* [ltt-dev] [PATCH urcu 1/5] Provide pthread_atfork-friendly interfaces
2011-06-02 23:44 [ltt-dev] [PATCH userspace-rcu] Allow multiple flavors of RCU in same executable Paul E. McKenney
@ 2011-06-02 23:45 ` Paul E. McKenney
2011-06-02 23:45 ` [ltt-dev] [PATCH urcu 2/5] Map symbols to allow multiple RCU flavors to be used in one binary Paul E. McKenney
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: Paul E. McKenney @ 2011-06-02 23:45 UTC (permalink / raw)
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 | 26 +++++++++++++++++++++++++-
2 files changed, 29 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..9cc56c5 100644
--- a/urcu-call-rcu.c
+++ b/urcu-call-rcu.c
@@ -566,13 +566,37 @@ 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;
+ /* Release the mutex. */
+ call_rcu_unlock(&call_rcu_mutex);
+
/*
* 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
^ permalink raw reply [flat|nested] 7+ messages in thread* [ltt-dev] [PATCH urcu 2/5] Map symbols to allow multiple RCU flavors to be used in one binary
2011-06-02 23:44 [ltt-dev] [PATCH userspace-rcu] Allow multiple flavors of RCU in same executable Paul E. McKenney
2011-06-02 23:45 ` [ltt-dev] [PATCH urcu 1/5] Provide pthread_atfork-friendly interfaces Paul E. McKenney
@ 2011-06-02 23:45 ` Paul E. McKenney
2011-06-02 23:45 ` [ltt-dev] [PATCH urcu 3/5] Allow taking address of rcu_read_lock() and rcu_read_unlock() Paul E. McKenney
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: Paul E. McKenney @ 2011-06-02 23:45 UTC (permalink / raw)
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 | 615 +++++++++++++++++++++++++++++++++++++++++++++++++
urcu-call-rcu.c | 617 --------------------------------------------------
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, 942 insertions(+), 672 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 776fa2b..4b70644 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..9fa6aa6
--- /dev/null
+++ b/urcu-call-rcu-impl.h
@@ -0,0 +1,615 @@
+/*
+ * 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;
+
+ /* Release the mutex. */
+ call_rcu_unlock(&call_rcu_mutex);
+
+ /*
+ * 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 9cc56c5..0000000
--- a/urcu-call-rcu.c
+++ /dev/null
@@ -1,617 +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;
-
- /* Release the mutex. */
- call_rcu_unlock(&call_rcu_mutex);
-
- /*
- * 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(®istry));
}
+
+#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(®istry));
}
+
#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
^ permalink raw reply [flat|nested] 7+ messages in thread* [ltt-dev] [PATCH urcu 3/5] Allow taking address of rcu_read_lock() and rcu_read_unlock()
2011-06-02 23:44 [ltt-dev] [PATCH userspace-rcu] Allow multiple flavors of RCU in same executable Paul E. McKenney
2011-06-02 23:45 ` [ltt-dev] [PATCH urcu 1/5] Provide pthread_atfork-friendly interfaces Paul E. McKenney
2011-06-02 23:45 ` [ltt-dev] [PATCH urcu 2/5] Map symbols to allow multiple RCU flavors to be used in one binary Paul E. McKenney
@ 2011-06-02 23:45 ` Paul E. McKenney
2011-06-02 23:45 ` [ltt-dev] [PATCH urcu 4/5] Make defer_rcu() usable from library using multiple URCU implementations Paul E. McKenney
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: Paul E. McKenney @ 2011-06-02 23:45 UTC (permalink / raw)
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
^ permalink raw reply [flat|nested] 7+ messages in thread* [ltt-dev] [PATCH urcu 4/5] Make defer_rcu() usable from library using multiple URCU implementations
2011-06-02 23:44 [ltt-dev] [PATCH userspace-rcu] Allow multiple flavors of RCU in same executable Paul E. McKenney
` (2 preceding siblings ...)
2011-06-02 23:45 ` [ltt-dev] [PATCH urcu 3/5] Allow taking address of rcu_read_lock() and rcu_read_unlock() Paul E. McKenney
@ 2011-06-02 23:45 ` Paul E. McKenney
2011-06-02 23:45 ` [ltt-dev] [PATCH urcu 5/5] Document the new call_rcu() primitives Paul E. McKenney
2011-06-03 16:47 ` [ltt-dev] [PATCH userspace-rcu] Allow multiple flavors of RCU in same executable Mathieu Desnoyers
5 siblings, 0 replies; 7+ messages in thread
From: Paul E. McKenney @ 2011-06-02 23:45 UTC (permalink / raw)
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 4b70644..1589884 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, ®istry_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(®istry_defer))
+ return;
+
+ mutex_lock_defer(&rcu_defer_mutex);
+ cds_list_for_each_entry(index, ®istry_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, ®istry_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(®istry_defer);
+ cds_list_add(&defer_queue.list, ®istry_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(®istry_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(®istry_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, ®istry, 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(®istry))
- return;
-
- mutex_lock(&rcu_defer_mutex);
- cds_list_for_each_entry(index, ®istry, 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, ®istry, 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(®istry);
- cds_list_add(&defer_queue.list, ®istry);
- 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(®istry);
- 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(®istry));
-}
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
^ permalink raw reply [flat|nested] 7+ messages in thread* [ltt-dev] [PATCH urcu 5/5] Document the new call_rcu() primitives.
2011-06-02 23:44 [ltt-dev] [PATCH userspace-rcu] Allow multiple flavors of RCU in same executable Paul E. McKenney
` (3 preceding siblings ...)
2011-06-02 23:45 ` [ltt-dev] [PATCH urcu 4/5] Make defer_rcu() usable from library using multiple URCU implementations Paul E. McKenney
@ 2011-06-02 23:45 ` Paul E. McKenney
2011-06-03 16:47 ` [ltt-dev] [PATCH userspace-rcu] Allow multiple flavors of RCU in same executable Mathieu Desnoyers
5 siblings, 0 replies; 7+ messages in thread
From: Paul E. McKenney @ 2011-06-02 23:45 UTC (permalink / raw)
Signed-off-by: Paul E. McKenney <paulmck at linux.vnet.ibm.com>
---
API.txt | 120 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
README | 16 ++++++++
2 files changed, 136 insertions(+), 0 deletions(-)
create mode 100644 API.txt
diff --git a/API.txt b/API.txt
new file mode 100644
index 0000000..162ca93
--- /dev/null
+++ b/API.txt
@@ -0,0 +1,120 @@
+Userspace RCU API
+by Mathieu Desnoyers and Paul E. McKenney
+
+
+void rcu_init(void);
+
+ This must be called before any of the following functions
+ are invoked.
+
+void rcu_read_lock(void);
+
+ Begin an RCU read-side critical section. These critical
+ sections may be nested.
+
+void rcu_read_unlock(void);
+
+ End an RCU read-side critical section.
+
+void rcu_register_thread(void)
+
+ Each thread must invoke this function before its first call to
+ rcu_read_lock(). Threads that never call rcu_read_lock() need
+ not invoke this function. In addition, rcu-bp ("bullet proof"
+ RCU) does not require any thread to invoke rcu_register_thread().
+
+void rcu_unregister_thread(void)
+
+ Each thread that invokes rcu_register_thread() must invoke
+ rcu_unregister_thread() before invoking pthread_exit()
+ or before returning from its top-level function.
+
+void synchronize_rcu(void);
+
+ Wait until every pre-existing RCU read-side critical section
+ has completed. Note that this primitive will not necessarily
+ wait for RCU read-side critical sections that have not yet
+ started: this is not a reader-writer lock. The duration
+ actually waited is called an RCU grace period.
+
+void call_rcu(struct rcu_head *head,
+ void (*func)(struct rcu_head *head));
+
+ Registers the callback indicated by "head". This means
+ that "func" will be invoked after the end of a future
+ RCU grace period. The rcu_head structure referenced
+ by "head" will normally be a field in a larger RCU-protected
+ structure. A typical implementation of "func" is as
+ follows:
+
+ void func(struct rcu_head *head)
+ {
+ struct foo *p = container_of(head, struct foo, rcu);
+
+ free(p);
+ }
+
+ This RCU callback function can be registered as follows
+ given a pointer "p" to the enclosing structure:
+
+ call_rcu(&p->rcu, func);
+
+struct call_rcu_data *create_call_rcu_data(unsigned long flags);
+
+ Returns a handle that can be passed to the following
+ primitives. The "flags" argument can be zero, or can be
+ URCU_CALL_RCU_RT if the worker threads associated with the
+ new helper thread are to get real-time response.
+
+struct call_rcu_data *get_default_call_rcu_data(void);
+
+ Returns the handle of the default call_rcu() helper thread.
+
+struct call_rcu_data *get_call_rcu_data(void);
+
+ Returns the handle of the current thread's call_rcu() helper
+ thread, which might well be the default helper thread.
+
+struct call_rcu_data *get_thread_call_rcu_data(void);
+
+ Returns the handle for the current thread's hard-assigned
+ call_rcu() helper thread, or NULL if the current thread is
+ instead using a per-CPU or the default helper thread.
+
+void set_thread_call_rcu_data(struct call_rcu_data *crdp);
+
+ Sets the current thread's hard-assigned call_rcu() helper to the
+ handle specified by "crdp". Note that "crdp" can be NULL to
+ disassociate this thread from its helper. Once a thread is
+ disassociated from its helper, further call_rcu() invocations
+ use the current CPU's helper if there is one and the default
+ helper otherwise.
+
+int set_cpu_call_rcu_data(int cpu, struct call_rcu_data *crdp);
+
+ Sets the specified CPU's call_rcu() helper to the handle
+ specified by "crdp". Again, "crdp" can be NULL to disassociate
+ this CPU from its helper thread. Once a CPU has been
+ disassociated from its helper, further call_rcu() invocations
+ that would otherwise have used this CPU's helper will instead
+ use the default helper.
+
+int create_all_cpu_call_rcu_data(unsigned long flags)
+
+ Creates a separate call_rcu() helper thread for each CPU.
+ After this primitive is invoked, the global default call_rcu()
+ helper thread will not be called.
+
+ The set_thread_call_rcu_data(), set_cpu_call_rcu_data(), and
+ create_all_cpu_call_rcu_data() functions may be combined to set up
+ pretty much any desired association between worker and call_rcu()
+ helper threads. If a given executable calls only call_rcu(),
+ then that executable will have only the single global default
+ call_rcu() helper thread. This will suffice in most cases.
+
+void call_rcu_data_free(struct call_rcu_data *crdp)
+
+ Terminates a call_rcu() helper thread and frees its associated
+ data. The caller must have ensured that this thread is no longer
+ in use, for example, by passing NULL to set_thread_call_rcu_data()
+ and set_cpu_call_rcu_data() as required.
diff --git a/README b/README
index 7d97f19..a6e29c8 100644
--- a/README
+++ b/README
@@ -139,6 +139,22 @@ Usage of liburcu-defer
* Its API is currently experimental. It may change in future library
releases.
+Usage of urcu-call-rcu
+
+ * Follow instructions for either liburcu, liburcu-qsbr,
+ liburcu-mb, liburcu-signal, or liburcu-bp above.
+ The urcu-call-rcu functionality is provided for each of
+ these library modules.
+ * Provides the call_rcu() primitive to enqueue delayed callbacks
+ in a manner similar to defer_rcu(), but without ever delaying
+ for a grace period. On the other hand, call_rcu()'s best-case
+ overhead is not quite as good as that of defer_rcu().
+ * Provides call_rcu() to allow asynchronous handling of RCU
+ grace periods. A number of additional functions are provided
+ to manage the helper threads used by call_rcu(), but reasonable
+ defaults are used if these additional functions are not invoked.
+ See API.txt for more details.
+
Being careful with signals
The liburcu library uses signals internally. The signal handler is
--
1.7.3.2
^ permalink raw reply [flat|nested] 7+ messages in thread* [ltt-dev] [PATCH userspace-rcu] Allow multiple flavors of RCU in same executable
2011-06-02 23:44 [ltt-dev] [PATCH userspace-rcu] Allow multiple flavors of RCU in same executable Paul E. McKenney
` (4 preceding siblings ...)
2011-06-02 23:45 ` [ltt-dev] [PATCH urcu 5/5] Document the new call_rcu() primitives Paul E. McKenney
@ 2011-06-03 16:47 ` Mathieu Desnoyers
5 siblings, 0 replies; 7+ messages in thread
From: Mathieu Desnoyers @ 2011-06-03 16:47 UTC (permalink / raw)
* Paul E. McKenney (paulmck at linux.vnet.ibm.com) wrote:
> Hello!
>
> This series of patches permits a single executable to use multiple
> flavors of userspace RCU. This is important, as it allows userspace
> RCU to be used freely by multiple libraries without requiring that
> the multiple authors of this library code to come to agreement about
> which flavor of userspace RCU they will all use.
>
> This is updated from the version posted on May 31st to add documentation
> and to make the child atfork interface use unlocking rather than
> re-initialization.
All merged and pushed, thanks Paul !
Mathieu
>
> Thanx, Paul
>
> ------------------------------------------------------------------------
>
> Makefile.am | 4
> README | 36 ++
> a/urcu-call-rcu.c | 617 -------------------------------------------------
> b/API.txt | 120 +++++++++
> 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 | 615 ++++++++++++++++++++++++++++++++++++++++++++++++
> b/urcu-call-rcu.c | 26 +-
> 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 -
> 33 files changed, 1627 insertions(+), 1192 deletions(-)
>
> _______________________________________________
> 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
^ permalink raw reply [flat|nested] 7+ messages in thread