From: Minchan Kim <minchan@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>,
Xishi Qiu <qiuxishi@huawei.com>, Mel Gorman <mgorman@suse.de>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Minchan Kim <minchan@kernel.org>
Subject: [PATCH 3/3] memory-hotplug: bug fix race between isolation and allocation
Date: Wed, 5 Sep 2012 16:26:02 +0900 [thread overview]
Message-ID: <1346829962-31989-4-git-send-email-minchan@kernel.org> (raw)
In-Reply-To: <1346829962-31989-1-git-send-email-minchan@kernel.org>
Like below, memory-hotplug makes race between page-isolation
and page-allocation so it can hit BUG_ON in __offline_isolated_pages.
CPU A CPU B
start_isolate_page_range
set_migratetype_isolate
spin_lock_irqsave(zone->lock)
free_hot_cold_page(Page A)
/* without zone->lock */
migratetype = get_pageblock_migratetype(Page A);
/*
* Page could be moved into MIGRATE_MOVABLE
* of per_cpu_pages
*/
list_add_tail(&page->lru, &pcp->lists[migratetype]);
set_pageblock_isolate
move_freepages_block
drain_all_pages
/* Page A could be in MIGRATE_MOVABLE of free_list. */
check_pages_isolated
__test_page_isolated_in_pageblock
/*
* We can't catch freed page which
* is free_list[MIGRATE_MOVABLE]
*/
if (PageBuddy(page A))
pfn += 1 << page_order(page A);
/* So, Page A could be allocated */
__offline_isolated_pages
/*
* BUG_ON hit or offline page
* which is used by someone
*/
BUG_ON(!PageBuddy(page A));
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
mm/page_isolation.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index acf65a7..4699d1f 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -196,8 +196,11 @@ __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn)
continue;
}
page = pfn_to_page(pfn);
- if (PageBuddy(page))
+ if (PageBuddy(page)) {
+ if (get_page_migratetype(page) != MIGRATE_ISOLATE)
+ break;
pfn += 1 << page_order(page);
+ }
else if (page_count(page) == 0 &&
get_page_migratetype(page) == MIGRATE_ISOLATE)
pfn += 1;
--
1.7.9.5
next prev parent reply other threads:[~2012-09-05 7:24 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-05 7:25 [PATCH 0/3] memory-hotplug: handle page race between allocation and isolation Minchan Kim
2012-09-05 7:26 ` [PATCH 1/3] mm: use get_page_migratetype instead of page_private Minchan Kim
2012-09-05 9:09 ` Mel Gorman
2012-09-06 2:17 ` Minchan Kim
2012-09-06 2:02 ` Kamezawa Hiroyuki
2012-09-06 2:19 ` Minchan Kim
2012-09-05 7:26 ` [PATCH 2/3] mm: remain migratetype in freed page Minchan Kim
2012-09-05 9:25 ` Mel Gorman
2012-09-06 2:28 ` Minchan Kim
2012-09-05 7:26 ` Minchan Kim [this message]
2012-09-05 9:40 ` [PATCH 3/3] memory-hotplug: bug fix race between isolation and allocation Mel Gorman
2012-09-06 4:49 ` Minchan Kim
2012-09-06 9:24 ` Mel Gorman
2012-09-06 23:32 ` Minchan Kim
2012-09-07 6:26 ` jencce zhou
2012-09-06 2:35 qiuxishi
2012-09-06 2:59 ` Minchan Kim
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