Commit 9b272977 authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds
Browse files

memcg: skip scanning active lists based on individual size 



Reclaim decides to skip scanning an active list when the corresponding
inactive list is above a certain size in comparison to leave the assumed
working set alone while there are still enough reclaim candidates around.

The memcg implementation of comparing those lists instead reports whether
the whole memcg is low on the requested type of inactive pages,
considering all nodes and zones.

This can lead to an oversized active list not being scanned because of the
state of the other lists in the memcg, as well as an active list being
scanned while its corresponding inactive list has enough pages.

Not only is this wrong, it's also a scalability hazard, because the global
memory state over all nodes and zones has to be gathered for each memcg
and zone scanned.

Make these calculations purely based on the size of the two LRU lists
that are actually affected by the outcome of the decision.

Signed-off-by: default avatarJohannes Weiner <jweiner@redhat.com>
Reviewed-by: default avatarRik van Riel <riel@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
Reviewed-by: default avatarYing Han <yinghan@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0a619e58

Documentation/cgroups/memory.txt

+0 −1
Original line number Diff line number Diff line
@@ -418,7 +418,6 @@ total_unevictable - sum of all children's "unevictable" 


# The following additional stats are dependent on CONFIG_DEBUG_VM.



inactive_ratio		- VM internal parameter. (see mm/page_alloc.c)

recent_rotated_anon	- VM internal parameter. (see mm/vmscan.c)

recent_rotated_file	- VM internal parameter. (see mm/vmscan.c)

recent_scanned_anon	- VM internal parameter. (see mm/vmscan.c)

include/linux/memcontrol.h

+6 −4
Original line number Diff line number Diff line
@@ -106,8 +106,10 @@ extern void mem_cgroup_end_migration(struct mem_cgroup *memcg, 
/*

 * For memory reclaim.

 */

int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg);

int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg);

int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg,

				    struct zone *zone);

int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg,

				    struct zone *zone);

int mem_cgroup_select_victim_node(struct mem_cgroup *memcg);

unsigned long mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg,

					int nid, int zid, unsigned int lrumask);
@@ -295,13 +297,13 @@ static inline bool mem_cgroup_disabled(void) 
}



static inline int

mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)

mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg, struct zone *zone)

{

	return 1;

}



static inline int

mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg)

mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg, struct zone *zone)

{

	return 1;

}

mm/memcontrol.c

+17 −34
Original line number Diff line number Diff line
@@ -1104,15 +1104,19 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg) 
	return ret;

}



static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)

int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg, struct zone *zone)

{

	unsigned long active;

	unsigned long inactive_ratio;

	int nid = zone_to_nid(zone);

	int zid = zone_idx(zone);

	unsigned long inactive;

	unsigned long active;

	unsigned long gb;

	unsigned long inactive_ratio;



	inactive = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_INACTIVE_ANON));

	active = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_ACTIVE_ANON));

	inactive = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid,

						BIT(LRU_INACTIVE_ANON));

	active = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid,

					      BIT(LRU_ACTIVE_ANON));



	gb = (inactive + active) >> (30 - PAGE_SHIFT);

	if (gb)
@@ -1120,39 +1124,20 @@ static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_ 
	else

		inactive_ratio = 1;



	if (present_pages) {

		present_pages[0] = inactive;

		present_pages[1] = active;

	return inactive * inactive_ratio < active;

}



	return inactive_ratio;

}



int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)

{

	unsigned long active;

	unsigned long inactive;

	unsigned long present_pages[2];

	unsigned long inactive_ratio;



	inactive_ratio = calc_inactive_ratio(memcg, present_pages);



	inactive = present_pages[0];

	active = present_pages[1];



	if (inactive * inactive_ratio < active)

		return 1;



	return 0;

}



int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg)

int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg, struct zone *zone)

{

	unsigned long active;

	unsigned long inactive;

	int zid = zone_idx(zone);

	int nid = zone_to_nid(zone);



	inactive = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_INACTIVE_FILE));

	active = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_ACTIVE_FILE));

	inactive = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid,

						BIT(LRU_INACTIVE_FILE));

	active = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid,

					      BIT(LRU_ACTIVE_FILE));



	return (active > inactive);

}
@@ -4192,8 +4177,6 @@ static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft, 
	}



#ifdef CONFIG_DEBUG_VM

	cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));



	{

		int nid, zid;

		struct mem_cgroup_per_zone *mz;

mm/vmscan.c

+2 −2
Original line number Diff line number Diff line
@@ -1767,7 +1767,7 @@ static int inactive_anon_is_low(struct zone *zone, struct scan_control *sc) 
	if (scanning_global_lru(sc))

		low = inactive_anon_is_low_global(zone);

	else

		low = mem_cgroup_inactive_anon_is_low(sc->mem_cgroup);

		low = mem_cgroup_inactive_anon_is_low(sc->mem_cgroup, zone);

	return low;

}

#else
@@ -1810,7 +1810,7 @@ static int inactive_file_is_low(struct zone *zone, struct scan_control *sc) 
	if (scanning_global_lru(sc))

		low = inactive_file_is_low_global(zone);

	else

		low = mem_cgroup_inactive_file_is_low(sc->mem_cgroup);

		low = mem_cgroup_inactive_file_is_low(sc->mem_cgroup, zone);

	return low;

}

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