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=-2.2 required=3.0 tests=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 B2625C5321D for ; Sat, 18 Apr 2020 15:56:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9C4B221D93 for ; Sat, 18 Apr 2020 15:56:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726699AbgDRP4x (ORCPT ); Sat, 18 Apr 2020 11:56:53 -0400 Received: from mail-pj1-f65.google.com ([209.85.216.65]:56012 "EHLO mail-pj1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725879AbgDRP4w (ORCPT ); Sat, 18 Apr 2020 11:56:52 -0400 Received: by mail-pj1-f65.google.com with SMTP id a32so2519421pje.5; Sat, 18 Apr 2020 08:56:51 -0700 (PDT) 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:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=HnN+4R9VnGvVtFRaSn9immSfu526GuFnV34NPuc3GJ4=; b=FgYy+wT1Ser6GDI8gBVjfFmegC/sMorPV9TSU0pIowGot5Ct+OjQ6LbWxK8K0EMjwY Vvy7yqyqh8CrPruPezePLxC64VJGwDm9JPJp2aWVorcfKENUM32p0+Q219BnwG7nxDSD YfnkQySlxHdcvrC3IYvolq2SxhfN5RQnara3I10/FUIDvubBqviEDe9s0CszcsnhvZ0K FA5yO/b4AM6WqDCurCRON8crDbaQgJ1Sebv3ow/2FRoHvGksoOmIW4GjuSnmgkEOMgB2 jOaCLnilHAzF/v1ZVyn9hjYEohKg4k+vV6Q8OU9pV2SGwZi8peVT1OqLHXFi8W0GdsOf rl9A== X-Gm-Message-State: AGi0PuYSSJn99JxwcE5P8VU0msbnveSn6+Z0BpxkX/x/zWAqTqSuj2rV 9+OnygSVTGTQ/x6zgfishqw= X-Google-Smtp-Source: APiQypJQm7KDxqeoXzsUCOSRwsfZZCKF62wDEpEX9w3v38O0ZeIERlSVUTpFH4OkBtpVHSsww5t6fg== X-Received: by 2002:a17:902:b418:: with SMTP id x24mr585768plr.260.1587225411195; Sat, 18 Apr 2020 08:56:51 -0700 (PDT) Received: from ?IPv6:2601:647:4000:d7:551:c132:d476:f445? ([2601:647:4000:d7:551:c132:d476:f445]) by smtp.gmail.com with ESMTPSA id 23sm7632557pjb.11.2020.04.18.08.56.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 18 Apr 2020 08:56:50 -0700 (PDT) Subject: Re: [PATCH v7 00/11] Introduce Zone Append for writing to zoned block devices To: Johannes Thumshirn , Jens Axboe Cc: Christoph Hellwig , linux-block , Damien Le Moal , Keith Busch , "linux-scsi @ vger . kernel . org" , "Martin K . Petersen" , "linux-fsdevel @ vger . kernel . org" , Daniel Wagner References: <20200417121536.5393-1-johannes.thumshirn@wdc.com> From: Bart Van Assche Autocrypt: addr=bvanassche@acm.org; prefer-encrypt=mutual; keydata= mQENBFSOu4oBCADcRWxVUvkkvRmmwTwIjIJvZOu6wNm+dz5AF4z0FHW2KNZL3oheO3P8UZWr LQOrCfRcK8e/sIs2Y2D3Lg/SL7qqbMehGEYcJptu6mKkywBfoYbtBkVoJ/jQsi2H0vBiiCOy fmxMHIPcYxaJdXxrOG2UO4B60Y/BzE6OrPDT44w4cZA9DH5xialliWU447Bts8TJNa3lZKS1 AvW1ZklbvJfAJJAwzDih35LxU2fcWbmhPa7EO2DCv/LM1B10GBB/oQB5kvlq4aA2PSIWkqz4 3SI5kCPSsygD6wKnbRsvNn2mIACva6VHdm62A7xel5dJRfpQjXj2snd1F/YNoNc66UUTABEB AAG0JEJhcnQgVmFuIEFzc2NoZSA8YnZhbmFzc2NoZUBhY20ub3JnPokBOQQTAQIAIwUCVI67 igIbAwcLCQgHAwIBBhUIAgkKCwQWAgMBAh4BAheAAAoJEHFcPTXFzhAJ8QkH/1AdXblKL65M Y1Zk1bYKnkAb4a98LxCPm/pJBilvci6boefwlBDZ2NZuuYWYgyrehMB5H+q+Kq4P0IBbTqTa jTPAANn62A6jwJ0FnCn6YaM9TZQjM1F7LoDX3v+oAkaoXuq0dQ4hnxQNu792bi6QyVdZUvKc macVFVgfK9n04mL7RzjO3f+X4midKt/s+G+IPr4DGlrq+WH27eDbpUR3aYRk8EgbgGKvQFdD CEBFJi+5ZKOArmJVBSk21RHDpqyz6Vit3rjep7c1SN8s7NhVi9cjkKmMDM7KYhXkWc10lKx2 RTkFI30rkDm4U+JpdAd2+tP3tjGf9AyGGinpzE2XY1K5AQ0EVI67igEIAKiSyd0nECrgz+H5 PcFDGYQpGDMTl8MOPCKw/F3diXPuj2eql4xSbAdbUCJzk2ETif5s3twT2ER8cUTEVOaCEUY3 eOiaFgQ+nGLx4BXqqGewikPJCe+UBjFnH1m2/IFn4T9jPZkV8xlkKmDUqMK5EV9n3eQLkn5g lco+FepTtmbkSCCjd91EfThVbNYpVQ5ZjdBCXN66CKyJDMJ85HVr5rmXG/nqriTh6cv1l1Js T7AFvvPjUPknS6d+BETMhTkbGzoyS+sywEsQAgA+BMCxBH4LvUmHYhpS+W6CiZ3ZMxjO8Hgc ++w1mLeRUvda3i4/U8wDT3SWuHcB3DWlcppECLkAEQEAAYkBHwQYAQIACQUCVI67igIbDAAK CRBxXD01xc4QCZ4dB/0QrnEasxjM0PGeXK5hcZMT9Eo998alUfn5XU0RQDYdwp6/kMEXMdmT oH0F0xB3SQ8WVSXA9rrc4EBvZruWQ+5/zjVrhhfUAx12CzL4oQ9Ro2k45daYaonKTANYG22y //x8dLe2Fv1By4SKGhmzwH87uXxbTJAUxiWIi1np0z3/RDnoVyfmfbbL1DY7zf2hYXLLzsJR mSsED/1nlJ9Oq5fALdNEPgDyPUerqHxcmIub+pF0AzJoYHK5punqpqfGmqPbjxrJLPJfHVKy goMj5DlBMoYqEgpbwdUYkH6QdizJJCur4icy8GUNbisFYABeoJ91pnD4IGei3MTdvINSZI5e Message-ID: Date: Sat, 18 Apr 2020 08:56:48 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200417121536.5393-1-johannes.thumshirn@wdc.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 2020-04-17 05:15, Johannes Thumshirn wrote: > In order to reduce memory consumption, the only cached item is the offset > of the write pointer from the start of the zone, everything else can be > calculated. On an example drive with 52156 zones, the additional memory > consumption of the cache is thus 52156 * 4 = 208624 Bytes or 51 4k Byte > pages. The performance impact is neglectable for a spinning drive. What will happen if e.g. syzkaller mixes write() system calls with SG_IO writes? Can that cause a mismatch between the cached write pointer and the write pointer maintained by the drive? If so, should SG_IO perhaps be disallowed if the write pointer is cached? Thanks, Bart.