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=-5.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 E7D7FC4727E for ; Fri, 2 Oct 2020 01:46:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A5EBE20719 for ; Fri, 2 Oct 2020 01:46:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gmx.net header.i=@gmx.net header.b="ITEA3qzh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387572AbgJBBqj (ORCPT ); Thu, 1 Oct 2020 21:46:39 -0400 Received: from mout.gmx.net ([212.227.17.21]:56693 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727780AbgJBBqj (ORCPT ); Thu, 1 Oct 2020 21:46:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1601603190; bh=gM/nXgbSLHFvzm5V9Rol34yUPu3VLYm5mLt7Va+OAUM=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=ITEA3qzhY73rQtkT6aWuN9XvQhKVTidopOo2aV7WMRvCF+4E1Ocv5rEf5aPdvhRqj 1iDD2yop0tHp5ABbUiRHvgxtGPjSkyeFEmHnkyrR10yPx1qbBmkG+LvD0LC1nzX+nu +hC6SZnE4OuYw2T/VX2CVyMFsB4htVwifQPF9gmQ= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([149.28.201.231]) by mail.gmx.com (mrgmx105 [212.227.17.174]) with ESMTPSA (Nemesis) id 1MFKGP-1kDV1w1LGD-00Fj3I; Fri, 02 Oct 2020 03:46:30 +0200 Subject: Re: simple Chunk allocator like calculation to replace Factor based calculation To: Wang Yugui , Qu Wenruo Cc: "linux-btrfs@vger.kernel.org" References: <20201001233649.888B.409509F4@e16-tech.com> <7b8600fa-e04e-2b87-3ddb-ba16d4f2824f@suse.com> <20201002093001.19E0.409509F4@e16-tech.com> From: Qu Wenruo Autocrypt: addr=quwenruo.btrfs@gmx.com; prefer-encrypt=mutual; keydata= mQENBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAG0IlF1IFdlbnJ1byA8cXV3ZW5ydW8uYnRyZnNAZ214LmNvbT6JAU4EEwEIADgCGwMFCwkI BwIGFQgJCgsCBBYCAwECHgECF4AWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCXZw1oQAKCRDC PZHzoSX+qCY6CACd+mWu3okGwRKXju6bou+7VkqCaHTdyXwWFTsr+/0ly5nUdDtT3yEVggPJ 3VP70wjlrxUjNjFb6iIvGYxiPOrop1NGwGYvQktgRhaIhALG6rPoSSAhGNjwGVRw0km0PlIN D29BTj/lYEk+jVM1YL0QLgAE1AI3krihg/lp/fQT53wLhR8YZIF8ETXbClQG1vJ0cllPuEEv efKxRyiTSjB+PsozSvYWhXsPeJ+KKjFen7ebE5reQTPFzSHctCdPnoR/4jSPlnTlnEvLeqcD ZTuKfQe1gWrPeevQzgCtgBF/WjIOeJs41klnYzC3DymuQlmFubss0jShLOW8eSOOWhLRuQEN BFnVga8BCACqU+th4Esy/c8BnvliFAjAfpzhI1wH76FD1MJPmAhA3DnX5JDORcgaCbPEwhLj 1xlwTgpeT+QfDmGJ5B5BlrrQFZVE1fChEjiJvyiSAO4yQPkrPVYTI7Xj34FnscPj/IrRUUka 68MlHxPtFnAHr25VIuOS41lmYKYNwPNLRz9Ik6DmeTG3WJO2BQRNvXA0pXrJH1fNGSsRb+pK EKHKtL1803x71zQxCwLh+zLP1iXHVM5j8gX9zqupigQR/Cel2XPS44zWcDW8r7B0q1eW4Jrv 0x19p4P923voqn+joIAostyNTUjCeSrUdKth9jcdlam9X2DziA/DHDFfS5eq4fEvABEBAAGJ ATwEGAEIACYCGwwWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCXZw1rgUJCWpOfwAKCRDCPZHz oSX+qFcEB/95cs8cM1OQdE/GgOfCGxwgckMeWyzOR7bkAWW0lDVp2hpgJuxBW/gyfmtBnUai fnggx3EE3ev8HTysZU9q0h+TJwwJKGv6sUc8qcTGFDtavnnl+r6xDUY7A6GvXEsSoCEEynby 72byGeSovfq/4AWGNPBG1L61Exl+gbqfvbECP3ziXnob009+z9I4qXodHSYINfAkZkA523JG ap12LndJeLk3gfWNZfXEWyGnuciRGbqESkhIRav8ootsCIops/SqXm0/k+Kcl4gGUO/iD/T5 oagaDh0QtOd8RWSMwLxwn8uIhpH84Q4X1LadJ5NCgGa6xPP5qqRuiC+9gZqbq4Nj Message-ID: <6941eed6-19a3-add6-6608-8a5d5ec86006@gmx.com> Date: Fri, 2 Oct 2020 09:46:25 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20201002093001.19E0.409509F4@e16-tech.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="pgpjsVSTLG89vUHQ1CiqLs3fIGRheY8ne" X-Provags-ID: V03:K1:3O6cev7M+qP0SfIZmukntglFO/kVtf9Q0yaAwSo6NrukCl0lkg8 h/TOBm3Z70eNZ3gSwty9G6W7ua5NpjTyoq/cSV2oE3y9JncscW0IXR8rq3ZS6JzXldZ+BHy uU8cd1TIje3ovlFHua6ycBfjAkhNddI6TJ1U2151uhVVAtggiANcKbe05W9sAGHVJGxLgIh EyUt3pkOI/TKa6hX+CVeg== X-UI-Out-Filterresults: notjunk:1;V03:K0:UhSUxtvWeVw=:Nyp/LSUXjkuYmd+wT7ogVH Y6wY+3z0gPGzsL+Fp0jURERiKNO0krPadI8iu+b2qpnC+VY9CBEs5cOXxMfzV93LbqIdz2oZN YXHz+dlxg6vhRklJPrpn1tR8CBOZ6lNynvouIpRfkS17XhVLCkjpzGzwzr+RWeXIbZbrcfq7d 3EdozMzEU+Xh3vQwcYoWGMnkFBpXb6MfyTwz713mDwWiOBBYx2IpsgwgjruUJUs0iXV7i4e/N CuLNvZhyqmnKoJtadtwqHgSFeUPTdowmwLz0Ev6zlKL9yh+kdfTTwDcRR5mQeREDrs3M6exTE DW0/JbXS7vVbT3bXKWzAItQ6DoPl7rTGa+gKwQSYxh/1CNazhcWgTn92pp5XJs5DgrB/GiEhg YMLRciIkLpTQzstddx466g29szKUphSvPiLwzJMh9kF5glLbkCCcSyDnPmnc1HtPy5d0DWWoO ce+SvPeBNCYthO573MykHfbAkl5idw0DrdU1VwNn086V1xouND8iTY7u1qx5Cge/8eI5ftqV9 I+PzoVTvGAxYHm6Ps8Am0UcQOaEIiAjHQWCDgIah0U8L8fdO8IU/1pMtc12jYNoHKvK3d2rwa LqKNY7UMU6VBII/RZqkwRmIFluOLcq7R3IIE3YxNFawJ0DOTtWkgiO0+1H14equfOQ8AXENTE untwqQ1LmsS/SsMpxrf6t9yj+8ETfuFKNFZQAl74WkBt7ZVeIKiiKD5IuGHPSEjDnAUw98l0u os5Q+dlsgKTeVImvi3zLER9zq2mSs2rKqiy8FEpUBCSwB26DWVySU6T1kgh/KOwVg17vKDD+V i42SeNeRp2SEczzEkE+nydPPGlmoCroR77N2h111ZZhjKNIj+oudBS7jSXMzJzP1TwGvd/0SY lxYWCm5nEGEu2LKygIk8HW8vlGvOvWZziELA9Z9RYBfDQgxGjNL/uBfOz9JJmDAf2Gwe1eHy/ dsACEG5E08ppC7UUiKvDmFMrQQQeOYODlgdbYUGkIkUqx4VtsZs9Jr30D+UbEGos44Eev3vhd QPRaETPIi8auehas8Dm+nK7NP6RlM+50p0pyOGyAxdnC4af/opZd4o8bxXvE8VSXXbAGYzip7 olKPLZPM/B1fqzdDkzOUlupRkJu4br+7iqDYFF5e+yMeD3rcpuPWFtkWeYf8ASrlyf85RVvmL 30ZkYDdYwDnPRLrkHHSLOg1iMJ0xGClqmVxKpoFGwEaPkwzeohmypooQbtv1tkyYRPYGEIoKP pUG6hAsOrUe8OAAiGQSq60SxNW36sR9M/euiyZQ== Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --pgpjsVSTLG89vUHQ1CiqLs3fIGRheY8ne Content-Type: multipart/mixed; boundary="T9rf6oajRtEhoexNzXAPjCpYLsqI6iwIG" --T9rf6oajRtEhoexNzXAPjCpYLsqI6iwIG Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2020/10/2 =E4=B8=8A=E5=8D=889:30, Wang Yugui wrote: > Hi, Qu Wenruo >=20 >> On 2020/10/1 =E4=B8=8B=E5=8D=8811:36, Wang Yugui wrote: >>> Hi, Qu Wenruo >>> >>> Chunk allocator like calculation will get the right value, but it is >>> slow for big file system such as 500T. >> >> Nope, the ballon allocator doesn't have any size limit, thus it will t= ry >> to use as much space as possible in a single run. >> >> If the 500T fs only has say 100T used, and the remaining 400T is split= >> into, say 2 parts, then just two small run would finish. >> >> On the other hand, if the 500T is mostly used, only 100T unallocated a= nd >> the 100T is in a big unallocate chunk (under most cases it's true), th= en >> just one allocation run is enough. >> >> So in short, it's unrelated to the fs, but how fragmented the >> unallocated space is. >> And normally unallocated space is not fragmented at all, thus it's ver= y >> speedy. >=20 > We need some more complex example for 'Chunk allocator like calculation= ' > to make it easy to understand. >=20 > such as > 1) RAID10 with 8T,1T,1T,1T,1T > the virtal chunk size of 1st iteration: 1T or 0.33T? > 1T chunk will use 4T at most > 0.33T chunk will use 5.33T at most? You didn't get the point. For the each loop we: - Sort the devices with their free space. In this case, it's 8, 1, 1, 1, 1. - Round down to dev increament Then we got 8, 1, 1, 1. - Then allocate chunk Since the biggest unallocated space is 1T, we allocate a RAID10 with 1T stripe size, which will be a 2T chunk. The remaining size is 7, 0, 0, 0, 1. - We go to next round. No way to allocate new chunk. In this case, we can only get 2T chunk. Just as the chunk allocator do. >=20 > 2) RAID10 with 8T,1T,1T,1T,0.5T > the virtal chunk size of 1st iteration:0.5T or smaller? Still the same, 2T chunk can be allocated using the largest 4 devices. Thanks, Qu >=20 > Best Regards > =E7=8E=8B=E7=8E=89=E8=B4=B5 > 2020/10/02 >=20 >=20 > -------------------------------------- > =E5=8C=97=E4=BA=AC=E4=BA=AC=E5=9E=93=E7=A7=91=E6=8A=80=E6=9C=89=E9=99=90= =E5=85=AC=E5=8F=B8 > =E7=8E=8B=E7=8E=89=E8=B4=B5 wangyugui@e16-tech.com > =E7=94=B5=E8=AF=9D=EF=BC=9A+86-136-71123776 >=20 --T9rf6oajRtEhoexNzXAPjCpYLsqI6iwIG-- --pgpjsVSTLG89vUHQ1CiqLs3fIGRheY8ne Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAl92hnIACgkQwj2R86El /qhVzQgAjBPIeWjEh1T1EVQw3ndC6nUHbrBfXt/3Fnp/sUc4lQc3KTHtcbGSrL0g u3+Qsbi5Pmo9jST/iBz4g55FiS12Zpztr9uVo6G16Fqlqtt+LgCO/gW5pF4VHFx5 hP1/4CKLI7t5A8YstdfzCn274/pB0gDakCfUuy/kTH0kk6K664LkCpYrt8LDritM FXwMB6cOtVsFnmEMt1XXLqfDta0VPy4ct5+oxCP5ZmRuAwoEMBulW4ElG7mvI9ca 2USK8IqSZSzfkJd2xD2U+k4PmCxiBbXuNC4J/Fb9e0YoPyzlcFkSFJ/PkBWR02u8 86clMhgHpaIq9V015rPA8D3ZtFBSvg== =GKjq -----END PGP SIGNATURE----- --pgpjsVSTLG89vUHQ1CiqLs3fIGRheY8ne--