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authorPeter Zijlstra <peterz@infradead.org>2016-04-04 10:57:12 +0200
committerIngo Molnar <mingo@kernel.org>2016-06-14 11:54:27 +0200
commit1f03e8d2919270bd6ef64f39a45ce8df8a9f012a (patch)
tree0cdd5de370212a021d0a1a3439bbc4b0a77fea8b /kernel/smp.c
parentMerge branch 'linus' into locking/core, to pick up fixes before merging new c... (diff)
downloadlinux-1f03e8d2919270bd6ef64f39a45ce8df8a9f012a.tar.xz
linux-1f03e8d2919270bd6ef64f39a45ce8df8a9f012a.zip
locking/barriers: Replace smp_cond_acquire() with smp_cond_load_acquire()
This new form allows using hardware assisted waiting. Some hardware (ARM64 and x86) allow monitoring an address for changes, so by providing a pointer we can use this to replace the cpu_relax() with hardware optimized methods in the future. Requested-by: Will Deacon <will.deacon@arm.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/smp.c')
-rw-r--r--kernel/smp.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/smp.c b/kernel/smp.c
index 74165443c240..36552beed397 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -107,7 +107,7 @@ void __init call_function_init(void)
*/
static __always_inline void csd_lock_wait(struct call_single_data *csd)
{
- smp_cond_acquire(!(csd->flags & CSD_FLAG_LOCK));
+ smp_cond_load_acquire(&csd->flags, !(VAL & CSD_FLAG_LOCK));
}
static __always_inline void csd_lock(struct call_single_data *csd)