Messages in this thread Patch in this message | | | From | Davidlohr Bueso <> | Subject | [PATCH 2/2] kernel/smp: Use make csd_lock_wait be smp_cond_acquire | Date | Wed, 9 Mar 2016 17:55:36 -0800 |
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From: Davidlohr Bueso <dave@stgolabs>
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> --- kernel/smp.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/kernel/smp.c b/kernel/smp.c index c91e00178f8f..74165443c240 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) -- 2.1.4
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