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 740ADC19F2D for ; Sun, 7 Aug 2022 01:24:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231822AbiHGBYT (ORCPT ); Sat, 6 Aug 2022 21:24:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36730 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230407AbiHGBYR (ORCPT ); Sat, 6 Aug 2022 21:24:17 -0400 Received: from mout.gmx.net (mout.gmx.net [212.227.17.21]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CEB94E0DC for ; Sat, 6 Aug 2022 18:24:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1659835449; bh=1CPbgUlCkJu3WeVUCnpJvzTR1+WrqFUzXF7dAsSvKZw=; h=X-UI-Sender-Class:Date:Subject:To:References:From:In-Reply-To; b=Zh8hiKsZE/GcTjtZ7/TD1DIaTNQdmrWKXB4aFNW4l8RBGNoNlx35+MCHQledkSHPV r+E+z0rjOot6FiktCdZ7PTSgRfOrX7abUXP/HbajeVVT8gSPnKzw2qesw1BAPqGqWf uHVhIOCxHMyeUxCfNCQhOs3fHmZxooBkMxX83YAQ= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([149.28.201.231]) by mail.gmx.net (mrgmx105 [212.227.17.174]) with ESMTPSA (Nemesis) id 1MowKc-1ndDJ01pra-00qO68; Sun, 07 Aug 2022 03:24:09 +0200 Message-ID: <80e1fe42-6c9e-0da3-fa1c-434e3577033d@gmx.com> Date: Sun, 7 Aug 2022 09:24:05 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: the 1st data chunk(8M) allocated by mkfs.btrfs can not be allocated again after full balance? Content-Language: en-US To: Wang Yugui , linux-btrfs@vger.kernel.org References: <20220807091957.17D7.409509F4@e16-tech.com> From: Qu Wenruo In-Reply-To: <20220807091957.17D7.409509F4@e16-tech.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:IKhCBhHdYjjxkbG570SQ1oKq4KFMni46FiyGeKYoEpP6KX0DiVE ixa0XrHedVQ0fqCnNHAcohaypCv3Q+SSmTf1BRz11L1usNoIu7KMnvrAlMu7aSPhsYbZNoF AxD9baDUfo+3iqBHUPnt9GZlaQcPGcjA/WWUFoZTGcneldr27K9AF7XH+o6Piqi9B1ceZNl /5MTqlDc/RU2XBMpWmcTA== X-UI-Out-Filterresults: notjunk:1;V03:K0:8Zik7Hyux74=:TXJPncVSIx7yfLEpaaW9eL AL58CW7ZsYYzEDjbKZdsmmYTlXd+ngDXwx/5jzhfVoLdJoeGmS3YrVpzDRBN6L6oVXw2dd8RS 2ycfGv1k7GoVGPW1Rh19eetV5pWIicwihTp9K/GUZlkpWjiaryQe5Fudyymbg5h3uXwIpp6Sz CWH2jL9aGzF04LWhRlqML4DHcDStW4DG+CJnIwxcGSpl0pQCFERVcCaLEnoLBkkJPhnEl7K70 6td8WMLNsKQ0/sSHhf7oCjHICvQLngC4l2bhxUk7ZS2uPQGPJo1260z1TYDzxTVf9aRhOSblE efsMQcfPDi5eKgeWHlXpCKuAua3dJ/vGIxAdEU3xsdTDy+O8auucGuSESnTZCJjGKY0Hgo+Vl Bh6CQCtWotHjcy/EUMlI6eKi6ELqFWT1y5NYsdMlHanfvd5JlclRsCeS8AVdNThSmQ0IUYlBp 5EHbnvZKqJSa4/vRKKyu6iAy46Zc0nQ8AEwoCdYA82r+0d3i/0eQfqAcfv03Yhpx38lPl39B2 VN5AV5rErpvs3L74g7p4/O1+xkL1ZN6GIshnYyj6nOTi6EQAkIfNU0DlCtTFo7qmUoO3uDAv8 3fjthD7c4TCYdNZmezgKD7nhUMphSWwSJth5S2/JudCPY5TU6wqHiW2fcbomE+6XpiUt4W+MW dVJmCmrrp612X3vf4PBNo/JCyLyZ1S5nOKLmmR+JXkLqh71rGIwu6xJKrNKFUV2fTed/0Xxcq DBo0qP8fDEai8UMa+ypexVbnVi0/OW8rxUZMUN66899esIb9IXfZPjYF1yB4XWF2Zjdf4EZpf cRFQhgpjyHrYPHfFk16DoV1kBKjVZkxELcnV4u/VVcSU8nxXi5bWtxxXOsOW1nXcVAu/4e2Z9 +pguWdb6J3vBHAi9MciNiSHpWm0whIooR8XzsxNcNJ22DEzCmFpT8Y1qelMMwd9WMbPkYpk6i nXuweDai8bGX8S6Dquk0M7aJ0O3S/W3nfb+ByXC3E/aHWY2skBSOzQkT+AF3Q95n4KfADGoLB e+Q9EmnpleHQudMt7tjN1/r7zC7CHSGOwWrcQ4ElKDLuZPf+Z/OfmnFBAZs4G56+BikjHbsPd nEuDGrF2EogL2rP/oNXHPxPuWx0SuULvxG4MJZf5kziT8gE4+bDfXptLQ== Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 2022/8/7 09:19, Wang Yugui wrote: > Hi, > > The 1st data chunk allocated by mkfs.btrfs is 8M. After full balance, > this 8M chunk is freed, and new allocated chunk size > is changed to 1G. > > Then this 8M space can't be allocated again? It can, but needs very complex relcation, e.g. relocate all chunks to other devices (e.g. delete the device and add back). Or run very low on unallocated space. The reason why it can not be really utilized is, chunk allocator will always use the largest unallocated range by default. Thus such small 8M will not be utilized until no more free space. > Or we should allocate 1G for 1st data chunk in mkfs.btrfs? I think we should follow kernel allocation size, but I'm not confident on small devices. Thanks, Qu > > Best Regards > Wang Yugui (wangyugui@e16-tech.com) > 2022/08/07 >