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author | Minchan Kim <minchan@kernel.org> | 2012-10-08 16:32:14 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-10-09 16:22:46 +0900 |
commit | 41d575ad4a511b71a4a41c8313004212f5c229b1 (patch) | |
tree | 04d9fe90086a7c4be7b680c3adc592086baccfe5 /fs | |
parent | 95e3441248053fc06bbb1dbbd34409a84211619e (diff) | |
download | linux-3.10-41d575ad4a511b71a4a41c8313004212f5c229b1.tar.gz linux-3.10-41d575ad4a511b71a4a41c8313004212f5c229b1.tar.bz2 linux-3.10-41d575ad4a511b71a4a41c8313004212f5c229b1.zip |
memory-hotplug: bug fix race between isolation and allocation
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));
This patch checks page's migratetype in freelist in
__test_page_isolated_in_pageblock. So now
__test_page_isolated_in_pageblock can check the page caused by above race
and can fail of memory offlining.
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
0 files changed, 0 insertions, 0 deletions