Commit 56e49d21 authored by Rik van Riel's avatar Rik van Riel Committed by Linus Torvalds
Browse files

vmscan: evict use-once pages first 



When the file LRU lists are dominated by streaming IO pages, evict those
pages first, before considering evicting other pages.

This should be safe from deadlocks or performance problems
because only three things can happen to an inactive file page:

1) referenced twice and promoted to the active list
2) evicted by the pageout code
3) under IO, after which it will get evicted or promoted

The pages freed in this way can either be reused for streaming IO, or
allocated for something else.  If the pages are used for streaming IO,
this pageout pattern continues.  Otherwise, we will fall back to the
normal pageout pattern.

Signed-off-by: default avatarRik van Riel <riel@redhat.com>
Reported-by: default avatarElladan <elladan@eskimo.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 35efa5e9

include/linux/memcontrol.h

+7 −0
Original line number Diff line number Diff line
@@ -94,6 +94,7 @@ extern void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, 
extern void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem,

							int priority);

int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg);

int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg);

unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,

				       struct zone *zone,

				       enum lru_list lru);
@@ -239,6 +240,12 @@ mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg) 
	return 1;

}



static inline int

mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg)

{

	return 1;

}



static inline unsigned long

mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg, struct zone *zone,

			 enum lru_list lru)

mm/memcontrol.c

+11 −0
Original line number Diff line number Diff line
@@ -570,6 +570,17 @@ int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg) 
	return 0;

}



int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg)

{

	unsigned long active;

	unsigned long inactive;



	inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_FILE);

	active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_FILE);



	return (active > inactive);

}



unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,

				       struct zone *zone,

				       enum lru_list lru)

mm/vmscan.c

+37 −1
Original line number Diff line number Diff line
@@ -1351,12 +1351,48 @@ static int inactive_anon_is_low(struct zone *zone, struct scan_control *sc) 
	return low;

}



static int inactive_file_is_low_global(struct zone *zone)

{

	unsigned long active, inactive;



	active = zone_page_state(zone, NR_ACTIVE_FILE);

	inactive = zone_page_state(zone, NR_INACTIVE_FILE);



	return (active > inactive);

}



/**

 * inactive_file_is_low - check if file pages need to be deactivated

 * @zone: zone to check

 * @sc:   scan control of this context

 *

 * When the system is doing streaming IO, memory pressure here

 * ensures that active file pages get deactivated, until more

 * than half of the file pages are on the inactive list.

 *

 * Once we get to that situation, protect the system's working

 * set from being evicted by disabling active file page aging.

 *

 * This uses a different ratio than the anonymous pages, because

 * the page cache uses a use-once replacement algorithm.

 */

static int inactive_file_is_low(struct zone *zone, struct scan_control *sc)

{

	int low;



	if (scanning_global_lru(sc))

		low = inactive_file_is_low_global(zone);

	else

		low = mem_cgroup_inactive_file_is_low(sc->mem_cgroup);

	return low;

}



static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan,

	struct zone *zone, struct scan_control *sc, int priority)

{

	int file = is_file_lru(lru);



	if (lru == LRU_ACTIVE_FILE) {

	if (lru == LRU_ACTIVE_FILE && inactive_file_is_low(zone, sc)) {

		shrink_active_list(nr_to_scan, zone, sc, priority, file);

		return 0;

	}

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