linux-kernel - [RFC][PATCH 2/2] mm: unreserve highatomic pageblock if direct reclaim failed

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Date:   Tue, 7 Mar 2017 18:44:23 +0800
From:   Xishi Qiu <qiuxishi@...wei.com>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Vlastimil Babka <vbabka@...e.cz>,
        Mel Gorman <mgorman@...hsingularity.net>,
        Minchan Kim <minchan@...nel.org>,
        Michal Hocko <mhocko@...nel.org>,
        Joonsoo Kim <iamjoonsoo.kim@....com>
CC:     Yisheng Xie <xieyisheng1@...wei.com>,
        Linux MM <linux-mm@...ck.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [RFC][PATCH 2/2] mm: unreserve highatomic pageblock if direct reclaim
 failed

If direct reclaim failed, unreserve highatomic pageblock
immediately is better than unreserve in should_reclaim_retry().
We may get page in next try rather than reclaim-compact-reclaim-compact...

Signed-off-by: Xishi Qiu <qiuxishi@...wei.com>
---
 mm/page_alloc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2331840..2bd19d0 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3421,7 +3421,8 @@ void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...)
 	bool drained = false;
 
 	*did_some_progress = __perform_reclaim(gfp_mask, order, ac);
-	if (unlikely(!(*did_some_progress)))
+	if (unlikely(!(*did_some_progress)
+	    && !unreserve_highatomic_pageblock(ac, false)))
 		return NULL;
 
 retry:
-- 
1.8.3.1