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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1383AC433F5 for ; Wed, 2 Feb 2022 00:07:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231205AbiBBAHa (ORCPT ); Tue, 1 Feb 2022 19:07:30 -0500 Received: from mout.gmx.net ([212.227.15.15]:47607 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230376AbiBBAH3 (ORCPT ); Tue, 1 Feb 2022 19:07:29 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1643760446; bh=PGJXaYIKuBOVZ5Ui0U+Qx6WzRo1bn6zdl/eRd6n3Kk0=; h=X-UI-Sender-Class:Date:Subject:To:References:From:In-Reply-To; b=RCcNjM/IkDgbxafDTVhgkI17E62cl5vN6PC1kaiCbS5dGI79TFUdVd9bxF1OO971B sftMbXQ2oLBmUQdhcq94FWSvJ+wVWQ3XA4XG9fbhkhAny8zF34fbSRaeVHFDXmVITy +Xv23Lm+XQ9daKl0JzXFYpG0ZUCntCmG5PAuz65g= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([149.28.201.231]) by mail.gmx.net (mrgmx005 [212.227.17.184]) with ESMTPSA (Nemesis) id 1N7zBR-1mBAju0u0J-0153Az; Wed, 02 Feb 2022 01:07:26 +0100 Message-ID: <9d3b5405-2d76-dd2e-1b1b-a404d3cb4db1@gmx.com> Date: Wed, 2 Feb 2022 08:07:22 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.1 Subject: Re: [PATCH] btrfs: add test case to verify that btrfs won't waste IO/CPU to defrag compressed extents already at their max size Content-Language: en-US To: dsterba@suse.cz, Qu Wenruo , fstests@vger.kernel.org, linux-btrfs@vger.kernel.org References: <20220127055306.30252-1-wqu@suse.com> <20220201151439.GR14046@twin.jikos.cz> From: Qu Wenruo In-Reply-To: <20220201151439.GR14046@twin.jikos.cz> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:9L9JVEuiX17JWyYtn3bFXjiIXOI5/k8jYH77n4L4mR3Z9j3MQJq S+xQ3yUfRzQikNdwKaTb+mp+n0kYLn7Zcsof7LM/AMSjujF7hNHcOUWzN+nI77so590NI8b PF1kPWcxs2BBapgJehayttEieKL6AEv3hpieOZi0BRIXmt03BYuYUIyFKHxGnWP2we7gp23 FeUDoe8BAIT8iW5ySGU6A== X-UI-Out-Filterresults: notjunk:1;V03:K0:t1+TYKKwDRM=:2R2czcv+qxFE41jOu4iq8p pcCXmXgzTug/5pR0CbRGWwOSNA9p9w3ZK/A1KhFLK2v35iGM8snXyShItV6B1jc12EYidrjzP DYsEM2CjBV8ZJnQ04ysXM9V4sZbM+DQViN2Bf9cm3djtGp5fNF6l8+0J0jZD7xPtLC88OLnI6 snVjKRCgvIdwd3zvESUTxbJcC6O5J94lcc2HExGntNYvD4sd/zPtipbKo51HQGSjpzLOf1svW edY7cwhs8m6CibBS1mLtTPqSpBsOdQrS2keZwJAn/arHAh79JXf524LZOVG59a06HRmq2tfcL N3UemA54UgfgG2SpvLhNF5u9M9hqOd6xv54mArvgUanBhE98T2eEflEfTszPEPJMMHPXICqm9 9/Wb4rjDVlEbFFxsbcAIJYjnU3VhcfI283lcpO498CuhxePDanDjt+1EG7t00AJ5ofWmC+pki G1p14hPbg+dny/HeBO17HGkLT3wqCMaMVy9R+LPRJ83y5UVJ6KkDcV5uFrY3PtpUVgYWFWIqY rvP8bumGw2rH2w9yTlTxMkk2uQ17zU2MvCvbGZCBiqZ9Z5kv39pSf/1yLM0DlMpoLIAEV+sWa EewpRLNWecsIF5fmfSx3EL7n4quUYYXnK5hbX+vAMG4R28FcZ1DJL+hrzW0jhZ5j5Vx9cgttz tilSIdtTgn6m6Gic0EuV5X5v4QHbXnzCy6+ywg4qK8IdungrAFVG33FIY9tfR4eA+ccJdiSkp QbpNfe6OHUa+9kt6amcIW7iZhMawhCorSX4O6JtSfn3eZoolpv6TJcqL+r30wQ1ymE0r8sKhl 44AVaIY05dYsa7g3eEne2ITpovHLr3mtuKRVNUP04q3/jMClqexe1Y3dfOLg8ggeU7b9mqPGj dpfM5f8GxikmBiOAB4pJBdN6gxtbZxgkedQhbZ6bmkSC1qLWKg8KM5bC6baRR/czEwU/O3wCn L8+AHLrEsutVYocP13NX1I8tWlXb+uyi6ki0CvaEJRQzPn1Zos+9n+r8q1Kic9SN/HaaFsibn CfuTyJL3fbfMqyrMFICCJJaHtNMQiKePMxuZpKcohzJvxJxJedt6vdn+HHmRVR3jjzDqi+LTI lpOnJ4WhoWcjLs= Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 2022/2/1 23:14, David Sterba wrote: > On Thu, Jan 27, 2022 at 01:53:06PM +0800, Qu Wenruo wrote: >> There is a long existing bug in btrfs defrag code that it will always >> try to defrag compressed extents, even they are already at max capacity= . > > As commended under the patch, this not considered a bug, because the > defrag ioctl is expected to reshuffle the extents, with or without > compression and improving the compression ratio if asked to recompress > with hither level. What is not perfect is the kernel side that could try > harder to merge extents into bigger contiguous chunks, but as long as > the compression is involved it's not possible to decide if the extents > should be skipped or not. What I can do is to add extra test to make sure if "btrfs fi defrag -c" always defrag the file no matter whatever. To me, these two factors don't conflict with each other at all. Thanks, Qu