diff options
| author | Uros Bizjak <ubizjak@gmail.com> | 2023-07-06 16:16:48 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2023-07-10 09:52:35 +0200 |
| commit | 4c1c9dea2089374cb58505a0df6136969ff3c8b9 (patch) | |
| tree | 31ccb01e981ee0bf63342378bbd0f1e3c2ff3474 /kernel/events | |
| parent | perf/amd: Prevent grouping of IBS events (diff) | |
| download | linux-4c1c9dea2089374cb58505a0df6136969ff3c8b9.tar.xz linux-4c1c9dea2089374cb58505a0df6136969ff3c8b9.zip | |
perf/x86: Use local64_try_cmpxchg
Use local64_try_cmpxchg instead of local64_cmpxchg (*ptr, old, new) == old.
x86 CMPXCHG instruction returns success in ZF flag, so this change saves a
compare after cmpxchg (and related move instruction in front of cmpxchg).
Also, try_cmpxchg implicitly assigns old *ptr value to "old" when cmpxchg
fails. There is no need to re-read the value in the loop.
No functional change intended.
Cc. "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230706141720.2672-1-ubizjak@gmail.com
Diffstat (limited to 'kernel/events')
0 files changed, 0 insertions, 0 deletions