From patchwork Tue Aug 15 17:31:42 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Begunkov X-Patchwork-Id: 13354004 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 92086C41513 for ; Tue, 15 Aug 2023 17:34:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238873AbjHORdb (ORCPT ); Tue, 15 Aug 2023 13:33:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49760 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238933AbjHORdZ (ORCPT ); Tue, 15 Aug 2023 13:33:25 -0400 Received: from mail-ej1-x635.google.com (mail-ej1-x635.google.com [IPv6:2a00:1450:4864:20::635]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B51F11BDC for ; Tue, 15 Aug 2023 10:33:24 -0700 (PDT) Received: by mail-ej1-x635.google.com with SMTP id a640c23a62f3a-986d8332f50so765027066b.0 for ; Tue, 15 Aug 2023 10:33:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1692120803; x=1692725603; 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=cvhsasKZJnva2wCI0Nz03kKnyZToCj12NVuapLyWr3E=; b=QXOuJsGn0ubTXKg7iFhwp218Gn17b+QOWBWZ7v5Z1Syj9NX/QRiLwKvZj6CGvfB6A+ dUs+XbfdUd+YmB5oFO/ROlxqsLbhKsig7Cdnm53oq294v2VFLBmpbpbNpx86cQXbB2Rk JLcX7oWSDYpwgg/qneeI+VrYjhpb1p8d6jDti0Yxu9mSyVYTM4R8S9f+QOc/QtbwtQkS PgWoAOkmVkg7kCpn+x6S1qXN6OG4XhR+MTB7xm/VIIAqUE7Ozqny192lJ+fqnFTCklr2 mYKM6heVoeuWtUoqU0L6QCFn6UKsobVn5u6K1VGN7Hb7hfwyqwNvUmYFBocj/ZJZWMo1 7pTg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692120803; x=1692725603; 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=cvhsasKZJnva2wCI0Nz03kKnyZToCj12NVuapLyWr3E=; b=TE22TcJfkGDNQhAqXFOdlHt4QGIZTO/m88H+mPxyAhkKJnYsCrKzzttpxHipUTSls+ 3j3mUoNsnMpGdMhEGCxOdG8cQncJDicGCbqWK3HwyoNIElMSO6HADco1wrRf1bzxAfiG qoikgMRlZA/lUBIdzBoWvOEcxggfU8u+emzJKB9Lj4L5RHRrAIU76I2XIinm94LCB5Hi Y9qqljImG9OW4zny8e/qBy+hOiU4oCZXJ3vEkzU7LiF2mNBAJjaMWfeN3FWt8R7H1G5+ zPUIrTEgiVcwBvKU0CUfsEgC6RqGhbV9zKw773/RrqCQAlTxZtG7eoUEdBwlMNnnLCPL 273w== X-Gm-Message-State: AOJu0YwG6V1ELBzMIwsD7DkRXEiSKiLDLRMOzN2/vw2ZXlPc6xMV83uR LdM09ZP1NekWCIkl6lsMyzQ8C0k7VLA= X-Google-Smtp-Source: AGHT+IEPp/DvW2GuU3r3wzBD04B8ywxjV7YDaoEUK4NouO6zrB1K5n4APRiRVlOa+V+U3ljLX/KUWQ== X-Received: by 2002:a17:907:2ceb:b0:99c:22e0:ae84 with SMTP id hz11-20020a1709072ceb00b0099c22e0ae84mr10192137ejc.28.1692120802969; Tue, 15 Aug 2023 10:33:22 -0700 (PDT) Received: from 127.com ([2620:10d:c092:600::2:6d35]) by smtp.gmail.com with ESMTPSA id kk9-20020a170907766900b0099cc36c4681sm7269878ejc.157.2023.08.15.10.33.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Aug 2023 10:33:22 -0700 (PDT) From: Pavel Begunkov To: io-uring@vger.kernel.org Cc: Jens Axboe , asml.silence@gmail.com Subject: [PATCH 13/16] io_uring: separate task_work/waiting cache line Date: Tue, 15 Aug 2023 18:31:42 +0100 Message-ID: <37c3b2f2563587f531dbc9cb4cf3ad6da1e33a94.1692119257.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org task_work's are typically queued up from IRQ/softirq potentially by a random CPU like in case of networking. Batch ctx fields bouncing as this into a separate cache line. We also move ->cq_timeouts there because waiters have to read and check it. We can also conditionally hide ->cq_timeouts in the future from the CQ wait path as a not really useful rudiment. Signed-off-by: Pavel Begunkov --- include/linux/io_uring_types.h | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h index 72e609752323..5de5dffe29df 100644 --- a/include/linux/io_uring_types.h +++ b/include/linux/io_uring_types.h @@ -270,15 +270,25 @@ struct io_ring_ctx { unsigned cached_cq_tail; unsigned cq_entries; struct io_ev_fd __rcu *io_ev_fd; - struct wait_queue_head cq_wait; unsigned cq_extra; } ____cacheline_aligned_in_smp; + /* + * task_work and async notification delivery cacheline. Expected to + * regularly bounce b/w CPUs. + */ + struct { + struct llist_head work_llist; + unsigned long check_cq; + atomic_t cq_wait_nr; + atomic_t cq_timeouts; + struct wait_queue_head cq_wait; + } ____cacheline_aligned_in_smp; + struct { spinlock_t completion_lock; bool poll_multi_queue; - atomic_t cq_wait_nr; /* * ->iopoll_list is protected by the ctx->uring_lock for @@ -287,14 +297,11 @@ struct io_ring_ctx { * manipulate the list, hence no extra locking is needed there. */ struct io_wq_work_list iopoll_list; - - struct llist_head work_llist; } ____cacheline_aligned_in_smp; /* timeouts */ struct { spinlock_t timeout_lock; - atomic_t cq_timeouts; struct list_head timeout_list; struct list_head ltimeout_list; unsigned cq_last_tm_flush; @@ -314,8 +321,6 @@ struct io_ring_ctx { struct wait_queue_head sqo_sq_wait; struct list_head sqd_list; - unsigned long check_cq; - unsigned int file_alloc_start; unsigned int file_alloc_end;