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From: Hao Xu <[email protected]>
To: Jens Axboe <[email protected]>
Cc: [email protected], Pavel Begunkov <[email protected]>,
	Joseph Qi <[email protected]>
Subject: [PATCH RESEND 6/6] io_uring: batch completion in prior_task_list
Date: Fri, 26 Nov 2021 21:37:49 +0800	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

In previous patches, we have already gathered some tw with
io_req_task_complete() as callback in prior_task_list, let's complete
them in batch while we cannot grab uring lock. In this way, we batch
the req_complete_post path.

Signed-off-by: Hao Xu <[email protected]>
---
 fs/io_uring.c | 58 ++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 51 insertions(+), 7 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index e9c67f19d585..b7515de45c00 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2223,6 +2223,43 @@ static inline unsigned int io_put_rw_kbuf(struct io_kiocb *req)
 	return io_put_kbuf(req, req->kbuf);
 }
 
+static inline void ctx_commit_and_unlock(struct io_ring_ctx *ctx)
+{
+	io_commit_cqring(ctx);
+	spin_unlock(&ctx->completion_lock);
+	io_cqring_ev_posted(ctx);
+}
+
+static void handle_prior_tw_list(struct io_wq_work_node *node, struct io_ring_ctx **ctx,
+				 bool *locked)
+{
+	do {
+		struct io_wq_work_node *next = node->next;
+		struct io_kiocb *req = container_of(node, struct io_kiocb,
+						    io_task_work.node);
+
+		if (req->ctx != *ctx) {
+			if (unlikely(!*locked) && *ctx)
+				ctx_commit_and_unlock(*ctx);
+			ctx_flush_and_put(*ctx, locked);
+			*ctx = req->ctx;
+			/* if not contended, grab and improve batching */
+			*locked = mutex_trylock(&(*ctx)->uring_lock);
+			percpu_ref_get(&(*ctx)->refs);
+			if (unlikely(!*locked))
+				spin_lock(&(*ctx)->completion_lock);
+		}
+		if (likely(*locked))
+			req->io_task_work.func(req, locked);
+		else
+			__io_req_complete_post(req, req->result, io_put_rw_kbuf(req));
+		node = next;
+	} while (node);
+
+	if (unlikely(!*locked) && *ctx)
+		ctx_commit_and_unlock(*ctx);
+}
+
 static void handle_tw_list(struct io_wq_work_node *node, struct io_ring_ctx **ctx, bool *locked)
 {
 	do {
@@ -2250,21 +2287,28 @@ static void tctx_task_work(struct callback_head *cb)
 						  task_work);
 
 	while (1) {
-		struct io_wq_work_node *node;
+		struct io_wq_work_node *node1, *node2;
 
-		if (!tctx->prior_task_list.first &&
-		    !tctx->task_list.first && locked)
+		if (!tctx->task_list.first &&
+		    !tctx->prior_task_list.first && locked)
 			io_submit_flush_completions(ctx);
 
 		spin_lock_irq(&tctx->task_lock);
-		node= wq_list_merge(&tctx->prior_task_list, &tctx->task_list);
-		if (!node)
+		node1 = tctx->prior_task_list.first;
+		node2 = tctx->task_list.first;
+		INIT_WQ_LIST(&tctx->task_list);
+		INIT_WQ_LIST(&tctx->prior_task_list);
+		if (!node2 && !node1)
 			tctx->task_running = false;
 		spin_unlock_irq(&tctx->task_lock);
-		if (!node)
+		if (!node2 && !node1)
 			break;
 
-		handle_tw_list(node, &ctx, &locked);
+		if (node1)
+			handle_prior_tw_list(node1, &ctx, &locked);
+
+		if (node2)
+			handle_tw_list(node2, &ctx, &locked);
 		cond_resched();
 	}
 
-- 
2.24.4


  parent reply	other threads:[~2021-11-26 13:39 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-26 10:07 [PATCH v6 0/6] task work optimization Hao Xu
2021-11-26 10:07 ` [PATCH 1/6] io-wq: add helper to merge two wq_lists Hao Xu
2021-11-26 10:07 ` [PATCH 2/6] io_uring: add a priority tw list for irq completion work Hao Xu
2021-11-26 10:07 ` [PATCH 3/6] io_uring: add helper for task work execution code Hao Xu
2021-11-26 10:07 ` [PATCH 4/6] io_uring: split io_req_complete_post() and add a helper Hao Xu
2021-11-26 10:07 ` [PATCH 5/6] io_uring: move up io_put_kbuf() and io_put_rw_kbuf() Hao Xu
2021-11-26 10:07 ` [PATCH 6/6] io_uring: batch completion in prior_task_list Hao Xu
2021-11-26 12:56   ` Hao Xu
2021-11-26 13:37 ` Hao Xu [this message]
2021-11-27 15:24   ` [PATCH v7] " Hao Xu
2021-11-28 15:28     ` Pavel Begunkov
2021-12-03  1:39 ` [PATCH v6 0/6] task work optimization Pavel Begunkov
2021-12-03  2:01   ` Pavel Begunkov
2021-12-03  7:30     ` Hao Xu
2021-12-03 14:21       ` Pavel Begunkov
2021-12-05 15:02         ` Hao Xu
2021-12-05 15:42           ` Pavel Begunkov
2021-12-06  8:35             ` Hao Xu
2021-12-06  9:48               ` Hao Xu
2021-12-03  3:24   ` Hao Xu
2021-12-04 20:58 ` Pavel Begunkov
2021-12-05 15:11   ` Hao Xu

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