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| author |   Uros Bizjak <ubizjak@gmail.com> | 2022-07-14 19:32:55 +0200 |
|---|---|---|
| committer |   Andrew Morton <akpm@linux-foundation.org> | 2022-09-11 21:55:07 -0700 |
| commit | 693fc06e98514c2d5951ead4aca40cf8b21100b1 (patch) | |
| tree | 442f100b654ab0af29f2e068850c0d88eb1fbe5f /fs/eventpoll.c | |
| parent | ia64: fix clock_getres(CLOCK_MONOTONIC) to report ITC frequency (diff) | |
| download | linux-dev-693fc06e98514c2d5951ead4aca40cf8b21100b1.tar.xz linux-dev-693fc06e98514c2d5951ead4aca40cf8b21100b1.zip | |
epoll: use try_cmpxchg in list_add_tail_lockless
Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in
list_add_tail_lockless. x86 CMPXCHG instruction returns success in ZF
flag, so this change saves a compare after cmpxchg (and related move
instruction in front of cmpxchg).
No functional change intended.
Link: https://lkml.kernel.org/r/20220714173255.12987-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/eventpoll.c')
| -rw-r--r-- | fs/eventpoll.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 8b56b94e2f56..52954d4637b5 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -1065,7 +1065,7 @@ static inline bool list_add_tail_lockless(struct list_head *new, * added to the list from another CPU: the winner observes * new->next == new. */ - if (cmpxchg(&new->next, new, head) != new) + if (!try_cmpxchg(&new->next, &new, head)) return false; /* |