[ltt-dev] [URCU PATCH v2 1/2] caa: let per-arch files provide cmm_smp_* barriers

[pbonzini@redhat.com (Paolo Bonzini)]

x86 instructions lfence and sfence are rarely needed, and we want
the cmm_smp_rmb/cmm_smp_wmb macros to be simple compiler barriers.
So, let the per-arch files override the default definitions in
arch/generic.h.

Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
---
 urcu/arch/generic.h |   28 ++++++++++++++++++++++++++++
 1 files changed, 28 insertions(+), 0 deletions(-)

diff --git a/urcu/arch/generic.h b/urcu/arch/generic.h
index 100d3c6..1ea7f59 100644
--- a/urcu/arch/generic.h
+++ b/urcu/arch/generic.h
@@ -100,22 +100,50 @@ extern "C" {
 #endif
 
 #ifdef CONFIG_RCU_SMP
+#ifndef cmm_smp_mb
 #define cmm_smp_mb()	cmm_mb()
+#endif
+#ifndef cmm_smp_rmb
 #define cmm_smp_rmb()	cmm_rmb()
+#endif
+#ifndef cmm_smp_wmb
 #define cmm_smp_wmb()	cmm_wmb()
+#endif
+#ifndef cmm_smp_mc
 #define cmm_smp_mc()	cmm_mc()
+#endif
+#ifndef cmm_smp_rmc
 #define cmm_smp_rmc()	cmm_rmc()
+#endif
+#ifndef cmm_smp_wmc
 #define cmm_smp_wmc()	cmm_wmc()
+#endif
+#ifndef cmm_smp_read_barrier_depends
 #define cmm_smp_read_barrier_depends()	cmm_read_barrier_depends()
+#endif
 #else
+#ifndef cmm_smp_mb
 #define cmm_smp_mb()	cmm_barrier()
+#endif
+#ifndef cmm_smp_rmb
 #define cmm_smp_rmb()	cmm_barrier()
+#endif
+#ifndef cmm_smp_wmb
 #define cmm_smp_wmb()	cmm_barrier()
+#endif
+#ifndef cmm_smp_mc
 #define cmm_smp_mc()	cmm_barrier()
+#endif
+#ifndef cmm_smp_rmc
 #define cmm_smp_rmc()	cmm_barrier()
+#endif
+#ifndef cmm_smp_wmc
 #define cmm_smp_wmc()	cmm_barrier()
+#endif
+#ifndef cmm_smp_read_barrier_depends
 #define cmm_smp_read_barrier_depends()
 #endif
+#endif
 
 #ifndef caa_cpu_relax
 #define caa_cpu_relax()		cmm_barrier()
-- 
1.7.6