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mm: restore zone->all_unreclaimable to independence word

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commit e815af95 ("change all_unreclaimable zone member to flags") changed
all_unreclaimable member to bit flag.  But it had an undesireble side
effect.  free_one_page() is one of most hot path in linux kernel and
increasing atomic ops in it can reduce kernel performance a bit.

Thus, this patch revert such commit partially. at least
all_unreclaimable shouldn't share memory word with other zone flags.

[akpm@linux-foundation.org: fix patch interaction]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Huang Shijie <shijie8@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
KOSAKI Motohiro
2010-03-05 13:41:55 -08:00
committed by Linus Torvalds
parent fc91668eaf
commit 93e4a89a8c
4 changed files with 14 additions and 23 deletions
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7
include/linux/mmzone.h
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@@ -306,6 +306,7 @@ struct zone {
* free areas of different sizes
*/
spinlock_t lock;
int all_unreclaimable; /* All pages pinned */
#ifdef CONFIG_MEMORY_HOTPLUG
/* see spanned/present_pages for more description */
seqlock_t span_seqlock;
@@ -417,7 +418,6 @@ struct zone {
} ____cacheline_internodealigned_in_smp;
typedef enum {
ZONE_ALL_UNRECLAIMABLE, /* all pages pinned */
ZONE_RECLAIM_LOCKED, /* prevents concurrent reclaim */
ZONE_OOM_LOCKED, /* zone is in OOM killer zonelist */
} zone_flags_t;
@@ -437,11 +437,6 @@ static inline void zone_clear_flag(struct zone *zone, zone_flags_t flag)
clear_bit(flag, &zone->flags);
}
static inline int zone_is_all_unreclaimable(const struct zone *zone)
{
return test_bit(ZONE_ALL_UNRECLAIMABLE, &zone->flags);
}
static inline int zone_is_reclaim_locked(const struct zone *zone)
{
return test_bit(ZONE_RECLAIM_LOCKED, &zone->flags);