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io_uring: limit {io|sq}poll submit locking scope

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We don't need to take uring_lock for SQPOLL|IOPOLL to do
io_cqring_overflow_flush() when cq_overflow_list is empty, remove it
from the hot path.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2020-12-17 00:24:39 +00:00 committed by Jens Axboe
parent 09e88404f4
commit 89448c47b8
1 changed files with 6 additions and 3 deletions
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9
fs/io_uring.c
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@ -9154,10 +9154,13 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
*/
ret = 0;
if (ctx->flags & IORING_SETUP_SQPOLL) {
io_ring_submit_lock(ctx, (ctx->flags & IORING_SETUP_IOPOLL));
if (!list_empty_careful(&ctx->cq_overflow_list))
if (!list_empty_careful(&ctx->cq_overflow_list)) {
bool needs_lock = ctx->flags & IORING_SETUP_IOPOLL;
io_ring_submit_lock(ctx, needs_lock);
io_cqring_overflow_flush(ctx, false, NULL, NULL);
io_ring_submit_unlock(ctx, (ctx->flags & IORING_SETUP_IOPOLL));
io_ring_submit_unlock(ctx, needs_lock);
}
if (flags & IORING_ENTER_SQ_WAKEUP)
wake_up(&ctx->sq_data->wait);
if (flags & IORING_ENTER_SQ_WAIT)