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| author |   Uros Bizjak <ubizjak@gmail.com> | 2022-07-12 17:05:47 +0200 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2022-07-12 14:38:52 -0600 |
| commit | f4b1e27db49c8b985b116aa99481b4c6a4342ed4 (patch) | |
| tree | 00b3861f47de1e179c300fc038c78fc1a3854a5f /tools/perf/scripts/python/bin/stackcollapse-report | |
| parent | blk-mq: don't create hctx debugfs dir until q->debugfs_dir is created (diff) | |
block/rq_qos: Use atomic_try_cmpxchg in atomic_inc_below
Use atomic_try_cmpxchg instead of atomic_cmpxchg (*ptr, old, new) == old in
atomic_inc_below. 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.
No functional change intended.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20220712150547.5786-1-ubizjak@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'tools/perf/scripts/python/bin/stackcollapse-report')
0 files changed, 0 insertions, 0 deletions