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| author | Uros Bizjak <ubizjak@gmail.com> | 2023-07-08 10:10:57 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2023-07-10 09:52:35 +0200 |
| commit | 28fd85a10a2a73658c6e26056d9e093de06b5a22 (patch) | |
| tree | 2f5baf61f8679a758238d02b337b3a3bc515ca57 /arch/mips/include/asm | |
| parent | 4c1c9dea2089374cb58505a0df6136969ff3c8b9 (diff) | |
| download | lwn-28fd85a10a2a73658c6e26056d9e093de06b5a22.tar.gz lwn-28fd85a10a2a73658c6e26056d9e093de06b5a22.zip | |
perf/core: Use local64_try_cmpxchg in perf_swevent_set_period
Use local64_try_cmpxchg instead of local64_cmpxchg (*ptr, old, new) == old
in perf_swevent_set_period. 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.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230708081129.45915-1-ubizjak@gmail.com
Diffstat (limited to 'arch/mips/include/asm')
0 files changed, 0 insertions, 0 deletions