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| author | Davidlohr Bueso <dave@stgolabs> | 2016-03-09 17:55:36 -0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-03-10 10:28:35 +0100 |
| commit | 38460a2178d225b39ade5ac66586c3733391cf86 (patch) | |
| tree | 189a70cb0386f09af432c2580b03c404bc6e24b3 /kernel/smp.c | |
| parent | 90d1098478fb08a1ef166fe91622d8046869e17b (diff) | |
| download | linux-38460a2178d225b39ade5ac66586c3733391cf86.tar.gz linux-38460a2178d225b39ade5ac66586c3733391cf86.tar.bz2 linux-38460a2178d225b39ade5ac66586c3733391cf86.zip | |
locking/csd_lock: Use smp_cond_acquire() in csd_lock_wait()
We can micro-optimize this call and mildly relax the
barrier requirements by relying on ctrl + rmb, keeping
the acquire semantics. In addition, this is pretty much
the now standard for busy-waiting under such restraints.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Link: http://lkml.kernel.org/r/1457574936-19065-3-git-send-email-dbueso@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/smp.c')
| -rw-r--r-- | kernel/smp.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/kernel/smp.c b/kernel/smp.c index 5099db15c5fb..300d29391e07 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -107,8 +107,7 @@ void __init call_function_init(void) */ static __always_inline void csd_lock_wait(struct call_single_data *csd) { - while (smp_load_acquire(&csd->flags) & CSD_FLAG_LOCK) - cpu_relax(); + smp_cond_acquire(!(csd->flags & CSD_FLAG_LOCK)); } static __always_inline void csd_lock(struct call_single_data *csd) |