From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5B0FBC43217 for ; Fri, 24 Sep 2021 16:36:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 45CF761250 for ; Fri, 24 Sep 2021 16:36:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344536AbhIXQh7 (ORCPT ); Fri, 24 Sep 2021 12:37:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38466 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344295AbhIXQhe (ORCPT ); Fri, 24 Sep 2021 12:37:34 -0400 Received: from mail-ed1-x530.google.com (mail-ed1-x530.google.com [IPv6:2a00:1450:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B2491C0613B2 for ; Fri, 24 Sep 2021 09:32:56 -0700 (PDT) Received: by mail-ed1-x530.google.com with SMTP id v10so33637927edj.10 for ; Fri, 24 Sep 2021 09:32:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:subject:date:message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=ICK5PzlL5i2QqvO+uOhA/pZmBoa9TwplmAAuAcPIBcc=; b=CziP585WNT67ciQYCRUgjAC9MJp1hZxgs75RXjWO+Addd/OH7I7NUcYxc6o0YFBIjt oVk59QXVx6T93e8QJMlQdJ3mpTiRKlXWNJomUM8ZeFPw+7U3HWOYGtpzwPIq79A+mnTG O6G2p2xPaPoj3eq5lmGCJ7eVAfmtaMwwL9h57wKhh6F1YKFIEsCnX1VYl6vgjGk3TCy4 b+EZgaYxGEx41YVCGk+9XDfMkmkjx4ySVsF5n+foOXtQNkV6cgcKNkC2E00+lmbWczbB eNXqxF4SOVzVUjsPBVsflVCVU9sEpkEdszCiA4+zCSPyQuNcCgcoiBAx/TLW0BVNe6DN eCng== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=ICK5PzlL5i2QqvO+uOhA/pZmBoa9TwplmAAuAcPIBcc=; b=siQoHrJGj0+LDHkT+x1T8w0RaauJhh7EVauzdfLmwMhpQ29RoidTsm1QMdEB5nUlp6 hT/QT/H90Yc7RbVeHo6t+VBvFc9kX/qulzL7FYW3w2PoFm+G+T0prq2lVWlxETVAMkxa ubileMdTcI9avnwcG9upnUGNwBEOwfXEfav6iORqbammhTUgWRO6kwnObSeyjhZQk8tA NRlzCDHB/6xTU6agTog6NWJShXKlegu8U5ZLdSOWHXgFGMEoUN4sMWUHarFVv4YAOFI6 UYAK9AnOP+jU0VgCqWDGqWofX67ApFIOnN7UGGSQ7RmjAz+bVLu5ILLsplXvLYxMoQz2 +JSA== X-Gm-Message-State: AOAM531uN1HlViI/26wxOhijRqo15cinDYHE8HYUJbY+lJ3owsag6QUx yM/9lz700J8enVLQQrRqofn/uHZ1hy4= X-Google-Smtp-Source: ABdhPJw2WCKI0L3fhQ9gwWZ3DerIr+QLb8+ZSnkvZmToOitE8XlRaG53C4Qs9I8J8JW62D+8goVH3Q== X-Received: by 2002:a17:906:cc57:: with SMTP id mm23mr12417867ejb.540.1632501175290; Fri, 24 Sep 2021 09:32:55 -0700 (PDT) Received: from localhost.localdomain ([85.255.232.225]) by smtp.gmail.com with ESMTPSA id w10sm6167021eds.30.2021.09.24.09.32.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 24 Sep 2021 09:32:54 -0700 (PDT) From: Pavel Begunkov To: Jens Axboe , io-uring@vger.kernel.org Subject: [PATCH 09/23] io_uring: use single linked list for iopoll Date: Fri, 24 Sep 2021 17:31:47 +0100 Message-Id: X-Mailer: git-send-email 2.33.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Use single linked lists for keeping iopoll requests, takes less space, may be faster, but mostly will be of benefit for further patches. Signed-off-by: Pavel Begunkov --- fs/io-wq.h | 3 +++ fs/io_uring.c | 53 ++++++++++++++++++++++++++------------------------- 2 files changed, 30 insertions(+), 26 deletions(-) diff --git a/fs/io-wq.h b/fs/io-wq.h index c870062105d1..87ba6a733630 100644 --- a/fs/io-wq.h +++ b/fs/io-wq.h @@ -32,6 +32,9 @@ struct io_wq_work_list { #define wq_list_for_each(pos, prv, head) \ for (pos = (head)->first, prv = NULL; pos; prv = pos, pos = (pos)->next) +#define wq_list_for_each_resume(pos, prv) \ + for (; pos; prv = pos, pos = (pos)->next) + #define wq_list_empty(list) (READ_ONCE((list)->first) == NULL) #define INIT_WQ_LIST(list) do { \ (list)->first = NULL; \ diff --git a/fs/io_uring.c b/fs/io_uring.c index e0f897c3779d..f4a7468c4570 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -413,7 +413,7 @@ struct io_ring_ctx { * For SQPOLL, only the single threaded io_sq_thread() will * manipulate the list, hence no extra locking is needed there. */ - struct list_head iopoll_list; + struct io_wq_work_list iopoll_list; struct hlist_head *cancel_hash; unsigned cancel_hash_bits; bool poll_multi_queue; @@ -1307,7 +1307,7 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) init_waitqueue_head(&ctx->cq_wait); spin_lock_init(&ctx->completion_lock); spin_lock_init(&ctx->timeout_lock); - INIT_LIST_HEAD(&ctx->iopoll_list); + INIT_WQ_LIST(&ctx->iopoll_list); INIT_LIST_HEAD(&ctx->defer_list); INIT_LIST_HEAD(&ctx->timeout_list); INIT_LIST_HEAD(&ctx->ltimeout_list); @@ -2443,15 +2443,9 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, struct list_head *done) io_req_free_batch_finish(ctx, &rb); } -/* same as "continue" but starts from the pos, not next to it */ -#define list_for_each_entry_safe_resume(pos, n, head, member) \ - for (n = list_next_entry(pos, member); \ - !list_entry_is_head(pos, head, member); \ - pos = n, n = list_next_entry(n, member)) - static int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin) { - struct io_kiocb *req, *tmp; + struct io_wq_work_node *pos, *start, *prev; LIST_HEAD(done); int nr_events = 0; bool spin; @@ -2462,7 +2456,8 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin) */ spin = !ctx->poll_multi_queue && !force_nonspin; - list_for_each_entry(req, &ctx->iopoll_list, inflight_entry) { + wq_list_for_each(pos, start, &ctx->iopoll_list) { + struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list); struct kiocb *kiocb = &req->rw.kiocb; int ret; @@ -2485,14 +2480,20 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin) break; } - list_for_each_entry_safe_resume(req, tmp, &ctx->iopoll_list, - inflight_entry) { + if (!pos) + return 0; + + prev = start; + wq_list_for_each_resume(pos, prev) { + struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list); + if (!READ_ONCE(req->iopoll_completed)) break; - list_move_tail(&req->inflight_entry, &done); + list_add_tail(&req->inflight_entry, &done); nr_events++; } + wq_list_cut(&ctx->iopoll_list, prev, start); if (nr_events) io_iopoll_complete(ctx, &done); return nr_events; @@ -2508,7 +2509,7 @@ static void io_iopoll_try_reap_events(struct io_ring_ctx *ctx) return; mutex_lock(&ctx->uring_lock); - while (!list_empty(&ctx->iopoll_list)) { + while (!wq_list_empty(&ctx->iopoll_list)) { /* let it sleep and repeat later if can't complete a request */ if (io_do_iopoll(ctx, true) == 0) break; @@ -2557,7 +2558,7 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, long min) * forever, while the workqueue is stuck trying to acquire the * very same mutex. */ - if (list_empty(&ctx->iopoll_list)) { + if (wq_list_empty(&ctx->iopoll_list)) { u32 tail = ctx->cached_cq_tail; mutex_unlock(&ctx->uring_lock); @@ -2566,7 +2567,7 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, long min) /* some requests don't go through iopoll_list */ if (tail != ctx->cached_cq_tail || - list_empty(&ctx->iopoll_list)) + wq_list_empty(&ctx->iopoll_list)) break; } ret = io_do_iopoll(ctx, !min); @@ -2726,14 +2727,14 @@ static void io_iopoll_req_issued(struct io_kiocb *req) * how we do polling eventually, not spinning if we're on potentially * different devices. */ - if (list_empty(&ctx->iopoll_list)) { + if (wq_list_empty(&ctx->iopoll_list)) { ctx->poll_multi_queue = false; } else if (!ctx->poll_multi_queue) { struct io_kiocb *list_req; unsigned int queue_num0, queue_num1; - list_req = list_first_entry(&ctx->iopoll_list, struct io_kiocb, - inflight_entry); + list_req = container_of(ctx->iopoll_list.first, struct io_kiocb, + comp_list); if (list_req->file != req->file) { ctx->poll_multi_queue = true; @@ -2750,9 +2751,9 @@ static void io_iopoll_req_issued(struct io_kiocb *req) * it to the front so we find it first. */ if (READ_ONCE(req->iopoll_completed)) - list_add(&req->inflight_entry, &ctx->iopoll_list); + wq_list_add_head(&req->comp_list, &ctx->iopoll_list); else - list_add_tail(&req->inflight_entry, &ctx->iopoll_list); + wq_list_add_tail(&req->comp_list, &ctx->iopoll_list); if (unlikely(in_async)) { /* @@ -7313,14 +7314,14 @@ static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries) if (cap_entries && to_submit > IORING_SQPOLL_CAP_ENTRIES_VALUE) to_submit = IORING_SQPOLL_CAP_ENTRIES_VALUE; - if (!list_empty(&ctx->iopoll_list) || to_submit) { + if (!wq_list_empty(&ctx->iopoll_list) || to_submit) { const struct cred *creds = NULL; if (ctx->sq_creds != current_cred()) creds = override_creds(ctx->sq_creds); mutex_lock(&ctx->uring_lock); - if (!list_empty(&ctx->iopoll_list)) + if (!wq_list_empty(&ctx->iopoll_list)) io_do_iopoll(ctx, true); /* @@ -7398,7 +7399,7 @@ static int io_sq_thread(void *data) list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) { int ret = __io_sq_thread(ctx, cap_entries); - if (!sqt_spin && (ret > 0 || !list_empty(&ctx->iopoll_list))) + if (!sqt_spin && (ret > 0 || !wq_list_empty(&ctx->iopoll_list))) sqt_spin = true; } if (io_run_task_work()) @@ -7419,7 +7420,7 @@ static int io_sq_thread(void *data) io_ring_set_wakeup_flag(ctx); if ((ctx->flags & IORING_SETUP_IOPOLL) && - !list_empty_careful(&ctx->iopoll_list)) { + !wq_list_empty(&ctx->iopoll_list)) { needs_sched = false; break; } @@ -9541,7 +9542,7 @@ static void io_uring_try_cancel_requests(struct io_ring_ctx *ctx, /* SQPOLL thread does its own polling */ if ((!(ctx->flags & IORING_SETUP_SQPOLL) && cancel_all) || (ctx->sq_data && ctx->sq_data->thread == current)) { - while (!list_empty_careful(&ctx->iopoll_list)) { + while (!wq_list_empty(&ctx->iopoll_list)) { io_iopoll_try_reap_events(ctx); ret = true; } -- 2.33.0