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=-5.4 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, 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 A51ADC4338F for ; Wed, 4 Aug 2021 17:58:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 830D760F94 for ; Wed, 4 Aug 2021 17:58:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237764AbhHDR67 (ORCPT ); Wed, 4 Aug 2021 13:58:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46932 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237302AbhHDR67 (ORCPT ); Wed, 4 Aug 2021 13:58:59 -0400 Received: from mail-pj1-x1030.google.com (mail-pj1-x1030.google.com [IPv6:2607:f8b0:4864:20::1030]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5EC2CC0613D5 for ; Wed, 4 Aug 2021 10:58:46 -0700 (PDT) Received: by mail-pj1-x1030.google.com with SMTP id e2-20020a17090a4a02b029016f3020d867so4664410pjh.3 for ; Wed, 04 Aug 2021 10:58:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=DY1ycG0HBesX9rvAByRfVLd6t1wgu6XO9EafdSK48o8=; b=zyYaF/u/+977dGXhPDXs9Ua0ZvqvMA1ni1OcOzmjlkmy9v7MGVBaE9AF9H1eBTXSek HlZtnk5b5LWGv9LEncyUw4jCn+TQuPEP3ma+8w8W6bpnenGNaiReAS5tMQfwgrs+tMuk U/b5cwODgsM1aOZkV0UULL7xXaN68WrkfFmCnyuhNWhUCW3G8JPJfxFjas/8t/c/azBj jKSFWPmYpYNIuPUT7E8V3lApjlO1PZ51bHYQe/o/uSnm/Qc7zIbNc1PQIA5/lesh4S+l LSKePvBNwtsfFm0dZDQd7kNsvBvoON+OD8kX89ak+grRckMfpvXfunaY7jg2PANg9ygf hS6g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=DY1ycG0HBesX9rvAByRfVLd6t1wgu6XO9EafdSK48o8=; b=lUSWaydx2lypQa1rdngYa22giXKoeOt64C2LJUgK/Vyb8JneqoTdiKWYYMYWDApdog Khip2IZjy8FxuU3LFyZqnnanTULDE1GGQ/VVq2M+jPUf2Ce2PsyJ9zCKW+odsnYybKK3 ygrxHRuuQ4TrjOSqh9PfnMhetQ9vmoKr/+Ii2Mkps5Z5UrgYB0kajIY7BnexV8GmiaKT mYubPv/nXmdfPElE/t2qUY/CHVvpcEaca9185Agpn5PvOrsPC2WAb5z7cyq/5tVhThiL WNU5MN5kR38XP7Zso7UfXHsu4xK+PqSDWrCH2C1hXISkSBClZHtatgWUL6uF2eNLlPtL HAiw== X-Gm-Message-State: AOAM530l5JH43FeD7zsd/M8s3e5wDgIPX6XF/gLmXRUDDwlpwYxoe/SH 70aMaSsQUx6iy4Z5gN1UZM2b6A== X-Google-Smtp-Source: ABdhPJy5jpHHGPknD2dqSLsbeDhrdiVGBmW3Q77gHMla/7KYLK8bVwIQI+ftF425xV/nvhNIu0Zi4g== X-Received: by 2002:a65:42c3:: with SMTP id l3mr118926pgp.377.1628099925853; Wed, 04 Aug 2021 10:58:45 -0700 (PDT) Received: from [192.168.1.116] ([198.8.77.61]) by smtp.gmail.com with ESMTPSA id f66sm3860247pfa.21.2021.08.04.10.58.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 04 Aug 2021 10:58:45 -0700 (PDT) Subject: Re: [PATCH v2 2/3] loop: Select I/O scheduler 'none' from inside add_disk() To: Ming Lei , Bart Van Assche Cc: linux-block@vger.kernel.org, Christoph Hellwig , Jaegeuk Kim , Tetsuo Handa , Martijn Coenen References: <20210803182304.365053-1-bvanassche@acm.org> <20210803182304.365053-3-bvanassche@acm.org> From: Jens Axboe Message-ID: <7cf7cf6d-bf89-0df2-9aec-6ea7d3efd515@kernel.dk> Date: Wed, 4 Aug 2021 11:58:43 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 8/3/21 8:39 PM, Ming Lei wrote: > On Tue, Aug 03, 2021 at 11:23:03AM -0700, Bart Van Assche wrote: >> We noticed that the user interface of Android devices becomes very slow >> under memory pressure. This is because Android uses the zram driver on top >> of the loop driver for swapping, because under memory pressure the swap >> code alternates reads and writes quickly, because mq-deadline is the >> default scheduler for loop devices and because mq-deadline delays writes by > > Maybe we can bypass io scheduler always for request with REQ_SWAP, such as: I don't think that's a good idea at all, what happens if you have a mixed swap in/out on a rotating drive? -- Jens Axboe