linux-kernel - [PATCH v2 4/5] mm/page_owner: add zone range overlapping check

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Date:	Fri,  1 Apr 2016 11:06:45 +0900
From:	js1304@...il.com
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Rik van Riel <riel@...hat.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Mel Gorman <mgorman@...e.de>,
	Laura Abbott <lauraa@...eaurora.org>,
	Minchan Kim <minchan@...nel.org>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Michal Nazarewicz <mina86@...a86.com>,
	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>,
	Vlastimil Babka <vbabka@...e.cz>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, Joonsoo Kim <iamjoonsoo.kim@....com>
Subject: [PATCH v2 4/5] mm/page_owner: add zone range overlapping check

From: Joonsoo Kim <iamjoonsoo.kim@....com>

There is a system that node's pfn are overlapped like as following.

-----pfn-------->
N0 N1 N2 N0 N1 N2

Therefore, we need to care this overlapping when iterating pfn range.

There are one place in page_owner.c that iterates pfn range and
it doesn't consider this overlapping. Add it.

Without this patch, above system could over count early allocated
page number before page_owner is activated.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@....com>
---
 mm/page_owner.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mm/page_owner.c b/mm/page_owner.c
index ac3d8d1..438768c 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -301,6 +301,9 @@ static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
 
 			page = pfn_to_page(pfn);
 
+			if (page_zone(page) != zone)
+				continue;
+
 			/*
 			 * We are safe to check buddy flag and order, because
 			 * this is init stage and only single thread runs.
-- 
1.9.1