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| author | Uros Bizjak <ubizjak@gmail.com> | 2023-07-08 12:00:37 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2023-07-10 10:52:36 +0300 |
| commit | 1af61adb3a23192023fec1733bd4c8500f53e546 (patch) | |
| tree | c30d7a1b15c81c6a191937315acb04f4231b9b2d /scripts/gdb/linux/proc.py | |
| parent | d6b45484c130f4095313ae3edeb4aae662c12fb1 (diff) | |
| download | linux-1af61adb3a23192023fec1733bd4c8500f53e546.tar.xz | |
perf/ring_buffer: Use local_try_cmpxchg in __perf_output_begin
Use local_try_cmpxchg instead of local_cmpxchg (*ptr, old, new) == old
in __perf_output_begin. 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/20230708090048.63046-2-ubizjak@gmail.com
Diffstat (limited to 'scripts/gdb/linux/proc.py')
0 files changed, 0 insertions, 0 deletions