From f28c240e7152462f0750a8939db28d985ecf7c67 Mon Sep 17 00:00:00 2001 From: Hao Xu Date: Wed, 8 Dec 2021 13:21:25 +0800 Subject: [PATCH] io_uring: batch completion in prior_task_list 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 Link: https://lore.kernel.org/r/20211208052125.351587-1-haoxu@linux.alibaba.com Reviewed-by: Pavel Begunkov Signed-off-by: Jens Axboe --- fs/io_uring.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 60 insertions(+), 11 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 21738ed..92dc3351 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2225,7 +2225,49 @@ static void ctx_flush_and_put(struct io_ring_ctx *ctx, bool *locked) percpu_ref_put(&ctx->refs); } -static void handle_tw_list(struct io_wq_work_node *node, struct io_ring_ctx **ctx, bool *locked) +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_prev_tw_list(struct io_wq_work_node *node, + struct io_ring_ctx **ctx, bool *uring_locked) +{ + if (*ctx && !*uring_locked) + spin_lock(&(*ctx)->completion_lock); + + 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(!*uring_locked && *ctx)) + ctx_commit_and_unlock(*ctx); + + ctx_flush_and_put(*ctx, uring_locked); + *ctx = req->ctx; + /* if not contended, grab and improve batching */ + *uring_locked = mutex_trylock(&(*ctx)->uring_lock); + percpu_ref_get(&(*ctx)->refs); + if (unlikely(!*uring_locked)) + spin_lock(&(*ctx)->completion_lock); + } + if (likely(*uring_locked)) + req->io_task_work.func(req, uring_locked); + else + __io_req_complete_post(req, req->result, io_put_kbuf(req)); + node = next; + } while (node); + + if (unlikely(!*uring_locked)) + ctx_commit_and_unlock(*ctx); +} + +static void handle_tw_list(struct io_wq_work_node *node, + struct io_ring_ctx **ctx, bool *locked) { do { struct io_wq_work_node *next = node->next; @@ -2246,31 +2288,38 @@ static void handle_tw_list(struct io_wq_work_node *node, struct io_ring_ctx **ct static void tctx_task_work(struct callback_head *cb) { - bool locked = false; + bool uring_locked = false; struct io_ring_ctx *ctx = NULL; struct io_uring_task *tctx = container_of(cb, struct io_uring_task, 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 && uring_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_prev_tw_list(node1, &ctx, &uring_locked); + + if (node2) + handle_tw_list(node2, &ctx, &uring_locked); cond_resched(); } - ctx_flush_and_put(ctx, &locked); + ctx_flush_and_put(ctx, &uring_locked); } static void io_req_task_work_add(struct io_kiocb *req, bool priority) @@ -2759,7 +2808,7 @@ static void io_complete_rw(struct kiocb *kiocb, long res) return; req->result = res; req->io_task_work.func = io_req_task_complete; - io_req_task_work_add(req, true); + io_req_task_work_add(req, !!(req->ctx->flags & IORING_SETUP_SQPOLL)); } static void io_complete_rw_iopoll(struct kiocb *kiocb, long res) -- 2.7.4