[PATCH 06/11] memcg: make inactive_anon_is_low()

KOSAKI Motohiro
2008-12-01T12:16:03Z

Changelog:
v1 -> v2:
- add detail patch description
- fix coding style in mem_cgroup_set_inactive_ratio()
- add comment to mem_cgroup_set_inactive_ratio
- remove extra newline
- memcg::inactiveratio change type to unsigned int

The inactive_anon_is_low() is key component of active/inactive anon balancing on reclaim.
However current inactive_anon_is_low() function only consider global reclaim.

Therefore, we need following ugly scan_global_lru() condision.

if (lru == LRU_ACTIVE_ANON &&
(!scan_global_lru(sc) || inactive_anon_is_low(zone))) {
shrink_active_list(nr_to_scan, zone, sc, priority, file);
return 0;

it cause that memcg reclaim always deactivate pages when shrink_list() is called.
To make mem_cgroup_inactive_anon_is_low() improve active/inactive anon balancing of memcgroup.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Cyrill Gorcunov <gorcunov@gmail.com>
CC: "Pekka Enberg" <penberg@cs.helsinki.fi>
Acked-by: Rik van Riel <riel@redhat.com>
---
include/linux/memcontrol.h | 9 ++++++++
mm/memcontrol.c | 46 ++++++++++++++++++++++++++++++++++++++++++++-
mm/vmscan.c | 36 ++++++++++++++++++++++-------------
3 files changed, 77 insertions(+), 14 deletions(-)

Index: b/include/linux/memcontrol.h
===================================================================
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -90,6 +90,8 @@ extern void mem_cgroup_record_reclaim_pr

extern long mem_cgroup_calc_reclaim(struct mem_cgroup *mem, struct zone *zone,
int priority, enum lru_list lru);
+int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg,
+ struct zone *zone);

#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
extern int do_swap_account;
@@ -241,6 +243,13 @@ static inline bool mem_cgroup_oom_called
{
return false;
}
+
+static inline int
+mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg, struct zone *zone)
+{
+ return 1;
+}
+
#endif /* CONFIG_CGROUP_MEM_CONT */

#endif /* _LINUX_MEMCONTROL_H */
Index: b/mm/memcontrol.c
===================================================================
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -156,6 +156,9 @@ struct mem_cgroup {
unsigned long last_oom_jiffies;
int obsolete;
atomic_t refcnt;
+
+ unsigned int inactive_ratio;
+
/*
* statistics. This must be placed at the end of memcg.
*/
@@ -431,6 +434,20 @@ long mem_cgroup_calc_reclaim(struct mem_
return (nr_pages >> priority);
}

+int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg, struct zone *zone)
+{
+ unsigned long active;
+ unsigned long inactive;
+
+ inactive = mem_cgroup_get_all_zonestat(memcg, LRU_INACTIVE_ANON);
+ active = mem_cgroup_get_all_zonestat(memcg, LRU_ACTIVE_ANON);
+
+ if (inactive * memcg->inactive_ratio < active)
+ return 1;
+
+ return 0;
+}
+
unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
struct list_head *dst,
unsigned long *scanned, int order,
@@ -1346,6 +1363,29 @@ int mem_cgroup_shrink_usage(struct mm_st
return 0;
}

+/*
+ * The inactive anon list should be small enough that the VM never has to
+ * do too much work, but large enough that each inactive page has a chance
+ * to be referenced again before it is swapped out.
+ *
+ * this calculation is straightforward porting from
+ * page_alloc.c::setup_per_zone_inactive_ratio().
+ * it describe more detail.
+ */
+static void mem_cgroup_set_inactive_ratio(struct mem_cgroup *memcg)
+{
+ unsigned int gb, ratio;
+
+ gb = res_counter_read_u64(&memcg->res, RES_LIMIT) >> 30;
+ if (gb)
+ ratio = int_sqrt(10 * gb);
+ else
+ ratio = 1;
+
+ memcg->inactive_ratio = ratio;
+
+}
+
static DEFINE_MUTEX(set_limit_mutex);

static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
@@ -1384,6 +1424,10 @@ static int mem_cgroup_resize_limit(struc
GFP_HIGHUSER_MOVABLE, false);
if (!progress) retry_count--;
}
+
+ if (!ret)
+ mem_cgroup_set_inactive_ratio(memcg);
+
return ret;
}

@@ -1968,7 +2012,7 @@ mem_cgroup_create(struct cgroup_subsys *
res_counter_init(&mem->res, NULL);
res_counter_init(&mem->memsw, NULL);
}
-
+ mem_cgroup_set_inactive_ratio(mem);
mem->last_scanned_child = NULL;

return &mem->css;
Index: b/mm/vmscan.c
===================================================================
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1369,14 +1369,7 @@ static void shrink_active_list(unsigned
pagevec_release(&pvec);
}

-/**
- * inactive_anon_is_low - check if anonymous pages need to be deactivated
- * @zone: zone to check
- *
- * Returns true if the zone does not have enough inactive anon pages,
- * meaning some active anon pages need to be deactivated.
- */
-static int inactive_anon_is_low(struct zone *zone)
+static int inactive_anon_is_low_global(struct zone *zone)
{
unsigned long active, inactive;

@@ -1389,6 +1382,25 @@ static int inactive_anon_is_low(struct z
return 0;
}

+/**
+ * inactive_anon_is_low - check if anonymous pages need to be deactivated
+ * @zone: zone to check
+ * @sc: scan control of this context
+ *
+ * Returns true if the zone does not have enough inactive anon pages,
+ * meaning some active anon pages need to be deactivated.
+ */
+static int inactive_anon_is_low(struct zone *zone, struct scan_control *sc)
+{
+ int low;
+
+ if (scan_global_lru(sc))
+ low = inactive_anon_is_low_global(zone);
+ else
+ low = mem_cgroup_inactive_anon_is_low(sc->mem_cgroup, zone);
+ 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)
{
@@ -1400,7 +1412,7 @@ static unsigned long shrink_list(enum lr
}

if (lru == LRU_ACTIVE_ANON &&
- (!scan_global_lru(sc) || inactive_anon_is_low(zone))) {
+ inactive_anon_is_low(zone, sc)) {
shrink_active_list(nr_to_scan, zone, sc, priority, file);
return 0;
}
@@ -1565,9 +1577,7 @@ static void shrink_zone(int priority, st
* Even if we did not try to evict anon pages at all, we want to
* rebalance the anon lru active/inactive ratio.
*/
- if (!scan_global_lru(sc) || inactive_anon_is_low(zone))
- shrink_active_list(SWAP_CLUSTER_MAX, zone, sc, priority, 0);
- else if (!scan_global_lru(sc))
+ if (inactive_anon_is_low(zone, sc))
shrink_active_list(SWAP_CLUSTER_MAX, zone, sc, priority, 0);

throttle_vm_writeout(sc->gfp_mask);
@@ -1863,7 +1873,7 @@ loop_again:
* Do some background aging of the anon list, to give
* pages a chance to be referenced before reclaiming.
*/
- if (inactive_anon_is_low(zone))
+ if (inactive_anon_is_low(zone, &sc))
shrink_active_list(SWAP_CLUSTER_MAX, zone,
&sc, priority, 0);