From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) by kanga.kvack.org (Postfix) with ESMTP id C19308E0220 for ; Fri, 14 Dec 2018 18:03:14 -0500 (EST) Received: by mail-ed1-f69.google.com with SMTP id o21so3462957edq.4 for ; Fri, 14 Dec 2018 15:03:14 -0800 (PST) Received: from outbound-smtp12.blacknight.com (outbound-smtp12.blacknight.com. [46.22.139.17]) by mx.google.com with ESMTPS id p21-v6si2083183ejx.67.2018.12.14.15.03.13 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 14 Dec 2018 15:03:13 -0800 (PST) Received: from mail.blacknight.com (pemlinmail01.blacknight.ie [81.17.254.10]) by outbound-smtp12.blacknight.com (Postfix) with ESMTPS id 0911D1C1D97 for ; Fri, 14 Dec 2018 23:03:13 +0000 (GMT) From: Mel Gorman Subject: [PATCH 09/14] mm, compaction: Ignore the fragmentation avoidance boost for isolation and compaction Date: Fri, 14 Dec 2018 23:03:05 +0000 Message-Id: <20181214230310.572-10-mgorman@techsingularity.net> In-Reply-To: <20181214230310.572-1-mgorman@techsingularity.net> References: <20181214230310.572-1-mgorman@techsingularity.net> Sender: owner-linux-mm@kvack.org List-ID: To: Linux-MM Cc: David Rientjes , Andrea Arcangeli , Linus Torvalds , Michal Hocko , ying.huang@intel.com, kirill@shutemov.name, Andrew Morton , Linux List Kernel Mailing , Mel Gorman When pageblocks get fragmented, watermarks are artifically boosted to pages are reclaimed to avoid further fragmentation events. However, compaction is often either fragmentation-neutral or moving movable pages away from unmovable/reclaimable pages. As the actual watermarks are preserved, allow compaction to ignore the boost factor. 1-socket thpscale 4.20.0-rc6 4.20.0-rc6 finishscan-v1r4 noboost-v1r4 Amean fault-both-1 0.00 ( 0.00%) 0.00 * 0.00%* Amean fault-both-3 3849.90 ( 0.00%) 3753.53 ( 2.50%) Amean fault-both-5 5054.13 ( 0.00%) 5396.32 ( -6.77%) Amean fault-both-7 7061.77 ( 0.00%) 7393.46 ( -4.70%) Amean fault-both-12 11560.59 ( 0.00%) 12155.50 ( -5.15%) Amean fault-both-18 16120.15 ( 0.00%) 16445.96 ( -2.02%) Amean fault-both-24 19804.31 ( 0.00%) 20465.03 ( -3.34%) Amean fault-both-30 25018.73 ( 0.00%) 20813.54 * 16.81%* Amean fault-both-32 24380.19 ( 0.00%) 22384.02 ( 8.19%) The impact on the scan rates is a mixed bag because this patch is very sensitive to timing and whether the boost was active or not. However, detailed tracing indicated that failure of migration due to a premature ENOMEM triggered by watermark checks were eliminated. Signed-off-by: Mel Gorman --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 80535cd55a92..c7b80e62bfd9 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3043,7 +3043,7 @@ int __isolate_free_page(struct page *page, unsigned int order) * watermark, because we already know our high-order page * exists. */ - watermark = min_wmark_pages(zone) + (1UL << order); + watermark = zone->_watermark[WMARK_MIN] + (1UL << order); if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA)) return 0; -- 2.16.4