From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-100.freemail.mail.aliyun.com (out30-100.freemail.mail.aliyun.com [115.124.30.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 25B1234CDE for ; Mon, 8 Apr 2024 09:14:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.100 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712567646; cv=none; b=Xy+2NTI2QnLEFOI274W+9DgedNvglpmdw38ms+/61dBTHuYIyv6W2HdA5RquvLab7f7gD2ML/hE6jybDI/3vqSF/d8a+oBC45Nu96MBRy8myIm3QyPT2rdeGgibStrdzC8CDt3Y1mRo/6t58YnSBJqUm8D712+ksF3aVZPF6x28= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712567646; c=relaxed/simple; bh=8+I33Q7W7iw315CemMmiCzk+goWkzaVeSs5DNZuhE5g=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=imZROLSlgV80Qwv5StBdpwEkoe3kFp+4mFR6qIaHc5QKl+HuTjqs3yEsJIUjA/75hA1/E1eZqUWrnVc1C2b2QmFDH6OEOj1hkL77UKFElVWq5Acv/yCE2Om/afPvBV62EnNA2hS6slvkcTlYYeubE4kH3w6kaFXsIYjTeAx6+0M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=sskiNhnO; arc=none smtp.client-ip=115.124.30.100 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="sskiNhnO" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1712567635; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=K6qk+9ggjcNMTTz30BtXi3bL/FtbPiUNAq+6RisDvL0=; b=sskiNhnOELfdDhMzxz1CxYeQmMeTKW/ZTmd9BzUWBuaUz5N+AGe83ppE/SC001zvvErfghgujJpGL73i+hs4nRTyon+COn767kOJZKtsjxAdrM00fL0XMjSSrPwMYL3yOh0kmSIBCKob6WrxkdFRm/eFWrrSCu3I9IfgUm/pUcM= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R191e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046050;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0W46vhRi_1712567634; Received: from 30.97.56.71(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0W46vhRi_1712567634) by smtp.aliyun-inc.com; Mon, 08 Apr 2024 17:13:55 +0800 Message-ID: <8c811ea8-f4ea-4f0f-91f8-3bc798a19407@linux.alibaba.com> Date: Mon, 8 Apr 2024 17:13:53 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 10/10] mm: page_alloc: consolidate free page accounting To: Vlastimil Babka , Johannes Weiner , Andrew Morton Cc: Mel Gorman , Zi Yan , "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> From: Baolin Wang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2024/4/8 15:38, 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, Thanks for helping to confirm. > 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. Right, agree. > Actually wondering why we're not seeing -next failures already (or maybe I > just haven't noticed). > >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >> index 8330c5c2de6b..2facf844ef84 100644 >> --- a/mm/page_alloc.c >> +++ b/mm/page_alloc.c >> @@ -805,8 +805,10 @@ static inline void __free_one_page(struct page *page, >> while (order < MAX_PAGE_ORDER) { >> int buddy_mt = migratetype; >> >> - if (compaction_capture(capc, page, order, migratetype)) >> + if (compaction_capture(capc, page, order, migratetype)) { >> + account_freepages(zone, -(1 << order), migratetype); >> return; >> + } >> >> buddy = find_buddy_page_pfn(page, pfn, order, &buddy_pfn); >> if (!buddy) >> >> With my fix, the THP percentage looks better: >> k6.9-rc2-base base + patch10 + 2 fixes + >> my fix >> Percentage huge-1 78.18 ( 0.00%) 82.83 ( 5.94%) >> Percentage huge-3 86.70 ( 0.00%) 93.47 ( 7.81%) >> Percentage huge-5 90.26 ( 0.00%) 94.73 ( 4.95%) >> Percentage huge-7 92.34 ( 0.00%) 95.22 ( 3.12%) >> Percentage huge-12 91.18 ( 0.00%) 92.40 ( 1.34%) >> Percentage huge-18 89.00 ( 0.00%) 85.39 ( -4.06%) >> Percentage huge-24 90.52 ( 0.00%) 94.70 ( 4.61%) >> Percentage huge-30 94.44 ( 0.00%) 97.00 ( 2.71%) >> Percentage huge-32 93.09 ( 0.00%) 92.87 ( -0.24%)