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Message-Id: <1461769043-28337-4-git-send-email-mgorman@techsingularity.net>
Date: Wed, 27 Apr 2016 15:57:20 +0100
From: Mel Gorman <mgorman@...hsingularity.net>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Vlastimil Babka <vbabka@...e.cz>,
Jesper Dangaard Brouer <brouer@...hat.com>,
Linux-MM <linux-mm@...ck.org>,
LKML <linux-kernel@...r.kernel.org>,
Mel Gorman <mgorman@...hsingularity.net>
Subject: [PATCH 3/6] mm, page_alloc: Check once if a zone has isolated pageblocks -fix
Vlastimil Babka pointed out that the original code was protected by
the zone lock and provided a fix.
This is a fix to the mmotm patch
mm-page_alloc-check-once-if-a-zone-has-isolated-pageblocks.patch . Once
applied the following line should be removed from the changelog "Technically
this is race-prone but so is the existing code."
Signed-off-by: Vlastimil Babka <vbabka@...e.cz>
Signed-off-by: Mel Gorman <mgorman@...hsingularity.net>
---
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 9ad4e68486e9..c63e5e7e4864 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1098,9 +1098,10 @@ static void free_pcppages_bulk(struct zone *zone, int count,
int migratetype = 0;
int batch_free = 0;
unsigned long nr_scanned;
- bool isolated_pageblocks = has_isolate_pageblock(zone);
+ bool isolated_pageblocks;
spin_lock(&zone->lock);
+ isolated_pageblocks = has_isolate_pageblock(zone);
nr_scanned = zone_page_state(zone, NR_PAGES_SCANNED);
if (nr_scanned)
__mod_zone_page_state(zone, NR_PAGES_SCANNED, -nr_scanned);
--
2.6.4
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