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 39E9EC433F5 for ; Wed, 20 Oct 2021 20:03:30 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C0391610E7 for ; Wed, 20 Oct 2021 20:03:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org C0391610E7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id B777E940009; Wed, 20 Oct 2021 16:03:27 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AFF61940007; Wed, 20 Oct 2021 16:03:27 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9EFB4940009; Wed, 20 Oct 2021 16:03:27 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0145.hostedemail.com [216.40.44.145]) by kanga.kvack.org (Postfix) with ESMTP id 8E9EC940007 for ; Wed, 20 Oct 2021 16:03:27 -0400 (EDT) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 4D7DB2C6B8 for ; Wed, 20 Oct 2021 20:03:27 +0000 (UTC) X-FDA: 78717890454.09.7181C53 Received: from mail-wr1-f52.google.com (mail-wr1-f52.google.com [209.85.221.52]) by imf27.hostedemail.com (Postfix) with ESMTP id A5BBC70000A2 for ; Wed, 20 Oct 2021 20:03:25 +0000 (UTC) Received: by mail-wr1-f52.google.com with SMTP id g25so673617wrb.2 for ; Wed, 20 Oct 2021 13:03:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=q1EZc8F3LGa37Y9tu7Tob6o+fpihU/+4iG2rIzfXu/A=; b=WbgNFPzpqQwP0xWC2uli9FeYZOhufR5CXwXu9ncgcBUanmWs0Ez75Z5+fFvqOG5bt/ eJpYOZzGZ9tAkQgonvDFNrrYSFzu5esd6IyZyysSWI/h4WpmX6UDDLnVD27MjESegLuu 3NmuuSKZhY4d0/i2CFq9mvSrdzwWkLm5oC1Z4KiE+qQJQqTx15w3dHHYmkE36FUHQzk1 xvtbkRz63rAMB3yVc3yAWs5Exet7k2+Jg3/Yq1KtDHEytbGiJ9I/YC38HULEosaZ7ulB gxycBcHHjBN0VfIQQAIK58bdOyYVPQ/qXWa94VOYsXQyA7GqpxKeyeJJBA2Wvadnt4EG wXSA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=q1EZc8F3LGa37Y9tu7Tob6o+fpihU/+4iG2rIzfXu/A=; b=hsJSRm8lu8VbO/rDSInvUNe5qh4g5yndRtXPuqnD93Ip0sio4nvlXI5JkGB5F9U7CI dmiZFsD2vJSWJ1xHV0EiUraFIIAjPzvEe5DzX/1Frn0YshWQKNpBKzfdVRIKmMXmOZWH uuhV2O2LHicqTa3VDZus+ppkhvRQGh4yXaOHinD4EVwcdsIW8N8lEyf+MlYFGwY0uxUi n0ekQCCBfF9RsZ40chQ4pkqvhkCbRWzcNWixXNYhxwj+9JlUWx1v6Lyyv3fFVFBz0A4g 6f+nfC1qRZsvlKGUvnsz3t4De8PJ3xj7l3ZXERbmOBbBYad91vIWvbEhuVg+mUKXnU8e guzg== X-Gm-Message-State: AOAM530Yw83cpKvdtz2vU9ehVL2fnyio9W78WsssXL0AISKRRfLz8T8Y xMwUfdDViTRgoudzDBcayyo= X-Google-Smtp-Source: ABdhPJyHaPBBNKhdLB85ZPk4rJy40dUZ0AZiN0c283LaQx4WPK7+fyH8BjtbhoxBpccA3tSED0163A== X-Received: by 2002:a5d:414e:: with SMTP id c14mr1557870wrq.415.1634760205953; Wed, 20 Oct 2021 13:03:25 -0700 (PDT) Received: from 127.0.0.1localhost ([185.69.145.206]) by smtp.gmail.com with ESMTPSA id m14sm3600119wms.25.2021.10.20.13.03.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 Oct 2021 13:03:25 -0700 (PDT) From: Pavel Begunkov To: linux-block@vger.kernel.org Cc: Jens Axboe , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Christoph Lameter , Tejun Heo , Dennis Zhou , Pavel Begunkov Subject: [PATCH 2/2] block: kill extra rcu lock/unlock in queue enter Date: Wed, 20 Oct 2021 21:03:19 +0100 Message-Id: <159884e23f494a4b658c9cb66e36900c3c5800f5.1634759754.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.33.1 In-Reply-To: References: MIME-Version: 1.0 X-Rspamd-Queue-Id: A5BBC70000A2 X-Stat-Signature: rs8kjooncgajawmm4ex58t5ejitkos7d Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=WbgNFPzp; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf27.hostedemail.com: domain of asml.silence@gmail.com designates 209.85.221.52 as permitted sender) smtp.mailfrom=asml.silence@gmail.com X-Rspamd-Server: rspam01 X-HE-Tag: 1634760205-655108 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000069, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: blk_try_enter_queue() already takes rcu_read_lock/unlock, so we can avoid the second pair in percpu_ref_tryget_live(), use a newly added percpu_ref_tryget_live_rcu(). As rcu_read_lock/unlock imply barrier()s, it's pretty noticeable, especially for for !CONFIG_PREEMPT_RCU (default for some distributions), where __rcu_read_lock/unlock() are not inlined. 3.20% io_uring [kernel.vmlinux] [k] __rcu_read_unlock 3.05% io_uring [kernel.vmlinux] [k] __rcu_read_lock 2.52% io_uring [kernel.vmlinux] [k] __rcu_read_unlock 2.28% io_uring [kernel.vmlinux] [k] __rcu_read_lock Signed-off-by: Pavel Begunkov --- block/blk-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/blk-core.c b/block/blk-core.c index 88752e51d2b6..20e76aeb50f5 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -389,7 +389,7 @@ EXPORT_SYMBOL(blk_cleanup_queue); static bool blk_try_enter_queue(struct request_queue *q, bool pm) { rcu_read_lock(); - if (!percpu_ref_tryget_live(&q->q_usage_counter)) + if (!percpu_ref_tryget_live_rcu(&q->q_usage_counter)) goto fail; =20 /* --=20 2.33.1