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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 0D40FC4CEC4 for ; Wed, 18 Sep 2019 06:10:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D6A74218AE for ; Wed, 18 Sep 2019 06:10:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="T+rtTKk5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726705AbfIRGKV (ORCPT ); Wed, 18 Sep 2019 02:10:21 -0400 Received: from mail-ua1-f68.google.com ([209.85.222.68]:36356 "EHLO mail-ua1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726231AbfIRGKU (ORCPT ); Wed, 18 Sep 2019 02:10:20 -0400 Received: by mail-ua1-f68.google.com with SMTP id r25so1960013uam.3 for ; Tue, 17 Sep 2019 23:10:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=xTBwbLii9b70VDIiu2pkAKMCAWF61Wo+h6WzPYHryB4=; b=T+rtTKk5TFAHOQsUgV/It9GsfiXKaB+bhfa5dN/sLkCoY4OmhkyktixzO9f+8YwHkk cEwMurZ/Mg+6d/IyWE/VoTFh6ibwd0Mwl6dha6HSGU+9F+3oa3E4SG8ssP4tJD2gAj2Z CgfhsGf+P+xpNd67ACMjlLHF9Vo5pLWNL+0rS9zkvOMFSZdZhpHuEdLXnjGXRBDdZa05 gMHUHQCZdMtNI95/7aMMVk9PajYLgBwdgoxrI69ssFUOuabdzO4bzrjNDV04fRzwiUtG OU6mo3S5DUmnJ0GDQ58haSoMZ17PjkKDKF6Z+zaNrgrM1JI3wMct87apJQWCU/YgECc4 x8Ew== 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=xTBwbLii9b70VDIiu2pkAKMCAWF61Wo+h6WzPYHryB4=; b=lM+TN958O1gQUGGDLTFV8FRmWiKdMpZVS1z7BdjLMtQRWemRRqCNZr31WqUBaj73MI nbmPf05raR4kIZMztrxLJ6UBWRSeoKma9kIqUxvgHxulKpUpyXxsisFFWtgyY2/4/qeD O9H1iw3OqsqtEiqMytUMa6bzJED3rMPMEgbCVEFFPI8o0QpGxCjceoej8UDVavC7YEmp oNyY1rwU2zppm+SjzeruQDpM0lstNm+ycU9QqnekehG+MbYmPYZG4dNnDbOpEfvFeWSK jCvOuJ4+EmRT18028AcS22SafE/jcgJrUbGuL4l9KSIvgk5Lw7JoU0rq7BL0IZL+nJhE 7/2g== X-Gm-Message-State: APjAAAVfdlLRrbIGcwKXMAcGzOz/8Cm6SK0wykU57w025YF0wSmRSriX WyDPFy/2fDa0wwC9w/gIIuDa6xfHfKJwNLD83om3rA== X-Google-Smtp-Source: APXvYqw3WNN2Dndv9EUbQn4aZiKazwu1E6YluB67ZhBYYekBU3g4MWLJvI2vAwQzbc1TVbrUGcur2tykCtit3Ev9e/k= X-Received: by 2002:ab0:1856:: with SMTP id j22mr1425618uag.19.1568787019751; Tue, 17 Sep 2019 23:10:19 -0700 (PDT) MIME-Version: 1.0 References: <20190917165148.19146-1-paolo.valente@linaro.org> <20190917165148.19146-3-paolo.valente@linaro.org> <20190917213209.GK3084169@devbig004.ftw2.facebook.com> In-Reply-To: <20190917213209.GK3084169@devbig004.ftw2.facebook.com> From: Ulf Hansson Date: Wed, 18 Sep 2019 08:09:42 +0200 Message-ID: Subject: Re: [PATCH 2/2] block, bfq: delete "bfq" prefix from cgroup filenames To: Tejun Heo , Paolo Valente Cc: Jens Axboe , linux-block , Linux Kernel Mailing List , Linus Walleij , "'Paolo Valente' via bfq-iosched" , Oleksandr Natalenko , cgroups@vger.kernel.org, Angelo Ruocco Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Tejun, Paolo, On Tue, 17 Sep 2019 at 23:32, Tejun Heo wrote: > > Hello, > > On Tue, Sep 17, 2019 at 06:51:48PM +0200, Paolo Valente wrote: > > When bfq was merged into mainline, there were two I/O schedulers that > > implemented the proportional-share policy: bfq for blk-mq and cfq for > > legacy blk. bfq's interface files in the blkio/io controller have the > > same names as cfq. But the cgroups interface doesn't allow two > > entities to use the same name for their files, so for bfq we had to > > prepend the "bfq" prefix to each of its files. However no legacy code > > uses these modified file names. This naming also causes confusion, as, > > e.g., in [1]. > > > > Now cfq has gone with legacy blk, so there is no need any longer for > > these prefixes in (the never used) bfq names. In view of this fact, this > > commit removes these prefixes, thereby enabling legacy code to truly > > use the proportional share policy in blk-mq. > > So, I wrote the iocost switching patch and don't have a strong > interest in whether bfq prefix should get dropped or not. However, I > gotta point out that flipping interface this way is way out of the > norm. > > In the previous release cycle, the right thing to do was dropping the > bfq prefix but that wasn't possible because bfq's interface wasn't > compatible at that point and didn't made to be compatible in time. Sounds like we really should send those relevant patches for stable, to set the correct ground. Then using a symlink, to make sure we don't brake current ABI, right? [...] Kind regards Uffe