mm: restore zone->all_unreclaimable to independence word
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>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 80bcee0..0734bed 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -530,7 +530,7 @@
int batch_free = 0;
spin_lock(&zone->lock);
- zone_clear_flag(zone, ZONE_ALL_UNRECLAIMABLE);
+ zone->all_unreclaimable = 0;
zone->pages_scanned = 0;
__mod_zone_page_state(zone, NR_FREE_PAGES, count);
@@ -568,7 +568,7 @@
int migratetype)
{
spin_lock(&zone->lock);
- zone_clear_flag(zone, ZONE_ALL_UNRECLAIMABLE);
+ zone->all_unreclaimable = 0;
zone->pages_scanned = 0;
__mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
@@ -2262,7 +2262,7 @@
K(zone_page_state(zone, NR_BOUNCE)),
K(zone_page_state(zone, NR_WRITEBACK_TEMP)),
zone->pages_scanned,
- (zone_is_all_unreclaimable(zone) ? "yes" : "no")
+ (zone->all_unreclaimable ? "yes" : "no")
);
printk("lowmem_reserve[]:");
for (i = 0; i < MAX_NR_ZONES; i++)