From patchwork Mon Jan 9 14:46:10 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Begunkov X-Patchwork-Id: 13093691 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 15382C5479D for ; Mon, 9 Jan 2023 14:51:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234828AbjAIOve (ORCPT ); Mon, 9 Jan 2023 09:51:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41518 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229649AbjAIOvO (ORCPT ); Mon, 9 Jan 2023 09:51:14 -0500 Received: from mail-ej1-x62d.google.com (mail-ej1-x62d.google.com [IPv6:2a00:1450:4864:20::62d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E53E53E841 for ; Mon, 9 Jan 2023 06:47:38 -0800 (PST) Received: by mail-ej1-x62d.google.com with SMTP id az20so1624758ejc.1 for ; Mon, 09 Jan 2023 06:47:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=7g4vgDRhIhKHTbt0MChXU5vp/QdCButiCZ9Su7pb0b8=; b=CHbMHC0uXaxbNKNzqTBlD0wDepE3G6WeD0Z15shtB9BZt5mmj2MqtKaQ62HR/ukZ1E uX3ID5v9jrAw5U/LJwOQCb2R0cRJ99VRAQOK9ton95ti8Y88t6O93nCDlfYoNnUlMUvQ ptdpGrd3rZLouSoeDDYVom67/Wx3dvEPlXk+TnOoeG+P1TvOYCLce/maOmAyD5mvqw/x yEPddoM8KC6V3iDFVmNGSv75rRpYetFzMafJuBExUHyAIulIeVpgNQSlQVvSvniwIpQs uRtuqintDss0mH/pzNBlZ+9wOe6eHVuicvOXxVs6IzqXPQmlMiN2Muy8aGi5ghffeIjs UHhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=7g4vgDRhIhKHTbt0MChXU5vp/QdCButiCZ9Su7pb0b8=; b=AwkN1UZZlDNGLEVsZ8FR5bjujbw7FB4tsSXyHSpk8jfNNmeiFADOt5LqJlYnQqX5rA 71LC0/JHaTfeyuTgyVwhkz2kpGxPhQWflAnVNspBytCHMfqMS2b3EVSJmQjSD8kW+LVB 4FzWztRzNo0hg4moK7XldNSvApDKV4Fqwlxrlcq9CWer1I9ZQNF0VZRj4D8O6OFh/ZGg z+plFX4IQEhWLXDaN3KpSCX3kYb95ZpoedaAP+AQ5LHiQ5d1Q9pc+uyciLZXhTR/a99C bc1H88Ebh5reVVjOmAAbZwHovvPqa09EBJVNXpr9MmjfNVzMzzR12TIRhuejskejiGy6 m2xQ== X-Gm-Message-State: AFqh2kojfE7AhMH3KQ/ngimM0Xe4/Vw83nnOc9o1m44z38QwO/0JObxN AFEF5qX9MQ8EIEE9KZLo8F90vxRmoVw= X-Google-Smtp-Source: AMrXdXtAE+7WmhaMEg6Wk1Y95LJBvOVkgrCR1+XhVRX0hqfmvrQUNOMwraoOrIezC6oRcaF6z+0ACw== X-Received: by 2002:a17:907:c717:b0:7c1:ad6:638a with SMTP id ty23-20020a170907c71700b007c10ad6638amr60330073ejc.17.1673275657331; Mon, 09 Jan 2023 06:47:37 -0800 (PST) Received: from 127.0.0.1localhost (188.29.102.7.threembb.co.uk. [188.29.102.7]) by smtp.gmail.com with ESMTPSA id x11-20020a170906b08b00b0084c62b7b7d8sm3839578ejy.187.2023.01.09.06.47.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Jan 2023 06:47:37 -0800 (PST) From: Pavel Begunkov To: io-uring@vger.kernel.org Cc: Jens Axboe , asml.silence@gmail.com Subject: [PATCH v3 08/11] io_uring: wake up optimisations Date: Mon, 9 Jan 2023 14:46:10 +0000 Message-Id: <60ad9768ec74435a0ddaa6eec0ffa7729474f69f.1673274244.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Flush completions is done either from the submit syscall or by the task_work, both are in the context of the submitter task, and when it goes for a single threaded rings like implied by ->task_complete, there won't be any waiters on ->cq_wait but the master task. That means that there can be no tasks sleeping on cq_wait while we run __io_submit_flush_completions() and so waking up can be skipped. Signed-off-by: Pavel Begunkov --- io_uring/io_uring.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index a6ed022c1356..0dabd0f3271f 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -621,6 +621,25 @@ static inline void __io_cq_unlock_post(struct io_ring_ctx *ctx) io_cqring_wake(ctx); } +static inline void __io_cq_unlock_post_flush(struct io_ring_ctx *ctx) + __releases(ctx->completion_lock) +{ + io_commit_cqring(ctx); + __io_cq_unlock(ctx); + io_commit_cqring_flush(ctx); + + /* + * As ->task_complete implies that the ring is single tasked, cq_wait + * may only be waited on by the current in io_cqring_wait(), but since + * it will re-check the wakeup conditions once we return we can safely + * skip waking it up. + */ + if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) { + smp_mb(); + __io_cqring_wake(ctx); + } +} + void io_cq_unlock_post(struct io_ring_ctx *ctx) __releases(ctx->completion_lock) { @@ -1480,7 +1499,7 @@ static void __io_submit_flush_completions(struct io_ring_ctx *ctx) } } } - __io_cq_unlock_post(ctx); + __io_cq_unlock_post_flush(ctx); if (!wq_list_empty(&ctx->submit_state.compl_reqs)) { io_free_batch_list(ctx, state->compl_reqs.first);