-defer.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
 
 URCU_LIB=$(top_builddir)/liburcu.la
 URCU_QSBR_LIB=$(top_builddir)/liburcu-qsbr.la
 URCU_MB_LIB=$(top_builddir)/liburcu-mb.la
 URCU_SIGNAL_LIB=$(top_builddir)/liburcu-signal.la
 URCU_BP_LIB=$(top_builddir)/liburcu-bp.la
-URCU_CALL_LIB=$(top_builddir)/liburcu-call.la
 WFQUEUE_LIB=$(top_builddir)/libwfqueue.la
 WFSTACK_LIB=$(top_builddir)/libwfstack.la
 RCULFQUEUE_LIB=$(top_builddir)/librculfqueue.la
@@ -95,24 +94,24 @@ test_perthreadlock_SOURCES = test_perthreadlock.c $(URCU_SIGNAL)
 
 
 rcutorture_urcu_SOURCES = urcutorture.c
-rcutorture_urcu_CFLAGS = -DTORTURE_URCU $(AM_CFLAGS)
-rcutorture_urcu_LDADD = $(URCU) $(URCU_CALL_LIB) $(WFQUEUE_LIB)
+rcutorture_urcu_CFLAGS = -DRCU_MEMBARRIER $(AM_CFLAGS)
+rcutorture_urcu_LDADD = $(URCU) $(WFQUEUE_LIB)
 
 rcutorture_urcu_mb_SOURCES = urcutorture.c
-rcutorture_urcu_mb_CFLAGS = -DTORTURE_URCU_MB $(AM_CFLAGS)
-rcutorture_urcu_mb_LDADD = $(URCU_MB_LIB) $(URCU_CALL_LIB) $(WFQUEUE_LIB)
+rcutorture_urcu_mb_CFLAGS = -DRCU_MB $(AM_CFLAGS)
+rcutorture_urcu_mb_LDADD = $(URCU_MB_LIB) $(WFQUEUE_LIB)
 
 rcutorture_qsbr_SOURCES = urcutorture.c
-rcutorture_qsbr_CFLAGS = -DTORTURE_QSBR $(AM_CFLAGS)
-rcutorture_qsbr_LDADD = $(URCU_QSBR_LIB) $(URCU_CALL_LIB) $(WFQUEUE_LIB)
+rcutorture_qsbr_CFLAGS = -DRCU_QSBR $(AM_CFLAGS)
+rcutorture_qsbr_LDADD = $(URCU_QSBR_LIB) $(WFQUEUE_LIB)
 
 rcutorture_urcu_signal_SOURCES = urcutorture.c
-rcutorture_urcu_signal_CFLAGS = -DTORTURE_URCU_SIGNAL $(AM_CFLAGS)
-rcutorture_urcu_signal_LDADD = $(URCU_SIGNAL_LIB) $(URCU_CALL_LIB) $(WFQUEUE_LIB)
+rcutorture_urcu_signal_CFLAGS = -DRCU_SIGNAL $(AM_CFLAGS)
+rcutorture_urcu_signal_LDADD = $(URCU_SIGNAL_LIB) $(WFQUEUE_LIB)
 
 rcutorture_urcu_bp_SOURCES = urcutorture.c
-rcutorture_urcu_bp_CFLAGS = -DTORTURE_URCU_BP $(AM_CFLAGS)
-rcutorture_urcu_bp_LDADD = $(URCU_BP_LIB) $(URCU_CALL_LIB) $(WFQUEUE_LIB)
+rcutorture_urcu_bp_CFLAGS = -DRCU_BP $(AM_CFLAGS)
+rcutorture_urcu_bp_LDADD = $(URCU_BP_LIB) $(WFQUEUE_LIB)
 
 test_mutex_SOURCES = test_mutex.c $(URCU)
 
diff --git a/tests/rcutorture.h b/tests/rcutorture.h
index 66fdd7f..aba74b0 100644
--- a/tests/rcutorture.h
+++ b/tests/rcutorture.h
@@ -66,7 +66,6 @@
  */
 
 #include <stdlib.h>
-#include "../urcu-call-rcu.h"
 
 DEFINE_PER_THREAD(long long, n_reads_pt);
 DEFINE_PER_THREAD(long long, n_updates_pt);
diff --git a/tests/urcutorture.c b/tests/urcutorture.c
index 63fa386..a098d87 100644
--- a/tests/urcutorture.c
+++ b/tests/urcutorture.c
@@ -8,22 +8,19 @@
 #include "api.h"
 #define _LGPL_SOURCE
 
-#ifdef TORTURE_RCU_MEMBARRIER
-#define RCU_MEMBARRIER
+#ifdef RCU_MEMBARRIER
 #include <urcu.h>
 #endif
-#ifdef TORTURE_URCU_SIGNAL
-#define RCU_SIGNAL
+#ifdef RCU_SIGNAL
 #include <urcu.h>
 #endif
-#ifdef TORTURE_URCU_MB
-#define RCU_MB
+#ifdef RCU_MB
 #include <urcu.h>
 #endif
-#ifdef TORTURE_QSBR
+#ifdef RCU_QSBR
 #include <urcu-qsbr.h>
 #endif
-#ifdef TORTURE_URCU_BP
+#ifdef RCU_BP
 #include <urcu-bp.h>
 #endif
 
diff --git a/urcu-bp-map.h b/urcu-bp-map.h
new file mode 100644
index 0000000..6321802
--- /dev/null
+++ b/urcu-bp-map.h
@@ -0,0 +1,61 @@
+#ifndef _URCU_BP_MAP_H
+#define _URCU_BP_MAP_H
+
+/*
+ * urcu-map.h
+ *
+ * Userspace RCU header -- name mapping to allow multiple flavors to be
+ * used in the same executable.
+ *
+ * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
+ * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
+ *
+ * LGPL-compatible code should include this header with :
+ *
+ * #define _LGPL_SOURCE
+ * #include <urcu.h>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * IBM's contributions to this file may be relicensed under LGPLv2 or later.
+ */
+
+/* Mapping macros to allow multiple flavors in a single binary. */
+
+#define rcu_read_lock			rcu_read_lock_bp
+#define _rcu_read_lock			_rcu_read_lock_bp
+#define rcu_read_unlock			rcu_read_unlock_bp
+#define _rcu_read_unlock		_rcu_read_unlock_bp
+#define rcu_register_thread		rcu_register_thread_bp
+#define rcu_unregister_thread		rcu_unregister_thread_bp
+#define rcu_init			rcu_init_bp
+#define rcu_exit			rcu_exit_bp
+#define synchronize_rcu			synchronize_rcu_bp
+#define rcu_reader			rcu_reader_bp
+#define rcu_gp_ctr			rcu_gp_ctr_bp
+
+#define get_cpu_call_rcu_data		get_cpu_call_rcu_data_bp
+#define get_call_rcu_thread		get_call_rcu_thread_bp
+#define create_call_rcu_data		create_call_rcu_data_bp
+#define set_cpu_call_rcu_data		set_cpu_call_rcu_data_bp
+#define get_default_call_rcu_data	get_default_call_rcu_data_bp
+#define get_call_rcu_data		get_call_rcu_data_bp
+#define get_thread_call_rcu_data	get_thread_call_rcu_data_bp
+#define set_thread_call_rcu_data	set_thread_call_rcu_data_bp
+#define create_all_cpu_call_rcu_data	create_all_cpu_call_rcu_data_bp
+#define free_all_cpu_call_rcu_data	free_all_cpu_call_rcu_data_bp
+#define call_rcu			call_rcu_bp
+
+#endif /* _URCU_BP_MAP_H */
diff --git a/urcu-bp.c b/urcu-bp.c
index 04bb675..5474f9f 100644
--- a/urcu-bp.c
+++ b/urcu-bp.c
@@ -35,6 +35,8 @@
 #include <unistd.h>
 #include <sys/mman.h>
 
+#include "urcu-bp-map.h"
+
 #include "urcu-bp-static.h"
 /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
 #include "urcu-bp.h"
@@ -375,3 +377,5 @@ void rcu_bp_after_fork_child(void)
 	ret = pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
 	assert(!ret);
 }
+
+#include "urcu-call-rcu-impl.h"
diff --git a/urcu-bp.h b/urcu-bp.h
index d92fbd1..fdf885c 100644
--- a/urcu-bp.h
+++ b/urcu-bp.h
@@ -46,6 +46,8 @@
 extern "C" {
 #endif
 
+#include "urcu-bp-map.h"
+
 /*
  * Important !
  *
@@ -69,8 +71,8 @@ extern "C" {
  *
  * Mark the beginning and end of a read-side critical section.
  */
-#define rcu_read_lock()		_rcu_read_lock()
-#define rcu_read_unlock()	_rcu_read_unlock()
+#define rcu_read_lock_bp()		_rcu_read_lock()
+#define rcu_read_unlock_bp()		_rcu_read_unlock()
 
 #else /* !_LGPL_SOURCE */
 
@@ -115,4 +117,6 @@ static inline void rcu_init(void)
 }
 #endif
 
+#include "urcu-call-rcu.h"
+
 #endif /* _URCU_BP_H */
diff --git a/urcu-call-rcu-impl.h b/urcu-call-rcu-impl.h
new file mode 100644
index 0000000..68dbbdd
--- /dev/null
+++ b/urcu-call-rcu-impl.h
@@ -0,0 +1,618 @@
+/*
+ * urcu-call-rcu.c
+ *
+ * Userspace RCU library - batch memory reclamation with kernel API
+ *
+ * Copyright (c) 2010 Paul E. McKenney <paulmck at linux.vnet.ibm.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdio.h>
+#include <pthread.h>
+#include <signal.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <poll.h>
+#include <sys/time.h>
+#include <syscall.h>
+#include <unistd.h>
+
+#include "config.h"
+#include "urcu/wfqueue.h"
+#include "urcu-call-rcu.h"
+#include "urcu-pointer.h"
+#include "urcu/list.h"
+
+/* Data structure that identifies a call_rcu thread. */
+
+struct call_rcu_data {
+	struct cds_wfq_queue cbs;
+	unsigned long flags;
+	pthread_mutex_t mtx;
+	pthread_cond_t cond;
+	unsigned long qlen;
+	pthread_t tid;
+	struct cds_list_head list;
+} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
+
+/*
+ * List of all call_rcu_data structures to keep valgrind happy.
+ * Protected by call_rcu_mutex.
+ */
+
+CDS_LIST_HEAD(call_rcu_data_list);
+
+/* Link a thread using call_rcu() to its call_rcu thread. */
+
+static __thread struct call_rcu_data *thread_call_rcu_data;
+
+/* Guard call_rcu thread creation. */
+
+static pthread_mutex_t call_rcu_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+/* If a given thread does not have its own call_rcu thread, this is default. */
+
+static struct call_rcu_data *default_call_rcu_data;
+
+/*
+ * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are
+ * available, then we can have call_rcu threads assigned to individual
+ * CPUs rather than only to specific threads.
+ */
+
+#if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF)
+
+/*
+ * Pointer to array of pointers to per-CPU call_rcu_data structures
+ * and # CPUs.
+ */
+
+static struct call_rcu_data **per_cpu_call_rcu_data;
+static long maxcpus;
+
+/* Allocate the array if it has not already been allocated. */
+
+static void alloc_cpu_call_rcu_data(void)
+{
+	struct call_rcu_data **p;
+	static int warned = 0;
+
+	if (maxcpus != 0)
+		return;
+	maxcpus = sysconf(_SC_NPROCESSORS_CONF);
+	if (maxcpus <= 0) {
+		return;
+	}
+	p = malloc(maxcpus * sizeof(*per_cpu_call_rcu_data));
+	if (p != NULL) {
+		memset(p, '\0', maxcpus * sizeof(*per_cpu_call_rcu_data));
+		per_cpu_call_rcu_data = p;
+	} else {
+		if (!warned) {
+			fprintf(stderr, "[error] liburcu: unable to allocate per-CPU pointer array\n");
+		}
+		warned = 1;
+	}
+}
+
+#else /* #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */
+
+static const struct call_rcu_data **per_cpu_call_rcu_data = NULL;
+static const long maxcpus = -1;
+
+static void alloc_cpu_call_rcu_data(void)
+{
+}
+
+static int sched_getcpu(void)
+{
+	return -1;
+}
+
+#endif /* #else #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */
+
+/* Acquire the specified pthread mutex. */
+
+static void call_rcu_lock(pthread_mutex_t *pmp)
+{
+	if (pthread_mutex_lock(pmp) != 0) {
+		perror("pthread_mutex_lock");
+		exit(-1);
+	}
+}
+
+/* Release the specified pthread mutex. */
+
+static void call_rcu_unlock(pthread_mutex_t *pmp)
+{
+	if (pthread_mutex_unlock(pmp) != 0) {
+		perror("pthread_mutex_unlock");
+		exit(-1);
+	}
+}
+
+/* This is the code run by each call_rcu thread. */
+
+static void *call_rcu_thread(void *arg)
+{
+	unsigned long cbcount;
+	struct cds_wfq_node *cbs;
+	struct cds_wfq_node **cbs_tail;
+	struct call_rcu_data *crdp = (struct call_rcu_data *)arg;
+	struct rcu_head *rhp;
+
+	thread_call_rcu_data = crdp;
+	for (;;) {
+		if (&crdp->cbs.head != _CMM_LOAD_SHARED(crdp->cbs.tail)) {
+			while ((cbs = _CMM_LOAD_SHARED(crdp->cbs.head)) == NULL)
+				poll(NULL, 0, 1);
+			_CMM_STORE_SHARED(crdp->cbs.head, NULL);
+			cbs_tail = (struct cds_wfq_node **)
+				uatomic_xchg(&crdp->cbs.tail, &crdp->cbs.head);
+			synchronize_rcu();
+			cbcount = 0;
+			do {
+				while (cbs->next == NULL &&
+				       &cbs->next != cbs_tail)
+				       	poll(NULL, 0, 1);
+				if (cbs == &crdp->cbs.dummy) {
+					cbs = cbs->next;
+					continue;
+				}
+				rhp = (struct rcu_head *)cbs;
+				cbs = cbs->next;
+				rhp->func(rhp);
+				cbcount++;
+			} while (cbs != NULL);
+			uatomic_sub(&crdp->qlen, cbcount);
+		}
+		if (crdp->flags & URCU_CALL_RCU_STOP)
+			break;
+		if (crdp->flags & URCU_CALL_RCU_RT)
+			poll(NULL, 0, 10);
+		else {
+			call_rcu_lock(&crdp->mtx);
+			_CMM_STORE_SHARED(crdp->flags,
+				     crdp->flags & ~URCU_CALL_RCU_RUNNING);
+			if (&crdp->cbs.head ==
+			    _CMM_LOAD_SHARED(crdp->cbs.tail) &&
+			    pthread_cond_wait(&crdp->cond, &crdp->mtx) != 0) {
+				perror("pthread_cond_wait");
+				exit(-1);
+			}
+			_CMM_STORE_SHARED(crdp->flags,
+				     crdp->flags | URCU_CALL_RCU_RUNNING);
+			poll(NULL, 0, 10);
+			call_rcu_unlock(&crdp->mtx);
+		}
+	}
+	call_rcu_lock(&crdp->mtx);
+	crdp->flags |= URCU_CALL_RCU_STOPPED;
+	call_rcu_unlock(&crdp->mtx);
+	return NULL;
+}
+
+/*
+ * Create both a call_rcu thread and the corresponding call_rcu_data
+ * structure, linking the structure in as specified.  Caller must hold
+ * call_rcu_mutex.
+ */
+
+static void call_rcu_data_init(struct call_rcu_data **crdpp,
+			       unsigned long flags)
+{
+	struct call_rcu_data *crdp;
+
+	crdp = malloc(sizeof(*crdp));
+	if (crdp == NULL) {
+		fprintf(stderr, "Out of memory.\n");
+		exit(-1);
+	}
+	memset(crdp, '\0', sizeof(*crdp));
+	cds_wfq_init(&crdp->cbs);
+	crdp->qlen = 0;
+	if (pthread_mutex_init(&crdp->mtx, NULL) != 0) {
+		perror("pthread_mutex_init");
+		exit(-1);
+	}
+	if (pthread_cond_init(&crdp->cond, NULL) != 0) {
+		perror("pthread_cond_init");
+		exit(-1);
+	}
+	crdp->flags = flags | URCU_CALL_RCU_RUNNING;
+	cds_list_add(&crdp->list, &call_rcu_data_list);
+	cmm_smp_mb();  /* Structure initialized before pointer is planted. */
+	*crdpp = crdp;
+	if (pthread_create(&crdp->tid, NULL, call_rcu_thread, crdp) != 0) {
+		perror("pthread_create");
+		exit(-1);
+	}
+}
+
+/*
+ * Return a pointer to the call_rcu_data structure for the specified
+ * CPU, returning NULL if there is none.  We cannot automatically
+ * created it because the platform we are running on might not define
+ * sched_getcpu().
+ */
+
+struct call_rcu_data *get_cpu_call_rcu_data(int cpu)
+{
+	static int warned = 0;
+
+	if (per_cpu_call_rcu_data == NULL)
+		return NULL;
+	if (!warned && maxcpus > 0 && (cpu < 0 || maxcpus <= cpu)) {
+		fprintf(stderr, "[error] liburcu: get CPU # out of range\n");
+		warned = 1;
+	}
+	if (cpu < 0 || maxcpus <= cpu)
+		return NULL;
+	return per_cpu_call_rcu_data[cpu];
+}
+
+/*
+ * Return the tid corresponding to the call_rcu thread whose
+ * call_rcu_data structure is specified.
+ */
+
+pthread_t get_call_rcu_thread(struct call_rcu_data *crdp)
+{
+	return crdp->tid;
+}
+
+/*
+ * Create a call_rcu_data structure (with thread) and return a pointer.
+ */
+
+static struct call_rcu_data *__create_call_rcu_data(unsigned long flags)
+{
+	struct call_rcu_data *crdp;
+
+	call_rcu_data_init(&crdp, flags);
+	return crdp;
+}
+
+struct call_rcu_data *create_call_rcu_data(unsigned long flags)
+{
+	struct call_rcu_data *crdp;
+
+	call_rcu_lock(&call_rcu_mutex);
+	crdp = __create_call_rcu_data(flags);
+	call_rcu_unlock(&call_rcu_mutex);
+	return crdp;
+}
+
+/*
+ * Set the specified CPU to use the specified call_rcu_data structure.
+ *
+ * Use NULL to remove a CPU's call_rcu_data structure, but it is
+ * the caller's responsibility to dispose of the removed structure.
+ * Use get_cpu_call_rcu_data() to obtain a pointer to the old structure
+ * (prior to NULLing it out, of course).
+ */
+
+int set_cpu_call_rcu_data(int cpu, struct call_rcu_data *crdp)
+{
+	int warned = 0;
+
+	call_rcu_lock(&call_rcu_mutex);
+	if (cpu < 0 || maxcpus <= cpu) {
+		if (!warned) {
+			fprintf(stderr, "[error] liburcu: set CPU # out of range\n");
+			warned = 1;
+		}
+		call_rcu_unlock(&call_rcu_mutex);
+		errno = EINVAL;
+		return -EINVAL;
+	}
+	alloc_cpu_call_rcu_data();
+	call_rcu_unlock(&call_rcu_mutex);
+	if (per_cpu_call_rcu_data == NULL) {
+		errno = ENOMEM;
+		return -ENOMEM;
+	}
+	per_cpu_call_rcu_data[cpu] = crdp;
+	return 0;
+}
+
+/*
+ * Return a pointer to the default call_rcu_data structure, creating
+ * one if need be.  Because we never free call_rcu_data structures,
+ * we don't need to be in an RCU read-side critical section.
+ */
+
+struct call_rcu_data *get_default_call_rcu_data(void)
+{
+	if (default_call_rcu_data != NULL)
+		return rcu_dereference(default_call_rcu_data);
+	call_rcu_lock(&call_rcu_mutex);
+	if (default_call_rcu_data != NULL) {
+		call_rcu_unlock(&call_rcu_mutex);
+		return default_call_rcu_data;
+	}
+	call_rcu_data_init(&default_call_rcu_data, 0);
+	call_rcu_unlock(&call_rcu_mutex);
+	return default_call_rcu_data;
+}
+
+/*
+ * Return the call_rcu_data structure that applies to the currently
+ * running thread.  Any call_rcu_data structure assigned specifically
+ * to this thread has first priority, followed by any call_rcu_data
+ * structure assigned to the CPU on which the thread is running,
+ * followed by the default call_rcu_data structure.  If there is not
+ * yet a default call_rcu_data structure, one will be created.
+ */
+struct call_rcu_data *get_call_rcu_data(void)
+{
+	int curcpu;
+	static int warned = 0;
+
+	if (thread_call_rcu_data != NULL)
+		return thread_call_rcu_data;
+	if (maxcpus <= 0)
+		return get_default_call_rcu_data();
+	curcpu = sched_getcpu();
+	if (!warned && (curcpu < 0 || maxcpus <= curcpu)) {
+		fprintf(stderr, "[error] liburcu: gcrd CPU # out of range\n");
+		warned = 1;
+	}
+	if (curcpu >= 0 && maxcpus > curcpu &&
+	    per_cpu_call_rcu_data != NULL &&
+	    per_cpu_call_rcu_data[curcpu] != NULL)
+	    	return per_cpu_call_rcu_data[curcpu];
+	return get_default_call_rcu_data();
+}
+
+/*
+ * Return a pointer to this task's call_rcu_data if there is one.
+ */
+
+struct call_rcu_data *get_thread_call_rcu_data(void)
+{
+	return thread_call_rcu_data;
+}
+
+/*
+ * Set this task's call_rcu_data structure as specified, regardless
+ * of whether or not this task already had one.  (This allows switching
+ * to and from real-time call_rcu threads, for example.)
+ *
+ * Use NULL to remove a thread's call_rcu_data structure, but it is
+ * the caller's responsibility to dispose of the removed structure.
+ * Use get_thread_call_rcu_data() to obtain a pointer to the old structure
+ * (prior to NULLing it out, of course).
+ */
+
+void set_thread_call_rcu_data(struct call_rcu_data *crdp)
+{
+	thread_call_rcu_data = crdp;
+}
+
+/*
+ * Create a separate call_rcu thread for each CPU.  This does not
+ * replace a pre-existing call_rcu thread -- use the set_cpu_call_rcu_data()
+ * function if you want that behavior.
+ */
+
+int create_all_cpu_call_rcu_data(unsigned long flags)
+{
+	int i;
+	struct call_rcu_data *crdp;
+	int ret;
+
+	call_rcu_lock(&call_rcu_mutex);
+	alloc_cpu_call_rcu_data();
+	call_rcu_unlock(&call_rcu_mutex);
+	if (maxcpus <= 0) {
+		errno = EINVAL;
+		return -EINVAL;
+	}
+	if (per_cpu_call_rcu_data == NULL) {
+		errno = ENOMEM;
+		return -ENOMEM;
+	}
+	for (i = 0; i < maxcpus; i++) {
+		call_rcu_lock(&call_rcu_mutex);
+		if (get_cpu_call_rcu_data(i)) {
+			call_rcu_unlock(&call_rcu_mutex);
+			continue;
+		}
+		crdp = __create_call_rcu_data(flags);
+		if (crdp == NULL) {
+			call_rcu_unlock(&call_rcu_mutex);
+			errno = ENOMEM;
+			return -ENOMEM;
+		}
+		call_rcu_unlock(&call_rcu_mutex);
+		if ((ret = set_cpu_call_rcu_data(i, crdp)) != 0) {
+			/* FIXME: Leaks crdp for now. */
+			return ret; /* Can happen on race. */
+		}
+	}
+	return 0;
+}
+
+/*
+ * Wake up the call_rcu thread corresponding to the specified
+ * call_rcu_data structure.
+ */
+static void wake_call_rcu_thread(struct call_rcu_data *crdp)
+{
+	if (!(_CMM_LOAD_SHARED(crdp->flags) & URCU_CALL_RCU_RT)) {
+		call_rcu_lock(&crdp->mtx);
+		if (!(_CMM_LOAD_SHARED(crdp->flags) & URCU_CALL_RCU_RUNNING)) {
+			if (pthread_cond_signal(&crdp->cond) != 0) {
+				perror("pthread_cond_signal");
+				exit(-1);
+			}
+		}
+		call_rcu_unlock(&crdp->mtx);
+	}
+}
+
+/*
+ * Schedule a function to be invoked after a following grace period.
+ * This is the only function that must be called -- the others are
+ * only present to allow applications to tune their use of RCU for
+ * maximum performance.
+ *
+ * Note that unless a call_rcu thread has not already been created,
+ * the first invocation of call_rcu() will create one.  So, if you
+ * need the first invocation of call_rcu() to be fast, make sure
+ * to create a call_rcu thread first.  One way to accomplish this is
+ * "get_call_rcu_data();", and another is create_all_cpu_call_rcu_data().
+ */
+
+void call_rcu(struct rcu_head *head,
+	      void (*func)(struct rcu_head *head))
+{
+	struct call_rcu_data *crdp;
+
+	cds_wfq_node_init(&head->next);
+	head->func = func;
+	crdp = get_call_rcu_data();
+	cds_wfq_enqueue(&crdp->cbs, &head->next);
+	uatomic_inc(&crdp->qlen);
+	wake_call_rcu_thread(crdp);
+}
+
+/*
+ * Free up the specified call_rcu_data structure, terminating the
+ * associated call_rcu thread.  The caller must have previously
+ * removed the call_rcu_data structure from per-thread or per-CPU
+ * usage.  For example, set_cpu_call_rcu_data(cpu, NULL) for per-CPU
+ * call_rcu_data structures or set_thread_call_rcu_data(NULL) for
+ * per-thread call_rcu_data structures.
+ *
+ * We silently refuse to free up the default call_rcu_data structure
+ * because that is where we put any leftover callbacks.  Note that
+ * the possibility of self-spawning callbacks makes it impossible
+ * to execute all the callbacks in finite time without putting any
+ * newly spawned callbacks somewhere else.  The "somewhere else" of
+ * last resort is the default call_rcu_data structure.
+ *
+ * We also silently refuse to free NULL pointers.  This simplifies
+ * the calling code.
+ */
+void call_rcu_data_free(struct call_rcu_data *crdp)
+{
+	struct cds_wfq_node *cbs;
+	struct cds_wfq_node **cbs_tail;
+	struct cds_wfq_node **cbs_endprev;
+
+	if (crdp == NULL || crdp == default_call_rcu_data) {
+		return;
+	}
+	if ((crdp->flags & URCU_CALL_RCU_STOPPED) == 0) {
+		call_rcu_lock(&crdp->mtx);
+		crdp->flags |= URCU_CALL_RCU_STOP;
+		call_rcu_unlock(&crdp->mtx);
+		wake_call_rcu_thread(crdp);
+		while ((crdp->flags & URCU_CALL_RCU_STOPPED) == 0)
+			poll(NULL, 0, 1);
+	}
+	if (&crdp->cbs.head != _CMM_LOAD_SHARED(crdp->cbs.tail)) {
+		while ((cbs = _CMM_LOAD_SHARED(crdp->cbs.head)) == NULL)
+			poll(NULL, 0, 1);
+		_CMM_STORE_SHARED(crdp->cbs.head, NULL);
+		cbs_tail = (struct cds_wfq_node **)
+			uatomic_xchg(&crdp->cbs.tail, &crdp->cbs.head);
+		cbs_endprev = (struct cds_wfq_node **)
+			uatomic_xchg(&default_call_rcu_data, cbs_tail);
+		*cbs_endprev = cbs;
+		uatomic_add(&default_call_rcu_data->qlen,
+			    uatomic_read(&crdp->qlen));
+		cds_list_del(&crdp->list);
+		free(crdp);
+	}
+}
+
+/*
+ * Clean up all the per-CPU call_rcu threads.
+ */
+void free_all_cpu_call_rcu_data(void)
+{
+	int cpu;
+	struct call_rcu_data *crdp;
+
+	if (maxcpus <= 0)
+		return;
+	for (cpu = 0; cpu < maxcpus; cpu++) {
+		crdp = get_cpu_call_rcu_data(cpu);
+		if (crdp == NULL)
+			continue;
+		set_cpu_call_rcu_data(cpu, NULL);
+		call_rcu_data_free(crdp);
+	}
+}
+
+/*
+ * Acquire the call_rcu_mutex in order to ensure that the child sees
+ * all of the call_rcu() data structures in a consistent state.
+ * Suitable for pthread_atfork() and friends.
+ */
+void call_rcu_before_fork(void)
+{
+	call_rcu_lock(&call_rcu_mutex);
+}
+
+/*
+ * Clean up call_rcu data structures in the parent of a successful fork()
+ * that is not followed by exec() in the child.  Suitable for
+ * pthread_atfork() and friends.
+ */
+void call_rcu_after_fork_parent(void)
+{
+	call_rcu_unlock(&call_rcu_mutex);
+}
+
+/*
+ * Clean up call_rcu data structures in the child of a successful fork()
+ * that is not followed by exec().  Suitable for pthread_atfork() and
+ * friends.
+ */
+void call_rcu_after_fork_child(void)
+{
+	struct call_rcu_data *crdp;
+
+	/* Re-initialize the mutex. */
+	if (pthread_mutex_init(&call_rcu_mutex, NULL) != 0) {
+		perror("pthread_mutex_init");
+		exit(-1);
+	}
+
+	/*
+	 * Allocate a new default call_rcu_data structure in order
+	 * to get a working call_rcu thread to go with it.
+	 */
+	default_call_rcu_data = NULL;
+	(void)get_default_call_rcu_data();
+
+	/* Dispose of all of the rest of the call_rcu_data structures. */
+	while (call_rcu_data_list.next != call_rcu_data_list.prev) {
+		crdp = cds_list_entry(call_rcu_data_list.prev,
+				      struct call_rcu_data, list);
+		if (crdp == default_call_rcu_data)
+			crdp = cds_list_entry(crdp->list.prev,
+					      struct call_rcu_data, list);
+		crdp->flags = URCU_CALL_RCU_STOPPED;
+		call_rcu_data_free(crdp);
+	}
+}
diff --git a/urcu-call-rcu.c b/urcu-call-rcu.c
deleted file mode 100644
index 665f20c..0000000
--- a/urcu-call-rcu.c
+++ /dev/null
@@ -1,620 +0,0 @@
-/*
- * urcu-call-rcu.c
- *
- * Userspace RCU library - batch memory reclamation with kernel API
- *
- * Copyright (c) 2010 Paul E. McKenney <paulmck at linux.vnet.ibm.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-#include <stdio.h>
-#include <pthread.h>
-#include <signal.h>
-#include <assert.h>
-#include <stdlib.h>
-#include <string.h>
-#include <errno.h>
-#include <poll.h>
-#include <sys/time.h>
-#include <syscall.h>
-#include <unistd.h>
-
-#include "config.h"
-#include "urcu/wfqueue.h"
-#include "urcu-call-rcu.h"
-#include "urcu-pointer.h"
-#include "urcu/list.h"
-
-/* Data structure that identifies a call_rcu thread. */
-
-struct call_rcu_data {
-	struct cds_wfq_queue cbs;
-	unsigned long flags;
-	pthread_mutex_t mtx;
-	pthread_cond_t cond;
-	unsigned long qlen;
-	pthread_t tid;
-	struct cds_list_head list;
-} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
-
-/*
- * List of all call_rcu_data structures to keep valgrind happy.
- * Protected by call_rcu_mutex.
- */
-
-CDS_LIST_HEAD(call_rcu_data_list);
-
-/* Link a thread using call_rcu() to its call_rcu thread. */
-
-static __thread struct call_rcu_data *thread_call_rcu_data;
-
-/* Guard call_rcu thread creation. */
-
-static pthread_mutex_t call_rcu_mutex = PTHREAD_MUTEX_INITIALIZER;
-
-/* If a given thread does not have its own call_rcu thread, this is default. */
-
-static struct call_rcu_data *default_call_rcu_data;
-
-extern void synchronize_rcu(void);
-
-/*
- * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are
- * available, then we can have call_rcu threads assigned to individual
- * CPUs rather than only to specific threads.
- */
-
-#if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF)
-
-/*
- * Pointer to array of pointers to per-CPU call_rcu_data structures
- * and # CPUs.
- */
-
-static struct call_rcu_data **per_cpu_call_rcu_data;
-static long maxcpus;
-
-/* Allocate the array if it has not already been allocated. */
-
-static void alloc_cpu_call_rcu_data(void)
-{
-	struct call_rcu_data **p;
-	static int warned = 0;
-
-	if (maxcpus != 0)
-		return;
-	maxcpus = sysconf(_SC_NPROCESSORS_CONF);
-	if (maxcpus <= 0) {
-		return;
-	}
-	p = malloc(maxcpus * sizeof(*per_cpu_call_rcu_data));
-	if (p != NULL) {
-		memset(p, '\0', maxcpus * sizeof(*per_cpu_call_rcu_data));
-		per_cpu_call_rcu_data = p;
-	} else {
-		if (!warned) {
-			fprintf(stderr, "[error] liburcu: unable to allocate per-CPU pointer array\n");
-		}
-		warned = 1;
-	}
-}
-
-#else /* #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */
-
-static const struct call_rcu_data **per_cpu_call_rcu_data = NULL;
-static const long maxcpus = -1;
-
-static void alloc_cpu_call_rcu_data(void)
-{
-}
-
-static int sched_getcpu(void)
-{
-	return -1;
-}
-
-#endif /* #else #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */
-
-/* Acquire the specified pthread mutex. */
-
-static void call_rcu_lock(pthread_mutex_t *pmp)
-{
-	if (pthread_mutex_lock(pmp) != 0) {
-		perror("pthread_mutex_lock");
-		exit(-1);
-	}
-}
-
-/* Release the specified pthread mutex. */
-
-static void call_rcu_unlock(pthread_mutex_t *pmp)
-{
-	if (pthread_mutex_unlock(pmp) != 0) {
-		perror("pthread_mutex_unlock");
-		exit(-1);
-	}
-}
-
-/* This is the code run by each call_rcu thread. */
-
-static void *call_rcu_thread(void *arg)
-{
-	unsigned long cbcount;
-	struct cds_wfq_node *cbs;
-	struct cds_wfq_node **cbs_tail;
-	struct call_rcu_data *crdp = (struct call_rcu_data *)arg;
-	struct rcu_head *rhp;
-
-	thread_call_rcu_data = crdp;
-	for (;;) {
-		if (&crdp->cbs.head != _CMM_LOAD_SHARED(crdp->cbs.tail)) {
-			while ((cbs = _CMM_LOAD_SHARED(crdp->cbs.head)) == NULL)
-				poll(NULL, 0, 1);
-			_CMM_STORE_SHARED(crdp->cbs.head, NULL);
-			cbs_tail = (struct cds_wfq_node **)
-				uatomic_xchg(&crdp->cbs.tail, &crdp->cbs.head);
-			synchronize_rcu();
-			cbcount = 0;
-			do {
-				while (cbs->next == NULL &&
-				       &cbs->next != cbs_tail)
-				       	poll(NULL, 0, 1);
-				if (cbs == &crdp->cbs.dummy) {
-					cbs = cbs->next;
-					continue;
-				}
-				rhp = (struct rcu_head *)cbs;
-				cbs = cbs->next;
-				rhp->func(rhp);
-				cbcount++;
-			} while (cbs != NULL);
-			uatomic_sub(&crdp->qlen, cbcount);
-		}
-		if (crdp->flags & URCU_CALL_RCU_STOP)
-			break;
-		if (crdp->flags & URCU_CALL_RCU_RT)
-			poll(NULL, 0, 10);
-		else {
-			call_rcu_lock(&crdp->mtx);
-			_CMM_STORE_SHARED(crdp->flags,
-				     crdp->flags & ~URCU_CALL_RCU_RUNNING);
-			if (&crdp->cbs.head ==
-			    _CMM_LOAD_SHARED(crdp->cbs.tail) &&
-			    pthread_cond_wait(&crdp->cond, &crdp->mtx) != 0) {
-				perror("pthread_cond_wait");
-				exit(-1);
-			}
-			_CMM_STORE_SHARED(crdp->flags,
-				     crdp->flags | URCU_CALL_RCU_RUNNING);
-			poll(NULL, 0, 10);
-			call_rcu_unlock(&crdp->mtx);
-		}
-	}
-	call_rcu_lock(&crdp->mtx);
-	crdp->flags |= URCU_CALL_RCU_STOPPED;
-	call_rcu_unlock(&crdp->mtx);
-	return NULL;
-}
-
-/*
- * Create both a call_rcu thread and the corresponding call_rcu_data
- * structure, linking the structure in as specified.  Caller must hold
- * call_rcu_mutex.
- */
-
-static void call_rcu_data_init(struct call_rcu_data **crdpp,
-			       unsigned long flags)
-{
-	struct call_rcu_data *crdp;
-
-	crdp = malloc(sizeof(*crdp));
-	if (crdp == NULL) {
-		fprintf(stderr, "Out of memory.\n");
-		exit(-1);
-	}
-	memset(crdp, '\0', sizeof(*crdp));
-	cds_wfq_init(&crdp->cbs);
-	crdp->qlen = 0;
-	if (pthread_mutex_init(&crdp->mtx, NULL) != 0) {
-		perror("pthread_mutex_init");
-		exit(-1);
-	}
-	if (pthread_cond_init(&crdp->cond, NULL) != 0) {
-		perror("pthread_cond_init");
-		exit(-1);
-	}
-	crdp->flags = flags | URCU_CALL_RCU_RUNNING;
-	cds_list_add(&crdp->list, &call_rcu_data_list);
-	cmm_smp_mb();  /* Structure initialized before pointer is planted. */
-	*crdpp = crdp;
-	if (pthread_create(&crdp->tid, NULL, call_rcu_thread, crdp) != 0) {
-		perror("pthread_create");
-		exit(-1);
-	}
-}
-
-/*
- * Return a pointer to the call_rcu_data structure for the specified
- * CPU, returning NULL if there is none.  We cannot automatically
- * created it because the platform we are running on might not define
- * sched_getcpu().
- */
-
-struct call_rcu_data *get_cpu_call_rcu_data(int cpu)
-{
-	static int warned = 0;
-
-	if (per_cpu_call_rcu_data == NULL)
-		return NULL;
-	if (!warned && maxcpus > 0 && (cpu < 0 || maxcpus <= cpu)) {
-		fprintf(stderr, "[error] liburcu: get CPU # out of range\n");
-		warned = 1;
-	}
-	if (cpu < 0 || maxcpus <= cpu)
-		return NULL;
-	return per_cpu_call_rcu_data[cpu];
-}
-
-/*
- * Return the tid corresponding to the call_rcu thread whose
- * call_rcu_data structure is specified.
- */
-
-pthread_t get_call_rcu_thread(struct call_rcu_data *crdp)
-{
-	return crdp->tid;
-}
-
-/*
- * Create a call_rcu_data structure (with thread) and return a pointer.
- */
-
-static struct call_rcu_data *__create_call_rcu_data(unsigned long flags)
-{
-	struct call_rcu_data *crdp;
-
-	call_rcu_data_init(&crdp, flags);
-	return crdp;
-}
-
-struct call_rcu_data *create_call_rcu_data(unsigned long flags)
-{
-	struct call_rcu_data *crdp;
-
-	call_rcu_lock(&call_rcu_mutex);
-	crdp = __create_call_rcu_data(flags);
-	call_rcu_unlock(&call_rcu_mutex);
-	return crdp;
-}
-
-/*
- * Set the specified CPU to use the specified call_rcu_data structure.
- *
- * Use NULL to remove a CPU's call_rcu_data structure, but it is
- * the caller's responsibility to dispose of the removed structure.
- * Use get_cpu_call_rcu_data() to obtain a pointer to the old structure
- * (prior to NULLing it out, of course).
- */
-
-int set_cpu_call_rcu_data(int cpu, struct call_rcu_data *crdp)
-{
-	int warned = 0;
-
-	call_rcu_lock(&call_rcu_mutex);
-	if (cpu < 0 || maxcpus <= cpu) {
-		if (!warned) {
-			fprintf(stderr, "[error] liburcu: set CPU # out of range\n");
-			warned = 1;
-		}
-		call_rcu_unlock(&call_rcu_mutex);
-		errno = EINVAL;
-		return -EINVAL;
-	}
-	alloc_cpu_call_rcu_data();
-	call_rcu_unlock(&call_rcu_mutex);
-	if (per_cpu_call_rcu_data == NULL) {
-		errno = ENOMEM;
-		return -ENOMEM;
-	}
-	per_cpu_call_rcu_data[cpu] = crdp;
-	return 0;
-}
-
-/*
- * Return a pointer to the default call_rcu_data structure, creating
- * one if need be.  Because we never free call_rcu_data structures,
- * we don't need to be in an RCU read-side critical section.
- */
-
-struct call_rcu_data *get_default_call_rcu_data(void)
-{
-	if (default_call_rcu_data != NULL)
-		return rcu_dereference(default_call_rcu_data);
-	call_rcu_lock(&call_rcu_mutex);
-	if (default_call_rcu_data != NULL) {
-		call_rcu_unlock(&call_rcu_mutex);
-		return default_call_rcu_data;
-	}
-	call_rcu_data_init(&default_call_rcu_data, 0);
-	call_rcu_unlock(&call_rcu_mutex);
-	return default_call_rcu_data;
-}
-
-/*
- * Return the call_rcu_data structure that applies to the currently
- * running thread.  Any call_rcu_data structure assigned specifically
- * to this thread has first priority, followed by any call_rcu_data
- * structure assigned to the CPU on which the thread is running,
- * followed by the default call_rcu_data structure.  If there is not
- * yet a default call_rcu_data structure, one will be created.
- */
-struct call_rcu_data *get_call_rcu_data(void)
-{
-	int curcpu;
-	static int warned = 0;
-
-	if (thread_call_rcu_data != NULL)
-		return thread_call_rcu_data;
-	if (maxcpus <= 0)
-		return get_default_call_rcu_data();
-	curcpu = sched_getcpu();
-	if (!warned && (curcpu < 0 || maxcpus <= curcpu)) {
-		fprintf(stderr, "[error] liburcu: gcrd CPU # out of range\n");
-		warned = 1;
-	}
-	if (curcpu >= 0 && maxcpus > curcpu &&
-	    per_cpu_call_rcu_data != NULL &&
-	    per_cpu_call_rcu_data[curcpu] != NULL)
-	    	return per_cpu_call_rcu_data[curcpu];
-	return get_default_call_rcu_data();
-}
-
-/*
- * Return a pointer to this task's call_rcu_data if there is one.
- */
-
-struct call_rcu_data *get_thread_call_rcu_data(void)
-{
-	return thread_call_rcu_data;
-}
-
-/*
- * Set this task's call_rcu_data structure as specified, regardless
- * of whether or not this task already had one.  (This allows switching
- * to and from real-time call_rcu threads, for example.)
- *
- * Use NULL to remove a thread's call_rcu_data structure, but it is
- * the caller's responsibility to dispose of the removed structure.
- * Use get_thread_call_rcu_data() to obtain a pointer to the old structure
- * (prior to NULLing it out, of course).
- */
-
-void set_thread_call_rcu_data(struct call_rcu_data *crdp)
-{
-	thread_call_rcu_data = crdp;
-}
-
-/*
- * Create a separate call_rcu thread for each CPU.  This does not
- * replace a pre-existing call_rcu thread -- use the set_cpu_call_rcu_data()
- * function if you want that behavior.
- */
-
-int create_all_cpu_call_rcu_data(unsigned long flags)
-{
-	int i;
-	struct call_rcu_data *crdp;
-	int ret;
-
-	call_rcu_lock(&call_rcu_mutex);
-	alloc_cpu_call_rcu_data();
-	call_rcu_unlock(&call_rcu_mutex);
-	if (maxcpus <= 0) {
-		errno = EINVAL;
-		return -EINVAL;
-	}
-	if (per_cpu_call_rcu_data == NULL) {
-		errno = ENOMEM;
-		return -ENOMEM;
-	}
-	for (i = 0; i < maxcpus; i++) {
-		call_rcu_lock(&call_rcu_mutex);
-		if (get_cpu_call_rcu_data(i)) {
-			call_rcu_unlock(&call_rcu_mutex);
-			continue;
-		}
-		crdp = __create_call_rcu_data(flags);
-		if (crdp == NULL) {
-			call_rcu_unlock(&call_rcu_mutex);
-			errno = ENOMEM;
-			return -ENOMEM;
-		}
-		call_rcu_unlock(&call_rcu_mutex);
-		if ((ret = set_cpu_call_rcu_data(i, crdp)) != 0) {
-			/* FIXME: Leaks crdp for now. */
-			return ret; /* Can happen on race. */
-		}
-	}
-	return 0;
-}
-
-/*
- * Wake up the call_rcu thread corresponding to the specified
- * call_rcu_data structure.
- */
-static void wake_call_rcu_thread(struct call_rcu_data *crdp)
-{
-	if (!(_CMM_LOAD_SHARED(crdp->flags) & URCU_CALL_RCU_RT)) {
-		call_rcu_lock(&crdp->mtx);
-		if (!(_CMM_LOAD_SHARED(crdp->flags) & URCU_CALL_RCU_RUNNING)) {
-			if (pthread_cond_signal(&crdp->cond) != 0) {
-				perror("pthread_cond_signal");
-				exit(-1);
-			}
-		}
-		call_rcu_unlock(&crdp->mtx);
-	}
-}
-
-/*
- * Schedule a function to be invoked after a following grace period.
- * This is the only function that must be called -- the others are
- * only present to allow applications to tune their use of RCU for
- * maximum performance.
- *
- * Note that unless a call_rcu thread has not already been created,
- * the first invocation of call_rcu() will create one.  So, if you
- * need the first invocation of call_rcu() to be fast, make sure
- * to create a call_rcu thread first.  One way to accomplish this is
- * "get_call_rcu_data();", and another is create_all_cpu_call_rcu_data().
- */
-
-void call_rcu(struct rcu_head *head,
-	      void (*func)(struct rcu_head *head))
-{
-	struct call_rcu_data *crdp;
-
-	cds_wfq_node_init(&head->next);
-	head->func = func;
-	crdp = get_call_rcu_data();
-	cds_wfq_enqueue(&crdp->cbs, &head->next);
-	uatomic_inc(&crdp->qlen);
-	wake_call_rcu_thread(crdp);
-}
-
-/*
- * Free up the specified call_rcu_data structure, terminating the
- * associated call_rcu thread.  The caller must have previously
- * removed the call_rcu_data structure from per-thread or per-CPU
- * usage.  For example, set_cpu_call_rcu_data(cpu, NULL) for per-CPU
- * call_rcu_data structures or set_thread_call_rcu_data(NULL) for
- * per-thread call_rcu_data structures.
- *
- * We silently refuse to free up the default call_rcu_data structure
- * because that is where we put any leftover callbacks.  Note that
- * the possibility of self-spawning callbacks makes it impossible
- * to execute all the callbacks in finite time without putting any
- * newly spawned callbacks somewhere else.  The "somewhere else" of
- * last resort is the default call_rcu_data structure.
- *
- * We also silently refuse to free NULL pointers.  This simplifies
- * the calling code.
- */
-void call_rcu_data_free(struct call_rcu_data *crdp)
-{
-	struct cds_wfq_node *cbs;
-	struct cds_wfq_node **cbs_tail;
-	struct cds_wfq_node **cbs_endprev;
-
-	if (crdp == NULL || crdp == default_call_rcu_data) {
-		return;
-	}
-	if ((crdp->flags & URCU_CALL_RCU_STOPPED) == 0) {
-		call_rcu_lock(&crdp->mtx);
-		crdp->flags |= URCU_CALL_RCU_STOP;
-		call_rcu_unlock(&crdp->mtx);
-		wake_call_rcu_thread(crdp);
-		while ((crdp->flags & URCU_CALL_RCU_STOPPED) == 0)
-			poll(NULL, 0, 1);
-	}
-	if (&crdp->cbs.head != _CMM_LOAD_SHARED(crdp->cbs.tail)) {
-		while ((cbs = _CMM_LOAD_SHARED(crdp->cbs.head)) == NULL)
-			poll(NULL, 0, 1);
-		_CMM_STORE_SHARED(crdp->cbs.head, NULL);
-		cbs_tail = (struct cds_wfq_node **)
-			uatomic_xchg(&crdp->cbs.tail, &crdp->cbs.head);
-		cbs_endprev = (struct cds_wfq_node **)
-			uatomic_xchg(&default_call_rcu_data, cbs_tail);
-		*cbs_endprev = cbs;
-		uatomic_add(&default_call_rcu_data->qlen,
-			    uatomic_read(&crdp->qlen));
-		cds_list_del(&crdp->list);
-		free(crdp);
-	}
-}
-
-/*
- * Clean up all the per-CPU call_rcu threads.
- */
-void free_all_cpu_call_rcu_data(void)
-{
-	int cpu;
-	struct call_rcu_data *crdp;
-
-	if (maxcpus <= 0)
-		return;
-	for (cpu = 0; cpu < maxcpus; cpu++) {
-		crdp = get_cpu_call_rcu_data(cpu);
-		if (crdp == NULL)
-			continue;
-		set_cpu_call_rcu_data(cpu, NULL);
-		call_rcu_data_free(crdp);
-	}
-}
-
-/*
- * Acquire the call_rcu_mutex in order to ensure that the child sees
- * all of the call_rcu() data structures in a consistent state.
- * Suitable for pthread_atfork() and friends.
- */
-void call_rcu_before_fork(void)
-{
-	call_rcu_lock(&call_rcu_mutex);
-}
-
-/*
- * Clean up call_rcu data structures in the parent of a successful fork()
- * that is not followed by exec() in the child.  Suitable for
- * pthread_atfork() and friends.
- */
-void call_rcu_after_fork_parent(void)
-{
-	call_rcu_unlock(&call_rcu_mutex);
-}
-
-/*
- * Clean up call_rcu data structures in the child of a successful fork()
- * that is not followed by exec().  Suitable for pthread_atfork() and
- * friends.
- */
-void call_rcu_after_fork_child(void)
-{
-	struct call_rcu_data *crdp;
-
-	/* Re-initialize the mutex. */
-	if (pthread_mutex_init(&call_rcu_mutex, NULL) != 0) {
-		perror("pthread_mutex_init");
-		exit(-1);
-	}
-
-	/*
-	 * Allocate a new default call_rcu_data structure in order
-	 * to get a working call_rcu thread to go with it.
-	 */
-	default_call_rcu_data = NULL;
-	(void)get_default_call_rcu_data();
-
-	/* Dispose of all of the rest of the call_rcu_data structures. */
-	while (call_rcu_data_list.next != call_rcu_data_list.prev) {
-		crdp = cds_list_entry(call_rcu_data_list.prev,
-				      struct call_rcu_data, list);
-		if (crdp == default_call_rcu_data)
-			crdp = cds_list_entry(crdp->list.prev,
-					      struct call_rcu_data, list);
-		crdp->flags = URCU_CALL_RCU_STOPPED;
-		call_rcu_data_free(crdp);
-	}
-}
diff --git a/urcu-map.h b/urcu-map.h
new file mode 100644
index 0000000..eccaac2
--- /dev/null
+++ b/urcu-map.h
@@ -0,0 +1,117 @@
+#ifndef _URCU_MAP_H
+#define _URCU_MAP_H
+
+/*
+ * urcu-map.h
+ *
+ * Userspace RCU header -- name mapping to allow multiple flavors to be
+ * used in the same executable.
+ *
+ * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
+ * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
+ *
+ * LGPL-compatible code should include this header with :
+ *
+ * #define _LGPL_SOURCE
+ * #include <urcu.h>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * IBM's contributions to this file may be relicensed under LGPLv2 or later.
+ */
+
+/* Mapping macros to allow multiple flavors in a single binary. */
+
+#ifdef RCU_MEMBARRIER
+
+#define rcu_read_lock			rcu_read_lock_memb
+#define _rcu_read_lock			_rcu_read_lock_memb
+#define rcu_read_unlock			rcu_read_unlock_memb
+#define _rcu_read_unlock		_rcu_read_unlock_memb
+#define rcu_register_thread		rcu_register_thread_memb
+#define rcu_unregister_thread		rcu_unregister_thread_memb
+#define rcu_init			rcu_init_memb
+#define rcu_exit			rcu_exit_memb
+#define synchronize_rcu			synchronize_rcu_memb
+#define rcu_reader			rcu_reader_memb
+#define rcu_gp_ctr			rcu_gp_ctr_memb
+
+#define get_cpu_call_rcu_data		get_cpu_call_rcu_data_memb
+#define get_call_rcu_thread		get_call_rcu_thread_memb
+#define create_call_rcu_data		create_call_rcu_data_memb
+#define set_cpu_call_rcu_data		set_cpu_call_rcu_data_memb
+#define get_default_call_rcu_data	get_default_call_rcu_data_memb
+#define get_call_rcu_data		get_call_rcu_data_memb
+#define get_thread_call_rcu_data	get_thread_call_rcu_data_memb
+#define set_thread_call_rcu_data	set_thread_call_rcu_data_memb
+#define create_all_cpu_call_rcu_data	create_all_cpu_call_rcu_data_memb
+#define free_all_cpu_call_rcu_data	free_all_cpu_call_rcu_data_memb
+#define call_rcu			call_rcu_memb
+
+#elif defined(RCU_SIGNAL)
+
+#define rcu_read_lock			rcu_read_lock_sig
+#define _rcu_read_lock			_rcu_read_lock_sig
+#define rcu_read_unlock			rcu_read_unlock_sig
+#define _rcu_read_unlock		_rcu_read_unlock_sig
+#define rcu_register_thread		rcu_register_thread_sig
+#define rcu_unregister_thread		rcu_unregister_thread_sig
+#define rcu_init			rcu_init_sig
+#define rcu_exit			rcu_exit_sig
+#define synchronize_rcu			synchronize_rcu_sig
+#define rcu_reader			rcu_reader_sig
+#define rcu_gp_ctr			rcu_gp_ctr_sig
+
+#define get_cpu_call_rcu_data		get_cpu_call_rcu_data_sig
+#define get_call_rcu_thread		get_call_rcu_thread_sig
+#define create_call_rcu_data		create_call_rcu_data_sig
+#define set_cpu_call_rcu_data		set_cpu_call_rcu_data_sig
+#define get_default_call_rcu_data	get_default_call_rcu_data_sig
+#define get_call_rcu_data		get_call_rcu_data_sig
+#define get_thread_call_rcu_data	get_thread_call_rcu_data_sig
+#define set_thread_call_rcu_data	set_thread_call_rcu_data_sig
+#define create_all_cpu_call_rcu_data	create_all_cpu_call_rcu_data_sig
+#define free_all_cpu_call_rcu_data	free_all_cpu_call_rcu_data_sig
+#define call_rcu			call_rcu_sig
+
+#elif defined(RCU_MB)
+
+#define rcu_read_lock			rcu_read_lock_mb
+#define _rcu_read_lock			_rcu_read_lock_mb
+#define rcu_read_unlock			rcu_read_unlock_mb
+#define _rcu_read_unlock		_rcu_read_unlock_mb
+#define rcu_register_thread		rcu_register_thread_mb
+#define rcu_unregister_thread		rcu_unregister_thread_mb
+#define rcu_init			rcu_init_mb
+#define rcu_exit			rcu_exit_mb
+#define synchronize_rcu			synchronize_rcu_mb
+#define rcu_reader			rcu_reader_mb
+#define rcu_gp_ctr			rcu_gp_ctr_mb
+
+#define get_cpu_call_rcu_data		get_cpu_call_rcu_data_mb
+#define get_call_rcu_thread		get_call_rcu_thread_mb
+#define create_call_rcu_data		create_call_rcu_data_mb
+#define set_cpu_call_rcu_data		set_cpu_call_rcu_data_mb
+#define get_default_call_rcu_data	get_default_call_rcu_data_mb
+#define get_call_rcu_data		get_call_rcu_data_mb
+#define get_thread_call_rcu_data	get_thread_call_rcu_data_mb
+#define set_thread_call_rcu_data	set_thread_call_rcu_data_mb
+#define create_all_cpu_call_rcu_data	create_all_cpu_call_rcu_data_mb
+#define free_all_cpu_call_rcu_data	free_all_cpu_call_rcu_data_mb
+#define call_rcu			call_rcu_mb
+
+#endif
+
+#endif /* _URCU_MAP_H */
diff --git a/urcu-qsbr-map.h b/urcu-qsbr-map.h
new file mode 100644
index 0000000..2bce1b6
--- /dev/null
+++ b/urcu-qsbr-map.h
@@ -0,0 +1,63 @@
+#ifndef _URCU_QSBR_MAP_H
+#define _URCU_QSBR_MAP_H
+
+/*
+ * urcu-map.h
+ *
+ * Userspace RCU header -- name mapping to allow multiple flavors to be
+ * used in the same executable.
+ *
+ * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
+ * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
+ *
+ * LGPL-compatible code should include this header with :
+ *
+ * #define _LGPL_SOURCE
+ * #include <urcu.h>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * IBM's contributions to this file may be relicensed under LGPLv2 or later.
+ */
+
+/* Mapping macros to allow multiple flavors in a single binary. */
+
+#define rcu_read_lock			rcu_read_lock_qsbr
+#define _rcu_read_lock			_rcu_read_lock_qsbr
+#define rcu_read_unlock			rcu_read_unlock_qsbr
+#define _rcu_read_unlock		_rcu_read_unlock_qsbr
+#define rcu_quiescent_state		rcu_quiescent_state_qsbr
+#define _rcu_quiescent_state		_rcu_quiescent_state_qsbr
+#define rcu_thread_offline		rcu_thread_offline_qsbr
+#define rcu_thread_online		rcu_thread_online_qsbr
+#define rcu_register_thread		rcu_register_thread_qsbr
+#define rcu_unregister_thread		rcu_unregister_thread_qsbr
+#define rcu_exit			rcu_exit_qsbr
+#define synchronize_rcu			synchronize_rcu_qsbr
+#define rcu_reader			rcu_reader_qsbr
+#define rcu_gp_ctr			rcu_gp_ctr_qsbr
+
+#define get_cpu_call_rcu_data		get_cpu_call_rcu_data_qsbr
+#define get_call_rcu_thread		get_call_rcu_thread_qsbr
+#define create_call_rcu_data		create_call_rcu_data_qsbr
+#define set_cpu_call_rcu_data		set_cpu_call_rcu_data_qsbr
+#define get_default_call_rcu_data	get_default_call_rcu_data_qsbr
+#define get_call_rcu_data		get_call_rcu_data_qsbr
+#define get_thread_call_rcu_data	get_thread_call_rcu_data_qsbr
+#define set_thread_call_rcu_data	set_thread_call_rcu_data_qsbr
+#define create_all_cpu_call_rcu_data	create_all_cpu_call_rcu_data_qsbr
+#define call_rcu			call_rcu_qsbr
+
+#endif /* _URCU_QSBR_MAP_H */
diff --git a/urcu-qsbr.c b/urcu-qsbr.c
index 69effd5..8dcad33 100644
--- a/urcu-qsbr.c
+++ b/urcu-qsbr.c
@@ -32,6 +32,8 @@
 #include <errno.h>
 #include <poll.h>
 
+#include "urcu-qsbr-map.h"
+
 #define BUILD_QSBR_LIB
 #include "urcu-qsbr-static.h"
 /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
@@ -121,10 +123,11 @@ static void update_counter_and_wait(void)
 #endif	/* !(CAA_BITS_PER_LONG < 64) */
 
 	/*
-	 * Must commit rcu_gp_ctr update to memory before waiting for quiescent
-	 * state. Failure to do so could result in the writer waiting forever
-	 * while new readers are always accessing data (no progress). Enforce
-	 * compiler-order of store to rcu_gp_ctr before load rcu_reader ctr.
+	 * Must commit rcu_gp_ctr update to memory before waiting for
+	 * quiescent state. Failure to do so could result in the writer
+	 * waiting forever while new readers are always accessing data
+	 * (no progress). Enforce compiler-order of store to rcu_gp_ctr
+	 * before load rcu_reader ctr.
 	 */
 	cmm_barrier();
 
@@ -194,8 +197,8 @@ void synchronize_rcu(void)
 
 	/*
 	 * Mark the writer thread offline to make sure we don't wait for
-	 * our own quiescent state. This allows using synchronize_rcu() in
-	 * threads registered as readers.
+	 * our own quiescent state. This allows using synchronize_rcu()
+	 * in threads registered as readers.
 	 */
 	if (was_online)
 		CMM_STORE_SHARED(rcu_reader.ctr, 0);
@@ -212,10 +215,11 @@ void synchronize_rcu(void)
 
 	/*
 	 * Must finish waiting for quiescent state for parity 0 before
-	 * committing next rcu_gp_ctr update to memory. Failure to do so could
-	 * result in the writer waiting forever while new readers are always
-	 * accessing data (no progress).  Enforce compiler-order of load
-	 * rcu_reader ctr before store to rcu_gp_ctr.
+	 * committing next rcu_gp_ctr update to memory. Failure to
+	 * do so could result in the writer waiting forever while new
+	 * readers are always accessing data (no progress).  Enforce
+	 * compiler-order of load rcu_reader ctr before store to
+	 * rcu_gp_ctr.
 	 */
 	cmm_barrier();
 
@@ -238,7 +242,8 @@ out:
 	 * freed.
 	 */
 	if (was_online)
-		_CMM_STORE_SHARED(rcu_reader.ctr, CMM_LOAD_SHARED(rcu_gp_ctr));
+		_CMM_STORE_SHARED(rcu_reader.ctr,
+				  CMM_LOAD_SHARED(rcu_gp_ctr));
 	cmm_smp_mb();
 }
 #else /* !(CAA_BITS_PER_LONG < 64) */
@@ -250,8 +255,8 @@ void synchronize_rcu(void)
 
 	/*
 	 * Mark the writer thread offline to make sure we don't wait for
-	 * our own quiescent state. This allows using synchronize_rcu() in
-	 * threads registered as readers.
+	 * our own quiescent state. This allows using synchronize_rcu()
+	 * in threads registered as readers.
 	 */
 	cmm_smp_mb();
 	if (was_online)
@@ -265,7 +270,8 @@ out:
 	mutex_unlock(&rcu_gp_lock);
 
 	if (was_online)
-		_CMM_STORE_SHARED(rcu_reader.ctr, CMM_LOAD_SHARED(rcu_gp_ctr));
+		_CMM_STORE_SHARED(rcu_reader.ctr,
+				  CMM_LOAD_SHARED(rcu_gp_ctr));
 	cmm_smp_mb();
 }
 #endif  /* !(CAA_BITS_PER_LONG < 64) */
@@ -326,3 +332,5 @@ void rcu_exit(void)
 {
 	assert(cds_list_empty(&registry));
 }
+
+#include "urcu-call-rcu-impl.h"
diff --git a/urcu-qsbr.h b/urcu-qsbr.h
index 116fd77..984d70c 100644
--- a/urcu-qsbr.h
+++ b/urcu-qsbr.h
@@ -40,6 +40,8 @@
 extern "C" {
 #endif 
 
+#include "urcu-qsbr-map.h"
+
 /*
  * Important !
  *
@@ -62,15 +64,15 @@ extern "C" {
  * rcu_read_unlock()
  *
  * Mark the beginning and end of a read-side critical section.
- * DON'T FORGET TO USE rcu_register_thread/rcu_unregister_thread() FOR EACH
- * THREAD WITH READ-SIDE CRITICAL SECTION.
+ * DON'T FORGET TO USE rcu_register_thread/rcu_unregister_thread()
+ * FOR EACH THREAD WITH READ-SIDE CRITICAL SECTION.
  */
-#define rcu_read_lock()		_rcu_read_lock()
-#define rcu_read_unlock()	_rcu_read_unlock()
+#define rcu_read_lock_qsbr()		_rcu_read_lock()
+#define rcu_read_unlock_qsbr()		_rcu_read_unlock()
 
-#define rcu_quiescent_state()	_rcu_quiescent_state()
-#define rcu_thread_offline()	_rcu_thread_offline()
-#define rcu_thread_online()	_rcu_thread_online()
+#define rcu_quiescent_state_qsbr()	_rcu_quiescent_state()
+#define rcu_thread_offline_qsbr()	_rcu_thread_offline()
+#define rcu_thread_online_qsbr()	_rcu_thread_online()
 
 #else /* !_LGPL_SOURCE */
 
@@ -122,4 +124,6 @@ extern void rcu_unregister_thread(void);
 }
 #endif
 
+#include "urcu-call-rcu.h"
+
 #endif /* _URCU_QSBR_H */
diff --git a/urcu.c b/urcu.c
index e529ac0..4ee9e3b 100644
--- a/urcu.c
+++ b/urcu.c
@@ -33,6 +33,8 @@
 #include <errno.h>
 #include <poll.h>
 
+#include "urcu-map.h"
+
 #include "urcu-static.h"
 /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
 #include "urcu.h"
@@ -428,4 +430,7 @@ void rcu_exit(void)
 	assert(act.sa_sigaction == sigrcu_handler);
 	assert(cds_list_empty(&registry));
 }
+
 #endif /* #ifdef RCU_SIGNAL */
+
+#include "urcu-call-rcu-impl.h"
diff --git a/urcu.h b/urcu.h
index c6c54e7..00d9b75 100644
--- a/urcu.h
+++ b/urcu.h
@@ -43,12 +43,14 @@
 extern "C" {
 #endif 
 
+#include "urcu-map.h"
+
 /*
  * Important !
  *
  * Each thread containing read-side critical sections must be registered
- * with rcu_register_thread() before calling rcu_read_lock().
- * rcu_unregister_thread() should be called before the thread exits.
+ * with rcu_register_thread_mb() before calling rcu_read_lock_mb().
+ * rcu_unregister_thread_mb() should be called before the thread exits.
  */
 
 #ifdef _LGPL_SOURCE
@@ -68,8 +70,16 @@ extern "C" {
  * DON'T FORGET TO USE RCU_REGISTER/UNREGISTER_THREAD() FOR EACH THREAD WITH
  * READ-SIDE CRITICAL SECTION.
  */
-#define rcu_read_lock()		_rcu_read_lock()
-#define rcu_read_unlock()	_rcu_read_unlock()
+#ifdef RCU_MEMBARRIER
+#define rcu_read_lock_memb()		_rcu_read_lock()
+#define rcu_read_unlock_memb()		_rcu_read_unlock()
+#elif defined(RCU_SIGNAL)
+#define rcu_read_lock_sig()		_rcu_read_lock()
+#define rcu_read_unlock_sig()		_rcu_read_unlock()
+#elif defined(RCU_MB)
+#define rcu_read_lock_mb()		_rcu_read_lock()
+#define rcu_read_unlock_mb()		_rcu_read_unlock()
+#endif
 
 #else /* !_LGPL_SOURCE */
 
@@ -100,4 +110,6 @@ extern void rcu_init(void);
 }
 #endif
 
+#include "urcu-call-rcu.h"
+
 #endif /* _URCU_H */
-- 
1.7.3.2

[ltt-dev] [PATCH RFC urcu 3/4] Allow taking address of rcu_read_lock() and rcu_read_unlock()

[Paul E. McKenney]

Also incorporate README feedback from Mathieu and Josh.

Signed-off-by: Paul E. McKenney <paulmck at linux.vnet.ibm.com>
---
 README      |    9 ++++++---
 urcu-bp.h   |    4 ++--
 urcu-qsbr.h |   10 +++++-----
 urcu.h      |   12 ++++++------
 4 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/README b/README
index 56e98d7..659511f 100644
--- a/README
+++ b/README
@@ -205,6 +205,9 @@ Interaction with fork()
 	rcu_bp_before_fork, rcu_bp_after_fork_parent and
 	rcu_bp_after_fork_child.
 
-	Applications that use call_rcu() are required to invoke
-	call_rcu_after_fork_child() from the child process after a
-	successful fork() system call that is not followed by exec().
+	Applications that use call_rcu() and that fork() without
+	doing an immediate exec() must take special action.  The parent
+	must invoke call_rcu_before_fork() before the fork() and
+	call_rcu_after_fork_parent() after the fork().  The child
+	process must invoke call_rcu_after_fork_child().
+	These three APIs are suitable for passing to pthread_atfork().
diff --git a/urcu-bp.h b/urcu-bp.h
index fdf885c..bc2dbc3 100644
--- a/urcu-bp.h
+++ b/urcu-bp.h
@@ -71,8 +71,8 @@ extern "C" {
  *
  * Mark the beginning and end of a read-side critical section.
  */
-#define rcu_read_lock_bp()		_rcu_read_lock()
-#define rcu_read_unlock_bp()		_rcu_read_unlock()
+#define rcu_read_lock_bp		_rcu_read_lock
+#define rcu_read_unlock_bp		_rcu_read_unlock
 
 #else /* !_LGPL_SOURCE */
 
diff --git a/urcu-qsbr.h b/urcu-qsbr.h
index 984d70c..7ef1bfe 100644
--- a/urcu-qsbr.h
+++ b/urcu-qsbr.h
@@ -67,12 +67,12 @@ extern "C" {
  * DON'T FORGET TO USE rcu_register_thread/rcu_unregister_thread()
  * FOR EACH THREAD WITH READ-SIDE CRITICAL SECTION.
  */
-#define rcu_read_lock_qsbr()		_rcu_read_lock()
-#define rcu_read_unlock_qsbr()		_rcu_read_unlock()
+#define rcu_read_lock_qsbr		_rcu_read_lock
+#define rcu_read_unlock_qsbr		_rcu_read_unlock
 
-#define rcu_quiescent_state_qsbr()	_rcu_quiescent_state()
-#define rcu_thread_offline_qsbr()	_rcu_thread_offline()
-#define rcu_thread_online_qsbr()	_rcu_thread_online()
+#define rcu_quiescent_state_qsbr	_rcu_quiescent_state
+#define rcu_thread_offline_qsbr		_rcu_thread_offline
+#define rcu_thread_online_qsbr		_rcu_thread_online
 
 #else /* !_LGPL_SOURCE */
 
diff --git a/urcu.h b/urcu.h
index 00d9b75..417e609 100644
--- a/urcu.h
+++ b/urcu.h
@@ -71,14 +71,14 @@ extern "C" {
  * READ-SIDE CRITICAL SECTION.
  */
 #ifdef RCU_MEMBARRIER
-#define rcu_read_lock_memb()		_rcu_read_lock()
-#define rcu_read_unlock_memb()		_rcu_read_unlock()
+#define rcu_read_lock_memb		_rcu_read_lock
+#define rcu_read_unlock_memb		_rcu_read_unlock
 #elif defined(RCU_SIGNAL)
-#define rcu_read_lock_sig()		_rcu_read_lock()
-#define rcu_read_unlock_sig()		_rcu_read_unlock()
+#define rcu_read_lock_sig		_rcu_read_lock
+#define rcu_read_unlock_sig		_rcu_read_unlock
 #elif defined(RCU_MB)
-#define rcu_read_lock_mb()		_rcu_read_lock()
-#define rcu_read_unlock_mb()		_rcu_read_unlock()
+#define rcu_read_lock_mb		_rcu_read_lock
+#define rcu_read_unlock_mb		_rcu_read_unlock
 #endif
 
 #else /* !_LGPL_SOURCE */
-- 
1.7.3.2

[ltt-dev] [PATCH RFC urcu 4/4] Make defer_rcu() usable from library using multiple URCU implementations

[Paul E. McKenney]

Signed-off-by: Paul E. McKenney <paulmck at linux.vnet.ibm.com>
---
 Makefile.am         |    4 +-
 README              |   11 +-
 tests/Makefile.am   |    2 +-
 urcu-bp-map.h       |    6 +
 urcu-bp.c           |    1 +
 urcu-bp.h           |    1 +
 urcu-defer-impl.h   |  450 +++++++++++++++++++++++++++++++++++++++++++++++++++
 urcu-defer-static.h |  108 ------------
 urcu-defer.c        |  385 -------------------------------------------
 urcu-map.h          |   26 +++
 urcu-qsbr-map.h     |    6 +
 urcu-qsbr.c         |    1 +
 urcu-qsbr.h         |    1 +
 urcu.c              |    1 +
 urcu.h              |    1 +
 15 files changed, 501 insertions(+), 503 deletions(-)
 create mode 100644 urcu-defer-impl.h
 delete mode 100644 urcu-defer-static.h
 delete mode 100644 urcu-defer.c

diff --git a/Makefile.am b/Makefile.am
index ef3bfef..6ef80c2 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -30,7 +30,7 @@ COMPAT+=compat_futex.c
 endif
 
 lib_LTLIBRARIES = liburcu.la liburcu-qsbr.la liburcu-mb.la liburcu-signal.la \
-		  liburcu-bp.la liburcu-defer.la \
+		  liburcu-bp.la \
 		  libwfqueue.la libwfstack.la librculfqueue.la librculfstack.la
 
 liburcu_la_SOURCES = urcu.c urcu-pointer.c $(COMPAT)
@@ -45,8 +45,6 @@ liburcu_signal_la_CFLAGS = -DRCU_SIGNAL
 
 liburcu_bp_la_SOURCES = urcu-bp.c urcu-pointer.c $(COMPAT)
 
-liburcu_defer_la_SOURCES = urcu-defer.c $(COMPAT)
-
 libwfqueue_la_SOURCES = wfqueue.c $(COMPAT)
 libwfstack_la_SOURCES = wfstack.c $(COMPAT)
 librculfqueue_la_SOURCES = rculfqueue.c $(COMPAT)
diff --git a/README b/README
index 659511f..7d97f19 100644
--- a/README
+++ b/README
@@ -124,16 +124,15 @@ Writing
 
 Usage of liburcu-defer
 
-	* #include <urcu-defer.h>
-	* Link with "-lurcu-defer", and also with one of the urcu library
-	  (either urcu, urcu-bp, urcu-mb or urcu-qsbr).
+	* Follow instructions for either liburcu, liburcu-qsbr,
+	  liburcu-mb, liburcu-signal, or liburcu-bp above.
+	  The liburcu-defer functionality is pulled into each of
+	  those library modules.
 	* Provides defer_rcu() primitive to enqueue delayed callbacks. Queued
 	  callbacks are executed in batch periodically after a grace period.
 	  Do _not_ use defer_rcu() within a read-side critical section, because
 	  it may call synchronize_rcu() if the thread queue is full.
-	* Provides defer_rcu_ratelimit() primitive, which acts just like
-	  defer_rcu(), but takes an additional rate limiter callback forcing
-	  synchronized callback execution of the limiter returns non-zero.
+	  This can lead to deadlock or worse.
 	* Requires that rcu_defer_barrier() must be called in library destructor
 	  if a library queues callbacks and is expected to be unloaded with
 	  dlclose().
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 8dacb11..5598689 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -35,7 +35,7 @@ URCU_MB=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.
 # URCU_SIGNAL uses urcu.c but -DRCU_SIGNAL must be defined
 URCU_SIGNAL=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
 URCU_BP=$(top_srcdir)/urcu-bp.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
-URCU_DEFER=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-defer.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
+URCU_DEFER=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
 
 URCU_LIB=$(top_builddir)/liburcu.la
 URCU_QSBR_LIB=$(top_builddir)/liburcu-qsbr.la
diff --git a/urcu-bp-map.h b/urcu-bp-map.h
index 6321802..1d77006 100644
--- a/urcu-bp-map.h
+++ b/urcu-bp-map.h
@@ -58,4 +58,10 @@
 #define free_all_cpu_call_rcu_data	free_all_cpu_call_rcu_data_bp
 #define call_rcu			call_rcu_bp
 
+#define defer_rcu			defer_rcu_bp
+#define rcu_defer_register_thread	rcu_defer_register_thread_bp
+#define rcu_defer_unregister_thread	rcu_defer_unregister_thread_bp
+#define	rcu_defer_barrier		rcu_defer_barrier_bp
+#define rcu_defer_barrier_thread	rcu_defer_barrier_thread_bp
+
 #endif /* _URCU_BP_MAP_H */
diff --git a/urcu-bp.c b/urcu-bp.c
index 5474f9f..14b2001 100644
--- a/urcu-bp.c
+++ b/urcu-bp.c
@@ -379,3 +379,4 @@ void rcu_bp_after_fork_child(void)
 }
 
 #include "urcu-call-rcu-impl.h"
+#include "urcu-defer-impl.h"
diff --git a/urcu-bp.h b/urcu-bp.h
index bc2dbc3..21fe66a 100644
--- a/urcu-bp.h
+++ b/urcu-bp.h
@@ -118,5 +118,6 @@ static inline void rcu_init(void)
 #endif
 
 #include "urcu-call-rcu.h"
+#include "urcu-defer.h"
 
 #endif /* _URCU_BP_H */
diff --git a/urcu-defer-impl.h b/urcu-defer-impl.h
new file mode 100644
index 0000000..0aedd53
--- /dev/null
+++ b/urcu-defer-impl.h
@@ -0,0 +1,450 @@
+#ifndef _URCU_DEFER_IMPL_H
+#define _URCU_DEFER_IMPL_H
+
+/*
+ * urcu-defer-impl.h
+ *
+ * Userspace RCU header - memory reclamation.
+ *
+ * TO BE INCLUDED ONLY FROM URCU LIBRARY CODE. See urcu-defer.h for linking
+ * dynamically with the userspace rcu reclamation library.
+ *
+ * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
+ * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * IBM's contributions to this file may be relicensed under LGPLv2 or later.
+ */
+
+#include <stdlib.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <signal.h>
+#include <assert.h>
+#include <string.h>
+#include <errno.h>
+#include <poll.h>
+#include <sys/time.h>
+#include <syscall.h>
+#include <unistd.h>
+
+#include "urcu/urcu-futex.h"
+
+#include <urcu/compiler.h>
+#include <urcu/arch.h>
+#include <urcu/uatomic_arch.h>
+#include <urcu/list.h>
+#include <urcu/system.h>
+
+/*
+ * Number of entries in the per-thread defer queue. Must be power of 2.
+ */
+#define DEFER_QUEUE_SIZE	(1 << 12)
+#define DEFER_QUEUE_MASK	(DEFER_QUEUE_SIZE - 1)
+
+/*
+ * Typically, data is aligned at least on the architecture size.
+ * Use lowest bit to indicate that the current callback is changing.
+ * Assumes that (void *)-2L is not used often. Used to encode non-aligned
+ * functions and non-aligned data using extra space.
+ * We encode the (void *)-2L fct as: -2L, fct, data.
+ * We encode the (void *)-2L data as: -2L, fct, data.
+ * Here, DQ_FCT_MARK == ~DQ_FCT_BIT. Required for the test order.
+ */
+#define DQ_FCT_BIT		(1 << 0)
+#define DQ_IS_FCT_BIT(x)	((unsigned long)(x) & DQ_FCT_BIT)
+#define DQ_SET_FCT_BIT(x)	\
+	(x = (void *)((unsigned long)(x) | DQ_FCT_BIT))
+#define DQ_CLEAR_FCT_BIT(x)	\
+	(x = (void *)((unsigned long)(x) & ~DQ_FCT_BIT))
+#define DQ_FCT_MARK		((void *)(~DQ_FCT_BIT))
+
+/*
+ * This code section can only be included in LGPL 2.1 compatible source code.
+ * See below for the function call wrappers which can be used in code meant to
+ * be only linked with the Userspace RCU library. This comes with a small
+ * performance degradation on the read-side due to the added function calls.
+ * This is required to permit relinking with newer versions of the library.
+ */
+
+#ifdef DEBUG_RCU
+#define rcu_assert(args...)	assert(args)
+#else
+#define rcu_assert(args...)
+#endif
+
+/*
+ * defer queue.
+ * Contains pointers. Encoded to save space when same callback is often used.
+ * When looking up the next item:
+ * - if DQ_FCT_BIT is set, set the current callback to DQ_CLEAR_FCT_BIT(ptr)
+ *   - next element contains pointer to data.
+ * - else if item == DQ_FCT_MARK
+ *   - set the current callback to next element ptr
+ *   - following next element contains pointer to data.
+ * - else current element contains data
+ */
+struct defer_queue {
+	unsigned long head;	/* add element at head */
+	void *last_fct_in;	/* last fct pointer encoded */
+	unsigned long tail;	/* next element to remove at tail */
+	void *last_fct_out;	/* last fct pointer encoded */
+	void **q;
+	/* registry information */
+	unsigned long last_head;
+	struct cds_list_head list;	/* list of thread queues */
+};
+
+/* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
+#include "urcu-defer.h"
+
+void __attribute__((destructor)) rcu_defer_exit(void);
+
+extern void synchronize_rcu(void);
+
+/*
+ * rcu_defer_mutex nests inside defer_thread_mutex.
+ */
+static pthread_mutex_t rcu_defer_mutex = PTHREAD_MUTEX_INITIALIZER;
+static pthread_mutex_t defer_thread_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+static int defer_thread_futex;
+
+/*
+ * Written to only by each individual deferer. Read by both the deferer and
+ * the reclamation tread.
+ */
+static struct defer_queue __thread defer_queue;
+static CDS_LIST_HEAD(registry_defer);
+static pthread_t tid_defer;
+
+static void mutex_lock_defer(pthread_mutex_t *mutex)
+{
+	int ret;
+
+#ifndef DISTRUST_SIGNALS_EXTREME
+	ret = pthread_mutex_lock(mutex);
+	if (ret) {
+		perror("Error in pthread mutex lock");
+		exit(-1);
+	}
+#else /* #ifndef DISTRUST_SIGNALS_EXTREME */
+	while ((ret = pthread_mutex_trylock(mutex)) != 0) {
+		if (ret != EBUSY && ret != EINTR) {
+			printf("ret = %d, errno = %d\n", ret, errno);
+			perror("Error in pthread mutex lock");
+			exit(-1);
+		}
+		pthread_testcancel();
+		poll(NULL,0,10);
+	}
+#endif /* #else #ifndef DISTRUST_SIGNALS_EXTREME */
+}
+
+/*
+ * Wake-up any waiting defer thread. Called from many concurrent threads.
+ */
+static void wake_up_defer(void)
+{
+	if (unlikely(uatomic_read(&defer_thread_futex) == -1)) {
+		uatomic_set(&defer_thread_futex, 0);
+		futex_noasync(&defer_thread_futex, FUTEX_WAKE, 1,
+		      NULL, NULL, 0);
+	}
+}
+
+static unsigned long rcu_defer_num_callbacks(void)
+{
+	unsigned long num_items = 0, head;
+	struct defer_queue *index;
+
+	mutex_lock_defer(&rcu_defer_mutex);
+	cds_list_for_each_entry(index, &registry_defer, list) {
+		head = CMM_LOAD_SHARED(index->head);
+		num_items += head - index->tail;
+	}
+	mutex_unlock(&rcu_defer_mutex);
+	return num_items;
+}
+
+/*
+ * Defer thread waiting. Single thread.
+ */
+static void wait_defer(void)
+{
+	uatomic_dec(&defer_thread_futex);
+	cmm_smp_mb();	/* Write futex before read queue */
+	if (rcu_defer_num_callbacks()) {
+		cmm_smp_mb();	/* Read queue before write futex */
+		/* Callbacks are queued, don't wait. */
+		uatomic_set(&defer_thread_futex, 0);
+	} else {
+		cmm_smp_rmb();	/* Read queue before read futex */
+		if (uatomic_read(&defer_thread_futex) == -1)
+			futex_noasync(&defer_thread_futex, FUTEX_WAIT, -1,
+			      NULL, NULL, 0);
+	}
+}
+
+/*
+ * Must be called after Q.S. is reached.
+ */
+static void rcu_defer_barrier_queue(struct defer_queue *queue,
+				    unsigned long head)
+{
+	unsigned long i;
+	void (*fct)(void *p);
+	void *p;
+
+	/*
+	 * Tail is only modified when lock is held.
+	 * Head is only modified by owner thread.
+	 */
+
+	for (i = queue->tail; i != head;) {
+		cmm_smp_rmb();       /* read head before q[]. */
+		p = CMM_LOAD_SHARED(queue->q[i++ & DEFER_QUEUE_MASK]);
+		if (unlikely(DQ_IS_FCT_BIT(p))) {
+			DQ_CLEAR_FCT_BIT(p);
+			queue->last_fct_out = p;
+			p = CMM_LOAD_SHARED(queue->q[i++ & DEFER_QUEUE_MASK]);
+		} else if (unlikely(p == DQ_FCT_MARK)) {
+			p = CMM_LOAD_SHARED(queue->q[i++ & DEFER_QUEUE_MASK]);
+			queue->last_fct_out = p;
+			p = CMM_LOAD_SHARED(queue->q[i++ & DEFER_QUEUE_MASK]);
+		}
+		fct = queue->last_fct_out;
+		fct(p);
+	}
+	cmm_smp_mb();	/* push tail after having used q[] */
+	CMM_STORE_SHARED(queue->tail, i);
+}
+
+static void _rcu_defer_barrier_thread(void)
+{
+	unsigned long head, num_items;
+
+	head = defer_queue.head;
+	num_items = head - defer_queue.tail;
+	if (unlikely(!num_items))
+		return;
+	synchronize_rcu();
+	rcu_defer_barrier_queue(&defer_queue, head);
+}
+
+void rcu_defer_barrier_thread(void)
+{
+	mutex_lock_defer(&rcu_defer_mutex);
+	_rcu_defer_barrier_thread();
+	mutex_unlock(&rcu_defer_mutex);
+}
+
+/*
+ * rcu_defer_barrier - Execute all queued rcu callbacks.
+ *
+ * Execute all RCU callbacks queued before rcu_defer_barrier() execution.
+ * All callbacks queued on the local thread prior to a rcu_defer_barrier() call
+ * are guaranteed to be executed.
+ * Callbacks queued by other threads concurrently with rcu_defer_barrier()
+ * execution are not guaranteed to be executed in the current batch (could
+ * be left for the next batch). These callbacks queued by other threads are only
+ * guaranteed to be executed if there is explicit synchronization between
+ * the thread adding to the queue and the thread issuing the defer_barrier call.
+ */
+
+void rcu_defer_barrier(void)
+{
+	struct defer_queue *index;
+	unsigned long num_items = 0;
+
+	if (cds_list_empty(&registry_defer))
+		return;
+
+	mutex_lock_defer(&rcu_defer_mutex);
+	cds_list_for_each_entry(index, &registry_defer, list) {
+		index->last_head = CMM_LOAD_SHARED(index->head);
+		num_items += index->last_head - index->tail;
+	}
+	if (likely(!num_items)) {
+		/*
+		 * We skip the grace period because there are no queued
+		 * callbacks to execute.
+		 */
+		goto end;
+	}
+	synchronize_rcu();
+	cds_list_for_each_entry(index, &registry_defer, list)
+		rcu_defer_barrier_queue(index, index->last_head);
+end:
+	mutex_unlock(&rcu_defer_mutex);
+}
+
+/*
+ * _defer_rcu - Queue a RCU callback.
+ */
+void _defer_rcu(void (*fct)(void *p), void *p)
+{
+	unsigned long head, tail;
+
+	/*
+	 * Head is only modified by ourself. Tail can be modified by reclamation
+	 * thread.
+	 */
+	head = defer_queue.head;
+	tail = CMM_LOAD_SHARED(defer_queue.tail);
+
+	/*
+	 * If queue is full, or reached threshold. Empty queue ourself.
+	 * Worse-case: must allow 2 supplementary entries for fct pointer.
+	 */
+	if (unlikely(head - tail >= DEFER_QUEUE_SIZE - 2)) {
+		assert(head - tail <= DEFER_QUEUE_SIZE);
+		rcu_defer_barrier_thread();
+		assert(head - CMM_LOAD_SHARED(defer_queue.tail) == 0);
+	}
+
+	if (unlikely(defer_queue.last_fct_in != fct)) {
+		defer_queue.last_fct_in = fct;
+		if (unlikely(DQ_IS_FCT_BIT(fct) || fct == DQ_FCT_MARK)) {
+			/*
+			 * If the function to encode is not aligned or the
+			 * marker, write DQ_FCT_MARK followed by the function
+			 * pointer.
+			 */
+			_CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
+				      DQ_FCT_MARK);
+			_CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
+				      fct);
+		} else {
+			DQ_SET_FCT_BIT(fct);
+			_CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
+				      fct);
+		}
+	} else {
+		if (unlikely(DQ_IS_FCT_BIT(p) || p == DQ_FCT_MARK)) {
+			/*
+			 * If the data to encode is not aligned or the marker,
+			 * write DQ_FCT_MARK followed by the function pointer.
+			 */
+			_CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
+				      DQ_FCT_MARK);
+			_CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
+				      fct);
+		}
+	}
+	_CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK], p);
+	cmm_smp_wmb();	/* Publish new pointer before head */
+			/* Write q[] before head. */
+	CMM_STORE_SHARED(defer_queue.head, head);
+	cmm_smp_mb();	/* Write queue head before read futex */
+	/*
+	 * Wake-up any waiting defer thread.
+	 */
+	wake_up_defer();
+}
+
+void *thr_defer(void *args)
+{
+	for (;;) {
+		pthread_testcancel();
+		/*
+		 * "Be green". Don't wake up the CPU if there is no RCU work
+		 * to perform whatsoever. Aims at saving laptop battery life by
+		 * leaving the processor in sleep state when idle.
+		 */
+		wait_defer();
+		/* Sleeping after wait_defer to let many callbacks enqueue */
+		poll(NULL,0,100);	/* wait for 100ms */
+		rcu_defer_barrier();
+	}
+
+	return NULL;
+}
+
+/*
+ * library wrappers to be used by non-LGPL compatible source code.
+ */
+
+void defer_rcu(void (*fct)(void *p), void *p)
+{
+	_defer_rcu(fct, p);
+}
+
+static void start_defer_thread(void)
+{
+	int ret;
+
+	ret = pthread_create(&tid_defer, NULL, thr_defer, NULL);
+	assert(!ret);
+}
+
+static void stop_defer_thread(void)
+{
+	int ret;
+	void *tret;
+
+	pthread_cancel(tid_defer);
+	wake_up_defer();
+	ret = pthread_join(tid_defer, &tret);
+	assert(!ret);
+}
+
+int rcu_defer_register_thread(void)
+{
+	int was_empty;
+
+	assert(defer_queue.last_head == 0);
+	assert(defer_queue.q == NULL);
+	defer_queue.q = malloc(sizeof(void *) * DEFER_QUEUE_SIZE);
+	if (!defer_queue.q)
+		return -ENOMEM;
+
+	mutex_lock_defer(&defer_thread_mutex);
+	mutex_lock_defer(&rcu_defer_mutex);
+	was_empty = cds_list_empty(&registry_defer);
+	cds_list_add(&defer_queue.list, &registry_defer);
+	mutex_unlock(&rcu_defer_mutex);
+
+	if (was_empty)
+		start_defer_thread();
+	mutex_unlock(&defer_thread_mutex);
+	return 0;
+}
+
+void rcu_defer_unregister_thread(void)
+{
+	int is_empty;
+
+	mutex_lock_defer(&defer_thread_mutex);
+	mutex_lock_defer(&rcu_defer_mutex);
+	cds_list_del(&defer_queue.list);
+	_rcu_defer_barrier_thread();
+	free(defer_queue.q);
+	defer_queue.q = NULL;
+	is_empty = cds_list_empty(&registry_defer);
+	mutex_unlock(&rcu_defer_mutex);
+
+	if (is_empty)
+		stop_defer_thread();
+	mutex_unlock(&defer_thread_mutex);
+}
+
+void rcu_defer_exit(void)
+{
+	assert(cds_list_empty(&registry_defer));
+}
+
+#endif /* _URCU_DEFER_IMPL_H */
diff --git a/urcu-defer-static.h b/urcu-defer-static.h
deleted file mode 100644
index 3e5df3e..0000000
--- a/urcu-defer-static.h
+++ /dev/null
@@ -1,108 +0,0 @@
-#ifndef _URCU_DEFER_STATIC_H
-#define _URCU_DEFER_STATIC_H
-
-/*
- * urcu-defer-static.h
- *
- * Userspace RCU header - memory reclamation.
- *
- * TO BE INCLUDED ONLY IN LGPL-COMPATIBLE CODE. See urcu-defer.h for linking
- * dynamically with the userspace rcu reclamation library.
- *
- * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
- * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
- * IBM's contributions to this file may be relicensed under LGPLv2 or later.
- */
-
-#include <stdlib.h>
-#include <pthread.h>
-
-#include <urcu/compiler.h>
-#include <urcu/arch.h>
-#include <urcu/uatomic_arch.h>
-#include <urcu/list.h>
-#include <urcu/system.h>
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-/*
- * Number of entries in the per-thread defer queue. Must be power of 2.
- */
-#define DEFER_QUEUE_SIZE	(1 << 12)
-#define DEFER_QUEUE_MASK	(DEFER_QUEUE_SIZE - 1)
-
-/*
- * Typically, data is aligned at least on the architecture size.
- * Use lowest bit to indicate that the current callback is changing.
- * Assumes that (void *)-2L is not used often. Used to encode non-aligned
- * functions and non-aligned data using extra space.
- * We encode the (void *)-2L fct as: -2L, fct, data.
- * We encode the (void *)-2L data as: -2L, fct, data.
- * Here, DQ_FCT_MARK == ~DQ_FCT_BIT. Required for the test order.
- */
-#define DQ_FCT_BIT		(1 << 0)
-#define DQ_IS_FCT_BIT(x)	((unsigned long)(x) & DQ_FCT_BIT)
-#define DQ_SET_FCT_BIT(x)	\
-	(x = (void *)((unsigned long)(x) | DQ_FCT_BIT))
-#define DQ_CLEAR_FCT_BIT(x)	\
-	(x = (void *)((unsigned long)(x) & ~DQ_FCT_BIT))
-#define DQ_FCT_MARK		((void *)(~DQ_FCT_BIT))
-
-/*
- * This code section can only be included in LGPL 2.1 compatible source code.
- * See below for the function call wrappers which can be used in code meant to
- * be only linked with the Userspace RCU library. This comes with a small
- * performance degradation on the read-side due to the added function calls.
- * This is required to permit relinking with newer versions of the library.
- */
-
-#ifdef DEBUG_RCU
-#define rcu_assert(args...)	assert(args)
-#else
-#define rcu_assert(args...)
-#endif
-
-/*
- * defer queue.
- * Contains pointers. Encoded to save space when same callback is often used.
- * When looking up the next item:
- * - if DQ_FCT_BIT is set, set the current callback to DQ_CLEAR_FCT_BIT(ptr)
- *   - next element contains pointer to data.
- * - else if item == DQ_FCT_MARK
- *   - set the current callback to next element ptr
- *   - following next element contains pointer to data.
- * - else current element contains data
- */
-struct defer_queue {
-	unsigned long head;	/* add element at head */
-	void *last_fct_in;	/* last fct pointer encoded */
-	unsigned long tail;	/* next element to remove at tail */
-	void *last_fct_out;	/* last fct pointer encoded */
-	void **q;
-	/* registry information */
-	unsigned long last_head;
-	struct cds_list_head list;	/* list of thread queues */
-};
-
-#ifdef __cplusplus 
-}
-#endif
-
-#endif /* _URCU_DEFER_STATIC_H */
diff --git a/urcu-defer.c b/urcu-defer.c
deleted file mode 100644
index 3f596ae..0000000
--- a/urcu-defer.c
+++ /dev/null
@@ -1,385 +0,0 @@
-/*
- * urcu-defer.c
- *
- * Userspace RCU library - batch memory reclamation
- *
- * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-#include <stdio.h>
-#include <pthread.h>
-#include <signal.h>
-#include <assert.h>
-#include <stdlib.h>
-#include <string.h>
-#include <errno.h>
-#include <poll.h>
-#include <sys/time.h>
-#include <syscall.h>
-#include <unistd.h>
-
-#include "urcu/urcu-futex.h"
-#include "urcu-defer-static.h"
-/* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
-#include "urcu-defer.h"
-
-void __attribute__((destructor)) rcu_defer_exit(void);
-
-extern void synchronize_rcu(void);
-
-/*
- * rcu_defer_mutex nests inside defer_thread_mutex.
- */
-static pthread_mutex_t rcu_defer_mutex = PTHREAD_MUTEX_INITIALIZER;
-static pthread_mutex_t defer_thread_mutex = PTHREAD_MUTEX_INITIALIZER;
-
-static int defer_thread_futex;
-
-/*
- * Written to only by each individual deferer. Read by both the deferer and
- * the reclamation tread.
- */
-static struct defer_queue __thread defer_queue;
-static CDS_LIST_HEAD(registry);
-static pthread_t tid_defer;
-
-static void mutex_lock(pthread_mutex_t *mutex)
-{
-	int ret;
-
-#ifndef DISTRUST_SIGNALS_EXTREME
-	ret = pthread_mutex_lock(mutex);
-	if (ret) {
-		perror("Error in pthread mutex lock");
-		exit(-1);
-	}
-#else /* #ifndef DISTRUST_SIGNALS_EXTREME */
-	while ((ret = pthread_mutex_trylock(mutex)) != 0) {
-		if (ret != EBUSY && ret != EINTR) {
-			printf("ret = %d, errno = %d\n", ret, errno);
-			perror("Error in pthread mutex lock");
-			exit(-1);
-		}
-		pthread_testcancel();
-		poll(NULL,0,10);
-	}
-#endif /* #else #ifndef DISTRUST_SIGNALS_EXTREME */
-}
-
-static void mutex_unlock(pthread_mutex_t *mutex)
-{
-	int ret;
-
-	ret = pthread_mutex_unlock(mutex);
-	if (ret) {
-		perror("Error in pthread mutex unlock");
-		exit(-1);
-	}
-}
-
-/*
- * Wake-up any waiting defer thread. Called from many concurrent threads.
- */
-static void wake_up_defer(void)
-{
-	if (unlikely(uatomic_read(&defer_thread_futex) == -1)) {
-		uatomic_set(&defer_thread_futex, 0);
-		futex_noasync(&defer_thread_futex, FUTEX_WAKE, 1,
-		      NULL, NULL, 0);
-	}
-}
-
-static unsigned long rcu_defer_num_callbacks(void)
-{
-	unsigned long num_items = 0, head;
-	struct defer_queue *index;
-
-	mutex_lock(&rcu_defer_mutex);
-	cds_list_for_each_entry(index, &registry, list) {
-		head = CMM_LOAD_SHARED(index->head);
-		num_items += head - index->tail;
-	}
-	mutex_unlock(&rcu_defer_mutex);
-	return num_items;
-}
-
-/*
- * Defer thread waiting. Single thread.
- */
-static void wait_defer(void)
-{
-	uatomic_dec(&defer_thread_futex);
-	cmm_smp_mb();	/* Write futex before read queue */
-	if (rcu_defer_num_callbacks()) {
-		cmm_smp_mb();	/* Read queue before write futex */
-		/* Callbacks are queued, don't wait. */
-		uatomic_set(&defer_thread_futex, 0);
-	} else {
-		cmm_smp_rmb();	/* Read queue before read futex */
-		if (uatomic_read(&defer_thread_futex) == -1)
-			futex_noasync(&defer_thread_futex, FUTEX_WAIT, -1,
-			      NULL, NULL, 0);
-	}
-}
-
-/*
- * Must be called after Q.S. is reached.
- */
-static void rcu_defer_barrier_queue(struct defer_queue *queue,
-				    unsigned long head)
-{
-	unsigned long i;
-	void (*fct)(void *p);
-	void *p;
-
-	/*
-	 * Tail is only modified when lock is held.
-	 * Head is only modified by owner thread.
-	 */
-
-	for (i = queue->tail; i != head;) {
-		cmm_smp_rmb();       /* read head before q[]. */
-		p = CMM_LOAD_SHARED(queue->q[i++ & DEFER_QUEUE_MASK]);
-		if (unlikely(DQ_IS_FCT_BIT(p))) {
-			DQ_CLEAR_FCT_BIT(p);
-			queue->last_fct_out = p;
-			p = CMM_LOAD_SHARED(queue->q[i++ & DEFER_QUEUE_MASK]);
-		} else if (unlikely(p == DQ_FCT_MARK)) {
-			p = CMM_LOAD_SHARED(queue->q[i++ & DEFER_QUEUE_MASK]);
-			queue->last_fct_out = p;
-			p = CMM_LOAD_SHARED(queue->q[i++ & DEFER_QUEUE_MASK]);
-		}
-		fct = queue->last_fct_out;
-		fct(p);
-	}
-	cmm_smp_mb();	/* push tail after having used q[] */
-	CMM_STORE_SHARED(queue->tail, i);
-}
-
-static void _rcu_defer_barrier_thread(void)
-{
-	unsigned long head, num_items;
-
-	head = defer_queue.head;
-	num_items = head - defer_queue.tail;
-	if (unlikely(!num_items))
-		return;
-	synchronize_rcu();
-	rcu_defer_barrier_queue(&defer_queue, head);
-}
-
-void rcu_defer_barrier_thread(void)
-{
-	mutex_lock(&rcu_defer_mutex);
-	_rcu_defer_barrier_thread();
-	mutex_unlock(&rcu_defer_mutex);
-}
-
-/*
- * rcu_defer_barrier - Execute all queued rcu callbacks.
- *
- * Execute all RCU callbacks queued before rcu_defer_barrier() execution.
- * All callbacks queued on the local thread prior to a rcu_defer_barrier() call
- * are guaranteed to be executed.
- * Callbacks queued by other threads concurrently with rcu_defer_barrier()
- * execution are not guaranteed to be executed in the current batch (could
- * be left for the next batch). These callbacks queued by other threads are only
- * guaranteed to be executed if there is explicit synchronization between
- * the thread adding to the queue and the thread issuing the defer_barrier call.
- */
-
-void rcu_defer_barrier(void)
-{
-	struct defer_queue *index;
-	unsigned long num_items = 0;
-
-	if (cds_list_empty(&registry))
-		return;
-
-	mutex_lock(&rcu_defer_mutex);
-	cds_list_for_each_entry(index, &registry, list) {
-		index->last_head = CMM_LOAD_SHARED(index->head);
-		num_items += index->last_head - index->tail;
-	}
-	if (likely(!num_items)) {
-		/*
-		 * We skip the grace period because there are no queued
-		 * callbacks to execute.
-		 */
-		goto end;
-	}
-	synchronize_rcu();
-	cds_list_for_each_entry(index, &registry, list)
-		rcu_defer_barrier_queue(index, index->last_head);
-end:
-	mutex_unlock(&rcu_defer_mutex);
-}
-
-/*
- * _defer_rcu - Queue a RCU callback.
- */
-void _defer_rcu(void (*fct)(void *p), void *p)
-{
-	unsigned long head, tail;
-
-	/*
-	 * Head is only modified by ourself. Tail can be modified by reclamation
-	 * thread.
-	 */
-	head = defer_queue.head;
-	tail = CMM_LOAD_SHARED(defer_queue.tail);
-
-	/*
-	 * If queue is full, or reached threshold. Empty queue ourself.
-	 * Worse-case: must allow 2 supplementary entries for fct pointer.
-	 */
-	if (unlikely(head - tail >= DEFER_QUEUE_SIZE - 2)) {
-		assert(head - tail <= DEFER_QUEUE_SIZE);
-		rcu_defer_barrier_thread();
-		assert(head - CMM_LOAD_SHARED(defer_queue.tail) == 0);
-	}
-
-	if (unlikely(defer_queue.last_fct_in != fct)) {
-		defer_queue.last_fct_in = fct;
-		if (unlikely(DQ_IS_FCT_BIT(fct) || fct == DQ_FCT_MARK)) {
-			/*
-			 * If the function to encode is not aligned or the
-			 * marker, write DQ_FCT_MARK followed by the function
-			 * pointer.
-			 */
-			_CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
-				      DQ_FCT_MARK);
-			_CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
-				      fct);
-		} else {
-			DQ_SET_FCT_BIT(fct);
-			_CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
-				      fct);
-		}
-	} else {
-		if (unlikely(DQ_IS_FCT_BIT(p) || p == DQ_FCT_MARK)) {
-			/*
-			 * If the data to encode is not aligned or the marker,
-			 * write DQ_FCT_MARK followed by the function pointer.
-			 */
-			_CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
-				      DQ_FCT_MARK);
-			_CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
-				      fct);
-		}
-	}
-	_CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK], p);
-	cmm_smp_wmb();	/* Publish new pointer before head */
-			/* Write q[] before head. */
-	CMM_STORE_SHARED(defer_queue.head, head);
-	cmm_smp_mb();	/* Write queue head before read futex */
-	/*
-	 * Wake-up any waiting defer thread.
-	 */
-	wake_up_defer();
-}
-
-void *thr_defer(void *args)
-{
-	for (;;) {
-		pthread_testcancel();
-		/*
-		 * "Be green". Don't wake up the CPU if there is no RCU work
-		 * to perform whatsoever. Aims at saving laptop battery life by
-		 * leaving the processor in sleep state when idle.
-		 */
-		wait_defer();
-		/* Sleeping after wait_defer to let many callbacks enqueue */
-		poll(NULL,0,100);	/* wait for 100ms */
-		rcu_defer_barrier();
-	}
-
-	return NULL;
-}
-
-/*
- * library wrappers to be used by non-LGPL compatible source code.
- */
-
-void defer_rcu(void (*fct)(void *p), void *p)
-{
-	_defer_rcu(fct, p);
-}
-
-static void start_defer_thread(void)
-{
-	int ret;
-
-	ret = pthread_create(&tid_defer, NULL, thr_defer, NULL);
-	assert(!ret);
-}
-
-static void stop_defer_thread(void)
-{
-	int ret;
-	void *tret;
-
-	pthread_cancel(tid_defer);
-	wake_up_defer();
-	ret = pthread_join(tid_defer, &tret);
-	assert(!ret);
-}
-
-int rcu_defer_register_thread(void)
-{
-	int was_empty;
-
-	assert(defer_queue.last_head == 0);
-	assert(defer_queue.q == NULL);
-	defer_queue.q = malloc(sizeof(void *) * DEFER_QUEUE_SIZE);
-	if (!defer_queue.q)
-		return -ENOMEM;
-
-	mutex_lock(&defer_thread_mutex);
-	mutex_lock(&rcu_defer_mutex);
-	was_empty = cds_list_empty(&registry);
-	cds_list_add(&defer_queue.list, &registry);
-	mutex_unlock(&rcu_defer_mutex);
-
-	if (was_empty)
-		start_defer_thread();
-	mutex_unlock(&defer_thread_mutex);
-	return 0;
-}
-
-void rcu_defer_unregister_thread(void)
-{
-	int is_empty;
-
-	mutex_lock(&defer_thread_mutex);
-	mutex_lock(&rcu_defer_mutex);
-	cds_list_del(&defer_queue.list);
-	_rcu_defer_barrier_thread();
-	free(defer_queue.q);
-	defer_queue.q = NULL;
-	is_empty = cds_list_empty(&registry);
-	mutex_unlock(&rcu_defer_mutex);
-
-	if (is_empty)
-		stop_defer_thread();
-	mutex_unlock(&defer_thread_mutex);
-}
-
-void rcu_defer_exit(void)
-{
-	assert(cds_list_empty(&registry));
-}
diff --git a/urcu-map.h b/urcu-map.h
index eccaac2..93ac65c 100644
--- a/urcu-map.h
+++ b/urcu-map.h
@@ -34,6 +34,10 @@
 
 /* Mapping macros to allow multiple flavors in a single binary. */
 
+#if !defined(RCU_MEMBARRIER) && !defined(RCU_SIGNAL) && !defined(RCU_MB)
+#define RCU_MB
+#endif
+
 #ifdef RCU_MEMBARRIER
 
 #define rcu_read_lock			rcu_read_lock_memb
@@ -60,6 +64,12 @@
 #define free_all_cpu_call_rcu_data	free_all_cpu_call_rcu_data_memb
 #define call_rcu			call_rcu_memb
 
+#define defer_rcu			defer_rcu_memb
+#define rcu_defer_register_thread	rcu_defer_register_thread_memb
+#define rcu_defer_unregister_thread	rcu_defer_unregister_thread_memb
+#define	rcu_defer_barrier		rcu_defer_barrier_memb
+#define rcu_defer_barrier_thread	rcu_defer_barrier_thread_memb
+
 #elif defined(RCU_SIGNAL)
 
 #define rcu_read_lock			rcu_read_lock_sig
@@ -86,6 +96,12 @@
 #define free_all_cpu_call_rcu_data	free_all_cpu_call_rcu_data_sig
 #define call_rcu			call_rcu_sig
 
+#define defer_rcu			defer_rcu_sig
+#define rcu_defer_register_thread	rcu_defer_register_thread_sig
+#define rcu_defer_unregister_thread	rcu_defer_unregister_thread_sig
+#define	rcu_defer_barrier		rcu_defer_barrier_sig
+#define rcu_defer_barrier_thread	rcu_defer_barrier_thread_sig
+
 #elif defined(RCU_MB)
 
 #define rcu_read_lock			rcu_read_lock_mb
@@ -112,6 +128,16 @@
 #define free_all_cpu_call_rcu_data	free_all_cpu_call_rcu_data_mb
 #define call_rcu			call_rcu_mb
 
+#define defer_rcu			defer_rcu_mb
+#define rcu_defer_register_thread	rcu_defer_register_thread_mb
+#define rcu_defer_unregister_thread	rcu_defer_unregister_thread_mb
+#define	rcu_defer_barrier		rcu_defer_barrier_mb
+#define rcu_defer_barrier_thread	rcu_defer_barrier_thread_mb
+
+#else
+
+#error "Undefined selection"
+
 #endif
 
 #endif /* _URCU_MAP_H */
diff --git a/urcu-qsbr-map.h b/urcu-qsbr-map.h
index 2bce1b6..0d88d83 100644
--- a/urcu-qsbr-map.h
+++ b/urcu-qsbr-map.h
@@ -60,4 +60,10 @@
 #define create_all_cpu_call_rcu_data	create_all_cpu_call_rcu_data_qsbr
 #define call_rcu			call_rcu_qsbr
 
+#define defer_rcu			defer_rcu_qsbr
+#define rcu_defer_register_thread	rcu_defer_register_thread_qsbr
+#define rcu_defer_unregister_thread	rcu_defer_unregister_thread_qsbr
+#define	rcu_defer_barrier		rcu_defer_barrier_qsbr
+#define rcu_defer_barrier_thread	rcu_defer_barrier_thread_qsbr
+
 #endif /* _URCU_QSBR_MAP_H */
diff --git a/urcu-qsbr.c b/urcu-qsbr.c
index 8dcad33..cf8b5ce 100644
--- a/urcu-qsbr.c
+++ b/urcu-qsbr.c
@@ -334,3 +334,4 @@ void rcu_exit(void)
 }
 
 #include "urcu-call-rcu-impl.h"
+#include "urcu-defer-impl.h"
diff --git a/urcu-qsbr.h b/urcu-qsbr.h
index 7ef1bfe..a691c52 100644
--- a/urcu-qsbr.h
+++ b/urcu-qsbr.h
@@ -125,5 +125,6 @@ extern void rcu_unregister_thread(void);
 #endif
 
 #include "urcu-call-rcu.h"
+#include "urcu-defer.h"
 
 #endif /* _URCU_QSBR_H */
diff --git a/urcu.c b/urcu.c
index 4ee9e3b..d356f54 100644
--- a/urcu.c
+++ b/urcu.c
@@ -434,3 +434,4 @@ void rcu_exit(void)
 #endif /* #ifdef RCU_SIGNAL */
 
 #include "urcu-call-rcu-impl.h"
+#include "urcu-defer-impl.h"
diff --git a/urcu.h b/urcu.h
index 417e609..15c8c38 100644
--- a/urcu.h
+++ b/urcu.h
@@ -111,5 +111,6 @@ extern void rcu_init(void);
 #endif
 
 #include "urcu-call-rcu.h"
+#include "urcu-defer.h"
 
 #endif /* _URCU_H */
-- 
1.7.3.2

[ltt-dev] [PATCH RFC urcu 1/4] Provide pthread_atfork-friendly interfaces

[Mathieu Desnoyers]

* Paul E. McKenney (paulmck at linux.vnet.ibm.com) wrote:
> Provides call_rcu_before_fork() and call_rcu_after_fork_parent() to
> go with the existing call_rcu_after_fork_child().
> 
> Signed-off-by: Paul E. McKenney <paulmck at linux.vnet.ibm.com>
> ---
>  README          |    4 ++++
>  urcu-call-rcu.c |   29 ++++++++++++++++++++++++++++-
>  2 files changed, 32 insertions(+), 1 deletions(-)
> 
> diff --git a/README b/README
> index f7f0dec..56e98d7 100644
> --- a/README
> +++ b/README
> @@ -204,3 +204,7 @@ Interaction with fork()
>  	liburcu-bp, which is designed to handle fork() by calling
>  	rcu_bp_before_fork, rcu_bp_after_fork_parent and
>  	rcu_bp_after_fork_child.
> +
> +	Applications that use call_rcu() are required to invoke
> +	call_rcu_after_fork_child() from the child process after a
> +	successful fork() system call that is not followed by exec().

Is it possible that we should also mention the before fork and after
fork parent here ? If there is a reason why it is not needed, then we
should state this explicitly, because this is a little surprising.

Thanks,

Mathieu

> diff --git a/urcu-call-rcu.c b/urcu-call-rcu.c
> index bb56dbb..665f20c 100644
> --- a/urcu-call-rcu.c
> +++ b/urcu-call-rcu.c
> @@ -566,13 +566,40 @@ void free_all_cpu_call_rcu_data(void)
>  }
>  
>  /*
> + * Acquire the call_rcu_mutex in order to ensure that the child sees
> + * all of the call_rcu() data structures in a consistent state.
> + * Suitable for pthread_atfork() and friends.
> + */
> +void call_rcu_before_fork(void)
> +{
> +	call_rcu_lock(&call_rcu_mutex);
> +}
> +
> +/*
> + * Clean up call_rcu data structures in the parent of a successful fork()
> + * that is not followed by exec() in the child.  Suitable for
> + * pthread_atfork() and friends.
> + */
> +void call_rcu_after_fork_parent(void)
> +{
> +	call_rcu_unlock(&call_rcu_mutex);
> +}
> +
> +/*
>   * Clean up call_rcu data structures in the child of a successful fork()
> - * that is not followed by exec().
> + * that is not followed by exec().  Suitable for pthread_atfork() and
> + * friends.
>   */
>  void call_rcu_after_fork_child(void)
>  {
>  	struct call_rcu_data *crdp;
>  
> +	/* Re-initialize the mutex. */
> +	if (pthread_mutex_init(&call_rcu_mutex, NULL) != 0) {
> +		perror("pthread_mutex_init");
> +		exit(-1);
> +	}
> +
>  	/*
>  	 * Allocate a new default call_rcu_data structure in order
>  	 * to get a working call_rcu thread to go with it.
> -- 
> 1.7.3.2
> 

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com

[ltt-dev] [PATCH RFC urcu 2/4] Map symbols to allow multiple RCU flavors to be used in one binary

[Mathieu Desnoyers]

* Paul E. McKenney (paulmck at linux.vnet.ibm.com) wrote:
> Probably need similar mapping for rcu_defer().  Definitely need
> backwards-compatibility mapping for programs compiled against
> old versions of the library.

Either that or we bump the version to 0.6.x ? Otherwise, we'll have to
keep tons of .so around just to do the compatibility layer for older
linking behavior.

Thoughts ?

Mathieu

> 
> Signed-off-by: Paul E. McKenney <paulmck at linux.vnet.ibm.com>
> ---
>  Makefile.am          |    3 +-
>  tests/Makefile.am    |   33 ++--
>  tests/rcutorture.h   |    1 -
>  tests/urcutorture.c  |   13 +-
>  urcu-bp-map.h        |   61 +++++
>  urcu-bp.c            |    4 +
>  urcu-bp.h            |    8 +-
>  urcu-call-rcu-impl.h |  618 +++++++++++++++++++++++++++++++++++++++++++++++++
>  urcu-call-rcu.c      |  620 --------------------------------------------------
>  urcu-map.h           |  117 ++++++++++
>  urcu-qsbr-map.h      |   63 +++++
>  urcu-qsbr.c          |   36 ++--
>  urcu-qsbr.h          |   18 +-
>  urcu.c               |    5 +
>  urcu.h               |   20 ++-
>  15 files changed, 945 insertions(+), 675 deletions(-)
>  create mode 100644 urcu-bp-map.h
>  create mode 100644 urcu-call-rcu-impl.h
>  delete mode 100644 urcu-call-rcu.c
>  create mode 100644 urcu-map.h
>  create mode 100644 urcu-qsbr-map.h
> 
> diff --git a/Makefile.am b/Makefile.am
> index 7956e7e..ef3bfef 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -30,7 +30,7 @@ COMPAT+=compat_futex.c
>  endif
>  
>  lib_LTLIBRARIES = liburcu.la liburcu-qsbr.la liburcu-mb.la liburcu-signal.la \
> -		  liburcu-bp.la liburcu-defer.la liburcu-call.la \
> +		  liburcu-bp.la liburcu-defer.la \
>  		  libwfqueue.la libwfstack.la librculfqueue.la librculfstack.la
>  
>  liburcu_la_SOURCES = urcu.c urcu-pointer.c $(COMPAT)
> @@ -45,7 +45,6 @@ liburcu_signal_la_CFLAGS = -DRCU_SIGNAL
>  
>  liburcu_bp_la_SOURCES = urcu-bp.c urcu-pointer.c $(COMPAT)
>  
> -liburcu_call_la_SOURCES = urcu-call-rcu.c $(COMPAT)
>  liburcu_defer_la_SOURCES = urcu-defer.c $(COMPAT)
>  
>  libwfqueue_la_SOURCES = wfqueue.c $(COMPAT)
> diff --git a/tests/Makefile.am b/tests/Makefile.am
> index 3c025a4..8dacb11 100644
> --- a/tests/Makefile.am
> +++ b/tests/Makefile.am
> @@ -28,21 +28,20 @@ if COMPAT_FUTEX
>  COMPAT+=$(top_srcdir)/compat_futex.c
>  endif
>  
> -URCU=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT)
> -URCU_QSBR=$(top_srcdir)/urcu-qsbr.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT)
> +URCU=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
> +URCU_QSBR=$(top_srcdir)/urcu-qsbr.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
>  # URCU_MB uses urcu.c but -DRCU_MB must be defined
> -URCU_MB=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT)
> +URCU_MB=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
>  # URCU_SIGNAL uses urcu.c but -DRCU_SIGNAL must be defined
> -URCU_SIGNAL=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT)
> -URCU_BP=$(top_srcdir)/urcu-bp.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT)
> -URCU_DEFER=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-defer.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT)
> +URCU_SIGNAL=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
> +URCU_BP=$(top_srcdir)/urcu-bp.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
> +URCU_DEFER=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-defer.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
>  
>  URCU_LIB=$(top_builddir)/liburcu.la
>  URCU_QSBR_LIB=$(top_builddir)/liburcu-qsbr.la
>  URCU_MB_LIB=$(top_builddir)/liburcu-mb.la
>  URCU_SIGNAL_LIB=$(top_builddir)/liburcu-signal.la
>  URCU_BP_LIB=$(top_builddir)/liburcu-bp.la
> -URCU_CALL_LIB=$(top_builddir)/liburcu-call.la
>  WFQUEUE_LIB=$(top_builddir)/libwfqueue.la
>  WFSTACK_LIB=$(top_builddir)/libwfstack.la
>  RCULFQUEUE_LIB=$(top_builddir)/librculfqueue.la
> @@ -95,24 +94,24 @@ test_perthreadlock_SOURCES = test_perthreadlock.c $(URCU_SIGNAL)
>  
>  
>  rcutorture_urcu_SOURCES = urcutorture.c
> -rcutorture_urcu_CFLAGS = -DTORTURE_URCU $(AM_CFLAGS)
> -rcutorture_urcu_LDADD = $(URCU) $(URCU_CALL_LIB) $(WFQUEUE_LIB)
> +rcutorture_urcu_CFLAGS = -DRCU_MEMBARRIER $(AM_CFLAGS)
> +rcutorture_urcu_LDADD = $(URCU) $(WFQUEUE_LIB)
>  
>  rcutorture_urcu_mb_SOURCES = urcutorture.c
> -rcutorture_urcu_mb_CFLAGS = -DTORTURE_URCU_MB $(AM_CFLAGS)
> -rcutorture_urcu_mb_LDADD = $(URCU_MB_LIB) $(URCU_CALL_LIB) $(WFQUEUE_LIB)
> +rcutorture_urcu_mb_CFLAGS = -DRCU_MB $(AM_CFLAGS)
> +rcutorture_urcu_mb_LDADD = $(URCU_MB_LIB) $(WFQUEUE_LIB)
>  
>  rcutorture_qsbr_SOURCES = urcutorture.c
> -rcutorture_qsbr_CFLAGS = -DTORTURE_QSBR $(AM_CFLAGS)
> -rcutorture_qsbr_LDADD = $(URCU_QSBR_LIB) $(URCU_CALL_LIB) $(WFQUEUE_LIB)
> +rcutorture_qsbr_CFLAGS = -DRCU_QSBR $(AM_CFLAGS)
> +rcutorture_qsbr_LDADD = $(URCU_QSBR_LIB) $(WFQUEUE_LIB)
>  
>  rcutorture_urcu_signal_SOURCES = urcutorture.c
> -rcutorture_urcu_signal_CFLAGS = -DTORTURE_URCU_SIGNAL $(AM_CFLAGS)
> -rcutorture_urcu_signal_LDADD = $(URCU_SIGNAL_LIB) $(URCU_CALL_LIB) $(WFQUEUE_LIB)
> +rcutorture_urcu_signal_CFLAGS = -DRCU_SIGNAL $(AM_CFLAGS)
> +rcutorture_urcu_signal_LDADD = $(URCU_SIGNAL_LIB) $(WFQUEUE_LIB)
>  
>  rcutorture_urcu_bp_SOURCES = urcutorture.c
> -rcutorture_urcu_bp_CFLAGS = -DTORTURE_URCU_BP $(AM_CFLAGS)
> -rcutorture_urcu_bp_LDADD = $(URCU_BP_LIB) $(URCU_CALL_LIB) $(WFQUEUE_LIB)
> +rcutorture_urcu_bp_CFLAGS = -DRCU_BP $(AM_CFLAGS)
> +rcutorture_urcu_bp_LDADD = $(URCU_BP_LIB) $(WFQUEUE_LIB)
>  
>  test_mutex_SOURCES = test_mutex.c $(URCU)
>  
> diff --git a/tests/rcutorture.h b/tests/rcutorture.h
> index 66fdd7f..aba74b0 100644
> --- a/tests/rcutorture.h
> +++ b/tests/rcutorture.h
> @@ -66,7 +66,6 @@
>   */
>  
>  #include <stdlib.h>
> -#include "../urcu-call-rcu.h"
>  
>  DEFINE_PER_THREAD(long long, n_reads_pt);
>  DEFINE_PER_THREAD(long long, n_updates_pt);
> diff --git a/tests/urcutorture.c b/tests/urcutorture.c
> index 63fa386..a098d87 100644
> --- a/tests/urcutorture.c
> +++ b/tests/urcutorture.c
> @@ -8,22 +8,19 @@
>  #include "api.h"
>  #define _LGPL_SOURCE
>  
> -#ifdef TORTURE_RCU_MEMBARRIER
> -#define RCU_MEMBARRIER
> +#ifdef RCU_MEMBARRIER
>  #include <urcu.h>
>  #endif
> -#ifdef TORTURE_URCU_SIGNAL
> -#define RCU_SIGNAL
> +#ifdef RCU_SIGNAL
>  #include <urcu.h>
>  #endif
> -#ifdef TORTURE_URCU_MB
> -#define RCU_MB
> +#ifdef RCU_MB
>  #include <urcu.h>
>  #endif
> -#ifdef TORTURE_QSBR
> +#ifdef RCU_QSBR
>  #include <urcu-qsbr.h>
>  #endif
> -#ifdef TORTURE_URCU_BP
> +#ifdef RCU_BP
>  #include <urcu-bp.h>
>  #endif
>  
> diff --git a/urcu-bp-map.h b/urcu-bp-map.h
> new file mode 100644
> index 0000000..6321802
> --- /dev/null
> +++ b/urcu-bp-map.h
> @@ -0,0 +1,61 @@
> +#ifndef _URCU_BP_MAP_H
> +#define _URCU_BP_MAP_H
> +
> +/*
> + * urcu-map.h
> + *
> + * Userspace RCU header -- name mapping to allow multiple flavors to be
> + * used in the same executable.
> + *
> + * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> + * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
> + *
> + * LGPL-compatible code should include this header with :
> + *
> + * #define _LGPL_SOURCE
> + * #include <urcu.h>
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> + *
> + * IBM's contributions to this file may be relicensed under LGPLv2 or later.
> + */
> +
> +/* Mapping macros to allow multiple flavors in a single binary. */
> +
> +#define rcu_read_lock			rcu_read_lock_bp
> +#define _rcu_read_lock			_rcu_read_lock_bp
> +#define rcu_read_unlock			rcu_read_unlock_bp
> +#define _rcu_read_unlock		_rcu_read_unlock_bp
> +#define rcu_register_thread		rcu_register_thread_bp
> +#define rcu_unregister_thread		rcu_unregister_thread_bp
> +#define rcu_init			rcu_init_bp
> +#define rcu_exit			rcu_exit_bp
> +#define synchronize_rcu			synchronize_rcu_bp
> +#define rcu_reader			rcu_reader_bp
> +#define rcu_gp_ctr			rcu_gp_ctr_bp
> +
> +#define get_cpu_call_rcu_data		get_cpu_call_rcu_data_bp
> +#define get_call_rcu_thread		get_call_rcu_thread_bp
> +#define create_call_rcu_data		create_call_rcu_data_bp
> +#define set_cpu_call_rcu_data		set_cpu_call_rcu_data_bp
> +#define get_default_call_rcu_data	get_default_call_rcu_data_bp
> +#define get_call_rcu_data		get_call_rcu_data_bp
> +#define get_thread_call_rcu_data	get_thread_call_rcu_data_bp
> +#define set_thread_call_rcu_data	set_thread_call_rcu_data_bp
> +#define create_all_cpu_call_rcu_data	create_all_cpu_call_rcu_data_bp
> +#define free_all_cpu_call_rcu_data	free_all_cpu_call_rcu_data_bp
> +#define call_rcu			call_rcu_bp
> +
> +#endif /* _URCU_BP_MAP_H */
> diff --git a/urcu-bp.c b/urcu-bp.c
> index 04bb675..5474f9f 100644
> --- a/urcu-bp.c
> +++ b/urcu-bp.c
> @@ -35,6 +35,8 @@
>  #include <unistd.h>
>  #include <sys/mman.h>
>  
> +#include "urcu-bp-map.h"
> +
>  #include "urcu-bp-static.h"
>  /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
>  #include "urcu-bp.h"
> @@ -375,3 +377,5 @@ void rcu_bp_after_fork_child(void)
>  	ret = pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
>  	assert(!ret);
>  }
> +
> +#include "urcu-call-rcu-impl.h"
> diff --git a/urcu-bp.h b/urcu-bp.h
> index d92fbd1..fdf885c 100644
> --- a/urcu-bp.h
> +++ b/urcu-bp.h
> @@ -46,6 +46,8 @@
>  extern "C" {
>  #endif
>  
> +#include "urcu-bp-map.h"
> +
>  /*
>   * Important !
>   *
> @@ -69,8 +71,8 @@ extern "C" {
>   *
>   * Mark the beginning and end of a read-side critical section.
>   */
> -#define rcu_read_lock()		_rcu_read_lock()
> -#define rcu_read_unlock()	_rcu_read_unlock()
> +#define rcu_read_lock_bp()		_rcu_read_lock()
> +#define rcu_read_unlock_bp()		_rcu_read_unlock()
>  
>  #else /* !_LGPL_SOURCE */
>  
> @@ -115,4 +117,6 @@ static inline void rcu_init(void)
>  }
>  #endif
>  
> +#include "urcu-call-rcu.h"
> +
>  #endif /* _URCU_BP_H */
> diff --git a/urcu-call-rcu-impl.h b/urcu-call-rcu-impl.h
> new file mode 100644
> index 0000000..68dbbdd
> --- /dev/null
> +++ b/urcu-call-rcu-impl.h
> @@ -0,0 +1,618 @@
> +/*
> + * urcu-call-rcu.c
> + *
> + * Userspace RCU library - batch memory reclamation with kernel API
> + *
> + * Copyright (c) 2010 Paul E. McKenney <paulmck at linux.vnet.ibm.com>
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> + */
> +
> +#include <stdio.h>
> +#include <pthread.h>
> +#include <signal.h>
> +#include <assert.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <errno.h>
> +#include <poll.h>
> +#include <sys/time.h>
> +#include <syscall.h>
> +#include <unistd.h>
> +
> +#include "config.h"
> +#include "urcu/wfqueue.h"
> +#include "urcu-call-rcu.h"
> +#include "urcu-pointer.h"
> +#include "urcu/list.h"
> +
> +/* Data structure that identifies a call_rcu thread. */
> +
> +struct call_rcu_data {
> +	struct cds_wfq_queue cbs;
> +	unsigned long flags;
> +	pthread_mutex_t mtx;
> +	pthread_cond_t cond;
> +	unsigned long qlen;
> +	pthread_t tid;
> +	struct cds_list_head list;
> +} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
> +
> +/*
> + * List of all call_rcu_data structures to keep valgrind happy.
> + * Protected by call_rcu_mutex.
> + */
> +
> +CDS_LIST_HEAD(call_rcu_data_list);
> +
> +/* Link a thread using call_rcu() to its call_rcu thread. */
> +
> +static __thread struct call_rcu_data *thread_call_rcu_data;
> +
> +/* Guard call_rcu thread creation. */
> +
> +static pthread_mutex_t call_rcu_mutex = PTHREAD_MUTEX_INITIALIZER;
> +
> +/* If a given thread does not have its own call_rcu thread, this is default. */
> +
> +static struct call_rcu_data *default_call_rcu_data;
> +
> +/*
> + * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are
> + * available, then we can have call_rcu threads assigned to individual
> + * CPUs rather than only to specific threads.
> + */
> +
> +#if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF)
> +
> +/*
> + * Pointer to array of pointers to per-CPU call_rcu_data structures
> + * and # CPUs.
> + */
> +
> +static struct call_rcu_data **per_cpu_call_rcu_data;
> +static long maxcpus;
> +
> +/* Allocate the array if it has not already been allocated. */
> +
> +static void alloc_cpu_call_rcu_data(void)
> +{
> +	struct call_rcu_data **p;
> +	static int warned = 0;
> +
> +	if (maxcpus != 0)
> +		return;
> +	maxcpus = sysconf(_SC_NPROCESSORS_CONF);
> +	if (maxcpus <= 0) {
> +		return;
> +	}
> +	p = malloc(maxcpus * sizeof(*per_cpu_call_rcu_data));
> +	if (p != NULL) {
> +		memset(p, '\0', maxcpus * sizeof(*per_cpu_call_rcu_data));
> +		per_cpu_call_rcu_data = p;
> +	} else {
> +		if (!warned) {
> +			fprintf(stderr, "[error] liburcu: unable to allocate per-CPU pointer array\n");
> +		}
> +		warned = 1;
> +	}
> +}
> +
> +#else /* #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */
> +
> +static const struct call_rcu_data **per_cpu_call_rcu_data = NULL;
> +static const long maxcpus = -1;
> +
> +static void alloc_cpu_call_rcu_data(void)
> +{
> +}
> +
> +static int sched_getcpu(void)
> +{
> +	return -1;
> +}
> +
> +#endif /* #else #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */
> +
> +/* Acquire the specified pthread mutex. */
> +
> +static void call_rcu_lock(pthread_mutex_t *pmp)
> +{
> +	if (pthread_mutex_lock(pmp) != 0) {
> +		perror("pthread_mutex_lock");
> +		exit(-1);
> +	}
> +}
> +
> +/* Release the specified pthread mutex. */
> +
> +static void call_rcu_unlock(pthread_mutex_t *pmp)
> +{
> +	if (pthread_mutex_unlock(pmp) != 0) {
> +		perror("pthread_mutex_unlock");
> +		exit(-1);
> +	}
> +}
> +
> +/* This is the code run by each call_rcu thread. */
> +
> +static void *call_rcu_thread(void *arg)
> +{
> +	unsigned long cbcount;
> +	struct cds_wfq_node *cbs;
> +	struct cds_wfq_node **cbs_tail;
> +	struct call_rcu_data *crdp = (struct call_rcu_data *)arg;
> +	struct rcu_head *rhp;
> +
> +	thread_call_rcu_data = crdp;
> +	for (;;) {
> +		if (&crdp->cbs.head != _CMM_LOAD_SHARED(crdp->cbs.tail)) {
> +			while ((cbs = _CMM_LOAD_SHARED(crdp->cbs.head)) == NULL)
> +				poll(NULL, 0, 1);
> +			_CMM_STORE_SHARED(crdp->cbs.head, NULL);
> +			cbs_tail = (struct cds_wfq_node **)
> +				uatomic_xchg(&crdp->cbs.tail, &crdp->cbs.head);
> +			synchronize_rcu();
> +			cbcount = 0;
> +			do {
> +				while (cbs->next == NULL &&
> +				       &cbs->next != cbs_tail)
> +				       	poll(NULL, 0, 1);
> +				if (cbs == &crdp->cbs.dummy) {
> +					cbs = cbs->next;
> +					continue;
> +				}
> +				rhp = (struct rcu_head *)cbs;
> +				cbs = cbs->next;
> +				rhp->func(rhp);
> +				cbcount++;
> +			} while (cbs != NULL);
> +			uatomic_sub(&crdp->qlen, cbcount);
> +		}
> +		if (crdp->flags & URCU_CALL_RCU_STOP)
> +			break;
> +		if (crdp->flags & URCU_CALL_RCU_RT)
> +			poll(NULL, 0, 10);
> +		else {
> +			call_rcu_lock(&crdp->mtx);
> +			_CMM_STORE_SHARED(crdp->flags,
> +				     crdp->flags & ~URCU_CALL_RCU_RUNNING);
> +			if (&crdp->cbs.head ==
> +			    _CMM_LOAD_SHARED(crdp->cbs.tail) &&
> +			    pthread_cond_wait(&crdp->cond, &crdp->mtx) != 0) {
> +				perror("pthread_cond_wait");
> +				exit(-1);
> +			}
> +			_CMM_STORE_SHARED(crdp->flags,
> +				     crdp->flags | URCU_CALL_RCU_RUNNING);
> +			poll(NULL, 0, 10);
> +			call_rcu_unlock(&crdp->mtx);
> +		}
> +	}
> +	call_rcu_lock(&crdp->mtx);
> +	crdp->flags |= URCU_CALL_RCU_STOPPED;
> +	call_rcu_unlock(&crdp->mtx);
> +	return NULL;
> +}
> +
> +/*
> + * Create both a call_rcu thread and the corresponding call_rcu_data
> + * structure, linking the structure in as specified.  Caller must hold
> + * call_rcu_mutex.
> + */
> +
> +static void call_rcu_data_init(struct call_rcu_data **crdpp,
> +			       unsigned long flags)
> +{
> +	struct call_rcu_data *crdp;
> +
> +	crdp = malloc(sizeof(*crdp));
> +	if (crdp == NULL) {
> +		fprintf(stderr, "Out of memory.\n");
> +		exit(-1);
> +	}
> +	memset(crdp, '\0', sizeof(*crdp));
> +	cds_wfq_init(&crdp->cbs);
> +	crdp->qlen = 0;
> +	if (pthread_mutex_init(&crdp->mtx, NULL) != 0) {
> +		perror("pthread_mutex_init");
> +		exit(-1);
> +	}
> +	if (pthread_cond_init(&crdp->cond, NULL) != 0) {
> +		perror("pthread_cond_init");
> +		exit(-1);
> +	}
> +	crdp->flags = flags | URCU_CALL_RCU_RUNNING;
> +	cds_list_add(&crdp->list, &call_rcu_data_list);
> +	cmm_smp_mb();  /* Structure initialized before pointer is planted. */
> +	*crdpp = crdp;
> +	if (pthread_create(&crdp->tid, NULL, call_rcu_thread, crdp) != 0) {
> +		perror("pthread_create");
> +		exit(-1);
> +	}
> +}
> +
> +/*
> + * Return a pointer to the call_rcu_data structure for the specified
> + * CPU, returning NULL if there is none.  We cannot automatically
> + * created it because the platform we are running on might not define
> + * sched_getcpu().
> + */
> +
> +struct call_rcu_data *get_cpu_call_rcu_data(int cpu)
> +{
> +	static int warned = 0;
> +
> +	if (per_cpu_call_rcu_data == NULL)
> +		return NULL;
> +	if (!warned && maxcpus > 0 && (cpu < 0 || maxcpus <= cpu)) {
> +		fprintf(stderr, "[error] liburcu: get CPU # out of range\n");
> +		warned = 1;
> +	}
> +	if (cpu < 0 || maxcpus <= cpu)
> +		return NULL;
> +	return per_cpu_call_rcu_data[cpu];
> +}
> +
> +/*
> + * Return the tid corresponding to the call_rcu thread whose
> + * call_rcu_data structure is specified.
> + */
> +
> +pthread_t get_call_rcu_thread(struct call_rcu_data *crdp)
> +{
> +	return crdp->tid;
> +}
> +
> +/*
> + * Create a call_rcu_data structure (with thread) and return a pointer.
> + */
> +
> +static struct call_rcu_data *__create_call_rcu_data(unsigned long flags)
> +{
> +	struct call_rcu_data *crdp;
> +
> +	call_rcu_data_init(&crdp, flags);
> +	return crdp;
> +}
> +
> +struct call_rcu_data *create_call_rcu_data(unsigned long flags)
> +{
> +	struct call_rcu_data *crdp;
> +
> +	call_rcu_lock(&call_rcu_mutex);
> +	crdp = __create_call_rcu_data(flags);
> +	call_rcu_unlock(&call_rcu_mutex);
> +	return crdp;
> +}
> +
> +/*
> + * Set the specified CPU to use the specified call_rcu_data structure.
> + *
> + * Use NULL to remove a CPU's call_rcu_data structure, but it is
> + * the caller's responsibility to dispose of the removed structure.
> + * Use get_cpu_call_rcu_data() to obtain a pointer to the old structure
> + * (prior to NULLing it out, of course).
> + */
> +
> +int set_cpu_call_rcu_data(int cpu, struct call_rcu_data *crdp)
> +{
> +	int warned = 0;
> +
> +	call_rcu_lock(&call_rcu_mutex);
> +	if (cpu < 0 || maxcpus <= cpu) {
> +		if (!warned) {
> +			fprintf(stderr, "[error] liburcu: set CPU # out of range\n");
> +			warned = 1;
> +		}
> +		call_rcu_unlock(&call_rcu_mutex);
> +		errno = EINVAL;
> +		return -EINVAL;
> +	}
> +	alloc_cpu_call_rcu_data();
> +	call_rcu_unlock(&call_rcu_mutex);
> +	if (per_cpu_call_rcu_data == NULL) {
> +		errno = ENOMEM;
> +		return -ENOMEM;
> +	}
> +	per_cpu_call_rcu_data[cpu] = crdp;
> +	return 0;
> +}
> +
> +/*
> + * Return a pointer to the default call_rcu_data structure, creating
> + * one if need be.  Because we never free call_rcu_data structures,
> + * we don't need to be in an RCU read-side critical section.
> + */
> +
> +struct call_rcu_data *get_default_call_rcu_data(void)
> +{
> +	if (default_call_rcu_data != NULL)
> +		return rcu_dereference(default_call_rcu_data);
> +	call_rcu_lock(&call_rcu_mutex);
> +	if (default_call_rcu_data != NULL) {
> +		call_rcu_unlock(&call_rcu_mutex);
> +		return default_call_rcu_data;
> +	}
> +	call_rcu_data_init(&default_call_rcu_data, 0);
> +	call_rcu_unlock(&call_rcu_mutex);
> +	return default_call_rcu_data;
> +}
> +
> +/*
> + * Return the call_rcu_data structure that applies to the currently
> + * running thread.  Any call_rcu_data structure assigned specifically
> + * to this thread has first priority, followed by any call_rcu_data
> + * structure assigned to the CPU on which the thread is running,
> + * followed by the default call_rcu_data structure.  If there is not
> + * yet a default call_rcu_data structure, one will be created.
> + */
> +struct call_rcu_data *get_call_rcu_data(void)
> +{
> +	int curcpu;
> +	static int warned = 0;
> +
> +	if (thread_call_rcu_data != NULL)
> +		return thread_call_rcu_data;
> +	if (maxcpus <= 0)
> +		return get_default_call_rcu_data();
> +	curcpu = sched_getcpu();
> +	if (!warned && (curcpu < 0 || maxcpus <= curcpu)) {
> +		fprintf(stderr, "[error] liburcu: gcrd CPU # out of range\n");
> +		warned = 1;
> +	}
> +	if (curcpu >= 0 && maxcpus > curcpu &&
> +	    per_cpu_call_rcu_data != NULL &&
> +	    per_cpu_call_rcu_data[curcpu] != NULL)
> +	    	return per_cpu_call_rcu_data[curcpu];
> +	return get_default_call_rcu_data();
> +}
> +
> +/*
> + * Return a pointer to this task's call_rcu_data if there is one.
> + */
> +
> +struct call_rcu_data *get_thread_call_rcu_data(void)
> +{
> +	return thread_call_rcu_data;
> +}
> +
> +/*
> + * Set this task's call_rcu_data structure as specified, regardless
> + * of whether or not this task already had one.  (This allows switching
> + * to and from real-time call_rcu threads, for example.)
> + *
> + * Use NULL to remove a thread's call_rcu_data structure, but it is
> + * the caller's responsibility to dispose of the removed structure.
> + * Use get_thread_call_rcu_data() to obtain a pointer to the old structure
> + * (prior to NULLing it out, of course).
> + */
> +
> +void set_thread_call_rcu_data(struct call_rcu_data *crdp)
> +{
> +	thread_call_rcu_data = crdp;
> +}
> +
> +/*
> + * Create a separate call_rcu thread for each CPU.  This does not
> + * replace a pre-existing call_rcu thread -- use the set_cpu_call_rcu_data()
> + * function if you want that behavior.
> + */
> +
> +int create_all_cpu_call_rcu_data(unsigned long flags)
> +{
> +	int i;
> +	struct call_rcu_data *crdp;
> +	int ret;
> +
> +	call_rcu_lock(&call_rcu_mutex);
> +	alloc_cpu_call_rcu_data();
> +	call_rcu_unlock(&call_rcu_mutex);
> +	if (maxcpus <= 0) {
> +		errno = EINVAL;
> +		return -EINVAL;
> +	}
> +	if (per_cpu_call_rcu_data == NULL) {
> +		errno = ENOMEM;
> +		return -ENOMEM;
> +	}
> +	for (i = 0; i < maxcpus; i++) {
> +		call_rcu_lock(&call_rcu_mutex);
> +		if (get_cpu_call_rcu_data(i)) {
> +			call_rcu_unlock(&call_rcu_mutex);
> +			continue;
> +		}
> +		crdp = __create_call_rcu_data(flags);
> +		if (crdp == NULL) {
> +			call_rcu_unlock(&call_rcu_mutex);
> +			errno = ENOMEM;
> +			return -ENOMEM;
> +		}
> +		call_rcu_unlock(&call_rcu_mutex);
> +		if ((ret = set_cpu_call_rcu_data(i, crdp)) != 0) {
> +			/* FIXME: Leaks crdp for now. */
> +			return ret; /* Can happen on race. */
> +		}
> +	}
> +	return 0;
> +}
> +
> +/*
> + * Wake up the call_rcu thread corresponding to the specified
> + * call_rcu_data structure.
> + */
> +static void wake_call_rcu_thread(struct call_rcu_data *crdp)
> +{
> +	if (!(_CMM_LOAD_SHARED(crdp->flags) & URCU_CALL_RCU_RT)) {
> +		call_rcu_lock(&crdp->mtx);
> +		if (!(_CMM_LOAD_SHARED(crdp->flags) & URCU_CALL_RCU_RUNNING)) {
> +			if (pthread_cond_signal(&crdp->cond) != 0) {
> +				perror("pthread_cond_signal");
> +				exit(-1);
> +			}
> +		}
> +		call_rcu_unlock(&crdp->mtx);
> +	}
> +}
> +
> +/*
> + * Schedule a function to be invoked after a following grace period.
> + * This is the only function that must be called -- the others are
> + * only present to allow applications to tune their use of RCU for
> + * maximum performance.
> + *
> + * Note that unless a call_rcu thread has not already been created,
> + * the first invocation of call_rcu() will create one.  So, if you
> + * need the first invocation of call_rcu() to be fast, make sure
> + * to create a call_rcu thread first.  One way to accomplish this is
> + * "get_call_rcu_data();", and another is create_all_cpu_call_rcu_data().
> + */
> +
> +void call_rcu(struct rcu_head *head,
> +	      void (*func)(struct rcu_head *head))
> +{
> +	struct call_rcu_data *crdp;
> +
> +	cds_wfq_node_init(&head->next);
> +	head->func = func;
> +	crdp = get_call_rcu_data();
> +	cds_wfq_enqueue(&crdp->cbs, &head->next);
> +	uatomic_inc(&crdp->qlen);
> +	wake_call_rcu_thread(crdp);
> +}
> +
> +/*
> + * Free up the specified call_rcu_data structure, terminating the
> + * associated call_rcu thread.  The caller must have previously
> + * removed the call_rcu_data structure from per-thread or per-CPU
> + * usage.  For example, set_cpu_call_rcu_data(cpu, NULL) for per-CPU
> + * call_rcu_data structures or set_thread_call_rcu_data(NULL) for
> + * per-thread call_rcu_data structures.
> + *
> + * We silently refuse to free up the default call_rcu_data structure
> + * because that is where we put any leftover callbacks.  Note that
> + * the possibility of self-spawning callbacks makes it impossible
> + * to execute all the callbacks in finite time without putting any
> + * newly spawned callbacks somewhere else.  The "somewhere else" of
> + * last resort is the default call_rcu_data structure.
> + *
> + * We also silently refuse to free NULL pointers.  This simplifies
> + * the calling code.
> + */
> +void call_rcu_data_free(struct call_rcu_data *crdp)
> +{
> +	struct cds_wfq_node *cbs;
> +	struct cds_wfq_node **cbs_tail;
> +	struct cds_wfq_node **cbs_endprev;
> +
> +	if (crdp == NULL || crdp == default_call_rcu_data) {
> +		return;
> +	}
> +	if ((crdp->flags & URCU_CALL_RCU_STOPPED) == 0) {
> +		call_rcu_lock(&crdp->mtx);
> +		crdp->flags |= URCU_CALL_RCU_STOP;
> +		call_rcu_unlock(&crdp->mtx);
> +		wake_call_rcu_thread(crdp);
> +		while ((crdp->flags & URCU_CALL_RCU_STOPPED) == 0)
> +			poll(NULL, 0, 1);
> +	}
> +	if (&crdp->cbs.head != _CMM_LOAD_SHARED(crdp->cbs.tail)) {
> +		while ((cbs = _CMM_LOAD_SHARED(crdp->cbs.head)) == NULL)
> +			poll(NULL, 0, 1);
> +		_CMM_STORE_SHARED(crdp->cbs.head, NULL);
> +		cbs_tail = (struct cds_wfq_node **)
> +			uatomic_xchg(&crdp->cbs.tail, &crdp->cbs.head);
> +		cbs_endprev = (struct cds_wfq_node **)
> +			uatomic_xchg(&default_call_rcu_data, cbs_tail);
> +		*cbs_endprev = cbs;
> +		uatomic_add(&default_call_rcu_data->qlen,
> +			    uatomic_read(&crdp->qlen));
> +		cds_list_del(&crdp->list);
> +		free(crdp);
> +	}
> +}
> +
> +/*
> + * Clean up all the per-CPU call_rcu threads.
> + */
> +void free_all_cpu_call_rcu_data(void)
> +{
> +	int cpu;
> +	struct call_rcu_data *crdp;
> +
> +	if (maxcpus <= 0)
> +		return;
> +	for (cpu = 0; cpu < maxcpus; cpu++) {
> +		crdp = get_cpu_call_rcu_data(cpu);
> +		if (crdp == NULL)
> +			continue;
> +		set_cpu_call_rcu_data(cpu, NULL);
> +		call_rcu_data_free(crdp);
> +	}
> +}
> +
> +/*
> + * Acquire the call_rcu_mutex in order to ensure that the child sees
> + * all of the call_rcu() data structures in a consistent state.
> + * Suitable for pthread_atfork() and friends.
> + */
> +void call_rcu_before_fork(void)
> +{
> +	call_rcu_lock(&call_rcu_mutex);
> +}
> +
> +/*
> + * Clean up call_rcu data structures in the parent of a successful fork()
> + * that is not followed by exec() in the child.  Suitable for
> + * pthread_atfork() and friends.
> + */
> +void call_rcu_after_fork_parent(void)
> +{
> +	call_rcu_unlock(&call_rcu_mutex);
> +}
> +
> +/*
> + * Clean up call_rcu data structures in the child of a successful fork()
> + * that is not followed by exec().  Suitable for pthread_atfork() and
> + * friends.
> + */
> +void call_rcu_after_fork_child(void)
> +{
> +	struct call_rcu_data *crdp;
> +
> +	/* Re-initialize the mutex. */
> +	if (pthread_mutex_init(&call_rcu_mutex, NULL) != 0) {
> +		perror("pthread_mutex_init");
> +		exit(-1);
> +	}
> +
> +	/*
> +	 * Allocate a new default call_rcu_data structure in order
> +	 * to get a working call_rcu thread to go with it.
> +	 */
> +	default_call_rcu_data = NULL;
> +	(void)get_default_call_rcu_data();
> +
> +	/* Dispose of all of the rest of the call_rcu_data structures. */
> +	while (call_rcu_data_list.next != call_rcu_data_list.prev) {
> +		crdp = cds_list_entry(call_rcu_data_list.prev,
> +				      struct call_rcu_data, list);
> +		if (crdp == default_call_rcu_data)
> +			crdp = cds_list_entry(crdp->list.prev,
> +					      struct call_rcu_data, list);
> +		crdp->flags = URCU_CALL_RCU_STOPPED;
> +		call_rcu_data_free(crdp);
> +	}
> +}
> diff --git a/urcu-call-rcu.c b/urcu-call-rcu.c
> deleted file mode 100644
> index 665f20c..0000000
> --- a/urcu-call-rcu.c
> +++ /dev/null
> @@ -1,620 +0,0 @@
> -/*
> - * urcu-call-rcu.c
> - *
> - * Userspace RCU library - batch memory reclamation with kernel API
> - *
> - * Copyright (c) 2010 Paul E. McKenney <paulmck at linux.vnet.ibm.com>
> - *
> - * This library is free software; you can redistribute it and/or
> - * modify it under the terms of the GNU Lesser General Public
> - * License as published by the Free Software Foundation; either
> - * version 2.1 of the License, or (at your option) any later version.
> - *
> - * This library is distributed in the hope that it will be useful,
> - * but WITHOUT ANY WARRANTY; without even the implied warranty of
> - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> - * Lesser General Public License for more details.
> - *
> - * You should have received a copy of the GNU Lesser General Public
> - * License along with this library; if not, write to the Free Software
> - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> - */
> -
> -#include <stdio.h>
> -#include <pthread.h>
> -#include <signal.h>
> -#include <assert.h>
> -#include <stdlib.h>
> -#include <string.h>
> -#include <errno.h>
> -#include <poll.h>
> -#include <sys/time.h>
> -#include <syscall.h>
> -#include <unistd.h>
> -
> -#include "config.h"
> -#include "urcu/wfqueue.h"
> -#include "urcu-call-rcu.h"
> -#include "urcu-pointer.h"
> -#include "urcu/list.h"
> -
> -/* Data structure that identifies a call_rcu thread. */
> -
> -struct call_rcu_data {
> -	struct cds_wfq_queue cbs;
> -	unsigned long flags;
> -	pthread_mutex_t mtx;
> -	pthread_cond_t cond;
> -	unsigned long qlen;
> -	pthread_t tid;
> -	struct cds_list_head list;
> -} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
> -
> -/*
> - * List of all call_rcu_data structures to keep valgrind happy.
> - * Protected by call_rcu_mutex.
> - */
> -
> -CDS_LIST_HEAD(call_rcu_data_list);
> -
> -/* Link a thread using call_rcu() to its call_rcu thread. */
> -
> -static __thread struct call_rcu_data *thread_call_rcu_data;
> -
> -/* Guard call_rcu thread creation. */
> -
> -static pthread_mutex_t call_rcu_mutex = PTHREAD_MUTEX_INITIALIZER;
> -
> -/* If a given thread does not have its own call_rcu thread, this is default. */
> -
> -static struct call_rcu_data *default_call_rcu_data;
> -
> -extern void synchronize_rcu(void);
> -
> -/*
> - * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are
> - * available, then we can have call_rcu threads assigned to individual
> - * CPUs rather than only to specific threads.
> - */
> -
> -#if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF)
> -
> -/*
> - * Pointer to array of pointers to per-CPU call_rcu_data structures
> - * and # CPUs.
> - */
> -
> -static struct call_rcu_data **per_cpu_call_rcu_data;
> -static long maxcpus;
> -
> -/* Allocate the array if it has not already been allocated. */
> -
> -static void alloc_cpu_call_rcu_data(void)
> -{
> -	struct call_rcu_data **p;
> -	static int warned = 0;
> -
> -	if (maxcpus != 0)
> -		return;
> -	maxcpus = sysconf(_SC_NPROCESSORS_CONF);
> -	if (maxcpus <= 0) {
> -		return;
> -	}
> -	p = malloc(maxcpus * sizeof(*per_cpu_call_rcu_data));
> -	if (p != NULL) {
> -		memset(p, '\0', maxcpus * sizeof(*per_cpu_call_rcu_data));
> -		per_cpu_call_rcu_data = p;
> -	} else {
> -		if (!warned) {
> -			fprintf(stderr, "[error] liburcu: unable to allocate per-CPU pointer array\n");
> -		}
> -		warned = 1;
> -	}
> -}
> -
> -#else /* #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */
> -
> -static const struct call_rcu_data **per_cpu_call_rcu_data = NULL;
> -static const long maxcpus = -1;
> -
> -static void alloc_cpu_call_rcu_data(void)
> -{
> -}
> -
> -static int sched_getcpu(void)
> -{
> -	return -1;
> -}
> -
> -#endif /* #else #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */
> -
> -/* Acquire the specified pthread mutex. */
> -
> -static void call_rcu_lock(pthread_mutex_t *pmp)
> -{
> -	if (pthread_mutex_lock(pmp) != 0) {
> -		perror("pthread_mutex_lock");
> -		exit(-1);
> -	}
> -}
> -
> -/* Release the specified pthread mutex. */
> -
> -static void call_rcu_unlock(pthread_mutex_t *pmp)
> -{
> -	if (pthread_mutex_unlock(pmp) != 0) {
> -		perror("pthread_mutex_unlock");
> -		exit(-1);
> -	}
> -}
> -
> -/* This is the code run by each call_rcu thread. */
> -
> -static void *call_rcu_thread(void *arg)
> -{
> -	unsigned long cbcount;
> -	struct cds_wfq_node *cbs;
> -	struct cds_wfq_node **cbs_tail;
> -	struct call_rcu_data *crdp = (struct call_rcu_data *)arg;
> -	struct rcu_head *rhp;
> -
> -	thread_call_rcu_data = crdp;
> -	for (;;) {
> -		if (&crdp->cbs.head != _CMM_LOAD_SHARED(crdp->cbs.tail)) {
> -			while ((cbs = _CMM_LOAD_SHARED(crdp->cbs.head)) == NULL)
> -				poll(NULL, 0, 1);
> -			_CMM_STORE_SHARED(crdp->cbs.head, NULL);
> -			cbs_tail = (struct cds_wfq_node **)
> -				uatomic_xchg(&crdp->cbs.tail, &crdp->cbs.head);
> -			synchronize_rcu();
> -			cbcount = 0;
> -			do {
> -				while (cbs->next == NULL &&
> -				       &cbs->next != cbs_tail)
> -				       	poll(NULL, 0, 1);
> -				if (cbs == &crdp->cbs.dummy) {
> -					cbs = cbs->next;
> -					continue;
> -				}
> -				rhp = (struct rcu_head *)cbs;
> -				cbs = cbs->next;
> -				rhp->func(rhp);
> -				cbcount++;
> -			} while (cbs != NULL);
> -			uatomic_sub(&crdp->qlen, cbcount);
> -		}
> -		if (crdp->flags & URCU_CALL_RCU_STOP)
> -			break;
> -		if (crdp->flags & URCU_CALL_RCU_RT)
> -			poll(NULL, 0, 10);
> -		else {
> -			call_rcu_lock(&crdp->mtx);
> -			_CMM_STORE_SHARED(crdp->flags,
> -				     crdp->flags & ~URCU_CALL_RCU_RUNNING);
> -			if (&crdp->cbs.head ==
> -			    _CMM_LOAD_SHARED(crdp->cbs.tail) &&
> -			    pthread_cond_wait(&crdp->cond, &crdp->mtx) != 0) {
> -				perror("pthread_cond_wait");
> -				exit(-1);
> -			}
> -			_CMM_STORE_SHARED(crdp->flags,
> -				     crdp->flags | URCU_CALL_RCU_RUNNING);
> -			poll(NULL, 0, 10);
> -			call_rcu_unlock(&crdp->mtx);
> -		}
> -	}
> -	call_rcu_lock(&crdp->mtx);
> -	crdp->flags |= URCU_CALL_RCU_STOPPED;
> -	call_rcu_unlock(&crdp->mtx);
> -	return NULL;
> -}
> -
> -/*
> - * Create both a call_rcu thread and the corresponding call_rcu_data
> - * structure, linking the structure in as specified.  Caller must hold
> - * call_rcu_mutex.
> - */
> -
> -static void call_rcu_data_init(struct call_rcu_data **crdpp,
> -			       unsigned long flags)
> -{
> -	struct call_rcu_data *crdp;
> -
> -	crdp = malloc(sizeof(*crdp));
> -	if (crdp == NULL) {
> -		fprintf(stderr, "Out of memory.\n");
> -		exit(-1);
> -	}
> -	memset(crdp, '\0', sizeof(*crdp));
> -	cds_wfq_init(&crdp->cbs);
> -	crdp->qlen = 0;
> -	if (pthread_mutex_init(&crdp->mtx, NULL) != 0) {
> -		perror("pthread_mutex_init");
> -		exit(-1);
> -	}
> -	if (pthread_cond_init(&crdp->cond, NULL) != 0) {
> -		perror("pthread_cond_init");
> -		exit(-1);
> -	}
> -	crdp->flags = flags | URCU_CALL_RCU_RUNNING;
> -	cds_list_add(&crdp->list, &call_rcu_data_list);
> -	cmm_smp_mb();  /* Structure initialized before pointer is planted. */
> -	*crdpp = crdp;
> -	if (pthread_create(&crdp->tid, NULL, call_rcu_thread, crdp) != 0) {
> -		perror("pthread_create");
> -		exit(-1);
> -	}
> -}
> -
> -/*
> - * Return a pointer to the call_rcu_data structure for the specified
> - * CPU, returning NULL if there is none.  We cannot automatically
> - * created it because the platform we are running on might not define
> - * sched_getcpu().
> - */
> -
> -struct call_rcu_data *get_cpu_call_rcu_data(int cpu)
> -{
> -	static int warned = 0;
> -
> -	if (per_cpu_call_rcu_data == NULL)
> -		return NULL;
> -	if (!warned && maxcpus > 0 && (cpu < 0 || maxcpus <= cpu)) {
> -		fprintf(stderr, "[error] liburcu: get CPU # out of range\n");
> -		warned = 1;
> -	}
> -	if (cpu < 0 || maxcpus <= cpu)
> -		return NULL;
> -	return per_cpu_call_rcu_data[cpu];
> -}
> -
> -/*
> - * Return the tid corresponding to the call_rcu thread whose
> - * call_rcu_data structure is specified.
> - */
> -
> -pthread_t get_call_rcu_thread(struct call_rcu_data *crdp)
> -{
> -	return crdp->tid;
> -}
> -
> -/*
> - * Create a call_rcu_data structure (with thread) and return a pointer.
> - */
> -
> -static struct call_rcu_data *__create_call_rcu_data(unsigned long flags)
> -{
> -	struct call_rcu_data *crdp;
> -
> -	call_rcu_data_init(&crdp, flags);
> -	return crdp;
> -}
> -
> -struct call_rcu_data *create_call_rcu_data(unsigned long flags)
> -{
> -	struct call_rcu_data *crdp;
> -
> -	call_rcu_lock(&call_rcu_mutex);
> -	crdp = __create_call_rcu_data(flags);
> -	call_rcu_unlock(&call_rcu_mutex);
> -	return crdp;
> -}
> -
> -/*
> - * Set the specified CPU to use the specified call_rcu_data structure.
> - *
> - * Use NULL to remove a CPU's call_rcu_data structure, but it is
> - * the caller's responsibility to dispose of the removed structure.
> - * Use get_cpu_call_rcu_data() to obtain a pointer to the old structure
> - * (prior to NULLing it out, of course).
> - */
> -
> -int set_cpu_call_rcu_data(int cpu, struct call_rcu_data *crdp)
> -{
> -	int warned = 0;
> -
> -	call_rcu_lock(&call_rcu_mutex);
> -	if (cpu < 0 || maxcpus <= cpu) {
> -		if (!warned) {
> -			fprintf(stderr, "[error] liburcu: set CPU # out of range\n");
> -			warned = 1;
> -		}
> -		call_rcu_unlock(&call_rcu_mutex);
> -		errno = EINVAL;
> -		return -EINVAL;
> -	}
> -	alloc_cpu_call_rcu_data();
> -	call_rcu_unlock(&call_rcu_mutex);
> -	if (per_cpu_call_rcu_data == NULL) {
> -		errno = ENOMEM;
> -		return -ENOMEM;
> -	}
> -	per_cpu_call_rcu_data[cpu] = crdp;
> -	return 0;
> -}
> -
> -/*
> - * Return a pointer to the default call_rcu_data structure, creating
> - * one if need be.  Because we never free call_rcu_data structures,
> - * we don't need to be in an RCU read-side critical section.
> - */
> -
> -struct call_rcu_data *get_default_call_rcu_data(void)
> -{
> -	if (default_call_rcu_data != NULL)
> -		return rcu_dereference(default_call_rcu_data);
> -	call_rcu_lock(&call_rcu_mutex);
> -	if (default_call_rcu_data != NULL) {
> -		call_rcu_unlock(&call_rcu_mutex);
> -		return default_call_rcu_data;
> -	}
> -	call_rcu_data_init(&default_call_rcu_data, 0);
> -	call_rcu_unlock(&call_rcu_mutex);
> -	return default_call_rcu_data;
> -}
> -
> -/*
> - * Return the call_rcu_data structure that applies to the currently
> - * running thread.  Any call_rcu_data structure assigned specifically
> - * to this thread has first priority, followed by any call_rcu_data
> - * structure assigned to the CPU on which the thread is running,
> - * followed by the default call_rcu_data structure.  If there is not
> - * yet a default call_rcu_data structure, one will be created.
> - */
> -struct call_rcu_data *get_call_rcu_data(void)
> -{
> -	int curcpu;
> -	static int warned = 0;
> -
> -	if (thread_call_rcu_data != NULL)
> -		return thread_call_rcu_data;
> -	if (maxcpus <= 0)
> -		return get_default_call_rcu_data();
> -	curcpu = sched_getcpu();
> -	if (!warned && (curcpu < 0 || maxcpus <= curcpu)) {
> -		fprintf(stderr, "[error] liburcu: gcrd CPU # out of range\n");
> -		warned = 1;
> -	}
> -	if (curcpu >= 0 && maxcpus > curcpu &&
> -	    per_cpu_call_rcu_data != NULL &&
> -	    per_cpu_call_rcu_data[curcpu] != NULL)
> -	    	return per_cpu_call_rcu_data[curcpu];
> -	return get_default_call_rcu_data();
> -}
> -
> -/*
> - * Return a pointer to this task's call_rcu_data if there is one.
> - */
> -
> -struct call_rcu_data *get_thread_call_rcu_data(void)
> -{
> -	return thread_call_rcu_data;
> -}
> -
> -/*
> - * Set this task's call_rcu_data structure as specified, regardless
> - * of whether or not this task already had one.  (This allows switching
> - * to and from real-time call_rcu threads, for example.)
> - *
> - * Use NULL to remove a thread's call_rcu_data structure, but it is
> - * the caller's responsibility to dispose of the removed structure.
> - * Use get_thread_call_rcu_data() to obtain a pointer to the old structure
> - * (prior to NULLing it out, of course).
> - */
> -
> -void set_thread_call_rcu_data(struct call_rcu_data *crdp)
> -{
> -	thread_call_rcu_data = crdp;
> -}
> -
> -/*
> - * Create a separate call_rcu thread for each CPU.  This does not
> - * replace a pre-existing call_rcu thread -- use the set_cpu_call_rcu_data()
> - * function if you want that behavior.
> - */
> -
> -int create_all_cpu_call_rcu_data(unsigned long flags)
> -{
> -	int i;
> -	struct call_rcu_data *crdp;
> -	int ret;
> -
> -	call_rcu_lock(&call_rcu_mutex);
> -	alloc_cpu_call_rcu_data();
> -	call_rcu_unlock(&call_rcu_mutex);
> -	if (maxcpus <= 0) {
> -		errno = EINVAL;
> -		return -EINVAL;
> -	}
> -	if (per_cpu_call_rcu_data == NULL) {
> -		errno = ENOMEM;
> -		return -ENOMEM;
> -	}
> -	for (i = 0; i < maxcpus; i++) {
> -		call_rcu_lock(&call_rcu_mutex);
> -		if (get_cpu_call_rcu_data(i)) {
> -			call_rcu_unlock(&call_rcu_mutex);
> -			continue;
> -		}
> -		crdp = __create_call_rcu_data(flags);
> -		if (crdp == NULL) {
> -			call_rcu_unlock(&call_rcu_mutex);
> -			errno = ENOMEM;
> -			return -ENOMEM;
> -		}
> -		call_rcu_unlock(&call_rcu_mutex);
> -		if ((ret = set_cpu_call_rcu_data(i, crdp)) != 0) {
> -			/* FIXME: Leaks crdp for now. */
> -			return ret; /* Can happen on race. */
> -		}
> -	}
> -	return 0;
> -}
> -
> -/*
> - * Wake up the call_rcu thread corresponding to the specified
> - * call_rcu_data structure.
> - */
> -static void wake_call_rcu_thread(struct call_rcu_data *crdp)
> -{
> -	if (!(_CMM_LOAD_SHARED(crdp->flags) & URCU_CALL_RCU_RT)) {
> -		call_rcu_lock(&crdp->mtx);
> -		if (!(_CMM_LOAD_SHARED(crdp->flags) & URCU_CALL_RCU_RUNNING)) {
> -			if (pthread_cond_signal(&crdp->cond) != 0) {
> -				perror("pthread_cond_signal");
> -				exit(-1);
> -			}
> -		}
> -		call_rcu_unlock(&crdp->mtx);
> -	}
> -}
> -
> -/*
> - * Schedule a function to be invoked after a following grace period.
> - * This is the only function that must be called -- the others are
> - * only present to allow applications to tune their use of RCU for
> - * maximum performance.
> - *
> - * Note that unless a call_rcu thread has not already been created,
> - * the first invocation of call_rcu() will create one.  So, if you
> - * need the first invocation of call_rcu() to be fast, make sure
> - * to create a call_rcu thread first.  One way to accomplish this is
> - * "get_call_rcu_data();", and another is create_all_cpu_call_rcu_data().
> - */
> -
> -void call_rcu(struct rcu_head *head,
> -	      void (*func)(struct rcu_head *head))
> -{
> -	struct call_rcu_data *crdp;
> -
> -	cds_wfq_node_init(&head->next);
> -	head->func = func;
> -	crdp = get_call_rcu_data();
> -	cds_wfq_enqueue(&crdp->cbs, &head->next);
> -	uatomic_inc(&crdp->qlen);
> -	wake_call_rcu_thread(crdp);
> -}
> -
> -/*
> - * Free up the specified call_rcu_data structure, terminating the
> - * associated call_rcu thread.  The caller must have previously
> - * removed the call_rcu_data structure from per-thread or per-CPU
> - * usage.  For example, set_cpu_call_rcu_data(cpu, NULL) for per-CPU
> - * call_rcu_data structures or set_thread_call_rcu_data(NULL) for
> - * per-thread call_rcu_data structures.
> - *
> - * We silently refuse to free up the default call_rcu_data structure
> - * because that is where we put any leftover callbacks.  Note that
> - * the possibility of self-spawning callbacks makes it impossible
> - * to execute all the callbacks in finite time without putting any
> - * newly spawned callbacks somewhere else.  The "somewhere else" of
> - * last resort is the default call_rcu_data structure.
> - *
> - * We also silently refuse to free NULL pointers.  This simplifies
> - * the calling code.
> - */
> -void call_rcu_data_free(struct call_rcu_data *crdp)
> -{
> -	struct cds_wfq_node *cbs;
> -	struct cds_wfq_node **cbs_tail;
> -	struct cds_wfq_node **cbs_endprev;
> -
> -	if (crdp == NULL || crdp == default_call_rcu_data) {
> -		return;
> -	}
> -	if ((crdp->flags & URCU_CALL_RCU_STOPPED) == 0) {
> -		call_rcu_lock(&crdp->mtx);
> -		crdp->flags |= URCU_CALL_RCU_STOP;
> -		call_rcu_unlock(&crdp->mtx);
> -		wake_call_rcu_thread(crdp);
> -		while ((crdp->flags & URCU_CALL_RCU_STOPPED) == 0)
> -			poll(NULL, 0, 1);
> -	}
> -	if (&crdp->cbs.head != _CMM_LOAD_SHARED(crdp->cbs.tail)) {
> -		while ((cbs = _CMM_LOAD_SHARED(crdp->cbs.head)) == NULL)
> -			poll(NULL, 0, 1);
> -		_CMM_STORE_SHARED(crdp->cbs.head, NULL);
> -		cbs_tail = (struct cds_wfq_node **)
> -			uatomic_xchg(&crdp->cbs.tail, &crdp->cbs.head);
> -		cbs_endprev = (struct cds_wfq_node **)
> -			uatomic_xchg(&default_call_rcu_data, cbs_tail);
> -		*cbs_endprev = cbs;
> -		uatomic_add(&default_call_rcu_data->qlen,
> -			    uatomic_read(&crdp->qlen));
> -		cds_list_del(&crdp->list);
> -		free(crdp);
> -	}
> -}
> -
> -/*
> - * Clean up all the per-CPU call_rcu threads.
> - */
> -void free_all_cpu_call_rcu_data(void)
> -{
> -	int cpu;
> -	struct call_rcu_data *crdp;
> -
> -	if (maxcpus <= 0)
> -		return;
> -	for (cpu = 0; cpu < maxcpus; cpu++) {
> -		crdp = get_cpu_call_rcu_data(cpu);
> -		if (crdp == NULL)
> -			continue;
> -		set_cpu_call_rcu_data(cpu, NULL);
> -		call_rcu_data_free(crdp);
> -	}
> -}
> -
> -/*
> - * Acquire the call_rcu_mutex in order to ensure that the child sees
> - * all of the call_rcu() data structures in a consistent state.
> - * Suitable for pthread_atfork() and friends.
> - */
> -void call_rcu_before_fork(void)
> -{
> -	call_rcu_lock(&call_rcu_mutex);
> -}
> -
> -/*
> - * Clean up call_rcu data structures in the parent of a successful fork()
> - * that is not followed by exec() in the child.  Suitable for
> - * pthread_atfork() and friends.
> - */
> -void call_rcu_after_fork_parent(void)
> -{
> -	call_rcu_unlock(&call_rcu_mutex);
> -}
> -
> -/*
> - * Clean up call_rcu data structures in the child of a successful fork()
> - * that is not followed by exec().  Suitable for pthread_atfork() and
> - * friends.
> - */
> -void call_rcu_after_fork_child(void)
> -{
> -	struct call_rcu_data *crdp;
> -
> -	/* Re-initialize the mutex. */
> -	if (pthread_mutex_init(&call_rcu_mutex, NULL) != 0) {
> -		perror("pthread_mutex_init");
> -		exit(-1);
> -	}
> -
> -	/*
> -	 * Allocate a new default call_rcu_data structure in order
> -	 * to get a working call_rcu thread to go with it.
> -	 */
> -	default_call_rcu_data = NULL;
> -	(void)get_default_call_rcu_data();
> -
> -	/* Dispose of all of the rest of the call_rcu_data structures. */
> -	while (call_rcu_data_list.next != call_rcu_data_list.prev) {
> -		crdp = cds_list_entry(call_rcu_data_list.prev,
> -				      struct call_rcu_data, list);
> -		if (crdp == default_call_rcu_data)
> -			crdp = cds_list_entry(crdp->list.prev,
> -					      struct call_rcu_data, list);
> -		crdp->flags = URCU_CALL_RCU_STOPPED;
> -		call_rcu_data_free(crdp);
> -	}
> -}
> diff --git a/urcu-map.h b/urcu-map.h
> new file mode 100644
> index 0000000..eccaac2
> --- /dev/null
> +++ b/urcu-map.h
> @@ -0,0 +1,117 @@
> +#ifndef _URCU_MAP_H
> +#define _URCU_MAP_H
> +
> +/*
> + * urcu-map.h
> + *
> + * Userspace RCU header -- name mapping to allow multiple flavors to be
> + * used in the same executable.
> + *
> + * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> + * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
> + *
> + * LGPL-compatible code should include this header with :
> + *
> + * #define _LGPL_SOURCE
> + * #include <urcu.h>
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> + *
> + * IBM's contributions to this file may be relicensed under LGPLv2 or later.
> + */
> +
> +/* Mapping macros to allow multiple flavors in a single binary. */
> +
> +#ifdef RCU_MEMBARRIER
> +
> +#define rcu_read_lock			rcu_read_lock_memb
> +#define _rcu_read_lock			_rcu_read_lock_memb
> +#define rcu_read_unlock			rcu_read_unlock_memb
> +#define _rcu_read_unlock		_rcu_read_unlock_memb
> +#define rcu_register_thread		rcu_register_thread_memb
> +#define rcu_unregister_thread		rcu_unregister_thread_memb
> +#define rcu_init			rcu_init_memb
> +#define rcu_exit			rcu_exit_memb
> +#define synchronize_rcu			synchronize_rcu_memb
> +#define rcu_reader			rcu_reader_memb
> +#define rcu_gp_ctr			rcu_gp_ctr_memb
> +
> +#define get_cpu_call_rcu_data		get_cpu_call_rcu_data_memb
> +#define get_call_rcu_thread		get_call_rcu_thread_memb
> +#define create_call_rcu_data		create_call_rcu_data_memb
> +#define set_cpu_call_rcu_data		set_cpu_call_rcu_data_memb
> +#define get_default_call_rcu_data	get_default_call_rcu_data_memb
> +#define get_call_rcu_data		get_call_rcu_data_memb
> +#define get_thread_call_rcu_data	get_thread_call_rcu_data_memb
> +#define set_thread_call_rcu_data	set_thread_call_rcu_data_memb
> +#define create_all_cpu_call_rcu_data	create_all_cpu_call_rcu_data_memb
> +#define free_all_cpu_call_rcu_data	free_all_cpu_call_rcu_data_memb
> +#define call_rcu			call_rcu_memb
> +
> +#elif defined(RCU_SIGNAL)
> +
> +#define rcu_read_lock			rcu_read_lock_sig
> +#define _rcu_read_lock			_rcu_read_lock_sig
> +#define rcu_read_unlock			rcu_read_unlock_sig
> +#define _rcu_read_unlock		_rcu_read_unlock_sig
> +#define rcu_register_thread		rcu_register_thread_sig
> +#define rcu_unregister_thread		rcu_unregister_thread_sig
> +#define rcu_init			rcu_init_sig
> +#define rcu_exit			rcu_exit_sig
> +#define synchronize_rcu			synchronize_rcu_sig
> +#define rcu_reader			rcu_reader_sig
> +#define rcu_gp_ctr			rcu_gp_ctr_sig
> +
> +#define get_cpu_call_rcu_data		get_cpu_call_rcu_data_sig
> +#define get_call_rcu_thread		get_call_rcu_thread_sig
> +#define create_call_rcu_data		create_call_rcu_data_sig
> +#define set_cpu_call_rcu_data		set_cpu_call_rcu_data_sig
> +#define get_default_call_rcu_data	get_default_call_rcu_data_sig
> +#define get_call_rcu_data		get_call_rcu_data_sig
> +#define get_thread_call_rcu_data	get_thread_call_rcu_data_sig
> +#define set_thread_call_rcu_data	set_thread_call_rcu_data_sig
> +#define create_all_cpu_call_rcu_data	create_all_cpu_call_rcu_data_sig
> +#define free_all_cpu_call_rcu_data	free_all_cpu_call_rcu_data_sig
> +#define call_rcu			call_rcu_sig
> +
> +#elif defined(RCU_MB)
> +
> +#define rcu_read_lock			rcu_read_lock_mb
> +#define _rcu_read_lock			_rcu_read_lock_mb
> +#define rcu_read_unlock			rcu_read_unlock_mb
> +#define _rcu_read_unlock		_rcu_read_unlock_mb
> +#define rcu_register_thread		rcu_register_thread_mb
> +#define rcu_unregister_thread		rcu_unregister_thread_mb
> +#define rcu_init			rcu_init_mb
> +#define rcu_exit			rcu_exit_mb
> +#define synchronize_rcu			synchronize_rcu_mb
> +#define rcu_reader			rcu_reader_mb
> +#define rcu_gp_ctr			rcu_gp_ctr_mb
> +
> +#define get_cpu_call_rcu_data		get_cpu_call_rcu_data_mb
> +#define get_call_rcu_thread		get_call_rcu_thread_mb
> +#define create_call_rcu_data		create_call_rcu_data_mb
> +#define set_cpu_call_rcu_data		set_cpu_call_rcu_data_mb
> +#define get_default_call_rcu_data	get_default_call_rcu_data_mb
> +#define get_call_rcu_data		get_call_rcu_data_mb
> +#define get_thread_call_rcu_data	get_thread_call_rcu_data_mb
> +#define set_thread_call_rcu_data	set_thread_call_rcu_data_mb
> +#define create_all_cpu_call_rcu_data	create_all_cpu_call_rcu_data_mb
> +#define free_all_cpu_call_rcu_data	free_all_cpu_call_rcu_data_mb
> +#define call_rcu			call_rcu_mb
> +
> +#endif
> +
> +#endif /* _URCU_MAP_H */
> diff --git a/urcu-qsbr-map.h b/urcu-qsbr-map.h
> new file mode 100644
> index 0000000..2bce1b6
> --- /dev/null
> +++ b/urcu-qsbr-map.h
> @@ -0,0 +1,63 @@
> +#ifndef _URCU_QSBR_MAP_H
> +#define _URCU_QSBR_MAP_H
> +
> +/*
> + * urcu-map.h
> + *
> + * Userspace RCU header -- name mapping to allow multiple flavors to be
> + * used in the same executable.
> + *
> + * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> + * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
> + *
> + * LGPL-compatible code should include this header with :
> + *
> + * #define _LGPL_SOURCE
> + * #include <urcu.h>
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> + *
> + * IBM's contributions to this file may be relicensed under LGPLv2 or later.
> + */
> +
> +/* Mapping macros to allow multiple flavors in a single binary. */
> +
> +#define rcu_read_lock			rcu_read_lock_qsbr
> +#define _rcu_read_lock			_rcu_read_lock_qsbr
> +#define rcu_read_unlock			rcu_read_unlock_qsbr
> +#define _rcu_read_unlock		_rcu_read_unlock_qsbr
> +#define rcu_quiescent_state		rcu_quiescent_state_qsbr
> +#define _rcu_quiescent_state		_rcu_quiescent_state_qsbr
> +#define rcu_thread_offline		rcu_thread_offline_qsbr
> +#define rcu_thread_online		rcu_thread_online_qsbr
> +#define rcu_register_thread		rcu_register_thread_qsbr
> +#define rcu_unregister_thread		rcu_unregister_thread_qsbr
> +#define rcu_exit			rcu_exit_qsbr
> +#define synchronize_rcu			synchronize_rcu_qsbr
> +#define rcu_reader			rcu_reader_qsbr
> +#define rcu_gp_ctr			rcu_gp_ctr_qsbr
> +
> +#define get_cpu_call_rcu_data		get_cpu_call_rcu_data_qsbr
> +#define get_call_rcu_thread		get_call_rcu_thread_qsbr
> +#define create_call_rcu_data		create_call_rcu_data_qsbr
> +#define set_cpu_call_rcu_data		set_cpu_call_rcu_data_qsbr
> +#define get_default_call_rcu_data	get_default_call_rcu_data_qsbr
> +#define get_call_rcu_data		get_call_rcu_data_qsbr
> +#define get_thread_call_rcu_data	get_thread_call_rcu_data_qsbr
> +#define set_thread_call_rcu_data	set_thread_call_rcu_data_qsbr
> +#define create_all_cpu_call_rcu_data	create_all_cpu_call_rcu_data_qsbr
> +#define call_rcu			call_rcu_qsbr
> +
> +#endif /* _URCU_QSBR_MAP_H */
> diff --git a/urcu-qsbr.c b/urcu-qsbr.c
> index 69effd5..8dcad33 100644
> --- a/urcu-qsbr.c
> +++ b/urcu-qsbr.c
> @@ -32,6 +32,8 @@
>  #include <errno.h>
>  #include <poll.h>
>  
> +#include "urcu-qsbr-map.h"
> +
>  #define BUILD_QSBR_LIB
>  #include "urcu-qsbr-static.h"
>  /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
> @@ -121,10 +123,11 @@ static void update_counter_and_wait(void)
>  #endif	/* !(CAA_BITS_PER_LONG < 64) */
>  
>  	/*
> -	 * Must commit rcu_gp_ctr update to memory before waiting for quiescent
> -	 * state. Failure to do so could result in the writer waiting forever
> -	 * while new readers are always accessing data (no progress). Enforce
> -	 * compiler-order of store to rcu_gp_ctr before load rcu_reader ctr.
> +	 * Must commit rcu_gp_ctr update to memory before waiting for
> +	 * quiescent state. Failure to do so could result in the writer
> +	 * waiting forever while new readers are always accessing data
> +	 * (no progress). Enforce compiler-order of store to rcu_gp_ctr
> +	 * before load rcu_reader ctr.
>  	 */
>  	cmm_barrier();
>  
> @@ -194,8 +197,8 @@ void synchronize_rcu(void)
>  
>  	/*
>  	 * Mark the writer thread offline to make sure we don't wait for
> -	 * our own quiescent state. This allows using synchronize_rcu() in
> -	 * threads registered as readers.
> +	 * our own quiescent state. This allows using synchronize_rcu()
> +	 * in threads registered as readers.
>  	 */
>  	if (was_online)
>  		CMM_STORE_SHARED(rcu_reader.ctr, 0);
> @@ -212,10 +215,11 @@ void synchronize_rcu(void)
>  
>  	/*
>  	 * Must finish waiting for quiescent state for parity 0 before
> -	 * committing next rcu_gp_ctr update to memory. Failure to do so could
> -	 * result in the writer waiting forever while new readers are always
> -	 * accessing data (no progress).  Enforce compiler-order of load
> -	 * rcu_reader ctr before store to rcu_gp_ctr.
> +	 * committing next rcu_gp_ctr update to memory. Failure to
> +	 * do so could result in the writer waiting forever while new
> +	 * readers are always accessing data (no progress).  Enforce
> +	 * compiler-order of load rcu_reader ctr before store to
> +	 * rcu_gp_ctr.
>  	 */
>  	cmm_barrier();
>  
> @@ -238,7 +242,8 @@ out:
>  	 * freed.
>  	 */
>  	if (was_online)
> -		_CMM_STORE_SHARED(rcu_reader.ctr, CMM_LOAD_SHARED(rcu_gp_ctr));
> +		_CMM_STORE_SHARED(rcu_reader.ctr,
> +				  CMM_LOAD_SHARED(rcu_gp_ctr));
>  	cmm_smp_mb();
>  }
>  #else /* !(CAA_BITS_PER_LONG < 64) */
> @@ -250,8 +255,8 @@ void synchronize_rcu(void)
>  
>  	/*
>  	 * Mark the writer thread offline to make sure we don't wait for
> -	 * our own quiescent state. This allows using synchronize_rcu() in
> -	 * threads registered as readers.
> +	 * our own quiescent state. This allows using synchronize_rcu()
> +	 * in threads registered as readers.
>  	 */
>  	cmm_smp_mb();
>  	if (was_online)
> @@ -265,7 +270,8 @@ out:
>  	mutex_unlock(&rcu_gp_lock);
>  
>  	if (was_online)
> -		_CMM_STORE_SHARED(rcu_reader.ctr, CMM_LOAD_SHARED(rcu_gp_ctr));
> +		_CMM_STORE_SHARED(rcu_reader.ctr,
> +				  CMM_LOAD_SHARED(rcu_gp_ctr));
>  	cmm_smp_mb();
>  }
>  #endif  /* !(CAA_BITS_PER_LONG < 64) */
> @@ -326,3 +332,5 @@ void rcu_exit(void)
>  {
>  	assert(cds_list_empty(&registry));
>  }
> +
> +#include "urcu-call-rcu-impl.h"
> diff --git a/urcu-qsbr.h b/urcu-qsbr.h
> index 116fd77..984d70c 100644
> --- a/urcu-qsbr.h
> +++ b/urcu-qsbr.h
> @@ -40,6 +40,8 @@
>  extern "C" {
>  #endif 
>  
> +#include "urcu-qsbr-map.h"
> +
>  /*
>   * Important !
>   *
> @@ -62,15 +64,15 @@ extern "C" {
>   * rcu_read_unlock()
>   *
>   * Mark the beginning and end of a read-side critical section.
> - * DON'T FORGET TO USE rcu_register_thread/rcu_unregister_thread() FOR EACH
> - * THREAD WITH READ-SIDE CRITICAL SECTION.
> + * DON'T FORGET TO USE rcu_register_thread/rcu_unregister_thread()
> + * FOR EACH THREAD WITH READ-SIDE CRITICAL SECTION.
>   */
> -#define rcu_read_lock()		_rcu_read_lock()
> -#define rcu_read_unlock()	_rcu_read_unlock()
> +#define rcu_read_lock_qsbr()		_rcu_read_lock()
> +#define rcu_read_unlock_qsbr()		_rcu_read_unlock()
>  
> -#define rcu_quiescent_state()	_rcu_quiescent_state()
> -#define rcu_thread_offline()	_rcu_thread_offline()
> -#define rcu_thread_online()	_rcu_thread_online()
> +#define rcu_quiescent_state_qsbr()	_rcu_quiescent_state()
> +#define rcu_thread_offline_qsbr()	_rcu_thread_offline()
> +#define rcu_thread_online_qsbr()	_rcu_thread_online()
>  
>  #else /* !_LGPL_SOURCE */
>  
> @@ -122,4 +124,6 @@ extern void rcu_unregister_thread(void);
>  }
>  #endif
>  
> +#include "urcu-call-rcu.h"
> +
>  #endif /* _URCU_QSBR_H */
> diff --git a/urcu.c b/urcu.c
> index e529ac0..4ee9e3b 100644
> --- a/urcu.c
> +++ b/urcu.c
> @@ -33,6 +33,8 @@
>  #include <errno.h>
>  #include <poll.h>
>  
> +#include "urcu-map.h"
> +
>  #include "urcu-static.h"
>  /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
>  #include "urcu.h"
> @@ -428,4 +430,7 @@ void rcu_exit(void)
>  	assert(act.sa_sigaction == sigrcu_handler);
>  	assert(cds_list_empty(&registry));
>  }
> +
>  #endif /* #ifdef RCU_SIGNAL */
> +
> +#include "urcu-call-rcu-impl.h"
> diff --git a/urcu.h b/urcu.h
> index c6c54e7..00d9b75 100644
> --- a/urcu.h
> +++ b/urcu.h
> @@ -43,12 +43,14 @@
>  extern "C" {
>  #endif 
>  
> +#include "urcu-map.h"
> +
>  /*
>   * Important !
>   *
>   * Each thread containing read-side critical sections must be registered
> - * with rcu_register_thread() before calling rcu_read_lock().
> - * rcu_unregister_thread() should be called before the thread exits.
> + * with rcu_register_thread_mb() before calling rcu_read_lock_mb().
> + * rcu_unregister_thread_mb() should be called before the thread exits.
>   */
>  
>  #ifdef _LGPL_SOURCE
> @@ -68,8 +70,16 @@ extern "C" {
>   * DON'T FORGET TO USE RCU_REGISTER/UNREGISTER_THREAD() FOR EACH THREAD WITH
>   * READ-SIDE CRITICAL SECTION.
>   */
> -#define rcu_read_lock()		_rcu_read_lock()
> -#define rcu_read_unlock()	_rcu_read_unlock()
> +#ifdef RCU_MEMBARRIER
> +#define rcu_read_lock_memb()		_rcu_read_lock()
> +#define rcu_read_unlock_memb()		_rcu_read_unlock()
> +#elif defined(RCU_SIGNAL)
> +#define rcu_read_lock_sig()		_rcu_read_lock()
> +#define rcu_read_unlock_sig()		_rcu_read_unlock()
> +#elif defined(RCU_MB)
> +#define rcu_read_lock_mb()		_rcu_read_lock()
> +#define rcu_read_unlock_mb()		_rcu_read_unlock()
> +#endif
>  
>  #else /* !_LGPL_SOURCE */
>  
> @@ -100,4 +110,6 @@ extern void rcu_init(void);
>  }
>  #endif
>  
> +#include "urcu-call-rcu.h"
> +
>  #endif /* _URCU_H */
> -- 
> 1.7.3.2
> 

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com

[ltt-dev] [PATCH RFC urcu 1/4] Provide pthread_atfork-friendly interfaces

[Mathieu Desnoyers]

* Mathieu Desnoyers (compudj at krystal.dyndns.org) wrote:
> * Paul E. McKenney (paulmck at linux.vnet.ibm.com) wrote:
> > Provides call_rcu_before_fork() and call_rcu_after_fork_parent() to
> > go with the existing call_rcu_after_fork_child().
> > 
> > Signed-off-by: Paul E. McKenney <paulmck at linux.vnet.ibm.com>
> > ---
> >  README          |    4 ++++
> >  urcu-call-rcu.c |   29 ++++++++++++++++++++++++++++-
> >  2 files changed, 32 insertions(+), 1 deletions(-)
> > 
> > diff --git a/README b/README
> > index f7f0dec..56e98d7 100644
> > --- a/README
> > +++ b/README
> > @@ -204,3 +204,7 @@ Interaction with fork()
> >  	liburcu-bp, which is designed to handle fork() by calling
> >  	rcu_bp_before_fork, rcu_bp_after_fork_parent and
> >  	rcu_bp_after_fork_child.
> > +
> > +	Applications that use call_rcu() are required to invoke
> > +	call_rcu_after_fork_child() from the child process after a
> > +	successful fork() system call that is not followed by exec().
> 
> Is it possible that we should also mention the before fork and after
> fork parent here ? If there is a reason why it is not needed, then we
> should state this explicitly, because this is a little surprising.

Please disregard this question, it looks like your patch 3/4 takes care
of it.

Thanks,

Mathieu

> 
> Thanks,
> 
> Mathieu
> 
> > diff --git a/urcu-call-rcu.c b/urcu-call-rcu.c
> > index bb56dbb..665f20c 100644
> > --- a/urcu-call-rcu.c
> > +++ b/urcu-call-rcu.c
> > @@ -566,13 +566,40 @@ void free_all_cpu_call_rcu_data(void)
> >  }
> >  
> >  /*
> > + * Acquire the call_rcu_mutex in order to ensure that the child sees
> > + * all of the call_rcu() data structures in a consistent state.
> > + * Suitable for pthread_atfork() and friends.
> > + */
> > +void call_rcu_before_fork(void)
> > +{
> > +	call_rcu_lock(&call_rcu_mutex);
> > +}
> > +
> > +/*
> > + * Clean up call_rcu data structures in the parent of a successful fork()
> > + * that is not followed by exec() in the child.  Suitable for
> > + * pthread_atfork() and friends.
> > + */
> > +void call_rcu_after_fork_parent(void)
> > +{
> > +	call_rcu_unlock(&call_rcu_mutex);
> > +}
> > +
> > +/*
> >   * Clean up call_rcu data structures in the child of a successful fork()
> > - * that is not followed by exec().
> > + * that is not followed by exec().  Suitable for pthread_atfork() and
> > + * friends.
> >   */
> >  void call_rcu_after_fork_child(void)
> >  {
> >  	struct call_rcu_data *crdp;
> >  
> > +	/* Re-initialize the mutex. */
> > +	if (pthread_mutex_init(&call_rcu_mutex, NULL) != 0) {
> > +		perror("pthread_mutex_init");
> > +		exit(-1);
> > +	}
> > +
> >  	/*
> >  	 * Allocate a new default call_rcu_data structure in order
> >  	 * to get a working call_rcu thread to go with it.
> > -- 
> > 1.7.3.2
> > 
> 
> -- 
> Mathieu Desnoyers
> Operating System Efficiency R&D Consultant
> EfficiOS Inc.
> http://www.efficios.com
> 
> _______________________________________________
> ltt-dev mailing list
> ltt-dev at lists.casi.polymtl.ca
> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
> 

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com

[ltt-dev] [rp] [PATCH RFC urcu 2/4] Map symbols to allow multiple RCU flavors to be used in one binary

[Paul E. McKenney]

On Wed, Apr 13, 2011 at 05:24:49PM -0400, Mathieu Desnoyers wrote:
> * Paul E. McKenney (paulmck at linux.vnet.ibm.com) wrote:
> > Probably need similar mapping for rcu_defer().  Definitely need
> > backwards-compatibility mapping for programs compiled against
> > old versions of the library.
> 
> Either that or we bump the version to 0.6.x ? Otherwise, we'll have to
> keep tons of .so around just to do the compatibility layer for older
> linking behavior.
> 
> Thoughts ?

I think that bumping the version makes a lot of sense -- people can always
download the old version.  Good point!!!

							Thanx, Paul

> Mathieu
> 
> > 
> > Signed-off-by: Paul E. McKenney <paulmck at linux.vnet.ibm.com>
> > ---
> >  Makefile.am          |    3 +-
> >  tests/Makefile.am    |   33 ++--
> >  tests/rcutorture.h   |    1 -
> >  tests/urcutorture.c  |   13 +-
> >  urcu-bp-map.h        |   61 +++++
> >  urcu-bp.c            |    4 +
> >  urcu-bp.h            |    8 +-
> >  urcu-call-rcu-impl.h |  618 +++++++++++++++++++++++++++++++++++++++++++++++++
> >  urcu-call-rcu.c      |  620 --------------------------------------------------
> >  urcu-map.h           |  117 ++++++++++
> >  urcu-qsbr-map.h      |   63 +++++
> >  urcu-qsbr.c          |   36 ++--
> >  urcu-qsbr.h          |   18 +-
> >  urcu.c               |    5 +
> >  urcu.h               |   20 ++-
> >  15 files changed, 945 insertions(+), 675 deletions(-)
> >  create mode 100644 urcu-bp-map.h
> >  create mode 100644 urcu-call-rcu-impl.h
> >  delete mode 100644 urcu-call-rcu.c
> >  create mode 100644 urcu-map.h
> >  create mode 100644 urcu-qsbr-map.h
> > 
> > diff --git a/Makefile.am b/Makefile.am
> > index 7956e7e..ef3bfef 100644
> > --- a/Makefile.am
> > +++ b/Makefile.am
> > @@ -30,7 +30,7 @@ COMPAT+=compat_futex.c
> >  endif
> >  
> >  lib_LTLIBRARIES = liburcu.la liburcu-qsbr.la liburcu-mb.la liburcu-signal.la \
> > -		  liburcu-bp.la liburcu-defer.la liburcu-call.la \
> > +		  liburcu-bp.la liburcu-defer.la \
> >  		  libwfqueue.la libwfstack.la librculfqueue.la librculfstack.la
> >  
> >  liburcu_la_SOURCES = urcu.c urcu-pointer.c $(COMPAT)
> > @@ -45,7 +45,6 @@ liburcu_signal_la_CFLAGS = -DRCU_SIGNAL
> >  
> >  liburcu_bp_la_SOURCES = urcu-bp.c urcu-pointer.c $(COMPAT)
> >  
> > -liburcu_call_la_SOURCES = urcu-call-rcu.c $(COMPAT)
> >  liburcu_defer_la_SOURCES = urcu-defer.c $(COMPAT)
> >  
> >  libwfqueue_la_SOURCES = wfqueue.c $(COMPAT)
> > diff --git a/tests/Makefile.am b/tests/Makefile.am
> > index 3c025a4..8dacb11 100644
> > --- a/tests/Makefile.am
> > +++ b/tests/Makefile.am
> > @@ -28,21 +28,20 @@ if COMPAT_FUTEX
> >  COMPAT+=$(top_srcdir)/compat_futex.c
> >  endif
> >  
> > -URCU=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT)
> > -URCU_QSBR=$(top_srcdir)/urcu-qsbr.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT)
> > +URCU=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
> > +URCU_QSBR=$(top_srcdir)/urcu-qsbr.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
> >  # URCU_MB uses urcu.c but -DRCU_MB must be defined
> > -URCU_MB=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT)
> > +URCU_MB=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
> >  # URCU_SIGNAL uses urcu.c but -DRCU_SIGNAL must be defined
> > -URCU_SIGNAL=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT)
> > -URCU_BP=$(top_srcdir)/urcu-bp.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT)
> > -URCU_DEFER=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-defer.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/urcu-call-rcu.c $(top_srcdir)/wfqueue.c $(COMPAT)
> > +URCU_SIGNAL=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
> > +URCU_BP=$(top_srcdir)/urcu-bp.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
> > +URCU_DEFER=$(top_srcdir)/urcu.c $(top_srcdir)/urcu-defer.c $(top_srcdir)/urcu-pointer.c $(top_srcdir)/wfqueue.c $(COMPAT)
> >  
> >  URCU_LIB=$(top_builddir)/liburcu.la
> >  URCU_QSBR_LIB=$(top_builddir)/liburcu-qsbr.la
> >  URCU_MB_LIB=$(top_builddir)/liburcu-mb.la
> >  URCU_SIGNAL_LIB=$(top_builddir)/liburcu-signal.la
> >  URCU_BP_LIB=$(top_builddir)/liburcu-bp.la
> > -URCU_CALL_LIB=$(top_builddir)/liburcu-call.la
> >  WFQUEUE_LIB=$(top_builddir)/libwfqueue.la
> >  WFSTACK_LIB=$(top_builddir)/libwfstack.la
> >  RCULFQUEUE_LIB=$(top_builddir)/librculfqueue.la
> > @@ -95,24 +94,24 @@ test_perthreadlock_SOURCES = test_perthreadlock.c $(URCU_SIGNAL)
> >  
> >  
> >  rcutorture_urcu_SOURCES = urcutorture.c
> > -rcutorture_urcu_CFLAGS = -DTORTURE_URCU $(AM_CFLAGS)
> > -rcutorture_urcu_LDADD = $(URCU) $(URCU_CALL_LIB) $(WFQUEUE_LIB)
> > +rcutorture_urcu_CFLAGS = -DRCU_MEMBARRIER $(AM_CFLAGS)
> > +rcutorture_urcu_LDADD = $(URCU) $(WFQUEUE_LIB)
> >  
> >  rcutorture_urcu_mb_SOURCES = urcutorture.c
> > -rcutorture_urcu_mb_CFLAGS = -DTORTURE_URCU_MB $(AM_CFLAGS)
> > -rcutorture_urcu_mb_LDADD = $(URCU_MB_LIB) $(URCU_CALL_LIB) $(WFQUEUE_LIB)
> > +rcutorture_urcu_mb_CFLAGS = -DRCU_MB $(AM_CFLAGS)
> > +rcutorture_urcu_mb_LDADD = $(URCU_MB_LIB) $(WFQUEUE_LIB)
> >  
> >  rcutorture_qsbr_SOURCES = urcutorture.c
> > -rcutorture_qsbr_CFLAGS = -DTORTURE_QSBR $(AM_CFLAGS)
> > -rcutorture_qsbr_LDADD = $(URCU_QSBR_LIB) $(URCU_CALL_LIB) $(WFQUEUE_LIB)
> > +rcutorture_qsbr_CFLAGS = -DRCU_QSBR $(AM_CFLAGS)
> > +rcutorture_qsbr_LDADD = $(URCU_QSBR_LIB) $(WFQUEUE_LIB)
> >  
> >  rcutorture_urcu_signal_SOURCES = urcutorture.c
> > -rcutorture_urcu_signal_CFLAGS = -DTORTURE_URCU_SIGNAL $(AM_CFLAGS)
> > -rcutorture_urcu_signal_LDADD = $(URCU_SIGNAL_LIB) $(URCU_CALL_LIB) $(WFQUEUE_LIB)
> > +rcutorture_urcu_signal_CFLAGS = -DRCU_SIGNAL $(AM_CFLAGS)
> > +rcutorture_urcu_signal_LDADD = $(URCU_SIGNAL_LIB) $(WFQUEUE_LIB)
> >  
> >  rcutorture_urcu_bp_SOURCES = urcutorture.c
> > -rcutorture_urcu_bp_CFLAGS = -DTORTURE_URCU_BP $(AM_CFLAGS)
> > -rcutorture_urcu_bp_LDADD = $(URCU_BP_LIB) $(URCU_CALL_LIB) $(WFQUEUE_LIB)
> > +rcutorture_urcu_bp_CFLAGS = -DRCU_BP $(AM_CFLAGS)
> > +rcutorture_urcu_bp_LDADD = $(URCU_BP_LIB) $(WFQUEUE_LIB)
> >  
> >  test_mutex_SOURCES = test_mutex.c $(URCU)
> >  
> > diff --git a/tests/rcutorture.h b/tests/rcutorture.h
> > index 66fdd7f..aba74b0 100644
> > --- a/tests/rcutorture.h
> > +++ b/tests/rcutorture.h
> > @@ -66,7 +66,6 @@
> >   */
> >  
> >  #include <stdlib.h>
> > -#include "../urcu-call-rcu.h"
> >  
> >  DEFINE_PER_THREAD(long long, n_reads_pt);
> >  DEFINE_PER_THREAD(long long, n_updates_pt);
> > diff --git a/tests/urcutorture.c b/tests/urcutorture.c
> > index 63fa386..a098d87 100644
> > --- a/tests/urcutorture.c
> > +++ b/tests/urcutorture.c
> > @@ -8,22 +8,19 @@
> >  #include "api.h"
> >  #define _LGPL_SOURCE
> >  
> > -#ifdef TORTURE_RCU_MEMBARRIER
> > -#define RCU_MEMBARRIER
> > +#ifdef RCU_MEMBARRIER
> >  #include <urcu.h>
> >  #endif
> > -#ifdef TORTURE_URCU_SIGNAL
> > -#define RCU_SIGNAL
> > +#ifdef RCU_SIGNAL
> >  #include <urcu.h>
> >  #endif
> > -#ifdef TORTURE_URCU_MB
> > -#define RCU_MB
> > +#ifdef RCU_MB
> >  #include <urcu.h>
> >  #endif
> > -#ifdef TORTURE_QSBR
> > +#ifdef RCU_QSBR
> >  #include <urcu-qsbr.h>
> >  #endif
> > -#ifdef TORTURE_URCU_BP
> > +#ifdef RCU_BP
> >  #include <urcu-bp.h>
> >  #endif
> >  
> > diff --git a/urcu-bp-map.h b/urcu-bp-map.h
> > new file mode 100644
> > index 0000000..6321802
> > --- /dev/null
> > +++ b/urcu-bp-map.h
> > @@ -0,0 +1,61 @@
> > +#ifndef _URCU_BP_MAP_H
> > +#define _URCU_BP_MAP_H
> > +
> > +/*
> > + * urcu-map.h
> > + *
> > + * Userspace RCU header -- name mapping to allow multiple flavors to be
> > + * used in the same executable.
> > + *
> > + * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> > + * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
> > + *
> > + * LGPL-compatible code should include this header with :
> > + *
> > + * #define _LGPL_SOURCE
> > + * #include <urcu.h>
> > + *
> > + * This library is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU Lesser General Public
> > + * License as published by the Free Software Foundation; either
> > + * version 2.1 of the License, or (at your option) any later version.
> > + *
> > + * This library is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > + * Lesser General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU Lesser General Public
> > + * License along with this library; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> > + *
> > + * IBM's contributions to this file may be relicensed under LGPLv2 or later.
> > + */
> > +
> > +/* Mapping macros to allow multiple flavors in a single binary. */
> > +
> > +#define rcu_read_lock			rcu_read_lock_bp
> > +#define _rcu_read_lock			_rcu_read_lock_bp
> > +#define rcu_read_unlock			rcu_read_unlock_bp
> > +#define _rcu_read_unlock		_rcu_read_unlock_bp
> > +#define rcu_register_thread		rcu_register_thread_bp
> > +#define rcu_unregister_thread		rcu_unregister_thread_bp
> > +#define rcu_init			rcu_init_bp
> > +#define rcu_exit			rcu_exit_bp
> > +#define synchronize_rcu			synchronize_rcu_bp
> > +#define rcu_reader			rcu_reader_bp
> > +#define rcu_gp_ctr			rcu_gp_ctr_bp
> > +
> > +#define get_cpu_call_rcu_data		get_cpu_call_rcu_data_bp
> > +#define get_call_rcu_thread		get_call_rcu_thread_bp
> > +#define create_call_rcu_data		create_call_rcu_data_bp
> > +#define set_cpu_call_rcu_data		set_cpu_call_rcu_data_bp
> > +#define get_default_call_rcu_data	get_default_call_rcu_data_bp
> > +#define get_call_rcu_data		get_call_rcu_data_bp
> > +#define get_thread_call_rcu_data	get_thread_call_rcu_data_bp
> > +#define set_thread_call_rcu_data	set_thread_call_rcu_data_bp
> > +#define create_all_cpu_call_rcu_data	create_all_cpu_call_rcu_data_bp
> > +#define free_all_cpu_call_rcu_data	free_all_cpu_call_rcu_data_bp
> > +#define call_rcu			call_rcu_bp
> > +
> > +#endif /* _URCU_BP_MAP_H */
> > diff --git a/urcu-bp.c b/urcu-bp.c
> > index 04bb675..5474f9f 100644
> > --- a/urcu-bp.c
> > +++ b/urcu-bp.c
> > @@ -35,6 +35,8 @@
> >  #include <unistd.h>
> >  #include <sys/mman.h>
> >  
> > +#include "urcu-bp-map.h"
> > +
> >  #include "urcu-bp-static.h"
> >  /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
> >  #include "urcu-bp.h"
> > @@ -375,3 +377,5 @@ void rcu_bp_after_fork_child(void)
> >  	ret = pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
> >  	assert(!ret);
> >  }
> > +
> > +#include "urcu-call-rcu-impl.h"
> > diff --git a/urcu-bp.h b/urcu-bp.h
> > index d92fbd1..fdf885c 100644
> > --- a/urcu-bp.h
> > +++ b/urcu-bp.h
> > @@ -46,6 +46,8 @@
> >  extern "C" {
> >  #endif
> >  
> > +#include "urcu-bp-map.h"
> > +
> >  /*
> >   * Important !
> >   *
> > @@ -69,8 +71,8 @@ extern "C" {
> >   *
> >   * Mark the beginning and end of a read-side critical section.
> >   */
> > -#define rcu_read_lock()		_rcu_read_lock()
> > -#define rcu_read_unlock()	_rcu_read_unlock()
> > +#define rcu_read_lock_bp()		_rcu_read_lock()
> > +#define rcu_read_unlock_bp()		_rcu_read_unlock()
> >  
> >  #else /* !_LGPL_SOURCE */
> >  
> > @@ -115,4 +117,6 @@ static inline void rcu_init(void)
> >  }
> >  #endif
> >  
> > +#include "urcu-call-rcu.h"
> > +
> >  #endif /* _URCU_BP_H */
> > diff --git a/urcu-call-rcu-impl.h b/urcu-call-rcu-impl.h
> > new file mode 100644
> > index 0000000..68dbbdd
> > --- /dev/null
> > +++ b/urcu-call-rcu-impl.h
> > @@ -0,0 +1,618 @@
> > +/*
> > + * urcu-call-rcu.c
> > + *
> > + * Userspace RCU library - batch memory reclamation with kernel API
> > + *
> > + * Copyright (c) 2010 Paul E. McKenney <paulmck at linux.vnet.ibm.com>
> > + *
> > + * This library is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU Lesser General Public
> > + * License as published by the Free Software Foundation; either
> > + * version 2.1 of the License, or (at your option) any later version.
> > + *
> > + * This library is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > + * Lesser General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU Lesser General Public
> > + * License along with this library; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> > + */
> > +
> > +#include <stdio.h>
> > +#include <pthread.h>
> > +#include <signal.h>
> > +#include <assert.h>
> > +#include <stdlib.h>
> > +#include <string.h>
> > +#include <errno.h>
> > +#include <poll.h>
> > +#include <sys/time.h>
> > +#include <syscall.h>
> > +#include <unistd.h>
> > +
> > +#include "config.h"
> > +#include "urcu/wfqueue.h"
> > +#include "urcu-call-rcu.h"
> > +#include "urcu-pointer.h"
> > +#include "urcu/list.h"
> > +
> > +/* Data structure that identifies a call_rcu thread. */
> > +
> > +struct call_rcu_data {
> > +	struct cds_wfq_queue cbs;
> > +	unsigned long flags;
> > +	pthread_mutex_t mtx;
> > +	pthread_cond_t cond;
> > +	unsigned long qlen;
> > +	pthread_t tid;
> > +	struct cds_list_head list;
> > +} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
> > +
> > +/*
> > + * List of all call_rcu_data structures to keep valgrind happy.
> > + * Protected by call_rcu_mutex.
> > + */
> > +
> > +CDS_LIST_HEAD(call_rcu_data_list);
> > +
> > +/* Link a thread using call_rcu() to its call_rcu thread. */
> > +
> > +static __thread struct call_rcu_data *thread_call_rcu_data;
> > +
> > +/* Guard call_rcu thread creation. */
> > +
> > +static pthread_mutex_t call_rcu_mutex = PTHREAD_MUTEX_INITIALIZER;
> > +
> > +/* If a given thread does not have its own call_rcu thread, this is default. */
> > +
> > +static struct call_rcu_data *default_call_rcu_data;
> > +
> > +/*
> > + * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are
> > + * available, then we can have call_rcu threads assigned to individual
> > + * CPUs rather than only to specific threads.
> > + */
> > +
> > +#if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF)
> > +
> > +/*
> > + * Pointer to array of pointers to per-CPU call_rcu_data structures
> > + * and # CPUs.
> > + */
> > +
> > +static struct call_rcu_data **per_cpu_call_rcu_data;
> > +static long maxcpus;
> > +
> > +/* Allocate the array if it has not already been allocated. */
> > +
> > +static void alloc_cpu_call_rcu_data(void)
> > +{
> > +	struct call_rcu_data **p;
> > +	static int warned = 0;
> > +
> > +	if (maxcpus != 0)
> > +		return;
> > +	maxcpus = sysconf(_SC_NPROCESSORS_CONF);
> > +	if (maxcpus <= 0) {
> > +		return;
> > +	}
> > +	p = malloc(maxcpus * sizeof(*per_cpu_call_rcu_data));
> > +	if (p != NULL) {
> > +		memset(p, '\0', maxcpus * sizeof(*per_cpu_call_rcu_data));
> > +		per_cpu_call_rcu_data = p;
> > +	} else {
> > +		if (!warned) {
> > +			fprintf(stderr, "[error] liburcu: unable to allocate per-CPU pointer array\n");
> > +		}
> > +		warned = 1;
> > +	}
> > +}
> > +
> > +#else /* #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */
> > +
> > +static const struct call_rcu_data **per_cpu_call_rcu_data = NULL;
> > +static const long maxcpus = -1;
> > +
> > +static void alloc_cpu_call_rcu_data(void)
> > +{
> > +}
> > +
> > +static int sched_getcpu(void)
> > +{
> > +	return -1;
> > +}
> > +
> > +#endif /* #else #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */
> > +
> > +/* Acquire the specified pthread mutex. */
> > +
> > +static void call_rcu_lock(pthread_mutex_t *pmp)
> > +{
> > +	if (pthread_mutex_lock(pmp) != 0) {
> > +		perror("pthread_mutex_lock");
> > +		exit(-1);
> > +	}
> > +}
> > +
> > +/* Release the specified pthread mutex. */
> > +
> > +static void call_rcu_unlock(pthread_mutex_t *pmp)
> > +{
> > +	if (pthread_mutex_unlock(pmp) != 0) {
> > +		perror("pthread_mutex_unlock");
> > +		exit(-1);
> > +	}
> > +}
> > +
> > +/* This is the code run by each call_rcu thread. */
> > +
> > +static void *call_rcu_thread(void *arg)
> > +{
> > +	unsigned long cbcount;
> > +	struct cds_wfq_node *cbs;
> > +	struct cds_wfq_node **cbs_tail;
> > +	struct call_rcu_data *crdp = (struct call_rcu_data *)arg;
> > +	struct rcu_head *rhp;
> > +
> > +	thread_call_rcu_data = crdp;
> > +	for (;;) {
> > +		if (&crdp->cbs.head != _CMM_LOAD_SHARED(crdp->cbs.tail)) {
> > +			while ((cbs = _CMM_LOAD_SHARED(crdp->cbs.head)) == NULL)
> > +				poll(NULL, 0, 1);
> > +			_CMM_STORE_SHARED(crdp->cbs.head, NULL);
> > +			cbs_tail = (struct cds_wfq_node **)
> > +				uatomic_xchg(&crdp->cbs.tail, &crdp->cbs.head);
> > +			synchronize_rcu();
> > +			cbcount = 0;
> > +			do {
> > +				while (cbs->next == NULL &&
> > +				       &cbs->next != cbs_tail)
> > +				       	poll(NULL, 0, 1);
> > +				if (cbs == &crdp->cbs.dummy) {
> > +					cbs = cbs->next;
> > +					continue;
> > +				}
> > +				rhp = (struct rcu_head *)cbs;
> > +				cbs = cbs->next;
> > +				rhp->func(rhp);
> > +				cbcount++;
> > +			} while (cbs != NULL);
> > +			uatomic_sub(&crdp->qlen, cbcount);
> > +		}
> > +		if (crdp->flags & URCU_CALL_RCU_STOP)
> > +			break;
> > +		if (crdp->flags & URCU_CALL_RCU_RT)
> > +			poll(NULL, 0, 10);
> > +		else {
> > +			call_rcu_lock(&crdp->mtx);
> > +			_CMM_STORE_SHARED(crdp->flags,
> > +				     crdp->flags & ~URCU_CALL_RCU_RUNNING);
> > +			if (&crdp->cbs.head ==
> > +			    _CMM_LOAD_SHARED(crdp->cbs.tail) &&
> > +			    pthread_cond_wait(&crdp->cond, &crdp->mtx) != 0) {
> > +				perror("pthread_cond_wait");
> > +				exit(-1);
> > +			}
> > +			_CMM_STORE_SHARED(crdp->flags,
> > +				     crdp->flags | URCU_CALL_RCU_RUNNING);
> > +			poll(NULL, 0, 10);
> > +			call_rcu_unlock(&crdp->mtx);
> > +		}
> > +	}
> > +	call_rcu_lock(&crdp->mtx);
> > +	crdp->flags |= URCU_CALL_RCU_STOPPED;
> > +	call_rcu_unlock(&crdp->mtx);
> > +	return NULL;
> > +}
> > +
> > +/*
> > + * Create both a call_rcu thread and the corresponding call_rcu_data
> > + * structure, linking the structure in as specified.  Caller must hold
> > + * call_rcu_mutex.
> > + */
> > +
> > +static void call_rcu_data_init(struct call_rcu_data **crdpp,
> > +			       unsigned long flags)
> > +{
> > +	struct call_rcu_data *crdp;
> > +
> > +	crdp = malloc(sizeof(*crdp));
> > +	if (crdp == NULL) {
> > +		fprintf(stderr, "Out of memory.\n");
> > +		exit(-1);
> > +	}
> > +	memset(crdp, '\0', sizeof(*crdp));
> > +	cds_wfq_init(&crdp->cbs);
> > +	crdp->qlen = 0;
> > +	if (pthread_mutex_init(&crdp->mtx, NULL) != 0) {
> > +		perror("pthread_mutex_init");
> > +		exit(-1);
> > +	}
> > +	if (pthread_cond_init(&crdp->cond, NULL) != 0) {
> > +		perror("pthread_cond_init");
> > +		exit(-1);
> > +	}
> > +	crdp->flags = flags | URCU_CALL_RCU_RUNNING;
> > +	cds_list_add(&crdp->list, &call_rcu_data_list);
> > +	cmm_smp_mb();  /* Structure initialized before pointer is planted. */
> > +	*crdpp = crdp;
> > +	if (pthread_create(&crdp->tid, NULL, call_rcu_thread, crdp) != 0) {
> > +		perror("pthread_create");
> > +		exit(-1);
> > +	}
> > +}
> > +
> > +/*
> > + * Return a pointer to the call_rcu_data structure for the specified
> > + * CPU, returning NULL if there is none.  We cannot automatically
> > + * created it because the platform we are running on might not define
> > + * sched_getcpu().
> > + */
> > +
> > +struct call_rcu_data *get_cpu_call_rcu_data(int cpu)
> > +{
> > +	static int warned = 0;
> > +
> > +	if (per_cpu_call_rcu_data == NULL)
> > +		return NULL;
> > +	if (!warned && maxcpus > 0 && (cpu < 0 || maxcpus <= cpu)) {
> > +		fprintf(stderr, "[error] liburcu: get CPU # out of range\n");
> > +		warned = 1;
> > +	}
> > +	if (cpu < 0 || maxcpus <= cpu)
> > +		return NULL;
> > +	return per_cpu_call_rcu_data[cpu];
> > +}
> > +
> > +/*
> > + * Return the tid corresponding to the call_rcu thread whose
> > + * call_rcu_data structure is specified.
> > + */
> > +
> > +pthread_t get_call_rcu_thread(struct call_rcu_data *crdp)
> > +{
> > +	return crdp->tid;
> > +}
> > +
> > +/*
> > + * Create a call_rcu_data structure (with thread) and return a pointer.
> > + */
> > +
> > +static struct call_rcu_data *__create_call_rcu_data(unsigned long flags)
> > +{
> > +	struct call_rcu_data *crdp;
> > +
> > +	call_rcu_data_init(&crdp, flags);
> > +	return crdp;
> > +}
> > +
> > +struct call_rcu_data *create_call_rcu_data(unsigned long flags)
> > +{
> > +	struct call_rcu_data *crdp;
> > +
> > +	call_rcu_lock(&call_rcu_mutex);
> > +	crdp = __create_call_rcu_data(flags);
> > +	call_rcu_unlock(&call_rcu_mutex);
> > +	return crdp;
> > +}
> > +
> > +/*
> > + * Set the specified CPU to use the specified call_rcu_data structure.
> > + *
> > + * Use NULL to remove a CPU's call_rcu_data structure, but it is
> > + * the caller's responsibility to dispose of the removed structure.
> > + * Use get_cpu_call_rcu_data() to obtain a pointer to the old structure
> > + * (prior to NULLing it out, of course).
> > + */
> > +
> > +int set_cpu_call_rcu_data(int cpu, struct call_rcu_data *crdp)
> > +{
> > +	int warned = 0;
> > +
> > +	call_rcu_lock(&call_rcu_mutex);
> > +	if (cpu < 0 || maxcpus <= cpu) {
> > +		if (!warned) {
> > +			fprintf(stderr, "[error] liburcu: set CPU # out of range\n");
> > +			warned = 1;
> > +		}
> > +		call_rcu_unlock(&call_rcu_mutex);
> > +		errno = EINVAL;
> > +		return -EINVAL;
> > +	}
> > +	alloc_cpu_call_rcu_data();
> > +	call_rcu_unlock(&call_rcu_mutex);
> > +	if (per_cpu_call_rcu_data == NULL) {
> > +		errno = ENOMEM;
> > +		return -ENOMEM;
> > +	}
> > +	per_cpu_call_rcu_data[cpu] = crdp;
> > +	return 0;
> > +}
> > +
> > +/*
> > + * Return a pointer to the default call_rcu_data structure, creating
> > + * one if need be.  Because we never free call_rcu_data structures,
> > + * we don't need to be in an RCU read-side critical section.
> > + */
> > +
> > +struct call_rcu_data *get_default_call_rcu_data(void)
> > +{
> > +	if (default_call_rcu_data != NULL)
> > +		return rcu_dereference(default_call_rcu_data);
> > +	call_rcu_lock(&call_rcu_mutex);
> > +	if (default_call_rcu_data != NULL) {
> > +		call_rcu_unlock(&call_rcu_mutex);
> > +		return default_call_rcu_data;
> > +	}
> > +	call_rcu_data_init(&default_call_rcu_data, 0);
> > +	call_rcu_unlock(&call_rcu_mutex);
> > +	return default_call_rcu_data;
> > +}
> > +
> > +/*
> > + * Return the call_rcu_data structure that applies to the currently
> > + * running thread.  Any call_rcu_data structure assigned specifically
> > + * to this thread has first priority, followed by any call_rcu_data
> > + * structure assigned to the CPU on which the thread is running,
> > + * followed by the default call_rcu_data structure.  If there is not
> > + * yet a default call_rcu_data structure, one will be created.
> > + */
> > +struct call_rcu_data *get_call_rcu_data(void)
> > +{
> > +	int curcpu;
> > +	static int warned = 0;
> > +
> > +	if (thread_call_rcu_data != NULL)
> > +		return thread_call_rcu_data;
> > +	if (maxcpus <= 0)
> > +		return get_default_call_rcu_data();
> > +	curcpu = sched_getcpu();
> > +	if (!warned && (curcpu < 0 || maxcpus <= curcpu)) {
> > +		fprintf(stderr, "[error] liburcu: gcrd CPU # out of range\n");
> > +		warned = 1;
> > +	}
> > +	if (curcpu >= 0 && maxcpus > curcpu &&
> > +	    per_cpu_call_rcu_data != NULL &&
> > +	    per_cpu_call_rcu_data[curcpu] != NULL)
> > +	    	return per_cpu_call_rcu_data[curcpu];
> > +	return get_default_call_rcu_data();
> > +}
> > +
> > +/*
> > + * Return a pointer to this task's call_rcu_data if there is one.
> > + */
> > +
> > +struct call_rcu_data *get_thread_call_rcu_data(void)
> > +{
> > +	return thread_call_rcu_data;
> > +}
> > +
> > +/*
> > + * Set this task's call_rcu_data structure as specified, regardless
> > + * of whether or not this task already had one.  (This allows switching
> > + * to and from real-time call_rcu threads, for example.)
> > + *
> > + * Use NULL to remove a thread's call_rcu_data structure, but it is
> > + * the caller's responsibility to dispose of the removed structure.
> > + * Use get_thread_call_rcu_data() to obtain a pointer to the old structure
> > + * (prior to NULLing it out, of course).
> > + */
> > +
> > +void set_thread_call_rcu_data(struct call_rcu_data *crdp)
> > +{
> > +	thread_call_rcu_data = crdp;
> > +}
> > +
> > +/*
> > + * Create a separate call_rcu thread for each CPU.  This does not
> > + * replace a pre-existing call_rcu thread -- use the set_cpu_call_rcu_data()
> > + * function if you want that behavior.
> > + */
> > +
> > +int create_all_cpu_call_rcu_data(unsigned long flags)
> > +{
> > +	int i;
> > +	struct call_rcu_data *crdp;
> > +	int ret;
> > +
> > +	call_rcu_lock(&call_rcu_mutex);
> > +	alloc_cpu_call_rcu_data();
> > +	call_rcu_unlock(&call_rcu_mutex);
> > +	if (maxcpus <= 0) {
> > +		errno = EINVAL;
> > +		return -EINVAL;
> > +	}
> > +	if (per_cpu_call_rcu_data == NULL) {
> > +		errno = ENOMEM;
> > +		return -ENOMEM;
> > +	}
> > +	for (i = 0; i < maxcpus; i++) {
> > +		call_rcu_lock(&call_rcu_mutex);
> > +		if (get_cpu_call_rcu_data(i)) {
> > +			call_rcu_unlock(&call_rcu_mutex);
> > +			continue;
> > +		}
> > +		crdp = __create_call_rcu_data(flags);
> > +		if (crdp == NULL) {
> > +			call_rcu_unlock(&call_rcu_mutex);
> > +			errno = ENOMEM;
> > +			return -ENOMEM;
> > +		}
> > +		call_rcu_unlock(&call_rcu_mutex);
> > +		if ((ret = set_cpu_call_rcu_data(i, crdp)) != 0) {
> > +			/* FIXME: Leaks crdp for now. */
> > +			return ret; /* Can happen on race. */
> > +		}
> > +	}
> > +	return 0;
> > +}
> > +
> > +/*
> > + * Wake up the call_rcu thread corresponding to the specified
> > + * call_rcu_data structure.
> > + */
> > +static void wake_call_rcu_thread(struct call_rcu_data *crdp)
> > +{
> > +	if (!(_CMM_LOAD_SHARED(crdp->flags) & URCU_CALL_RCU_RT)) {
> > +		call_rcu_lock(&crdp->mtx);
> > +		if (!(_CMM_LOAD_SHARED(crdp->flags) & URCU_CALL_RCU_RUNNING)) {
> > +			if (pthread_cond_signal(&crdp->cond) != 0) {
> > +				perror("pthread_cond_signal");
> > +				exit(-1);
> > +			}
> > +		}
> > +		call_rcu_unlock(&crdp->mtx);
> > +	}
> > +}
> > +
> > +/*
> > + * Schedule a function to be invoked after a following grace period.
> > + * This is the only function that must be called -- the others are
> > + * only present to allow applications to tune their use of RCU for
> > + * maximum performance.
> > + *
> > + * Note that unless a call_rcu thread has not already been created,
> > + * the first invocation of call_rcu() will create one.  So, if you
> > + * need the first invocation of call_rcu() to be fast, make sure
> > + * to create a call_rcu thread first.  One way to accomplish this is
> > + * "get_call_rcu_data();", and another is create_all_cpu_call_rcu_data().
> > + */
> > +
> > +void call_rcu(struct rcu_head *head,
> > +	      void (*func)(struct rcu_head *head))
> > +{
> > +	struct call_rcu_data *crdp;
> > +
> > +	cds_wfq_node_init(&head->next);
> > +	head->func = func;
> > +	crdp = get_call_rcu_data();
> > +	cds_wfq_enqueue(&crdp->cbs, &head->next);
> > +	uatomic_inc(&crdp->qlen);
> > +	wake_call_rcu_thread(crdp);
> > +}
> > +
> > +/*
> > + * Free up the specified call_rcu_data structure, terminating the
> > + * associated call_rcu thread.  The caller must have previously
> > + * removed the call_rcu_data structure from per-thread or per-CPU
> > + * usage.  For example, set_cpu_call_rcu_data(cpu, NULL) for per-CPU
> > + * call_rcu_data structures or set_thread_call_rcu_data(NULL) for
> > + * per-thread call_rcu_data structures.
> > + *
> > + * We silently refuse to free up the default call_rcu_data structure
> > + * because that is where we put any leftover callbacks.  Note that
> > + * the possibility of self-spawning callbacks makes it impossible
> > + * to execute all the callbacks in finite time without putting any
> > + * newly spawned callbacks somewhere else.  The "somewhere else" of
> > + * last resort is the default call_rcu_data structure.
> > + *
> > + * We also silently refuse to free NULL pointers.  This simplifies
> > + * the calling code.
> > + */
> > +void call_rcu_data_free(struct call_rcu_data *crdp)
> > +{
> > +	struct cds_wfq_node *cbs;
> > +	struct cds_wfq_node **cbs_tail;
> > +	struct cds_wfq_node **cbs_endprev;
> > +
> > +	if (crdp == NULL || crdp == default_call_rcu_data) {
> > +		return;
> > +	}
> > +	if ((crdp->flags & URCU_CALL_RCU_STOPPED) == 0) {
> > +		call_rcu_lock(&crdp->mtx);
> > +		crdp->flags |= URCU_CALL_RCU_STOP;
> > +		call_rcu_unlock(&crdp->mtx);
> > +		wake_call_rcu_thread(crdp);
> > +		while ((crdp->flags & URCU_CALL_RCU_STOPPED) == 0)
> > +			poll(NULL, 0, 1);
> > +	}
> > +	if (&crdp->cbs.head != _CMM_LOAD_SHARED(crdp->cbs.tail)) {
> > +		while ((cbs = _CMM_LOAD_SHARED(crdp->cbs.head)) == NULL)
> > +			poll(NULL, 0, 1);
> > +		_CMM_STORE_SHARED(crdp->cbs.head, NULL);
> > +		cbs_tail = (struct cds_wfq_node **)
> > +			uatomic_xchg(&crdp->cbs.tail, &crdp->cbs.head);
> > +		cbs_endprev = (struct cds_wfq_node **)
> > +			uatomic_xchg(&default_call_rcu_data, cbs_tail);
> > +		*cbs_endprev = cbs;
> > +		uatomic_add(&default_call_rcu_data->qlen,
> > +			    uatomic_read(&crdp->qlen));
> > +		cds_list_del(&crdp->list);
> > +		free(crdp);
> > +	}
> > +}
> > +
> > +/*
> > + * Clean up all the per-CPU call_rcu threads.
> > + */
> > +void free_all_cpu_call_rcu_data(void)
> > +{
> > +	int cpu;
> > +	struct call_rcu_data *crdp;
> > +
> > +	if (maxcpus <= 0)
> > +		return;
> > +	for (cpu = 0; cpu < maxcpus; cpu++) {
> > +		crdp = get_cpu_call_rcu_data(cpu);
> > +		if (crdp == NULL)
> > +			continue;
> > +		set_cpu_call_rcu_data(cpu, NULL);
> > +		call_rcu_data_free(crdp);
> > +	}
> > +}
> > +
> > +/*
> > + * Acquire the call_rcu_mutex in order to ensure that the child sees
> > + * all of the call_rcu() data structures in a consistent state.
> > + * Suitable for pthread_atfork() and friends.
> > + */
> > +void call_rcu_before_fork(void)
> > +{
> > +	call_rcu_lock(&call_rcu_mutex);
> > +}
> > +
> > +/*
> > + * Clean up call_rcu data structures in the parent of a successful fork()
> > + * that is not followed by exec() in the child.  Suitable for
> > + * pthread_atfork() and friends.
> > + */
> > +void call_rcu_after_fork_parent(void)
> > +{
> > +	call_rcu_unlock(&call_rcu_mutex);
> > +}
> > +
> > +/*
> > + * Clean up call_rcu data structures in the child of a successful fork()
> > + * that is not followed by exec().  Suitable for pthread_atfork() and
> > + * friends.
> > + */
> > +void call_rcu_after_fork_child(void)
> > +{
> > +	struct call_rcu_data *crdp;
> > +
> > +	/* Re-initialize the mutex. */
> > +	if (pthread_mutex_init(&call_rcu_mutex, NULL) != 0) {
> > +		perror("pthread_mutex_init");
> > +		exit(-1);
> > +	}
> > +
> > +	/*
> > +	 * Allocate a new default call_rcu_data structure in order
> > +	 * to get a working call_rcu thread to go with it.
> > +	 */
> > +	default_call_rcu_data = NULL;
> > +	(void)get_default_call_rcu_data();
> > +
> > +	/* Dispose of all of the rest of the call_rcu_data structures. */
> > +	while (call_rcu_data_list.next != call_rcu_data_list.prev) {
> > +		crdp = cds_list_entry(call_rcu_data_list.prev,
> > +				      struct call_rcu_data, list);
> > +		if (crdp == default_call_rcu_data)
> > +			crdp = cds_list_entry(crdp->list.prev,
> > +					      struct call_rcu_data, list);
> > +		crdp->flags = URCU_CALL_RCU_STOPPED;
> > +		call_rcu_data_free(crdp);
> > +	}
> > +}
> > diff --git a/urcu-call-rcu.c b/urcu-call-rcu.c
> > deleted file mode 100644
> > index 665f20c..0000000
> > --- a/urcu-call-rcu.c
> > +++ /dev/null
> > @@ -1,620 +0,0 @@
> > -/*
> > - * urcu-call-rcu.c
> > - *
> > - * Userspace RCU library - batch memory reclamation with kernel API
> > - *
> > - * Copyright (c) 2010 Paul E. McKenney <paulmck at linux.vnet.ibm.com>
> > - *
> > - * This library is free software; you can redistribute it and/or
> > - * modify it under the terms of the GNU Lesser General Public
> > - * License as published by the Free Software Foundation; either
> > - * version 2.1 of the License, or (at your option) any later version.
> > - *
> > - * This library is distributed in the hope that it will be useful,
> > - * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > - * Lesser General Public License for more details.
> > - *
> > - * You should have received a copy of the GNU Lesser General Public
> > - * License along with this library; if not, write to the Free Software
> > - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> > - */
> > -
> > -#include <stdio.h>
> > -#include <pthread.h>
> > -#include <signal.h>
> > -#include <assert.h>
> > -#include <stdlib.h>
> > -#include <string.h>
> > -#include <errno.h>
> > -#include <poll.h>
> > -#include <sys/time.h>
> > -#include <syscall.h>
> > -#include <unistd.h>
> > -
> > -#include "config.h"
> > -#include "urcu/wfqueue.h"
> > -#include "urcu-call-rcu.h"
> > -#include "urcu-pointer.h"
> > -#include "urcu/list.h"
> > -
> > -/* Data structure that identifies a call_rcu thread. */
> > -
> > -struct call_rcu_data {
> > -	struct cds_wfq_queue cbs;
> > -	unsigned long flags;
> > -	pthread_mutex_t mtx;
> > -	pthread_cond_t cond;
> > -	unsigned long qlen;
> > -	pthread_t tid;
> > -	struct cds_list_head list;
> > -} __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
> > -
> > -/*
> > - * List of all call_rcu_data structures to keep valgrind happy.
> > - * Protected by call_rcu_mutex.
> > - */
> > -
> > -CDS_LIST_HEAD(call_rcu_data_list);
> > -
> > -/* Link a thread using call_rcu() to its call_rcu thread. */
> > -
> > -static __thread struct call_rcu_data *thread_call_rcu_data;
> > -
> > -/* Guard call_rcu thread creation. */
> > -
> > -static pthread_mutex_t call_rcu_mutex = PTHREAD_MUTEX_INITIALIZER;
> > -
> > -/* If a given thread does not have its own call_rcu thread, this is default. */
> > -
> > -static struct call_rcu_data *default_call_rcu_data;
> > -
> > -extern void synchronize_rcu(void);
> > -
> > -/*
> > - * If the sched_getcpu() and sysconf(_SC_NPROCESSORS_CONF) calls are
> > - * available, then we can have call_rcu threads assigned to individual
> > - * CPUs rather than only to specific threads.
> > - */
> > -
> > -#if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF)
> > -
> > -/*
> > - * Pointer to array of pointers to per-CPU call_rcu_data structures
> > - * and # CPUs.
> > - */
> > -
> > -static struct call_rcu_data **per_cpu_call_rcu_data;
> > -static long maxcpus;
> > -
> > -/* Allocate the array if it has not already been allocated. */
> > -
> > -static void alloc_cpu_call_rcu_data(void)
> > -{
> > -	struct call_rcu_data **p;
> > -	static int warned = 0;
> > -
> > -	if (maxcpus != 0)
> > -		return;
> > -	maxcpus = sysconf(_SC_NPROCESSORS_CONF);
> > -	if (maxcpus <= 0) {
> > -		return;
> > -	}
> > -	p = malloc(maxcpus * sizeof(*per_cpu_call_rcu_data));
> > -	if (p != NULL) {
> > -		memset(p, '\0', maxcpus * sizeof(*per_cpu_call_rcu_data));
> > -		per_cpu_call_rcu_data = p;
> > -	} else {
> > -		if (!warned) {
> > -			fprintf(stderr, "[error] liburcu: unable to allocate per-CPU pointer array\n");
> > -		}
> > -		warned = 1;
> > -	}
> > -}
> > -
> > -#else /* #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */
> > -
> > -static const struct call_rcu_data **per_cpu_call_rcu_data = NULL;
> > -static const long maxcpus = -1;
> > -
> > -static void alloc_cpu_call_rcu_data(void)
> > -{
> > -}
> > -
> > -static int sched_getcpu(void)
> > -{
> > -	return -1;
> > -}
> > -
> > -#endif /* #else #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */
> > -
> > -/* Acquire the specified pthread mutex. */
> > -
> > -static void call_rcu_lock(pthread_mutex_t *pmp)
> > -{
> > -	if (pthread_mutex_lock(pmp) != 0) {
> > -		perror("pthread_mutex_lock");
> > -		exit(-1);
> > -	}
> > -}
> > -
> > -/* Release the specified pthread mutex. */
> > -
> > -static void call_rcu_unlock(pthread_mutex_t *pmp)
> > -{
> > -	if (pthread_mutex_unlock(pmp) != 0) {
> > -		perror("pthread_mutex_unlock");
> > -		exit(-1);
> > -	}
> > -}
> > -
> > -/* This is the code run by each call_rcu thread. */
> > -
> > -static void *call_rcu_thread(void *arg)
> > -{
> > -	unsigned long cbcount;
> > -	struct cds_wfq_node *cbs;
> > -	struct cds_wfq_node **cbs_tail;
> > -	struct call_rcu_data *crdp = (struct call_rcu_data *)arg;
> > -	struct rcu_head *rhp;
> > -
> > -	thread_call_rcu_data = crdp;
> > -	for (;;) {
> > -		if (&crdp->cbs.head != _CMM_LOAD_SHARED(crdp->cbs.tail)) {
> > -			while ((cbs = _CMM_LOAD_SHARED(crdp->cbs.head)) == NULL)
> > -				poll(NULL, 0, 1);
> > -			_CMM_STORE_SHARED(crdp->cbs.head, NULL);
> > -			cbs_tail = (struct cds_wfq_node **)
> > -				uatomic_xchg(&crdp->cbs.tail, &crdp->cbs.head);
> > -			synchronize_rcu();
> > -			cbcount = 0;
> > -			do {
> > -				while (cbs->next == NULL &&
> > -				       &cbs->next != cbs_tail)
> > -				       	poll(NULL, 0, 1);
> > -				if (cbs == &crdp->cbs.dummy) {
> > -					cbs = cbs->next;
> > -					continue;
> > -				}
> > -				rhp = (struct rcu_head *)cbs;
> > -				cbs = cbs->next;
> > -				rhp->func(rhp);
> > -				cbcount++;
> > -			} while (cbs != NULL);
> > -			uatomic_sub(&crdp->qlen, cbcount);
> > -		}
> > -		if (crdp->flags & URCU_CALL_RCU_STOP)
> > -			break;
> > -		if (crdp->flags & URCU_CALL_RCU_RT)
> > -			poll(NULL, 0, 10);
> > -		else {
> > -			call_rcu_lock(&crdp->mtx);
> > -			_CMM_STORE_SHARED(crdp->flags,
> > -				     crdp->flags & ~URCU_CALL_RCU_RUNNING);
> > -			if (&crdp->cbs.head ==
> > -			    _CMM_LOAD_SHARED(crdp->cbs.tail) &&
> > -			    pthread_cond_wait(&crdp->cond, &crdp->mtx) != 0) {
> > -				perror("pthread_cond_wait");
> > -				exit(-1);
> > -			}
> > -			_CMM_STORE_SHARED(crdp->flags,
> > -				     crdp->flags | URCU_CALL_RCU_RUNNING);
> > -			poll(NULL, 0, 10);
> > -			call_rcu_unlock(&crdp->mtx);
> > -		}
> > -	}
> > -	call_rcu_lock(&crdp->mtx);
> > -	crdp->flags |= URCU_CALL_RCU_STOPPED;
> > -	call_rcu_unlock(&crdp->mtx);
> > -	return NULL;
> > -}
> > -
> > -/*
> > - * Create both a call_rcu thread and the corresponding call_rcu_data
> > - * structure, linking the structure in as specified.  Caller must hold
> > - * call_rcu_mutex.
> > - */
> > -
> > -static void call_rcu_data_init(struct call_rcu_data **crdpp,
> > -			       unsigned long flags)
> > -{
> > -	struct call_rcu_data *crdp;
> > -
> > -	crdp = malloc(sizeof(*crdp));
> > -	if (crdp == NULL) {
> > -		fprintf(stderr, "Out of memory.\n");
> > -		exit(-1);
> > -	}
> > -	memset(crdp, '\0', sizeof(*crdp));
> > -	cds_wfq_init(&crdp->cbs);
> > -	crdp->qlen = 0;
> > -	if (pthread_mutex_init(&crdp->mtx, NULL) != 0) {
> > -		perror("pthread_mutex_init");
> > -		exit(-1);
> > -	}
> > -	if (pthread_cond_init(&crdp->cond, NULL) != 0) {
> > -		perror("pthread_cond_init");
> > -		exit(-1);
> > -	}
> > -	crdp->flags = flags | URCU_CALL_RCU_RUNNING;
> > -	cds_list_add(&crdp->list, &call_rcu_data_list);
> > -	cmm_smp_mb();  /* Structure initialized before pointer is planted. */
> > -	*crdpp = crdp;
> > -	if (pthread_create(&crdp->tid, NULL, call_rcu_thread, crdp) != 0) {
> > -		perror("pthread_create");
> > -		exit(-1);
> > -	}
> > -}
> > -
> > -/*
> > - * Return a pointer to the call_rcu_data structure for the specified
> > - * CPU, returning NULL if there is none.  We cannot automatically
> > - * created it because the platform we are running on might not define
> > - * sched_getcpu().
> > - */
> > -
> > -struct call_rcu_data *get_cpu_call_rcu_data(int cpu)
> > -{
> > -	static int warned = 0;
> > -
> > -	if (per_cpu_call_rcu_data == NULL)
> > -		return NULL;
> > -	if (!warned && maxcpus > 0 && (cpu < 0 || maxcpus <= cpu)) {
> > -		fprintf(stderr, "[error] liburcu: get CPU # out of range\n");
> > -		warned = 1;
> > -	}
> > -	if (cpu < 0 || maxcpus <= cpu)
> > -		return NULL;
> > -	return per_cpu_call_rcu_data[cpu];
> > -}
> > -
> > -/*
> > - * Return the tid corresponding to the call_rcu thread whose
> > - * call_rcu_data structure is specified.
> > - */
> > -
> > -pthread_t get_call_rcu_thread(struct call_rcu_data *crdp)
> > -{
> > -	return crdp->tid;
> > -}
> > -
> > -/*
> > - * Create a call_rcu_data structure (with thread) and return a pointer.
> > - */
> > -
> > -static struct call_rcu_data *__create_call_rcu_data(unsigned long flags)
> > -{
> > -	struct call_rcu_data *crdp;
> > -
> > -	call_rcu_data_init(&crdp, flags);
> > -	return crdp;
> > -}
> > -
> > -struct call_rcu_data *create_call_rcu_data(unsigned long flags)
> > -{
> > -	struct call_rcu_data *crdp;
> > -
> > -	call_rcu_lock(&call_rcu_mutex);
> > -	crdp = __create_call_rcu_data(flags);
> > -	call_rcu_unlock(&call_rcu_mutex);
> > -	return crdp;
> > -}
> > -
> > -/*
> > - * Set the specified CPU to use the specified call_rcu_data structure.
> > - *
> > - * Use NULL to remove a CPU's call_rcu_data structure, but it is
> > - * the caller's responsibility to dispose of the removed structure.
> > - * Use get_cpu_call_rcu_data() to obtain a pointer to the old structure
> > - * (prior to NULLing it out, of course).
> > - */
> > -
> > -int set_cpu_call_rcu_data(int cpu, struct call_rcu_data *crdp)
> > -{
> > -	int warned = 0;
> > -
> > -	call_rcu_lock(&call_rcu_mutex);
> > -	if (cpu < 0 || maxcpus <= cpu) {
> > -		if (!warned) {
> > -			fprintf(stderr, "[error] liburcu: set CPU # out of range\n");
> > -			warned = 1;
> > -		}
> > -		call_rcu_unlock(&call_rcu_mutex);
> > -		errno = EINVAL;
> > -		return -EINVAL;
> > -	}
> > -	alloc_cpu_call_rcu_data();
> > -	call_rcu_unlock(&call_rcu_mutex);
> > -	if (per_cpu_call_rcu_data == NULL) {
> > -		errno = ENOMEM;
> > -		return -ENOMEM;
> > -	}
> > -	per_cpu_call_rcu_data[cpu] = crdp;
> > -	return 0;
> > -}
> > -
> > -/*
> > - * Return a pointer to the default call_rcu_data structure, creating
> > - * one if need be.  Because we never free call_rcu_data structures,
> > - * we don't need to be in an RCU read-side critical section.
> > - */
> > -
> > -struct call_rcu_data *get_default_call_rcu_data(void)
> > -{
> > -	if (default_call_rcu_data != NULL)
> > -		return rcu_dereference(default_call_rcu_data);
> > -	call_rcu_lock(&call_rcu_mutex);
> > -	if (default_call_rcu_data != NULL) {
> > -		call_rcu_unlock(&call_rcu_mutex);
> > -		return default_call_rcu_data;
> > -	}
> > -	call_rcu_data_init(&default_call_rcu_data, 0);
> > -	call_rcu_unlock(&call_rcu_mutex);
> > -	return default_call_rcu_data;
> > -}
> > -
> > -/*
> > - * Return the call_rcu_data structure that applies to the currently
> > - * running thread.  Any call_rcu_data structure assigned specifically
> > - * to this thread has first priority, followed by any call_rcu_data
> > - * structure assigned to the CPU on which the thread is running,
> > - * followed by the default call_rcu_data structure.  If there is not
> > - * yet a default call_rcu_data structure, one will be created.
> > - */
> > -struct call_rcu_data *get_call_rcu_data(void)
> > -{
> > -	int curcpu;
> > -	static int warned = 0;
> > -
> > -	if (thread_call_rcu_data != NULL)
> > -		return thread_call_rcu_data;
> > -	if (maxcpus <= 0)
> > -		return get_default_call_rcu_data();
> > -	curcpu = sched_getcpu();
> > -	if (!warned && (curcpu < 0 || maxcpus <= curcpu)) {
> > -		fprintf(stderr, "[error] liburcu: gcrd CPU # out of range\n");
> > -		warned = 1;
> > -	}
> > -	if (curcpu >= 0 && maxcpus > curcpu &&
> > -	    per_cpu_call_rcu_data != NULL &&
> > -	    per_cpu_call_rcu_data[curcpu] != NULL)
> > -	    	return per_cpu_call_rcu_data[curcpu];
> > -	return get_default_call_rcu_data();
> > -}
> > -
> > -/*
> > - * Return a pointer to this task's call_rcu_data if there is one.
> > - */
> > -
> > -struct call_rcu_data *get_thread_call_rcu_data(void)
> > -{
> > -	return thread_call_rcu_data;
> > -}
> > -
> > -/*
> > - * Set this task's call_rcu_data structure as specified, regardless
> > - * of whether or not this task already had one.  (This allows switching
> > - * to and from real-time call_rcu threads, for example.)
> > - *
> > - * Use NULL to remove a thread's call_rcu_data structure, but it is
> > - * the caller's responsibility to dispose of the removed structure.
> > - * Use get_thread_call_rcu_data() to obtain a pointer to the old structure
> > - * (prior to NULLing it out, of course).
> > - */
> > -
> > -void set_thread_call_rcu_data(struct call_rcu_data *crdp)
> > -{
> > -	thread_call_rcu_data = crdp;
> > -}
> > -
> > -/*
> > - * Create a separate call_rcu thread for each CPU.  This does not
> > - * replace a pre-existing call_rcu thread -- use the set_cpu_call_rcu_data()
> > - * function if you want that behavior.
> > - */
> > -
> > -int create_all_cpu_call_rcu_data(unsigned long flags)
> > -{
> > -	int i;
> > -	struct call_rcu_data *crdp;
> > -	int ret;
> > -
> > -	call_rcu_lock(&call_rcu_mutex);
> > -	alloc_cpu_call_rcu_data();
> > -	call_rcu_unlock(&call_rcu_mutex);
> > -	if (maxcpus <= 0) {
> > -		errno = EINVAL;
> > -		return -EINVAL;
> > -	}
> > -	if (per_cpu_call_rcu_data == NULL) {
> > -		errno = ENOMEM;
> > -		return -ENOMEM;
> > -	}
> > -	for (i = 0; i < maxcpus; i++) {
> > -		call_rcu_lock(&call_rcu_mutex);
> > -		if (get_cpu_call_rcu_data(i)) {
> > -			call_rcu_unlock(&call_rcu_mutex);
> > -			continue;
> > -		}
> > -		crdp = __create_call_rcu_data(flags);
> > -		if (crdp == NULL) {
> > -			call_rcu_unlock(&call_rcu_mutex);
> > -			errno = ENOMEM;
> > -			return -ENOMEM;
> > -		}
> > -		call_rcu_unlock(&call_rcu_mutex);
> > -		if ((ret = set_cpu_call_rcu_data(i, crdp)) != 0) {
> > -			/* FIXME: Leaks crdp for now. */
> > -			return ret; /* Can happen on race. */
> > -		}
> > -	}
> > -	return 0;
> > -}
> > -
> > -/*
> > - * Wake up the call_rcu thread corresponding to the specified
> > - * call_rcu_data structure.
> > - */
> > -static void wake_call_rcu_thread(struct call_rcu_data *crdp)
> > -{
> > -	if (!(_CMM_LOAD_SHARED(crdp->flags) & URCU_CALL_RCU_RT)) {
> > -		call_rcu_lock(&crdp->mtx);
> > -		if (!(_CMM_LOAD_SHARED(crdp->flags) & URCU_CALL_RCU_RUNNING)) {
> > -			if (pthread_cond_signal(&crdp->cond) != 0) {
> > -				perror("pthread_cond_signal");
> > -				exit(-1);
> > -			}
> > -		}
> > -		call_rcu_unlock(&crdp->mtx);
> > -	}
> > -}
> > -
> > -/*
> > - * Schedule a function to be invoked after a following grace period.
> > - * This is the only function that must be called -- the others are
> > - * only present to allow applications to tune their use of RCU for
> > - * maximum performance.
> > - *
> > - * Note that unless a call_rcu thread has not already been created,
> > - * the first invocation of call_rcu() will create one.  So, if you
> > - * need the first invocation of call_rcu() to be fast, make sure
> > - * to create a call_rcu thread first.  One way to accomplish this is
> > - * "get_call_rcu_data();", and another is create_all_cpu_call_rcu_data().
> > - */
> > -
> > -void call_rcu(struct rcu_head *head,
> > -	      void (*func)(struct rcu_head *head))
> > -{
> > -	struct call_rcu_data *crdp;
> > -
> > -	cds_wfq_node_init(&head->next);
> > -	head->func = func;
> > -	crdp = get_call_rcu_data();
> > -	cds_wfq_enqueue(&crdp->cbs, &head->next);
> > -	uatomic_inc(&crdp->qlen);
> > -	wake_call_rcu_thread(crdp);
> > -}
> > -
> > -/*
> > - * Free up the specified call_rcu_data structure, terminating the
> > - * associated call_rcu thread.  The caller must have previously
> > - * removed the call_rcu_data structure from per-thread or per-CPU
> > - * usage.  For example, set_cpu_call_rcu_data(cpu, NULL) for per-CPU
> > - * call_rcu_data structures or set_thread_call_rcu_data(NULL) for
> > - * per-thread call_rcu_data structures.
> > - *
> > - * We silently refuse to free up the default call_rcu_data structure
> > - * because that is where we put any leftover callbacks.  Note that
> > - * the possibility of self-spawning callbacks makes it impossible
> > - * to execute all the callbacks in finite time without putting any
> > - * newly spawned callbacks somewhere else.  The "somewhere else" of
> > - * last resort is the default call_rcu_data structure.
> > - *
> > - * We also silently refuse to free NULL pointers.  This simplifies
> > - * the calling code.
> > - */
> > -void call_rcu_data_free(struct call_rcu_data *crdp)
> > -{
> > -	struct cds_wfq_node *cbs;
> > -	struct cds_wfq_node **cbs_tail;
> > -	struct cds_wfq_node **cbs_endprev;
> > -
> > -	if (crdp == NULL || crdp == default_call_rcu_data) {
> > -		return;
> > -	}
> > -	if ((crdp->flags & URCU_CALL_RCU_STOPPED) == 0) {
> > -		call_rcu_lock(&crdp->mtx);
> > -		crdp->flags |= URCU_CALL_RCU_STOP;
> > -		call_rcu_unlock(&crdp->mtx);
> > -		wake_call_rcu_thread(crdp);
> > -		while ((crdp->flags & URCU_CALL_RCU_STOPPED) == 0)
> > -			poll(NULL, 0, 1);
> > -	}
> > -	if (&crdp->cbs.head != _CMM_LOAD_SHARED(crdp->cbs.tail)) {
> > -		while ((cbs = _CMM_LOAD_SHARED(crdp->cbs.head)) == NULL)
> > -			poll(NULL, 0, 1);
> > -		_CMM_STORE_SHARED(crdp->cbs.head, NULL);
> > -		cbs_tail = (struct cds_wfq_node **)
> > -			uatomic_xchg(&crdp->cbs.tail, &crdp->cbs.head);
> > -		cbs_endprev = (struct cds_wfq_node **)
> > -			uatomic_xchg(&default_call_rcu_data, cbs_tail);
> > -		*cbs_endprev = cbs;
> > -		uatomic_add(&default_call_rcu_data->qlen,
> > -			    uatomic_read(&crdp->qlen));
> > -		cds_list_del(&crdp->list);
> > -		free(crdp);
> > -	}
> > -}
> > -
> > -/*
> > - * Clean up all the per-CPU call_rcu threads.
> > - */
> > -void free_all_cpu_call_rcu_data(void)
> > -{
> > -	int cpu;
> > -	struct call_rcu_data *crdp;
> > -
> > -	if (maxcpus <= 0)
> > -		return;
> > -	for (cpu = 0; cpu < maxcpus; cpu++) {
> > -		crdp = get_cpu_call_rcu_data(cpu);
> > -		if (crdp == NULL)
> > -			continue;
> > -		set_cpu_call_rcu_data(cpu, NULL);
> > -		call_rcu_data_free(crdp);
> > -	}
> > -}
> > -
> > -/*
> > - * Acquire the call_rcu_mutex in order to ensure that the child sees
> > - * all of the call_rcu() data structures in a consistent state.
> > - * Suitable for pthread_atfork() and friends.
> > - */
> > -void call_rcu_before_fork(void)
> > -{
> > -	call_rcu_lock(&call_rcu_mutex);
> > -}
> > -
> > -/*
> > - * Clean up call_rcu data structures in the parent of a successful fork()
> > - * that is not followed by exec() in the child.  Suitable for
> > - * pthread_atfork() and friends.
> > - */
> > -void call_rcu_after_fork_parent(void)
> > -{
> > -	call_rcu_unlock(&call_rcu_mutex);
> > -}
> > -
> > -/*
> > - * Clean up call_rcu data structures in the child of a successful fork()
> > - * that is not followed by exec().  Suitable for pthread_atfork() and
> > - * friends.
> > - */
> > -void call_rcu_after_fork_child(void)
> > -{
> > -	struct call_rcu_data *crdp;
> > -
> > -	/* Re-initialize the mutex. */
> > -	if (pthread_mutex_init(&call_rcu_mutex, NULL) != 0) {
> > -		perror("pthread_mutex_init");
> > -		exit(-1);
> > -	}
> > -
> > -	/*
> > -	 * Allocate a new default call_rcu_data structure in order
> > -	 * to get a working call_rcu thread to go with it.
> > -	 */
> > -	default_call_rcu_data = NULL;
> > -	(void)get_default_call_rcu_data();
> > -
> > -	/* Dispose of all of the rest of the call_rcu_data structures. */
> > -	while (call_rcu_data_list.next != call_rcu_data_list.prev) {
> > -		crdp = cds_list_entry(call_rcu_data_list.prev,
> > -				      struct call_rcu_data, list);
> > -		if (crdp == default_call_rcu_data)
> > -			crdp = cds_list_entry(crdp->list.prev,
> > -					      struct call_rcu_data, list);
> > -		crdp->flags = URCU_CALL_RCU_STOPPED;
> > -		call_rcu_data_free(crdp);
> > -	}
> > -}
> > diff --git a/urcu-map.h b/urcu-map.h
> > new file mode 100644
> > index 0000000..eccaac2
> > --- /dev/null
> > +++ b/urcu-map.h
> > @@ -0,0 +1,117 @@
> > +#ifndef _URCU_MAP_H
> > +#define _URCU_MAP_H
> > +
> > +/*
> > + * urcu-map.h
> > + *
> > + * Userspace RCU header -- name mapping to allow multiple flavors to be
> > + * used in the same executable.
> > + *
> > + * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> > + * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
> > + *
> > + * LGPL-compatible code should include this header with :
> > + *
> > + * #define _LGPL_SOURCE
> > + * #include <urcu.h>
> > + *
> > + * This library is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU Lesser General Public
> > + * License as published by the Free Software Foundation; either
> > + * version 2.1 of the License, or (at your option) any later version.
> > + *
> > + * This library is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > + * Lesser General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU Lesser General Public
> > + * License along with this library; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> > + *
> > + * IBM's contributions to this file may be relicensed under LGPLv2 or later.
> > + */
> > +
> > +/* Mapping macros to allow multiple flavors in a single binary. */
> > +
> > +#ifdef RCU_MEMBARRIER
> > +
> > +#define rcu_read_lock			rcu_read_lock_memb
> > +#define _rcu_read_lock			_rcu_read_lock_memb
> > +#define rcu_read_unlock			rcu_read_unlock_memb
> > +#define _rcu_read_unlock		_rcu_read_unlock_memb
> > +#define rcu_register_thread		rcu_register_thread_memb
> > +#define rcu_unregister_thread		rcu_unregister_thread_memb
> > +#define rcu_init			rcu_init_memb
> > +#define rcu_exit			rcu_exit_memb
> > +#define synchronize_rcu			synchronize_rcu_memb
> > +#define rcu_reader			rcu_reader_memb
> > +#define rcu_gp_ctr			rcu_gp_ctr_memb
> > +
> > +#define get_cpu_call_rcu_data		get_cpu_call_rcu_data_memb
> > +#define get_call_rcu_thread		get_call_rcu_thread_memb
> > +#define create_call_rcu_data		create_call_rcu_data_memb
> > +#define set_cpu_call_rcu_data		set_cpu_call_rcu_data_memb
> > +#define get_default_call_rcu_data	get_default_call_rcu_data_memb
> > +#define get_call_rcu_data		get_call_rcu_data_memb
> > +#define get_thread_call_rcu_data	get_thread_call_rcu_data_memb
> > +#define set_thread_call_rcu_data	set_thread_call_rcu_data_memb
> > +#define create_all_cpu_call_rcu_data	create_all_cpu_call_rcu_data_memb
> > +#define free_all_cpu_call_rcu_data	free_all_cpu_call_rcu_data_memb
> > +#define call_rcu			call_rcu_memb
> > +
> > +#elif defined(RCU_SIGNAL)
> > +
> > +#define rcu_read_lock			rcu_read_lock_sig
> > +#define _rcu_read_lock			_rcu_read_lock_sig
> > +#define rcu_read_unlock			rcu_read_unlock_sig
> > +#define _rcu_read_unlock		_rcu_read_unlock_sig
> > +#define rcu_register_thread		rcu_register_thread_sig
> > +#define rcu_unregister_thread		rcu_unregister_thread_sig
> > +#define rcu_init			rcu_init_sig
> > +#define rcu_exit			rcu_exit_sig
> > +#define synchronize_rcu			synchronize_rcu_sig
> > +#define rcu_reader			rcu_reader_sig
> > +#define rcu_gp_ctr			rcu_gp_ctr_sig
> > +
> > +#define get_cpu_call_rcu_data		get_cpu_call_rcu_data_sig
> > +#define get_call_rcu_thread		get_call_rcu_thread_sig
> > +#define create_call_rcu_data		create_call_rcu_data_sig
> > +#define set_cpu_call_rcu_data		set_cpu_call_rcu_data_sig
> > +#define get_default_call_rcu_data	get_default_call_rcu_data_sig
> > +#define get_call_rcu_data		get_call_rcu_data_sig
> > +#define get_thread_call_rcu_data	get_thread_call_rcu_data_sig
> > +#define set_thread_call_rcu_data	set_thread_call_rcu_data_sig
> > +#define create_all_cpu_call_rcu_data	create_all_cpu_call_rcu_data_sig
> > +#define free_all_cpu_call_rcu_data	free_all_cpu_call_rcu_data_sig
> > +#define call_rcu			call_rcu_sig
> > +
> > +#elif defined(RCU_MB)
> > +
> > +#define rcu_read_lock			rcu_read_lock_mb
> > +#define _rcu_read_lock			_rcu_read_lock_mb
> > +#define rcu_read_unlock			rcu_read_unlock_mb
> > +#define _rcu_read_unlock		_rcu_read_unlock_mb
> > +#define rcu_register_thread		rcu_register_thread_mb
> > +#define rcu_unregister_thread		rcu_unregister_thread_mb
> > +#define rcu_init			rcu_init_mb
> > +#define rcu_exit			rcu_exit_mb
> > +#define synchronize_rcu			synchronize_rcu_mb
> > +#define rcu_reader			rcu_reader_mb
> > +#define rcu_gp_ctr			rcu_gp_ctr_mb
> > +
> > +#define get_cpu_call_rcu_data		get_cpu_call_rcu_data_mb
> > +#define get_call_rcu_thread		get_call_rcu_thread_mb
> > +#define create_call_rcu_data		create_call_rcu_data_mb
> > +#define set_cpu_call_rcu_data		set_cpu_call_rcu_data_mb
> > +#define get_default_call_rcu_data	get_default_call_rcu_data_mb
> > +#define get_call_rcu_data		get_call_rcu_data_mb
> > +#define get_thread_call_rcu_data	get_thread_call_rcu_data_mb
> > +#define set_thread_call_rcu_data	set_thread_call_rcu_data_mb
> > +#define create_all_cpu_call_rcu_data	create_all_cpu_call_rcu_data_mb
> > +#define free_all_cpu_call_rcu_data	free_all_cpu_call_rcu_data_mb
> > +#define call_rcu			call_rcu_mb
> > +
> > +#endif
> > +
> > +#endif /* _URCU_MAP_H */
> > diff --git a/urcu-qsbr-map.h b/urcu-qsbr-map.h
> > new file mode 100644
> > index 0000000..2bce1b6
> > --- /dev/null
> > +++ b/urcu-qsbr-map.h
> > @@ -0,0 +1,63 @@
> > +#ifndef _URCU_QSBR_MAP_H
> > +#define _URCU_QSBR_MAP_H
> > +
> > +/*
> > + * urcu-map.h
> > + *
> > + * Userspace RCU header -- name mapping to allow multiple flavors to be
> > + * used in the same executable.
> > + *
> > + * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> > + * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
> > + *
> > + * LGPL-compatible code should include this header with :
> > + *
> > + * #define _LGPL_SOURCE
> > + * #include <urcu.h>
> > + *
> > + * This library is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU Lesser General Public
> > + * License as published by the Free Software Foundation; either
> > + * version 2.1 of the License, or (at your option) any later version.
> > + *
> > + * This library is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > + * Lesser General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU Lesser General Public
> > + * License along with this library; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> > + *
> > + * IBM's contributions to this file may be relicensed under LGPLv2 or later.
> > + */
> > +
> > +/* Mapping macros to allow multiple flavors in a single binary. */
> > +
> > +#define rcu_read_lock			rcu_read_lock_qsbr
> > +#define _rcu_read_lock			_rcu_read_lock_qsbr
> > +#define rcu_read_unlock			rcu_read_unlock_qsbr
> > +#define _rcu_read_unlock		_rcu_read_unlock_qsbr
> > +#define rcu_quiescent_state		rcu_quiescent_state_qsbr
> > +#define _rcu_quiescent_state		_rcu_quiescent_state_qsbr
> > +#define rcu_thread_offline		rcu_thread_offline_qsbr
> > +#define rcu_thread_online		rcu_thread_online_qsbr
> > +#define rcu_register_thread		rcu_register_thread_qsbr
> > +#define rcu_unregister_thread		rcu_unregister_thread_qsbr
> > +#define rcu_exit			rcu_exit_qsbr
> > +#define synchronize_rcu			synchronize_rcu_qsbr
> > +#define rcu_reader			rcu_reader_qsbr
> > +#define rcu_gp_ctr			rcu_gp_ctr_qsbr
> > +
> > +#define get_cpu_call_rcu_data		get_cpu_call_rcu_data_qsbr
> > +#define get_call_rcu_thread		get_call_rcu_thread_qsbr
> > +#define create_call_rcu_data		create_call_rcu_data_qsbr
> > +#define set_cpu_call_rcu_data		set_cpu_call_rcu_data_qsbr
> > +#define get_default_call_rcu_data	get_default_call_rcu_data_qsbr
> > +#define get_call_rcu_data		get_call_rcu_data_qsbr
> > +#define get_thread_call_rcu_data	get_thread_call_rcu_data_qsbr
> > +#define set_thread_call_rcu_data	set_thread_call_rcu_data_qsbr
> > +#define create_all_cpu_call_rcu_data	create_all_cpu_call_rcu_data_qsbr
> > +#define call_rcu			call_rcu_qsbr
> > +
> > +#endif /* _URCU_QSBR_MAP_H */
> > diff --git a/urcu-qsbr.c b/urcu-qsbr.c
> > index 69effd5..8dcad33 100644
> > --- a/urcu-qsbr.c
> > +++ b/urcu-qsbr.c
> > @@ -32,6 +32,8 @@
> >  #include <errno.h>
> >  #include <poll.h>
> >  
> > +#include "urcu-qsbr-map.h"
> > +
> >  #define BUILD_QSBR_LIB
> >  #include "urcu-qsbr-static.h"
> >  /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
> > @@ -121,10 +123,11 @@ static void update_counter_and_wait(void)
> >  #endif	/* !(CAA_BITS_PER_LONG < 64) */
> >  
> >  	/*
> > -	 * Must commit rcu_gp_ctr update to memory before waiting for quiescent
> > -	 * state. Failure to do so could result in the writer waiting forever
> > -	 * while new readers are always accessing data (no progress). Enforce
> > -	 * compiler-order of store to rcu_gp_ctr before load rcu_reader ctr.
> > +	 * Must commit rcu_gp_ctr update to memory before waiting for
> > +	 * quiescent state. Failure to do so could result in the writer
> > +	 * waiting forever while new readers are always accessing data
> > +	 * (no progress). Enforce compiler-order of store to rcu_gp_ctr
> > +	 * before load rcu_reader ctr.
> >  	 */
> >  	cmm_barrier();
> >  
> > @@ -194,8 +197,8 @@ void synchronize_rcu(void)
> >  
> >  	/*
> >  	 * Mark the writer thread offline to make sure we don't wait for
> > -	 * our own quiescent state. This allows using synchronize_rcu() in
> > -	 * threads registered as readers.
> > +	 * our own quiescent state. This allows using synchronize_rcu()
> > +	 * in threads registered as readers.
> >  	 */
> >  	if (was_online)
> >  		CMM_STORE_SHARED(rcu_reader.ctr, 0);
> > @@ -212,10 +215,11 @@ void synchronize_rcu(void)
> >  
> >  	/*
> >  	 * Must finish waiting for quiescent state for parity 0 before
> > -	 * committing next rcu_gp_ctr update to memory. Failure to do so could
> > -	 * result in the writer waiting forever while new readers are always
> > -	 * accessing data (no progress).  Enforce compiler-order of load
> > -	 * rcu_reader ctr before store to rcu_gp_ctr.
> > +	 * committing next rcu_gp_ctr update to memory. Failure to
> > +	 * do so could result in the writer waiting forever while new
> > +	 * readers are always accessing data (no progress).  Enforce
> > +	 * compiler-order of load rcu_reader ctr before store to
> > +	 * rcu_gp_ctr.
> >  	 */
> >  	cmm_barrier();
> >  
> > @@ -238,7 +242,8 @@ out:
> >  	 * freed.
> >  	 */
> >  	if (was_online)
> > -		_CMM_STORE_SHARED(rcu_reader.ctr, CMM_LOAD_SHARED(rcu_gp_ctr));
> > +		_CMM_STORE_SHARED(rcu_reader.ctr,
> > +				  CMM_LOAD_SHARED(rcu_gp_ctr));
> >  	cmm_smp_mb();
> >  }
> >  #else /* !(CAA_BITS_PER_LONG < 64) */
> > @@ -250,8 +255,8 @@ void synchronize_rcu(void)
> >  
> >  	/*
> >  	 * Mark the writer thread offline to make sure we don't wait for
> > -	 * our own quiescent state. This allows using synchronize_rcu() in
> > -	 * threads registered as readers.
> > +	 * our own quiescent state. This allows using synchronize_rcu()
> > +	 * in threads registered as readers.
> >  	 */
> >  	cmm_smp_mb();
> >  	if (was_online)
> > @@ -265,7 +270,8 @@ out:
> >  	mutex_unlock(&rcu_gp_lock);
> >  
> >  	if (was_online)
> > -		_CMM_STORE_SHARED(rcu_reader.ctr, CMM_LOAD_SHARED(rcu_gp_ctr));
> > +		_CMM_STORE_SHARED(rcu_reader.ctr,
> > +				  CMM_LOAD_SHARED(rcu_gp_ctr));
> >  	cmm_smp_mb();
> >  }
> >  #endif  /* !(CAA_BITS_PER_LONG < 64) */
> > @@ -326,3 +332,5 @@ void rcu_exit(void)
> >  {
> >  	assert(cds_list_empty(&registry));
> >  }
> > +
> > +#include "urcu-call-rcu-impl.h"
> > diff --git a/urcu-qsbr.h b/urcu-qsbr.h
> > index 116fd77..984d70c 100644
> > --- a/urcu-qsbr.h
> > +++ b/urcu-qsbr.h
> > @@ -40,6 +40,8 @@
> >  extern "C" {
> >  #endif 
> >  
> > +#include "urcu-qsbr-map.h"
> > +
> >  /*
> >   * Important !
> >   *
> > @@ -62,15 +64,15 @@ extern "C" {
> >   * rcu_read_unlock()
> >   *
> >   * Mark the beginning and end of a read-side critical section.
> > - * DON'T FORGET TO USE rcu_register_thread/rcu_unregister_thread() FOR EACH
> > - * THREAD WITH READ-SIDE CRITICAL SECTION.
> > + * DON'T FORGET TO USE rcu_register_thread/rcu_unregister_thread()
> > + * FOR EACH THREAD WITH READ-SIDE CRITICAL SECTION.
> >   */
> > -#define rcu_read_lock()		_rcu_read_lock()
> > -#define rcu_read_unlock()	_rcu_read_unlock()
> > +#define rcu_read_lock_qsbr()		_rcu_read_lock()
> > +#define rcu_read_unlock_qsbr()		_rcu_read_unlock()
> >  
> > -#define rcu_quiescent_state()	_rcu_quiescent_state()
> > -#define rcu_thread_offline()	_rcu_thread_offline()
> > -#define rcu_thread_online()	_rcu_thread_online()
> > +#define rcu_quiescent_state_qsbr()	_rcu_quiescent_state()
> > +#define rcu_thread_offline_qsbr()	_rcu_thread_offline()
> > +#define rcu_thread_online_qsbr()	_rcu_thread_online()
> >  
> >  #else /* !_LGPL_SOURCE */
> >  
> > @@ -122,4 +124,6 @@ extern void rcu_unregister_thread(void);
> >  }
> >  #endif
> >  
> > +#include "urcu-call-rcu.h"
> > +
> >  #endif /* _URCU_QSBR_H */
> > diff --git a/urcu.c b/urcu.c
> > index e529ac0..4ee9e3b 100644
> > --- a/urcu.c
> > +++ b/urcu.c
> > @@ -33,6 +33,8 @@
> >  #include <errno.h>
> >  #include <poll.h>
> >  
> > +#include "urcu-map.h"
> > +
> >  #include "urcu-static.h"
> >  /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
> >  #include "urcu.h"
> > @@ -428,4 +430,7 @@ void rcu_exit(void)
> >  	assert(act.sa_sigaction == sigrcu_handler);
> >  	assert(cds_list_empty(&registry));
> >  }
> > +
> >  #endif /* #ifdef RCU_SIGNAL */
> > +
> > +#include "urcu-call-rcu-impl.h"
> > diff --git a/urcu.h b/urcu.h
> > index c6c54e7..00d9b75 100644
> > --- a/urcu.h
> > +++ b/urcu.h
> > @@ -43,12 +43,14 @@
> >  extern "C" {
> >  #endif 
> >  
> > +#include "urcu-map.h"
> > +
> >  /*
> >   * Important !
> >   *
> >   * Each thread containing read-side critical sections must be registered
> > - * with rcu_register_thread() before calling rcu_read_lock().
> > - * rcu_unregister_thread() should be called before the thread exits.
> > + * with rcu_register_thread_mb() before calling rcu_read_lock_mb().
> > + * rcu_unregister_thread_mb() should be called before the thread exits.
> >   */
> >  
> >  #ifdef _LGPL_SOURCE
> > @@ -68,8 +70,16 @@ extern "C" {
> >   * DON'T FORGET TO USE RCU_REGISTER/UNREGISTER_THREAD() FOR EACH THREAD WITH
> >   * READ-SIDE CRITICAL SECTION.
> >   */
> > -#define rcu_read_lock()		_rcu_read_lock()
> > -#define rcu_read_unlock()	_rcu_read_unlock()
> > +#ifdef RCU_MEMBARRIER
> > +#define rcu_read_lock_memb()		_rcu_read_lock()
> > +#define rcu_read_unlock_memb()		_rcu_read_unlock()
> > +#elif defined(RCU_SIGNAL)
> > +#define rcu_read_lock_sig()		_rcu_read_lock()
> > +#define rcu_read_unlock_sig()		_rcu_read_unlock()
> > +#elif defined(RCU_MB)
> > +#define rcu_read_lock_mb()		_rcu_read_lock()
> > +#define rcu_read_unlock_mb()		_rcu_read_unlock()
> > +#endif
> >  
> >  #else /* !_LGPL_SOURCE */
> >  
> > @@ -100,4 +110,6 @@ extern void rcu_init(void);
> >  }
> >  #endif
> >  
> > +#include "urcu-call-rcu.h"
> > +
> >  #endif /* _URCU_H */
> > -- 
> > 1.7.3.2
> > 
> 
> -- 
> Mathieu Desnoyers
> Operating System Efficiency R&D Consultant
> EfficiOS Inc.
> http://www.efficios.com
> 
> _______________________________________________
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> http://svcs.cs.pdx.edu/mailman/listinfo/rp