From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f200.google.com (mail-pf0-f200.google.com [209.85.192.200]) by kanga.kvack.org (Postfix) with ESMTP id 9E412828E8 for ; Wed, 20 Apr 2016 15:47:46 -0400 (EDT) Received: by mail-pf0-f200.google.com with SMTP id u190so105904143pfb.0 for ; Wed, 20 Apr 2016 12:47:46 -0700 (PDT) Received: from mail-pf0-f176.google.com (mail-pf0-f176.google.com. [209.85.192.176]) by mx.google.com with ESMTPS id 190si19396303pfv.7.2016.04.20.12.47.45 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 20 Apr 2016 12:47:45 -0700 (PDT) Received: by mail-pf0-f176.google.com with SMTP id e128so21293886pfe.3 for ; Wed, 20 Apr 2016 12:47:45 -0700 (PDT) From: Michal Hocko Subject: [PATCH 04/14] mm, compaction: distinguish COMPACT_DEFERRED from COMPACT_SKIPPED Date: Wed, 20 Apr 2016 15:47:17 -0400 Message-Id: <1461181647-8039-5-git-send-email-mhocko@kernel.org> In-Reply-To: <1461181647-8039-1-git-send-email-mhocko@kernel.org> References: <1461181647-8039-1-git-send-email-mhocko@kernel.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Linus Torvalds , Johannes Weiner , Mel Gorman , David Rientjes , Tetsuo Handa , Joonsoo Kim , Hillf Danton , Vlastimil Babka , linux-mm@kvack.org, LKML , Michal Hocko From: Michal Hocko try_to_compact_pages can currently return COMPACT_SKIPPED even when the compaction is defered for some zone just because zone DMA is skipped in 99% of cases due to watermark checks. This makes COMPACT_DEFERRED basically unusable for the page allocator as a feedback mechanism. Make sure we distinguish those two states properly and switch their ordering in the enum. This would mean that the COMPACT_SKIPPED will be returned only when all eligible zones are skipped. As a result COMPACT_DEFERRED handling for THP in __alloc_pages_slowpath will be more precise and we would bail out rather than reclaim. Acked-by: Vlastimil Babka Signed-off-by: Michal Hocko --- include/linux/compaction.h | 7 +++++-- include/trace/events/compaction.h | 2 +- mm/compaction.c | 8 +++++--- 3 files changed, 11 insertions(+), 6 deletions(-) diff --git a/include/linux/compaction.h b/include/linux/compaction.h index 4458fd94170f..7e177d111c39 100644 --- a/include/linux/compaction.h +++ b/include/linux/compaction.h @@ -4,13 +4,16 @@ /* Return values for compact_zone() and try_to_compact_pages() */ /* When adding new states, please adjust include/trace/events/compaction.h */ enum compact_result { - /* compaction didn't start as it was deferred due to past failures */ - COMPACT_DEFERRED, /* * compaction didn't start as it was not possible or direct reclaim * was more suitable */ COMPACT_SKIPPED, + /* compaction didn't start as it was deferred due to past failures */ + COMPACT_DEFERRED, + /* compaction not active last round */ + COMPACT_INACTIVE = COMPACT_DEFERRED, + /* compaction should continue to another pageblock */ COMPACT_CONTINUE, /* diff --git a/include/trace/events/compaction.h b/include/trace/events/compaction.h index e215bf68f521..6ba16c86d7db 100644 --- a/include/trace/events/compaction.h +++ b/include/trace/events/compaction.h @@ -10,8 +10,8 @@ #include #define COMPACTION_STATUS \ - EM( COMPACT_DEFERRED, "deferred") \ EM( COMPACT_SKIPPED, "skipped") \ + EM( COMPACT_DEFERRED, "deferred") \ EM( COMPACT_CONTINUE, "continue") \ EM( COMPACT_PARTIAL, "partial") \ EM( COMPACT_COMPLETE, "complete") \ diff --git a/mm/compaction.c b/mm/compaction.c index b06de27b7f72..13709e33a2fc 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1637,7 +1637,7 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order, int may_perform_io = gfp_mask & __GFP_IO; struct zoneref *z; struct zone *zone; - enum compact_result rc = COMPACT_DEFERRED; + enum compact_result rc = COMPACT_SKIPPED; int all_zones_contended = COMPACT_CONTENDED_LOCK; /* init for &= op */ *contended = COMPACT_CONTENDED_NONE; @@ -1654,8 +1654,10 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order, enum compact_result status; int zone_contended; - if (compaction_deferred(zone, order)) + if (compaction_deferred(zone, order)) { + rc = max_t(enum compact_result, COMPACT_DEFERRED, rc); continue; + } status = compact_zone_order(zone, order, gfp_mask, mode, &zone_contended, alloc_flags, @@ -1726,7 +1728,7 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order, * If at least one zone wasn't deferred or skipped, we report if all * zones that were tried were lock contended. */ - if (rc > COMPACT_SKIPPED && all_zones_contended) + if (rc > COMPACT_INACTIVE && all_zones_contended) *contended = COMPACT_CONTENDED_LOCK; return rc; -- 2.8.0.rc3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org