From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-97.freemail.mail.aliyun.com (out30-97.freemail.mail.aliyun.com [115.124.30.97]) (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 088D52904 for ; Fri, 26 Jan 2024 02:29:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.97 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706236158; cv=none; b=mhYjiLvb/jzn7vB5iADCx55lcqxDY7Kud5TUPZxb8DiQ2RduLm2gQkkncaE2jXyxMt0rX7MszvzfBkYKpgP4E1aVzrvXYDLitFyRyRnKIB8D2CJ65V6nXr1O+s2wcCh6mwbVz+Pl6QBrG7hHAWznN7DSOlyozuxvxnMPosBImxc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706236158; c=relaxed/simple; bh=/R2quK6blVxTCWiAW55XFa8ou2yXcsviqHdnCoCAMhk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=QDOQS+AbwerDjvC9JwLkgjuyQB4lWligo4iCmx2FhScZ1BIj+adzp7m+bzCNZtbrTWgdKmgpu5+sZHzU7UStjIpgjZdzRx4Q/rwtW/65xUTTgww/gBavz5LLvLGT2Tj69Bjd3VM+1oDIa9MTCK1Ov2maiRFzmTp5UZWDiBuCSGk= 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=toaIe7Fq; arc=none smtp.client-ip=115.124.30.97 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="toaIe7Fq" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1706236146; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=dwkdvdG75eeYxlFk0pqOHQUVC2CDidFk3FKQ/WFen54=; b=toaIe7FqGkeJ2qB2Pi1zuknNqFgGB4ntGbgD69dg1QWe9PPeM5S/LbJcRCRVPDu9u1ULhs9WuUE9umK7E2JmPsgzEYAmKmnRep/aMVlIqy6lzDFiIjCI87fHjWlU+4BFlrQGCONo+XfFsB9BPgte13BQomtsMTmgyCsPmV6XStM= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R101e4;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=19;SR=0;TI=SMTPD_---0W.M69IO_1706236143; Received: from 30.97.56.57(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0W.M69IO_1706236143) by smtp.aliyun-inc.com; Fri, 26 Jan 2024 10:29:04 +0800 Message-ID: Date: Fri, 26 Jan 2024 10:29:28 +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 v2 1/3] mm/compaction: enable compacting >0 order folios. To: Zi Yan , linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: "Huang, Ying" , Ryan Roberts , Andrew Morton , "Matthew Wilcox (Oracle)" , David Hildenbrand , "Yin, Fengwei" , Yu Zhao , Vlastimil Babka , "Kirill A . Shutemov" , Johannes Weiner , Kemeng Shi , Mel Gorman , Rohan Puri , Mcgrof Chamberlain , Adam Manzanares , "Vishal Moola (Oracle)" References: <20240123034636.1095672-1-zi.yan@sent.com> <20240123034636.1095672-2-zi.yan@sent.com> From: Baolin Wang In-Reply-To: <20240123034636.1095672-2-zi.yan@sent.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 1/23/2024 11:46 AM, Zi Yan wrote: > From: Zi Yan > > migrate_pages() supports >0 order folio migration and during compaction, > even if compaction_alloc() cannot provide >0 order free pages, > migrate_pages() can split the source page and try to migrate the base pages > from the split. It can be a baseline and start point for adding support for > compacting >0 order folios. > > Suggested-by: Huang Ying > Signed-off-by: Zi Yan LGTM. Reviewed-by: Baolin Wang > --- > mm/compaction.c | 43 +++++++++++++++++++++++++++++++++++-------- > 1 file changed, 35 insertions(+), 8 deletions(-) > > diff --git a/mm/compaction.c b/mm/compaction.c > index 27ada42924d5..61389540e1f1 100644 > --- a/mm/compaction.c > +++ b/mm/compaction.c > @@ -816,6 +816,21 @@ static bool too_many_isolated(struct compact_control *cc) > return too_many; > } > > +/* > + * 1. if the page order is larger than or equal to target_order (i.e., > + * cc->order and when it is not -1 for global compaction), skip it since > + * target_order already indicates no free page with larger than target_order > + * exists and later migrating it will most likely fail; > + * > + * 2. compacting > pageblock_order pages does not improve memory fragmentation, > + * skip them; > + */ > +static bool skip_isolation_on_order(int order, int target_order) > +{ > + return (target_order != -1 && order >= target_order) || > + order >= pageblock_order; > +} > + > /** > * isolate_migratepages_block() - isolate all migrate-able pages within > * a single pageblock > @@ -1009,7 +1024,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, > /* > * Regardless of being on LRU, compound pages such as THP and > * hugetlbfs are not to be compacted unless we are attempting > - * an allocation much larger than the huge page size (eg CMA). > + * an allocation larger than the compound page size. > * We can potentially save a lot of iterations if we skip them > * at once. The check is racy, but we can consider only valid > * values and the only danger is skipping too much. > @@ -1017,11 +1032,18 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, > if (PageCompound(page) && !cc->alloc_contig) { > const unsigned int order = compound_order(page); > > - if (likely(order <= MAX_PAGE_ORDER)) { > - low_pfn += (1UL << order) - 1; > - nr_scanned += (1UL << order) - 1; > + /* > + * Skip based on page order and compaction target order > + * and skip hugetlbfs pages. > + */ > + if (skip_isolation_on_order(order, cc->order) || > + PageHuge(page)) { > + if (order <= MAX_PAGE_ORDER) { > + low_pfn += (1UL << order) - 1; > + nr_scanned += (1UL << order) - 1; > + } > + goto isolate_fail; > } > - goto isolate_fail; > } > > /* > @@ -1146,10 +1168,11 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, > } > > /* > - * folio become large since the non-locked check, > - * and it's on LRU. > + * Check LRU folio order under the lock > */ > - if (unlikely(folio_test_large(folio) && !cc->alloc_contig)) { > + if (unlikely(skip_isolation_on_order(folio_order(folio), > + cc->order) && > + !cc->alloc_contig)) { > low_pfn += folio_nr_pages(folio) - 1; > nr_scanned += folio_nr_pages(folio) - 1; > folio_set_lru(folio); > @@ -1767,6 +1790,10 @@ static struct folio *compaction_alloc(struct folio *src, unsigned long data) > struct compact_control *cc = (struct compact_control *)data; > struct folio *dst; > > + /* this makes migrate_pages() split the source page and retry */ > + if (folio_test_large(src) > 0) > + return NULL; > + > if (list_empty(&cc->freepages)) { > isolate_freepages(cc); >