From e58d498e81baa9fd8acf5132d8b2d4f829361f6b Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Tue, 12 Jul 2022 21:52:40 +0100 Subject: io_uring: complete notifiers in tw We need a task context to post CQEs but using wq is too expensive. Try to complete notifiers using task_work and fall back to wq if fails. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/089799ab665b10b78fdc614ae6d59fa7ef0d5f91.1657643355.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- io_uring/notif.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) (limited to 'io_uring/notif.c') diff --git a/io_uring/notif.c b/io_uring/notif.c index b257db2120b4..aec74f88fc33 100644 --- a/io_uring/notif.c +++ b/io_uring/notif.c @@ -13,6 +13,11 @@ static void __io_notif_complete_tw(struct callback_head *cb) struct io_notif *notif = container_of(cb, struct io_notif, task_work); struct io_ring_ctx *ctx = notif->ctx; + if (likely(notif->task)) { + io_put_task(notif->task, 1); + notif->task = NULL; + } + io_cq_lock(ctx); io_fill_cqe_aux(ctx, notif->tag, 0, notif->seq, true); @@ -43,6 +48,14 @@ static void io_uring_tx_zerocopy_callback(struct sk_buff *skb, if (!refcount_dec_and_test(&uarg->refcnt)) return; + + if (likely(notif->task)) { + init_task_work(¬if->task_work, __io_notif_complete_tw); + if (likely(!task_work_add(notif->task, ¬if->task_work, + TWA_SIGNAL))) + return; + } + INIT_WORK(¬if->commit_work, io_notif_complete_wq); queue_work(system_unbound_wq, ¬if->commit_work); } @@ -134,12 +147,15 @@ __cold int io_notif_unregister(struct io_ring_ctx *ctx) for (i = 0; i < ctx->nr_notif_slots; i++) { struct io_notif_slot *slot = &ctx->notif_slots[i]; - if (slot->notif) - io_notif_slot_flush(slot); + if (!slot->notif) + continue; + if (WARN_ON_ONCE(slot->notif->task)) + slot->notif->task = NULL; + io_notif_slot_flush(slot); } kvfree(ctx->notif_slots); ctx->notif_slots = NULL; ctx->nr_notif_slots = 0; return 0; -} \ No newline at end of file +} -- cgit v1.2.3