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authorMuchun Song <songmuchun@bytedance.com>2021-02-24 12:03:15 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-24 13:38:29 -0800
commitf3344adf38bdb3107d40483dd9501215ad40edce (patch)
treeafd77361c5a91919d9c953a3d6fc906b7da6ee54 /include
parent2e9bd483159939ed2c0704b914294653c8341d25 (diff)
mm: memcontrol: optimize per-lruvec stats counter memory usage
The vmstat threshold is 32 (MEMCG_CHARGE_BATCH), Actually the threshold can be as big as MEMCG_CHARGE_BATCH * PAGE_SIZE. It still fits into s32. So introduce struct batched_lruvec_stat to optimize memory usage. The size of struct lruvec_stat is 304 bytes on 64 bit systems. As it is a per-cpu structure. So with this patch, we can save 304 / 2 * ncpu bytes per-memcg per-node where ncpu is the number of the possible CPU. If there are c memory cgroup (include dying cgroup) and n NUMA node in the system. Finally, we can save (152 * ncpu * c * n) bytes. [akpm@linux-foundation.org: fix typo in comment] Link: https://lkml.kernel.org/r/20201210042121.39665-1-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Roman Gushchin <guro@fb.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Chris Down <chris@chrisdown.name> Cc: Yafang Shao <laoar.shao@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/memcontrol.h14
1 files changed, 12 insertions, 2 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 7a4dd1cb19fe..41bbf71edd9f 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -92,6 +92,10 @@ struct lruvec_stat {
long count[NR_VM_NODE_STAT_ITEMS];
};
+struct batched_lruvec_stat {
+ s32 count[NR_VM_NODE_STAT_ITEMS];
+};
+
/*
* Bitmap of shrinker::id corresponding to memcg-aware shrinkers,
* which have elements charged to this memcg.
@@ -107,11 +111,17 @@ struct memcg_shrinker_map {
struct mem_cgroup_per_node {
struct lruvec lruvec;
- /* Legacy local VM stats */
+ /*
+ * Legacy local VM stats. This should be struct lruvec_stat and
+ * cannot be optimized to struct batched_lruvec_stat. Because
+ * the threshold of the lruvec_stat_cpu can be as big as
+ * MEMCG_CHARGE_BATCH * PAGE_SIZE. It can fit into s32. But this
+ * filed has no upper limit.
+ */
struct lruvec_stat __percpu *lruvec_stat_local;
/* Subtree VM stats (batched updates) */
- struct lruvec_stat __percpu *lruvec_stat_cpu;
+ struct batched_lruvec_stat __percpu *lruvec_stat_cpu;
atomic_long_t lruvec_stat[NR_VM_NODE_STAT_ITEMS];
unsigned long lru_zone_size[MAX_NR_ZONES][NR_LRU_LISTS];