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| author | Pavel Begunkov <asml.silence@gmail.com> | 2023-04-06 14:20:12 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2023-04-06 16:23:28 -0600 |
| commit | 8751d15426a31baaf40f7570263c27c3e5d1dc44 (patch) | |
| tree | ce78034f5b032052374c63e97c403143511365a2 /io_uring/notif.h | |
| parent | 5150940079a3ce94d7474f6f5b0d6276569dc1de (diff) | |
| download | linux-8751d15426a31baaf40f7570263c27c3e5d1dc44.tar.gz linux-8751d15426a31baaf40f7570263c27c3e5d1dc44.tar.bz2 linux-8751d15426a31baaf40f7570263c27c3e5d1dc44.zip | |
io_uring: reduce scheduling due to tw
Every task_work will try to wake the task to be executed, which causes
excessive scheduling and additional overhead. For some tw it's
justified, but others won't do much but post a single CQE.
When a task waits for multiple cqes, every such task_work will wake it
up. Instead, the task may give a hint about how many cqes it waits for,
io_req_local_work_add() will compare against it and skip wake ups
if #cqes + #tw is not enough to satisfy the waiting condition. Task_work
that uses the optimisation should be simple enough and never post more
than one CQE. It's also ignored for non DEFER_TASKRUN rings.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d2b77e99d1e86624d8a69f7037d764b739dcd225.1680782017.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring/notif.h')
| -rw-r--r-- | io_uring/notif.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/io_uring/notif.h b/io_uring/notif.h index c88c800cd89d..6dd1b30a468f 100644 --- a/io_uring/notif.h +++ b/io_uring/notif.h @@ -33,7 +33,7 @@ static inline void io_notif_flush(struct io_kiocb *notif) /* drop slot's master ref */ if (refcount_dec_and_test(&nd->uarg.refcnt)) - io_req_task_work_add(notif); + __io_req_task_work_add(notif, IOU_F_TWQ_LAZY_WAKE); } static inline int io_notif_account_mem(struct io_kiocb *notif, unsigned len) |