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| author | Uros Bizjak <[email protected]> | 2022-10-20 15:51:04 +0000 |
|---|---|---|
| committer | Song Liu <[email protected]> | 2022-11-14 17:35:50 +0000 |
| commit | 9487a0f6855c1a28e4e39d41545cd19ed417c015 (patch) | |
| tree | 09b4b8c272be00cdb285275f17b11119bb167643 /lib/raid6/algos.c | |
| parent | drivers/md/md-bitmap: check the return value of md_bitmap_get_counter() (diff) | |
| download | kernel-9487a0f6855c1a28e4e39d41545cd19ed417c015.tar.gz kernel-9487a0f6855c1a28e4e39d41545cd19ed417c015.zip | |
raid5-cache: use try_cmpxchg in r5l_wake_reclaim
Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in
r5l_wake_reclaim. 86 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.
Note that the value from *ptr should be read using READ_ONCE to prevent
the compiler from merging, refetching or reordering the read.
No functional change intended.
Cc: Song Liu <[email protected]>
Signed-off-by: Uros Bizjak <[email protected]>
Signed-off-by: Song Liu <[email protected]>
Diffstat (limited to 'lib/raid6/algos.c')
0 files changed, 0 insertions, 0 deletions