io_uring: remove extra tw trylocks
authorPavel Begunkov <asml.silence@gmail.com>
Mon, 27 Mar 2023 15:38:14 +0000 (16:38 +0100)
committerJens Axboe <axboe@kernel.dk>
Mon, 3 Apr 2023 13:16:15 +0000 (07:16 -0600)
commit13bfa6f15d0b39254937076ab0557da6875bb455
tree673a5d032900decd9b93d7e4462a6b5696f608be
parent07d99096e1635805fb7c60382dc12554886a39b8
io_uring: remove extra tw trylocks

Before cond_resched()'ing in handle_tw_list() we also drop the current
ring context, and so the next loop iteration will need to pick/pin a new
context and do trylock.

The chunk removed by this patch was intended to be an optimisation
covering exactly this case, i.e. retaking the lock after reschedule, but
in reality it's skipped for the first iteration after resched as
described and will keep hammering the lock if it's contended.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1ecec9483d58696e248d1bfd52cf62b04442df1d.1679931367.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_uring/io_uring.c