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io_uring: separate wq for ring polling

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Don't use ->cq_wait for ring polling but add a separate wait queue for
it. We need it for following patches.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/dea0be0bf990503443c5c6c337fc66824af7d590.1673274244.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2023-01-09 14:46:08 +00:00 committed by Jens Axboe
parent 360173ab9e
commit 7b235dd82a
3 changed files with 12 additions and 2 deletions
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2
include/linux/io_uring_types.h
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@ -319,7 +319,7 @@ struct io_ring_ctx {
} ____cacheline_aligned_in_smp;
/* Keep this last, we don't need it for the fast path */
struct wait_queue_head poll_wq;
struct io_restriction restrictions;
/* slow path rsrc auxilary data, used by update/register */

3
io_uring/io_uring.c
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@ -316,6 +316,7 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
xa_init_flags(&ctx->personalities, XA_FLAGS_ALLOC1);
mutex_init(&ctx->uring_lock);
init_waitqueue_head(&ctx->cq_wait);
init_waitqueue_head(&ctx->poll_wq);
spin_lock_init(&ctx->completion_lock);
spin_lock_init(&ctx->timeout_lock);
INIT_WQ_LIST(&ctx->iopoll_list);
@ -2786,7 +2787,7 @@ static __poll_t io_uring_poll(struct file *file, poll_table *wait)
struct io_ring_ctx *ctx = file->private_data;
__poll_t mask = 0;
poll_wait(file, &ctx->cq_wait, wait);
poll_wait(file, &ctx->poll_wq, wait);
/*
* synchronizes with barrier from wq_has_sleeper call in
* io_commit_cqring

9
io_uring/io_uring.h
View File

@ -220,9 +220,18 @@ static inline void io_commit_cqring(struct io_ring_ctx *ctx)
smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail);
}
static inline void io_poll_wq_wake(struct io_ring_ctx *ctx)
{
if (waitqueue_active(&ctx->poll_wq))
__wake_up(&ctx->poll_wq, TASK_NORMAL, 0,
poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
}
/* requires smb_mb() prior, see wq_has_sleeper() */
static inline void __io_cqring_wake(struct io_ring_ctx *ctx)
{
io_poll_wq_wake(ctx);
/*
* Trigger waitqueue handler on all waiters on our waitqueue. This
* won't necessarily wake up all the tasks, io_should_wake() will make