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mm: fix zone_watermark_ok_safe() accounting of isolated pages

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Commit 702d1a6e07 ("memory-hotplug: fix kswapd looping forever
problem") added an isolated pageblocks counter (nr_pageblock_isolate in
struct zone) and used it to adjust free pages counter in
zone_watermark_ok_safe() to prevent kswapd looping forever problem.

Then later, commit 2139cbe627 ("cma: fix counting of isolated pages")
fixed accounting of isolated pages in global free pages counter.  It
made the previous zone_watermark_ok_safe() fix unnecessary and
potentially harmful (cause now isolated pages may be accounted twice
making free pages counter incorrect).

This patch removes the special isolated pageblocks counter altogether
which fixes zone_watermark_ok_safe() free pages check.

Reported-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Aaditya Kumar <aaditya.kumar.30@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Bartlomiej Zolnierkiewicz 2013-01-04 15:35:08 -08:00 • committed by Linus Torvalds
parent 358e419f82
commit a458431e17
3 changed files with 2 additions and 59 deletions
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8
include/linux/mmzone.h
View file

@ -503,14 +503,6 @@ struct zone {
* rarely used fields:
*/
const char *name;
#ifdef CONFIG_MEMORY_ISOLATION
/*
* the number of MIGRATE_ISOLATE *pageblock*.
* We need this for free page counting. Look at zone_watermark_ok_safe.
* It's protected by zone->lock
*/
int nr_pageblock_isolate;
#endif
} ____cacheline_internodealigned_in_smp;
typedef enum {