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 X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6DC06ECE58D for ; Tue, 8 Oct 2019 03:18:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 397B520867 for ; Tue, 8 Oct 2019 03:18:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="KwXd9fN7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729939AbfJHDSA (ORCPT ); Mon, 7 Oct 2019 23:18:00 -0400 Received: from mail-pg1-f195.google.com ([209.85.215.195]:43404 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729868AbfJHDSA (ORCPT ); Mon, 7 Oct 2019 23:18:00 -0400 Received: by mail-pg1-f195.google.com with SMTP id i32so2145011pgl.10 for ; Mon, 07 Oct 2019 20:17:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=sBhKqNlCBDPkftr27P/1IjQptr0YXTqXNyc4wrCVHCs=; b=KwXd9fN7sM6S4HqcH6F8Fq+m+XYPerHKPiNSvQR2F1QiQtVIQE+nIlWn6Q8PpHhho3 iKAX+N6dedzbUCk0rOTijgDmFBbGQtrLv6csEuCeXIQjzImHbAUoIN37aOc5gpctJxOF 5Yb3hQt9N8P0fH/XEiIrrHtWqRrpULXdYkgYDxM/+CbOlnP5yhRkxO94ecv+W1Wr0Nm1 YO7fIF7mJQ265INnz8hwnN3iqExG1g6CoqkHHHDDpjbhSQqpUSnIyQcF05FOL71TosBQ prc/hZax9kJYb46OUODcifTFk/n2fFG+Isyhs4q2PZUng5eh+rzPDInIdxsDVxA18Ohu T7/A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=sBhKqNlCBDPkftr27P/1IjQptr0YXTqXNyc4wrCVHCs=; b=h8X5auHWRqCOrlYd1LEEBc/FfR+3njZ1+b9KCX+QbC2e49kMm1/NRsqJ3Qj2iP40wi IerBrfNr33ColICGCuLCxIEmTDefS69ycfyLjbjh+FyHAxKaS0D3gUiJn0H9AlCB5vJk CSOouAsbEdPhe+OqTQkLf5+hLDP2vp1hYVrfkW+K8v/A1mRIOTns1qBk0ipJrpMjxFS6 L4t4aDtOS0ZUlndSqMTsfwA+c/xlBD9b7pRxJUgmAPshTLP9X+z+ABWvD1fij5VnDFII 8YeUJQ7lbhKjzqC5pe/xiAooWNemEq71W3oPKVLt4GcJSUaeQhh8pi/qf4YzaEFwzZMN Hptw== X-Gm-Message-State: APjAAAXfLDKVvOc2jxf/zjywy1yQecWp7NePRaEMtyX1lWBkKmQGqfqf 4yO0ALPPGGwQSMkXy7uAptBTxpqlMbZ2lg== X-Google-Smtp-Source: APXvYqyVEEx/94ZCOojqFRMZtKBTarDNA2EnBJ0TsDkKhroTKOhYv0wamthRODhio5AJVBqSSnilAg== X-Received: by 2002:a63:dc4c:: with SMTP id f12mr1766256pgj.29.1570504677476; Mon, 07 Oct 2019 20:17:57 -0700 (PDT) Received: from [192.168.1.188] ([66.219.217.79]) by smtp.gmail.com with ESMTPSA id 64sm19333739pfx.31.2019.10.07.20.17.55 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 07 Oct 2019 20:17:56 -0700 (PDT) Subject: Re: [PATCH] blk-stat: Optimise blk_stat_add() To: "Pavel Begunkov (Silence)" , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org References: <39dd33cc6f0264b2ec2f79f1dfe21466c2180851.1570482929.git.asml.silence@gmail.com> From: Jens Axboe Message-ID: Date: Mon, 7 Oct 2019 21:17:54 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <39dd33cc6f0264b2ec2f79f1dfe21466c2180851.1570482929.git.asml.silence@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/7/19 3:16 PM, Pavel Begunkov (Silence) wrote: > From: Pavel Begunkov > > blk_stat_add() calls {get,put}_cpu_ptr() in a loop, which entails > overhead of disabling/enabling preemption. The loop is under RCU > (i.e.short) anyway, so do get_cpu() in advance. Looks good, applied for 5.5. -- Jens Axboe