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author | Uros Bizjak <ubizjak@gmail.com> | 2022-09-08 18:12:00 +0300 |
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committer | Jens Axboe <axboe@kernel.dk> | 2022-09-08 18:22:42 +0300 |
commit | c35227d4e8cbc70a6622cc7cc5f8c3bff513f1fa (patch) | |
tree | 2cf72382f2a2bbedf515081f5fb6d4513742b82a /scripts/dev-needs.sh | |
parent | 1de7c3cf48fc41cd95adb12bd1ea9033a917798a (diff) | |
download | linux-c35227d4e8cbc70a6622cc7cc5f8c3bff513f1fa.tar.xz |
sbitmap: Use atomic_long_try_cmpxchg in __sbitmap_queue_get_batch
Use atomic_long_try_cmpxchg instead of
atomic_long_cmpxchg (*ptr, old, new) == old in __sbitmap_queue_get_batch.
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_long_cmpxchg implicitly assigns old *ptr value to "old"
when cmpxchg fails, enabling further code simplifications, e.g.
an extra memory read can be avoided in the loop.
No functional change intended.
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Link: https://lore.kernel.org/r/20220908151200.9993-1-ubizjak@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'scripts/dev-needs.sh')
0 files changed, 0 insertions, 0 deletions