vmscan: per memory cgroup slab shrinkers
This patch adds SHRINKER_MEMCG_AWARE flag. If a shrinker has this flag
set, it will be called per memory cgroup. The memory cgroup to scan
objects from is passed in shrink_control->memcg. If the memory cgroup
is NULL, a memcg aware shrinker is supposed to scan objects from the
global list. Unaware shrinkers are only called on global pressure with
memcg=NULL.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Greg Thelen <gthelen@google.com>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 8e645ee..803886b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -232,10 +232,10 @@
#define SHRINK_BATCH 128
-static unsigned long shrink_slabs(struct shrink_control *shrinkctl,
- struct shrinker *shrinker,
- unsigned long nr_scanned,
- unsigned long nr_eligible)
+static unsigned long do_shrink_slab(struct shrink_control *shrinkctl,
+ struct shrinker *shrinker,
+ unsigned long nr_scanned,
+ unsigned long nr_eligible)
{
unsigned long freed = 0;
unsigned long long delta;
@@ -344,9 +344,10 @@
}
/**
- * shrink_node_slabs - shrink slab caches of a given node
+ * shrink_slab - shrink slab caches
* @gfp_mask: allocation context
* @nid: node whose slab caches to target
+ * @memcg: memory cgroup whose slab caches to target
* @nr_scanned: pressure numerator
* @nr_eligible: pressure denominator
*
@@ -355,6 +356,12 @@
* @nid is passed along to shrinkers with SHRINKER_NUMA_AWARE set,
* unaware shrinkers will receive a node id of 0 instead.
*
+ * @memcg specifies the memory cgroup to target. If it is not NULL,
+ * only shrinkers with SHRINKER_MEMCG_AWARE set will be called to scan
+ * objects from the memory cgroup specified. Otherwise all shrinkers
+ * are called, and memcg aware shrinkers are supposed to scan the
+ * global list then.
+ *
* @nr_scanned and @nr_eligible form a ratio that indicate how much of
* the available objects should be scanned. Page reclaim for example
* passes the number of pages scanned and the number of pages on the
@@ -365,13 +372,17 @@
*
* Returns the number of reclaimed slab objects.
*/
-unsigned long shrink_node_slabs(gfp_t gfp_mask, int nid,
- unsigned long nr_scanned,
- unsigned long nr_eligible)
+static unsigned long shrink_slab(gfp_t gfp_mask, int nid,
+ struct mem_cgroup *memcg,
+ unsigned long nr_scanned,
+ unsigned long nr_eligible)
{
struct shrinker *shrinker;
unsigned long freed = 0;
+ if (memcg && !memcg_kmem_is_active(memcg))
+ return 0;
+
if (nr_scanned == 0)
nr_scanned = SWAP_CLUSTER_MAX;
@@ -390,12 +401,16 @@
struct shrink_control sc = {
.gfp_mask = gfp_mask,
.nid = nid,
+ .memcg = memcg,
};
+ if (memcg && !(shrinker->flags & SHRINKER_MEMCG_AWARE))
+ continue;
+
if (!(shrinker->flags & SHRINKER_NUMA_AWARE))
sc.nid = 0;
- freed += shrink_slabs(&sc, shrinker, nr_scanned, nr_eligible);
+ freed += do_shrink_slab(&sc, shrinker, nr_scanned, nr_eligible);
}
up_read(&shrinker_rwsem);
@@ -404,6 +419,29 @@
return freed;
}
+void drop_slab_node(int nid)
+{
+ unsigned long freed;
+
+ do {
+ struct mem_cgroup *memcg = NULL;
+
+ freed = 0;
+ do {
+ freed += shrink_slab(GFP_KERNEL, nid, memcg,
+ 1000, 1000);
+ } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
+ } while (freed > 10);
+}
+
+void drop_slab(void)
+{
+ int nid;
+
+ for_each_online_node(nid)
+ drop_slab_node(nid);
+}
+
static inline int is_page_cache_freeable(struct page *page)
{
/*
@@ -2276,6 +2314,7 @@
static bool shrink_zone(struct zone *zone, struct scan_control *sc,
bool is_classzone)
{
+ struct reclaim_state *reclaim_state = current->reclaim_state;
unsigned long nr_reclaimed, nr_scanned;
bool reclaimable = false;
@@ -2294,6 +2333,7 @@
memcg = mem_cgroup_iter(root, NULL, &reclaim);
do {
unsigned long lru_pages;
+ unsigned long scanned;
struct lruvec *lruvec;
int swappiness;
@@ -2305,10 +2345,16 @@
lruvec = mem_cgroup_zone_lruvec(zone, memcg);
swappiness = mem_cgroup_swappiness(memcg);
+ scanned = sc->nr_scanned;
shrink_lruvec(lruvec, swappiness, sc, &lru_pages);
zone_lru_pages += lru_pages;
+ if (memcg && is_classzone)
+ shrink_slab(sc->gfp_mask, zone_to_nid(zone),
+ memcg, sc->nr_scanned - scanned,
+ lru_pages);
+
/*
* Direct reclaim and kswapd have to scan all memory
* cgroups to fulfill the overall scan target for the
@@ -2330,19 +2376,14 @@
* Shrink the slab caches in the same proportion that
* the eligible LRU pages were scanned.
*/
- if (global_reclaim(sc) && is_classzone) {
- struct reclaim_state *reclaim_state;
+ if (global_reclaim(sc) && is_classzone)
+ shrink_slab(sc->gfp_mask, zone_to_nid(zone), NULL,
+ sc->nr_scanned - nr_scanned,
+ zone_lru_pages);
- shrink_node_slabs(sc->gfp_mask, zone_to_nid(zone),
- sc->nr_scanned - nr_scanned,
- zone_lru_pages);
-
- reclaim_state = current->reclaim_state;
- if (reclaim_state) {
- sc->nr_reclaimed +=
- reclaim_state->reclaimed_slab;
- reclaim_state->reclaimed_slab = 0;
- }
+ if (reclaim_state) {
+ sc->nr_reclaimed += reclaim_state->reclaimed_slab;
+ reclaim_state->reclaimed_slab = 0;
}
vmpressure(sc->gfp_mask, sc->target_mem_cgroup,