Home
last modified time | relevance | path

Searched hist:"7 c34e318" (Results 1 – 1 of 1) sorted by relevance

/linux/kernel/sched/
H A Dcompletion.c7c34e318 Fri Jan 23 11:41:47 GMT 2015 Nicholas Mc Guire <der.herr@hofr.at> sched/completion: Add lock-free checking of the blocking case

The "thread would block" case can be checked without grabbing ->wait.lock.

[ If the check does not return early then grab the lock and recheck.
A memory barrier is not needed as complete() and complete_all() imply
a barrier.

The ACCESS_ONCE() is needed for calls in a loop that, if inlined, could
optimize out the re-fetching of x->done. ]

Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1422013307-13200-1-git-send-email-der.herr@hofr.at
Signed-off-by: Ingo Molnar <mingo@kernel.org>