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 EF06EC433EF for ; Thu, 21 Oct 2021 13:30:58 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8B146611CE for ; Thu, 21 Oct 2021 13:30:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 8B146611CE 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 B2665900002; Thu, 21 Oct 2021 09:30:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AD6806B0073; Thu, 21 Oct 2021 09:30:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9EC99900002; Thu, 21 Oct 2021 09:30:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0026.hostedemail.com [216.40.44.26]) by kanga.kvack.org (Postfix) with ESMTP id 8B9716B006C for ; Thu, 21 Oct 2021 09:30:57 -0400 (EDT) Received: from smtpin32.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 46AC431E5E for ; Thu, 21 Oct 2021 13:30:57 +0000 (UTC) X-FDA: 78720530154.32.B6D94A5 Received: from mail-wr1-f42.google.com (mail-wr1-f42.google.com [209.85.221.42]) by imf16.hostedemail.com (Postfix) with ESMTP id E8817F000AD5 for ; Thu, 21 Oct 2021 13:30:53 +0000 (UTC) Received: by mail-wr1-f42.google.com with SMTP id i12so1112966wrb.7 for ; Thu, 21 Oct 2021 06:30:56 -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:mime-version :content-transfer-encoding; bh=3+0W4a7ajc/42At+/XY3zEOp2xDA6GsLU+vihGYQJjI=; b=GM6vEvDiq18fZTt/3BWPB8rL8xabNUDF7bvLouAZs+L4s+RL1SMqSH2p6migRbiJGj VqqznedHEpvspyDHA+J4EPPv0ZW7dYj9AP057Q6R6N7OxOiHuSK1+ZiPmqlsLct9sZMx Rp3FlH53+Be9eLmc7MAzO2Ar4Vr79mf5Jw18lCAtdczImfnubYQrRbWRar4g8t7rt2ak xKHmh790AB0pGslHQeYVpCn80eW9KCLBWX47FXPkdQ79u8rj1hWSiOM0UFMQc3a6j2Bj sARADMc0d2eyJ8PcgFIFLF8Kdb6KwzIUA9yyuj+SgeAj7OQpNld7/VnK2s3aj4id41gg D4SA== 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:mime-version :content-transfer-encoding; bh=3+0W4a7ajc/42At+/XY3zEOp2xDA6GsLU+vihGYQJjI=; b=n6NsvpA9QVyFes2MHniS8a8d1qP8x/64KSZJHaN8CbsJttOap8xiaQCePEHF/auAmb bzuQ6bKYhqBHO9oI7C8nQZuE3EjVNLmnJIZQDD6cVWIHiZw5tncshUO2RfStvqsWC//I E1EBZkCiQhRQYGSOYor73N5dR3oLx6G1X83yy9WQ1whX5qyo1eGTcauQL69BFh5IjNJr EFUwQ2Be4CA/EQu44zC44fMeJrtsn/CzBrYkipoJ9dkl+7KsRSuTOfbghD5sW2VgwRYl SjSkakGJ65/wGCGNds6g4OqH+D0mM/RlA9+wDJgYZkLRcgfdqUP5Dm5Re4lat15im6rf b2uw== X-Gm-Message-State: AOAM532J1Pjy5LteqeLGdyhVRmJ1Sdo3Fv3jKRPvZG4Tnit72/uEJx4t 75SsiL3UsznvJhIgkaic4zs= X-Google-Smtp-Source: ABdhPJzOTqbPi/I4x+EXVo8lE0cNw9TdqACGEBYPKCiYKpYoKaUh83al0Zl89H852GC6n6usWGyfYA== X-Received: by 2002:adf:ee8b:: with SMTP id b11mr7172855wro.349.1634823055644; Thu, 21 Oct 2021 06:30:55 -0700 (PDT) Received: from 127.0.0.1localhost ([185.69.145.206]) by smtp.gmail.com with ESMTPSA id q188sm1753987wma.1.2021.10.21.06.30.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Oct 2021 06:30:55 -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 v2 0/2] optimise blk_try_enter_queue() Date: Thu, 21 Oct 2021 14:30:50 +0100 Message-Id: X-Mailer: git-send-email 2.33.1 MIME-Version: 1.0 X-Stat-Signature: ibpoerx4cs6hywf1z9asu3srpaj76bw8 X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: E8817F000AD5 Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=GM6vEvDi; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf16.hostedemail.com: domain of asml.silence@gmail.com designates 209.85.221.42 as permitted sender) smtp.mailfrom=asml.silence@gmail.com X-HE-Tag: 1634823053-188603 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000500, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Kill extra rcu_read_lock/unlock() pair in blk_try_enter_queue(). Testing with io_uring (high batching) with nullblk: Before: 3.20% io_uring [kernel.vmlinux] [k] __rcu_read_unlock 3.05% io_uring [kernel.vmlinux] [k] __rcu_read_lock After: 2.52% io_uring [kernel.vmlinux] [k] __rcu_read_unlock 2.28% io_uring [kernel.vmlinux] [k] __rcu_read_lock Doesn't necessarily translates into 1.4% perfofrmance improvement but nice to have. v2: rcu_read_lock_held() warning (Tejun) Pavel Begunkov (2): percpu_ref: percpu_ref_tryget_live() version holding RCU block: kill extra rcu lock/unlock in queue enter block/blk-core.c | 2 +- include/linux/percpu-refcount.h | 33 +++++++++++++++++++++++---------- 2 files changed, 24 insertions(+), 11 deletions(-) --=20 2.33.1