Commit f80c0673 authored by Minchan Kim's avatar Minchan Kim Committed by Linus Torvalds
Browse files

mm: zone_reclaim: make isolate_lru_page() filter-aware 



In __zone_reclaim case, we don't want to shrink mapped page.  Nonetheless,
we have isolated mapped page and re-add it into LRU's head.  It's
unnecessary CPU overhead and makes LRU churning.

Of course, when we isolate the page, the page might be mapped but when we
try to migrate the page, the page would be not mapped.  So it could be
migrated.  But race is rare and although it happens, it's no big deal.

Signed-off-by: default avatarMinchan Kim <minchan.kim@gmail.com>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: default avatarMichal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 39deaf85

include/linux/mmzone.h

+2 −0
Original line number Diff line number Diff line
@@ -170,6 +170,8 @@ static inline int is_unevictable_lru(enum lru_list l) 
#define ISOLATE_ACTIVE		((__force isolate_mode_t)0x2)

/* Isolate clean file */

#define ISOLATE_CLEAN		((__force isolate_mode_t)0x4)

/* Isolate unmapped file */

#define ISOLATE_UNMAPPED	((__force isolate_mode_t)0x8)



/* LRU Isolation modes. */

typedef unsigned __bitwise__ isolate_mode_t;

mm/vmscan.c

+18 −2
Original line number Diff line number Diff line
@@ -1048,6 +1048,9 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode, int file) 
	if ((mode & ISOLATE_CLEAN) && (PageDirty(page) || PageWriteback(page)))

		return ret;



	if ((mode & ISOLATE_UNMAPPED) && page_mapped(page))

		return ret;



	if (likely(get_page_unless_zero(page))) {

		/*

		 * Be careful not to clear PageLRU until after we're
@@ -1471,6 +1474,12 @@ shrink_inactive_list(unsigned long nr_to_scan, struct zone *zone, 
		reclaim_mode |= ISOLATE_ACTIVE;



	lru_add_drain();



	if (!sc->may_unmap)

		reclaim_mode |= ISOLATE_UNMAPPED;

	if (!sc->may_writepage)

		reclaim_mode |= ISOLATE_CLEAN;



	spin_lock_irq(&zone->lru_lock);



	if (scanning_global_lru(sc)) {
@@ -1588,19 +1597,26 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone, 
	struct page *page;

	struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);

	unsigned long nr_rotated = 0;

	isolate_mode_t reclaim_mode = ISOLATE_ACTIVE;



	lru_add_drain();



	if (!sc->may_unmap)

		reclaim_mode |= ISOLATE_UNMAPPED;

	if (!sc->may_writepage)

		reclaim_mode |= ISOLATE_CLEAN;



	spin_lock_irq(&zone->lru_lock);

	if (scanning_global_lru(sc)) {

		nr_taken = isolate_pages_global(nr_pages, &l_hold,

						&pgscanned, sc->order,

						ISOLATE_ACTIVE, zone,

						reclaim_mode, zone,

						1, file);

		zone->pages_scanned += pgscanned;

	} else {

		nr_taken = mem_cgroup_isolate_pages(nr_pages, &l_hold,

						&pgscanned, sc->order,

						ISOLATE_ACTIVE, zone,

						reclaim_mode, zone,

						sc->mem_cgroup, 1, file);

		/*

		 * mem_cgroup_isolate_pages() keeps track of

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