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=-9.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MSGID_FROM_MTA_HEADER,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 49CA6C4338F for ; Wed, 25 Aug 2021 12:07:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2A223610C7 for ; Wed, 25 Aug 2021 12:07:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240456AbhHYMIB (ORCPT ); Wed, 25 Aug 2021 08:08:01 -0400 Received: from de-smtp-delivery-102.mimecast.com ([194.104.109.102]:54902 "EHLO de-smtp-delivery-102.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232681AbhHYMH6 (ORCPT ); Wed, 25 Aug 2021 08:07:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=mimecast20200619; t=1629893232; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=AJL9s4XfWqv2+aHInagyf9nbJ6QqcaTWBUyQmlCa9KU=; b=li44LRzy37BZeiOQX0kssriwkiMiMIezbICwccDnCFSv0fQMzgi021xaXYcZlbs6hkgfeG djcVTwDml05HtO+q3p1zQ6AYAHu/vkU2sU5UMABDjFOphXXnuJToTJfxSOlD+m65DRCxUC 2m3mW1aLpcsN7wGV4lZWOVUlDhSio2s= Received: from EUR05-VI1-obe.outbound.protection.outlook.com (mail-vi1eur05lp2173.outbound.protection.outlook.com [104.47.17.173]) (Using TLS) by relay.mimecast.com with ESMTP id de-mta-5-hznXtAJDP7G-88Jw78ZZoQ-1; Wed, 25 Aug 2021 14:07:10 +0200 X-MC-Unique: hznXtAJDP7G-88Jw78ZZoQ-1 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=VoOquMYail1n/o7QuFRM8kKCT/sqNCm5wvvjLDDq0FnwC48nZbwmwSlc43JDsoZFcXrJz+bt2+QMun15PDlKrUZGBH6h7H6AQ66cQAQhrs9GmqXBaR/D66gdM+fbpz1iFjarbiFkJVTlEoJXP606f+GWd6wAWVbkFNqW9KqU4ToS48VcOJfNUERnahsi7cbv7esZa8ptrMW1gxIH1A5q5HYjgqIkpHYb483gsgNmA1tz1dyF1A4gO+u/rGRdhcRENQoM+nXlICNHuB9i6cisBTt5kwincXV22RZQhp4bz+5FinCoeKmI2MKOfqhOlO4FjYdFQa8gKmNGd7M5OhUCjQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=kUrmXMSDevN3GzW2XiQnjOLDtw8DrfuX7wvWVhM0vug=; b=JyUBg3uACy2JClrj5loowLpIT3UQOc3A4/X99PInDvY7QQDr42dbDoEY9feAdOM12WOzai0abLWOex7BGfR1w5RR/XHpWenMotsM0Q3JZC0sfnGk3bJZ7skSh68QgbcVDWOw8m1ZSE3AFUkl5dP8V3dZvZHP1YHwBs22hY6Mcg+Bx9V3O29vVq2xMzK0d7g+xH2LuiAlG4WXSfmUf+gZ7p2lUfE2F7hLp9iA4OcRDfjaDfu+tRpt7fFHjUSzPSmm74JriDIgglcXmH6aNt+Jyx/mQolvtcrTPRecwWBr0gPReAbh9TqPReTWmafmbdzOKQ2yrbm583Aru5g5rWSKlA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=suse.com; dmarc=pass action=none header.from=suse.com; dkim=pass header.d=suse.com; arc=none Authentication-Results: vger.kernel.org; dkim=none (message not signed) header.d=none;vger.kernel.org; dmarc=none action=none header.from=suse.com; Received: from AM7PR04MB6821.eurprd04.prod.outlook.com (2603:10a6:20b:105::22) by AM6PR0402MB3893.eurprd04.prod.outlook.com (2603:10a6:209:16::24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4436.22; Wed, 25 Aug 2021 12:07:09 +0000 Received: from AM7PR04MB6821.eurprd04.prod.outlook.com ([fe80::3510:ed3f:66d7:cf48]) by AM7PR04MB6821.eurprd04.prod.outlook.com ([fe80::3510:ed3f:66d7:cf48%7]) with mapi id 15.20.4436.025; Wed, 25 Aug 2021 12:07:09 +0000 To: dsterba@suse.cz, linux-btrfs@vger.kernel.org References: <20210825054142.11579-1-wqu@suse.com> <20210825115559.GG3379@twin.jikos.cz> From: Qu Wenruo Subject: Re: [PATCH] Revert "btrfs: compression: don't try to compress if we don't have enough pages" Message-ID: Date: Wed, 25 Aug 2021 20:06:57 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 In-Reply-To: <20210825115559.GG3379@twin.jikos.cz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: BYAPR07CA0052.namprd07.prod.outlook.com (2603:10b6:a03:60::29) To AM7PR04MB6821.eurprd04.prod.outlook.com (2603:10a6:20b:105::22) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [0.0.0.0] (149.28.201.231) by BYAPR07CA0052.namprd07.prod.outlook.com (2603:10b6:a03:60::29) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4457.17 via Frontend Transport; Wed, 25 Aug 2021 12:07:05 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: c9d69757-e119-4dba-9c11-08d967c0dd0b X-MS-TrafficTypeDiagnostic: AM6PR0402MB3893: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:10000; X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:AM7PR04MB6821.eurprd04.prod.outlook.com;PTR:;CAT:NONE;SFS:(39860400002)(136003)(376002)(346002)(396003)(366004)(186003)(86362001)(26005)(83380400001)(6706004)(31696002)(6666004)(316002)(6486002)(2616005)(8676002)(31686004)(8936002)(66556008)(66946007)(2906002)(66476007)(956004)(36756003)(16576012)(5660300002)(478600001)(38100700002)(78286007)(45980500001)(43740500002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?Byptc6efaadskb6s5ndiU3sCz1kaptWWha4qVKZjfpZVRBR8JHXSzeuxbBFJ?= =?us-ascii?Q?p+dYqcStioKp3hpZs7py2Pk16Y9O0lOqieBX+gQZ2+o8cCMiXKoVOy4ULc5/?= =?us-ascii?Q?NCSSvdLLGyiHYcu+vdvnIz3Bf1264pQXYDbkxJ2JsoCAlmhenvzKJA2WK6pO?= =?us-ascii?Q?RK92tEj5t2hB7FQRsdQKHjyomPuyAi3CbPCkxOocUyq8cG5dnqLkUOcKsRhH?= =?us-ascii?Q?RcXidP7/Dk8xHEcpIdgqKMhwcmdFOoobX5+I6l3WCJWMGY0Sf714HrH5dtfT?= =?us-ascii?Q?JmhhQ/8hCmzM6XGY4P3g2OfbvYOhwCV7iLPTvmqRaEj5yYoMrB5NLx7hoOrR?= =?us-ascii?Q?C8Lsard1mOnsSHT/bEfbHiYlSUM5VoZ0aZGiFdE6kY6gZBRiGToX99vKR4Gs?= =?us-ascii?Q?5RsZo3j0JmCJE32+D2AXC64j2WGm3j3yrcVACIlK/t2TAWSGmzbHpPgUd9aV?= =?us-ascii?Q?DjGM+ECCw674QKQi+/tJl2mIaZDuAP7U68gf+XixejsnwLODLxDCBhSo4YJZ?= =?us-ascii?Q?rkVcclUlfxbU50CXnCQhhxHWm8GDWbOq1ufPa9fQMy23Y3piZWTg43cVyequ?= =?us-ascii?Q?HWVOoVlDjmQYPOAaUzcDCArHf4zh12JPdBr3BTULbQR5kUQgP2yjpk65wo0+?= =?us-ascii?Q?ZszU0iXEdkwMTB0BJV5K8nhncMYSXs3OfsIc1H0/hqQadXVzVhpJwHEZ8Q53?= =?us-ascii?Q?F7ThKMMSzSwBFzyRCmhmTzn+RFmo5MFiSCG9o/VY1x0iaHlxtjmr1J1frU1L?= =?us-ascii?Q?x35owgwEkmEY9LAj+f++MdAkQdzrc8hHKFK6eCA4WYyY5YE9KDpYUWutDCs6?= =?us-ascii?Q?AQfPiXR68H0Xct7ZtHmUhIy3AFbYhFkgmNszMIiITRjI0/IJqccBOE67i6WL?= =?us-ascii?Q?oCJvSbijM9HTHRdYe2iq8JNby9WTSa9f3yPsEN0LESSCGQyFXP7BR1COcAk0?= =?us-ascii?Q?hvELEgSM8fBc83G8g4n5Oa3+snX3LdC6iyGKjZqLPVvZtcm2P0sIw+/Ldf0n?= =?us-ascii?Q?PIN+8ddiWsHhQ7kHj3iOqQTGuIWpzt+Gj66YosxYlhW/Rsae6EMZxAmSN3ml?= =?us-ascii?Q?9dFvcyp9OGt83LANs0BP4xchIRP1ZReogOFG3ZCnULFXFzcyIsljqgUTVKuE?= =?us-ascii?Q?Fi9Fn9V50/8eCFcHNfHXbykoEchSSex2QygvUH3DL1HJhmdIUNAWdYO4wfYM?= =?us-ascii?Q?LvVPTwCpTd7ZS0wOU4P79aAx5LphR3B2kc0959ODjDnzvvAgCZrApb0dqAbI?= =?us-ascii?Q?qKeJLsWYaIQ4iMjyLm/M4m2g+RdXuc4L8zhfY5Mh7Fi1Ucv5vW8hUm/MwoQn?= =?us-ascii?Q?MZ2qCvlWuBhrJa8+KKt/2yQE?= X-OriginatorOrg: suse.com X-MS-Exchange-CrossTenant-Network-Message-Id: c9d69757-e119-4dba-9c11-08d967c0dd0b X-MS-Exchange-CrossTenant-AuthSource: AM7PR04MB6821.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 25 Aug 2021 12:07:09.1982 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: f7a17af6-1c5c-4a36-aa8b-f5be247aa4ba X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: wrQA1XjUHC8JYi3sQwH/l4PGbLqwrPBu4rLFrLDtEx4VrAHjbP3PUFp2Q9vCNJ8P X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM6PR0402MB3893 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 2021/8/25 =E4=B8=8B=E5=8D=887:55, David Sterba wrote: > On Wed, Aug 25, 2021 at 01:41:42PM +0800, Qu Wenruo wrote: >> This reverts commit f2165627319ffd33a6217275e5690b1ab5c45763. >=20 > At this point the revert is the simplest way to restore the inline > extent compression so that's what I'll probably do. However. >> >> [BUG] >> It's no longer possible to create compressed inline extent after commit >> f2165627319f ("btrfs: compression: don't try to compress if we don't >> have enough pages"). >> >> [CAUSE] >> For compression code, there are several possible reasons we have a range >> that needs to be compressed while it's no more than one page. >> >> - Compressed inline write >> The data is always smaller than one sector. >=20 > The missing logic was for the true inline extent. The patch was supposed > to skip compression for single pages other than inline extents, due to > efficiency. So I wonder if we want to do that or just don't bother as > it's probably a negligible amount of wasted time. Yeah, I guess that's the case. We may be able to do such check in the future, but at that time, we need=20 to take inline extents into consideration. Thus it won't be just a simple @nr_pages check, but with extra=20 @start/@len check. >> >> - Compressed subpage write >> For the incoming subpage compressed write support, we require page >> alignment of the delalloc range. >> And for 64K page size, we can compress just one page into smaller >> sectors. >=20 > Oh so the logic would have to be updated to distinguish sectors and > pages, but to simplify the code for subpage compression support it would > be easier to revert it and start from there. >=20 For subpage support, there will be no conflicts inside the that function. Just a reminder that we need to change our mindset to distinguish page=20 and sector more in the future. Anyway, if we really want to do the same check in the future, it will=20 take into @start, @len, and sectorsize into consider, and maybe more=20 factors to be consider. Thanks, Qu