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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87194CD11C2 for ; Wed, 10 Apr 2024 08:49:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1C0ED6B0087; Wed, 10 Apr 2024 04:49:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 149E56B0088; Wed, 10 Apr 2024 04:49:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F2C206B0089; Wed, 10 Apr 2024 04:49:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id CB67A6B0087 for ; Wed, 10 Apr 2024 04:49:52 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 70683A0E69 for ; Wed, 10 Apr 2024 08:49:52 +0000 (UTC) X-FDA: 81992999424.10.22DC655 Received: from out30-124.freemail.mail.aliyun.com (out30-124.freemail.mail.aliyun.com [115.124.30.124]) by imf10.hostedemail.com (Postfix) with ESMTP id C7F6FC0006 for ; Wed, 10 Apr 2024 08:49:48 +0000 (UTC) Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=linux.alibaba.com header.s=default header.b=IxVZulhC; spf=pass (imf10.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.124 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com; dmarc=pass (policy=none) header.from=linux.alibaba.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1712738990; a=rsa-sha256; cv=none; b=W8lJd/3yCaj3QYUT3i21QZ1YAzj4s1c0USJTHY8YmmOAYzwIPwBBuMlUrIlbrjBrVouX+8 k4r7OKYF0mFqarRc13FtJjYZ7zqn1cfFAt4Lo1UgLaTkMY0LTNCFnOnlHaONA4it3LuUkb YdEoO18bUpDhQPeab+54NV17w2DQJig= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=pass header.d=linux.alibaba.com header.s=default header.b=IxVZulhC; spf=pass (imf10.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.124 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com; dmarc=pass (policy=none) header.from=linux.alibaba.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1712738990; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=zi64y6gftwEUpOYycPmnGWa28oBRzWmtl7QJD3qYI3A=; b=6PWam/36X48UcrYOfmPoD5IoSFlNcOotxqWdw/STjJZTOBIE3eCjme2hOpP+uVH6zRqaif KikOtoGc3rWYk9BjhUVq+kMm3sDlswG+xgU3LSKQl1Qipdi0Ehyc4LcB4kaku/L2MutEXZ P1nZxDzdX9WJ0tq/Vzq5fqv2YLCS0nE= DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1712738985; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=zi64y6gftwEUpOYycPmnGWa28oBRzWmtl7QJD3qYI3A=; b=IxVZulhCDvU6qE3tGww2uvWqYIqxUeBiH17hxS35seFmkmOAj6wqVsF/qmzD6BFXBM4ZIHivYcpm/rExk01UAeLWAWN4gnZkPkZWdrGIJ65leNsi8cl2BNCMbgS6oHVZp45B3t8s0vx7miKnK82V+S1n+rwBr0K4WrM1lNqmKX8= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R371e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045176;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0W4HDLKP_1712738983; Received: from 30.97.56.65(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0W4HDLKP_1712738983) by smtp.aliyun-inc.com; Wed, 10 Apr 2024 16:49:44 +0800 Message-ID: <093e883e-4ac5-4772-9a85-0117c2d990f6@linux.alibaba.com> Date: Wed, 10 Apr 2024 16:49:42 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 10/10] mm: page_alloc: consolidate free page accounting To: Zi Yan Cc: Johannes Weiner , Vlastimil Babka , Andrew Morton , Mel Gorman , "Huang, Ying" , David Hildenbrand , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20240320180429.678181-1-hannes@cmpxchg.org> <20240320180429.678181-11-hannes@cmpxchg.org> <7b3b7f2e-7109-4e72-b1cf-259cb56f3629@linux.alibaba.com> <20240408142340.GA1057805@cmpxchg.org> <26cb722f-6e1c-4aaf-9edd-ed10a60e0018@linux.alibaba.com> From: Baolin Wang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: C7F6FC0006 X-Stat-Signature: t3oidk6akyfcubj18sknqf5nfhogg38t X-Rspam-User: X-HE-Tag: 1712738988-7768 X-HE-Meta: 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 JQM3pg2J QleBntR3b98oHoNTJjCAgGKm8mZ1ccAla43nTO4uqGG4Yoo7BILUnibuAwVLuSUT5WvJoOsVeYmyT+0xKVFNlXYMpZrXHGVTEwygWjbY5nAd0Uf7KLZkTzhtd9plPEg+uc0e8ba3WihKe4hDgRuZDlZrgYJLCdNkCZtNuPz0xYnOoIXbVqJ9WU24ZvIH2Z80x5uYwsfvXKUhMiz7JZusJSUrgPOHHPXS58tVI0kXqd3tmFxjK62NJwzazVNCGKtI7tSIG9ICjrWUKxNjcxQ6tgryXnieX+5II730wkxsCh1dV0Tw8qeOpIZe2ASUiB1t5XTFdiuOliuBP12dV6g6ipHP/bWI3BrfvHj28 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2024/4/9 22:46, Zi Yan wrote: > On 9 Apr 2024, at 5:31, Baolin Wang wrote: > >> On 2024/4/8 22:23, Johannes Weiner wrote: >>> On Mon, Apr 08, 2024 at 09:38:20AM +0200, Vlastimil Babka wrote: >>>> On 4/7/24 12:19 PM, Baolin Wang wrote: >>>>> On 2024/3/21 02:02, Johannes Weiner wrote: >>>>>> + account_freepages(page, zone, 1 << order, migratetype); >>>>>> + >>>>>> while (order < MAX_PAGE_ORDER) { >>>>>> - if (compaction_capture(capc, page, order, migratetype)) { >>>>>> - __mod_zone_freepage_state(zone, -(1 << order), >>>>>> - migratetype); >>>>>> + int buddy_mt = migratetype; >>>>>> + >>>>>> + if (compaction_capture(capc, page, order, migratetype)) >>>>>> return; >>>>>> - } >>>>> >>>>> IIUC, if the released page is captured by compaction, then the >>>>> statistics for free pages should be correspondingly decreased, >>>>> otherwise, there will be a slight regression for my thpcompact benchmark. >>>>> >>>>> thpcompact Percentage Faults Huge >>>>> k6.9-rc2-base base + patch10 + 2 fixes >>>>> Percentage huge-1 78.18 ( 0.00%) 71.92 ( -8.01%) >>>>> Percentage huge-3 86.70 ( 0.00%) 86.07 ( -0.73%) >>>>> Percentage huge-5 90.26 ( 0.00%) 78.02 ( -13.57%) >>>>> Percentage huge-7 92.34 ( 0.00%) 78.67 ( -14.81%) >>>>> Percentage huge-12 91.18 ( 0.00%) 81.04 ( -11.12%) >>>>> Percentage huge-18 89.00 ( 0.00%) 79.57 ( -10.60%) >>>>> Percentage huge-24 90.52 ( 0.00%) 80.07 ( -11.54%) >>>>> Percentage huge-30 94.44 ( 0.00%) 96.28 ( 1.95%) >>>>> Percentage huge-32 93.09 ( 0.00%) 99.39 ( 6.77%) >>>>> >>>>> I add below fix based on your fix 2, then the thpcompact Percentage >>>>> looks good. How do you think for the fix? >>>> >>>> Yeah another well spotted, thanks. "slight regression" is an understatement, >>>> this affects not just a "statistics" but very important counter >>>> NR_FREE_PAGES which IIUC would eventually become larger than reality, make >>>> the watermark checks false positive and result in depleted reserves etc etc. >>>> Actually wondering why we're not seeing -next failures already (or maybe I >>>> just haven't noticed). >>> >>> Good catch indeed. >>> >>> Trying to understand why I didn't notice this during testing, and I >>> think it's because I had order-10 pageblocks in my config. There is >>> this in compaction_capture(): >>> >>> if (order < pageblock_order && migratetype == MIGRATE_MOVABLE) >>> return false; >>> >>> Most compaction is for order-9 THPs on movable blocks, so I didn't get >>> much capturing in practice in order for that leak to be noticable. >> >> This makes me wonder why not use 'cc->migratetype' for migratetype comparison, so that low-order (like mTHP) compaction can directly get the released pages, which could avoid some compaction scans without mixing the migratetype? >> >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >> index 2facf844ef84..7a64020f8222 100644 >> --- a/mm/page_alloc.c >> +++ b/mm/page_alloc.c >> @@ -622,7 +622,7 @@ compaction_capture(struct capture_control *capc, struct page *page, >> * and vice-versa but no more than normal fallback logic which can >> * have trouble finding a high-order free page. >> */ >> - if (order < pageblock_order && migratetype == MIGRATE_MOVABLE) >> + if (order < pageblock_order && capc->cc->migratetype != migratetype) >> return false; >> >> capc->page = page; > > It is worth trying, since at the original patch time mTHP was not present and > not capturing any MIGRATE_MOVABLE makes sense. But with your change, the capture > will lose the opportunity of letting an unmovable request use a reclaimable > pageblock and vice-versa, like the comment says. Please change the comment > as well and we should monitor potential unmovable and reclaimable regression. Yes, but I think this case is easy to solve. Anyway let me try to do some measurement for mTHP.