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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 6452AC433E0 for ; Tue, 16 Jun 2020 11:13:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 36C4920786 for ; Tue, 16 Jun 2020 11:13:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="SUsfdubc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726452AbgFPLNE (ORCPT ); Tue, 16 Jun 2020 07:13:04 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:58392 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725775AbgFPLND (ORCPT ); Tue, 16 Jun 2020 07:13:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1592305982; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=fYBk2H3U1f+pIy7QDyXrQYJ9ikO/21+702smWTVcFik=; b=SUsfdubcTIE3CFZuY0+aK5rc1stp/7gNOdTNegiMG7nhd5YdgItXjgrYPsK4uEhxa+uwZe KWWVv413JkfuSa761G22pd/qO66VIP/UZXlH+g2hguZsvKyJNOHbL7fhIm+oowuqO04g4q I+TsgXdGWnb/4E+Ko73tXfi475hB0yk= Received: from mail-ua1-f71.google.com (mail-ua1-f71.google.com [209.85.222.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-136-DoQqIrDvMxCwl0GJtSeEWw-1; Tue, 16 Jun 2020 07:13:00 -0400 X-MC-Unique: DoQqIrDvMxCwl0GJtSeEWw-1 Received: by mail-ua1-f71.google.com with SMTP id k12so8341088uag.3 for ; Tue, 16 Jun 2020 04:13:00 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=fYBk2H3U1f+pIy7QDyXrQYJ9ikO/21+702smWTVcFik=; b=kLqRZt/pw5s9ALuXiScXRHu4LwL57eD2Tgpa2eDKxpObPjGVlDmduHZkgc5KXdkzdN ggGcosf0SG7nGQtdNAGF6NN4EHFzao6J+30ddIMt1bQuwqCerseCgv2wSHY9uAA/wbaD DWcPAjnOW/mjHNGRiWlHELhKV9HjJtCel4dipb6xfrS1RQzLoYx48DV4Ijg9CmKX9+sV zpWA6Wrco6z77Pwtn64kpjCdzxwEMqX4997QRGbWe1gopIrCg/LAUCeuwCzCn6bBILVM Zviv/YT6BkloYlw9xXRLsb07JfYSvsEK6xA223BIR9Cv5ughAy1hUApEPPwwwhF/N5qT 6IjQ== X-Gm-Message-State: AOAM530MSFAHbsVxffL2yATjK4gRq9chcHLW4jJI9/FnkiPGPhXwheTB vdr5wxrQlt2qV5yETtarE4JtJl7nkveoCMFnuJJ4NYs8PmEgJ16cYnW8387mnS6IFvw8Whj2u9L lWo45y5hUrOdosomNNAHuWKZx72NeqYc2/H2fv5s= X-Received: by 2002:a67:8c89:: with SMTP id o131mr1150039vsd.218.1592305979863; Tue, 16 Jun 2020 04:12:59 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzbkBrFFQdF4fYmZIOLCam06HEuM7KzNrul02YEkbn2UbOwmC7p9Jd7Wtd0K9SY09rpeXySGe37nevPAsXYsjY= X-Received: by 2002:a67:8c89:: with SMTP id o131mr1150028vsd.218.1592305979650; Tue, 16 Jun 2020 04:12:59 -0700 (PDT) MIME-Version: 1.0 References: <20200616005633.172804-1-harshadshirwadkar@gmail.com> <20200616072955.GA30385@infradead.org> In-Reply-To: <20200616072955.GA30385@infradead.org> From: Sweet Tea Dorminy Date: Tue, 16 Jun 2020 07:12:48 -0400 Message-ID: Subject: Re: [PATCH] block: add split_alignment for request queue To: Christoph Hellwig Cc: Harshad Shirwadkar , linux-block@vger.kernel.org, tytso@mit.edu Content-Type: text/plain; charset="UTF-8" Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hi Christoph; Forgive me my newness and not understanding most subtleties, but I don't actually understand why you say "that is a completely bogus assumption" -- could you please elaborate or point me at a document/code/list archive explaining? Thanks in advance! John On Tue, Jun 16, 2020 at 3:30 AM Christoph Hellwig wrote: > > On Mon, Jun 15, 2020 at 05:56:33PM -0700, Harshad Shirwadkar wrote: > > This feature allows the user to control the alignment at which request > > queue is allowed to split bios. Google CloudSQL's 16k user space > > application expects that direct io writes aligned at 16k boundary in > > the user-space are not split by kernel at non-16k boundaries. > > That is a completely bogus assumptions and people who think they can > make that assumption should not be allowed to write software. > > Can we stop this crap now please? >