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=-4.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 405A7C48BCD for ; Wed, 9 Jun 2021 10:53:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1E9056139A for ; Wed, 9 Jun 2021 10:53:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235506AbhFIKzg (ORCPT ); Wed, 9 Jun 2021 06:55:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46818 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234882AbhFIKze (ORCPT ); Wed, 9 Jun 2021 06:55:34 -0400 Received: from mail-qv1-xf2a.google.com (mail-qv1-xf2a.google.com [IPv6:2607:f8b0:4864:20::f2a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1EA54C061574; Wed, 9 Jun 2021 03:53:31 -0700 (PDT) Received: by mail-qv1-xf2a.google.com with SMTP id e18so12509069qvm.10; Wed, 09 Jun 2021 03:53:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=to:cc:from:subject:message-id:date:user-agent:mime-version :content-transfer-encoding:content-language; bh=0YVz+Tp9c/+BLdLLg/dEk8hVG2/4HLSUp+VXgepDnM0=; b=pf8nagyssHGUxyRjUvhABlSHergN77+RWaufZevQ2p17UnOXHE69CPPhR31vtc84sw WY5huLOmWveUt3LadLXtF34q/Q1CCQk0Q7x0PIw50J3+KuJUKlg9WGLrCgjVFzq6KIbZ XyuRt523PBVclEE3MKoU67oIXabWh2iGyC2Pm9DOHaOvusEy4LJtcAuQUZ4Yin9dnCeY LbGWTuSz9X5wQkaQZIiLPtpd0+f/vievjZT2nLfHxj7SPgoKQI0TVfRXeWM5BTKuvwWv ixn8BZRxbfGxvR/WZ3iDcC5wsa5yybvAnbzMrhYj1xVTsxbKlubyB0jrU/OBJp7YPuvc 8qfQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:cc:from:subject:message-id:date:user-agent :mime-version:content-transfer-encoding:content-language; bh=0YVz+Tp9c/+BLdLLg/dEk8hVG2/4HLSUp+VXgepDnM0=; b=DeeMYR2UTA3UlRVXuWeuy6uVmGOgin+Lu+W/yGyjy8fN8TR04p0Y3jHpQFKtVuqa6o Uvjd4/nTVSstg6Y5f9Ugq1dZKpiL8sTrteJaXo72NB56Kx6IaYDid1m0jivGLCrKSuzr SagrxatjXfNw+pz9JVxqbcy8o5Sm7xKQxj8RKp9aAKvp1F8bx0UHR1AgNyi8RUeBU8Wz r6WdwRCtVPmR4Z21C6TlD/1Vdfp7h6pG6dB/vSLrAcenjaI44GT1GNi6W6aTfSi4rwnX K0e0BipUFmAQoqkZKbcpjxf/7QnLQgWU/J0Ok6EG40jUzAXZVvH1hkVwAv7/6taHeMp7 p2QQ== X-Gm-Message-State: AOAM530/rzZYLKpus0I7kgp8JYRAtVFrWxHCN3xYYkm7PGoA2cigBXyG wqiFDg+FeAQpetGwMqO7IMzv7fIVSnmwbg== X-Google-Smtp-Source: ABdhPJwtZMHelbQEQM4fDC9UawbdbSF72e8Udsuo0J0026QmwPoeJr/GjVYT4nkOd+EDafShg6WIkA== X-Received: by 2002:a0c:d784:: with SMTP id z4mr5162868qvi.27.1623236009982; Wed, 09 Jun 2021 03:53:29 -0700 (PDT) Received: from localhost.localdomain (pool-173-48-195-35.bstnma.fios.verizon.net. [173.48.195.35]) by smtp.gmail.com with ESMTPSA id z2sm4794746qke.23.2021.06.09.03.53.29 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 09 Jun 2021 03:53:29 -0700 (PDT) To: lsf-pc@lists.linux-foundation.org Cc: Linux FS Devel , linux-block@vger.kernel.org From: Ric Wheeler Subject: [LSF/MM/BPF TOPIC] durability vs performance for flash devices (especially embedded!) Message-ID: <55d3434d-6837-3a56-32b7-7354e73eb258@gmail.com> Date: Wed, 9 Jun 2021 06:53:29 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Consumer devices are pushed to use the highest capacity emmc class devices, but they have horrible write durability. At the same time, we layer on top of these devices our normal stack - device mapper and ext4 or f2fs are common configurations today - which causes write amplification and can burn out storage even faster. I think it would be useful to discuss how we can minimize the write amplification when we need to run on these low end parts & see where the stack needs updating. Great background paper which inspired me to spend time tormenting emmc parts is: http://www.cs.unc.edu/~porter/pubs/hotos17-final29.pdf