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| author | Uros Bizjak <ubizjak@gmail.com> | 2022-08-23 17:26:32 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2022-09-11 21:55:10 -0700 |
| commit | 5fdfa161b2043001f82cbce49e87e8e9f581d510 (patch) | |
| tree | e3326441233ff70650de4244502dd08ea438cdd1 /virt | |
| parent | 977bbf4385fc64986f22b024858071a35c481a8a (diff) | |
task_work: use try_cmpxchg in task_work_add, task_work_cancel_match and task_work_run
Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in
task_work_add, task_work_cancel_match and task_work_run. 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, atomic_try_cmpxchg implicitly assigns old *ptr value to "old"
when cmpxchg fails, enabling further code simplifications.
The patch avoids extra memory read in case cmpxchg fails.
Link: https://lkml.kernel.org/r/20220823152632.4517-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'virt')
0 files changed, 0 insertions, 0 deletions