By default the per-memcg background reclaim is disabled when the limit_in_bytes
is set the maximum. The kswapd_run() is called when the memcg is being resized,
and kswapd_stop() is called when the memcg is being deleted.
The per-memcg kswapd is waked up based on the usage and low_wmark, which is
checked once per 1024 increments per cpu. The memcg's kswapd is waked up if the
usage is larger than the low_wmark.
changelog v4..v3:
1. move kswapd_stop to mem_cgroup_destroy based on comments from KAMAZAWA
2. move kswapd_run to setup_mem_cgroup_wmark, since the actual watermarks
determines whether or not enabling per-memcg background reclaim.
changelog v3..v2:
1. some clean-ups
changelog v2..v1:
1. start/stop the per-cgroup kswapd at create/delete cgroup stage.
2. remove checking the wmark from per-page charging. now it checks the wmark
periodically based on the event counter.
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Signed-off-by: Ying Han <yinghan@xxxxxxxxxx>
---
mm/memcontrol.c | 37 +++++++++++++++++++++++++++++++++++++
1 files changed, 37 insertions(+), 0 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 0dfdf27..d5b284c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -105,10 +105,12 @@ enum mem_cgroup_events_index {
enum mem_cgroup_events_target {
MEM_CGROUP_TARGET_THRESH,
MEM_CGROUP_TARGET_SOFTLIMIT,
+ MEM_CGROUP_WMARK_EVENTS_THRESH,
MEM_CGROUP_NTARGETS,
};
#define THRESHOLDS_EVENTS_TARGET (128)
#define SOFTLIMIT_EVENTS_TARGET (1024)
+#define WMARK_EVENTS_TARGET (1024)
struct mem_cgroup_stat_cpu {
long count[MEM_CGROUP_STAT_NSTATS];
@@ -371,6 +373,8 @@ static void mem_cgroup_put(struct mem_cgroup *mem);
static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
static void drain_all_stock_async(void);
+static void wake_memcg_kswapd(struct mem_cgroup *mem);
+
static struct mem_cgroup_per_zone *
mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
{
@@ -549,6 +553,12 @@ mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
return mz;
}
+static void mem_cgroup_check_wmark(struct mem_cgroup *mem)
+{
+ if (!mem_cgroup_watermark_ok(mem, CHARGE_WMARK_LOW))
+ wake_memcg_kswapd(mem);
+}
+
/*
* Implementation Note: reading percpu statistics for memcg.
*
@@ -679,6 +689,9 @@ static void __mem_cgroup_target_update(struct mem_cgroup *mem, int target)
case MEM_CGROUP_TARGET_SOFTLIMIT:
next = val + SOFTLIMIT_EVENTS_TARGET;
break;
+ case MEM_CGROUP_WMARK_EVENTS_THRESH:
+ next = val + WMARK_EVENTS_TARGET;
+ break;
default:
return;
}
@@ -702,6 +715,10 @@ static void memcg_check_events(struct mem_cgroup *mem, struct page *page)
__mem_cgroup_target_update(mem,
MEM_CGROUP_TARGET_SOFTLIMIT);
}
+ if (unlikely(__memcg_event_check(mem,
+ MEM_CGROUP_WMARK_EVENTS_THRESH))){
+ mem_cgroup_check_wmark(mem);
+ }
}
}
@@ -846,6 +863,9 @@ static void setup_per_memcg_wmarks(struct mem_cgroup *mem)
res_counter_set_low_wmark_limit(&mem->res, low_wmark);
res_counter_set_high_wmark_limit(&mem->res, high_wmark);
+
+ if (!mem_cgroup_is_root(mem) && !mem->kswapd_wait)
+ kswapd_run(0, mem);
}
}
@@ -4868,6 +4888,22 @@ int mem_cgroup_last_scanned_node(struct mem_cgroup *mem)
return mem->last_scanned_node;
}
+static inline
+void wake_memcg_kswapd(struct mem_cgroup *mem)
+{
+ wait_queue_head_t *wait;
+
+ if (!mem || !mem->high_wmark_distance)
+ return;
+
+ wait = mem->kswapd_wait;
+
+ if (!wait || !waitqueue_active(wait))
+ return;
+
+ wake_up_interruptible(wait);
+}
+
static int mem_cgroup_soft_limit_tree_init(void)
{
struct mem_cgroup_tree_per_node *rtpn;
@@ -4971,6 +5007,7 @@ static void mem_cgroup_destroy(struct cgroup_subsys *ss,
{
struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
+ kswapd_stop(0, mem);
mem_cgroup_put(mem);
}
--
1.7.3.1
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