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| author | Pavel Begunkov <asml.silence@gmail.com> | 2023-04-06 16:20:12 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2023-04-07 01:23:28 +0300 |
| commit | 8751d15426a31baaf40f7570263c27c3e5d1dc44 (patch) | |
| tree | ce78034f5b032052374c63e97c403143511365a2 /include/linux/io_uring_types.h | |
| parent | 5150940079a3ce94d7474f6f5b0d6276569dc1de (diff) | |
| download | linux-8751d15426a31baaf40f7570263c27c3e5d1dc44.tar.xz | |
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 'include/linux/io_uring_types.h')
| -rw-r--r-- | include/linux/io_uring_types.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h index 4a6ce03a4903..fa621a508a01 100644 --- a/include/linux/io_uring_types.h +++ b/include/linux/io_uring_types.h @@ -296,7 +296,7 @@ struct io_ring_ctx { spinlock_t completion_lock; bool poll_multi_queue; - bool cq_waiting; + atomic_t cq_wait_nr; /* * ->iopoll_list is protected by the ctx->uring_lock for @@ -566,6 +566,7 @@ struct io_kiocb { atomic_t refs; atomic_t poll_refs; struct io_task_work io_task_work; + unsigned nr_tw; /* for polled requests, i.e. IORING_OP_POLL_ADD and async armed poll */ union { struct hlist_node hash_node; |