From: Roman Gushchin <guro@xxxxxx> Subject: mm: memcg/percpu: per-memcg percpu memory statistics Percpu memory can represent a noticeable chunk of the total memory consumption, especially on big machines with many CPUs. Let's track percpu memory usage for each memcg and display it in memory.stat. A percpu allocation is usually scattered over multiple pages (and nodes), and can be significantly smaller than a page. So let's add a byte-sized counter on the memcg level: MEMCG_PERCPU_B. Byte-sized vmstat infra created for slabs can be perfectly reused for percpu case. [guro@xxxxxx: v3] Link: http://lkml.kernel.org/r/20200623184515.4132564-4-guro@xxxxxx Link: http://lkml.kernel.org/r/20200608230819.832349-4-guro@xxxxxx Signed-off-by: Roman Gushchin <guro@xxxxxx> Acked-by: Dennis Zhou <dennis@xxxxxxxxxx> Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Pekka Enberg <penberg@xxxxxxxxxx> Cc: Tejun Heo <tj@xxxxxxxxxx> Cc: Tobin C. Harding <tobin@xxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Waiman Long <longman@xxxxxxxxxx> Cc: Bixuan Cui <cuibixuan@xxxxxxxxxx> Cc: Michal Koutný <mkoutny@xxxxxxxx> Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/admin-guide/cgroup-v2.rst | 4 ++++ include/linux/memcontrol.h | 8 ++++++++ mm/memcontrol.c | 4 +++- mm/percpu.c | 10 ++++++++++ 4 files changed, 25 insertions(+), 1 deletion(-) --- a/Documentation/admin-guide/cgroup-v2.rst~mm-memcg-percpu-per-memcg-percpu-memory-statistics +++ a/Documentation/admin-guide/cgroup-v2.rst @@ -1274,6 +1274,10 @@ PAGE_SIZE multiple when read back. Amount of memory used for storing in-kernel data structures. + percpu + Amount of memory used for storing per-cpu kernel + data structures. + sock Amount of memory used in network transmission buffers --- a/include/linux/memcontrol.h~mm-memcg-percpu-per-memcg-percpu-memory-statistics +++ a/include/linux/memcontrol.h @@ -32,6 +32,7 @@ struct kmem_cache; enum memcg_stat_item { MEMCG_SWAP = NR_VM_NODE_STAT_ITEMS, MEMCG_SOCK, + MEMCG_PERCPU_B, MEMCG_NR_STAT, }; @@ -339,6 +340,13 @@ struct mem_cgroup { extern struct mem_cgroup *root_mem_cgroup; +static __always_inline bool memcg_stat_item_in_bytes(int idx) +{ + if (idx == MEMCG_PERCPU_B) + return true; + return vmstat_item_in_bytes(idx); +} + static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg) { return (memcg == root_mem_cgroup); --- a/mm/memcontrol.c~mm-memcg-percpu-per-memcg-percpu-memory-statistics +++ a/mm/memcontrol.c @@ -781,7 +781,7 @@ void __mod_memcg_state(struct mem_cgroup if (mem_cgroup_disabled()) return; - if (vmstat_item_in_bytes(idx)) + if (memcg_stat_item_in_bytes(idx)) threshold <<= PAGE_SHIFT; x = val + __this_cpu_read(memcg->vmstats_percpu->stat[idx]); @@ -1488,6 +1488,8 @@ static char *memory_stat_format(struct m seq_buf_printf(&s, "slab %llu\n", (u64)(memcg_page_state(memcg, NR_SLAB_RECLAIMABLE_B) + memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE_B))); + seq_buf_printf(&s, "percpu %llu\n", + (u64)memcg_page_state(memcg, MEMCG_PERCPU_B)); seq_buf_printf(&s, "sock %llu\n", (u64)memcg_page_state(memcg, MEMCG_SOCK) * PAGE_SIZE); --- a/mm/percpu.c~mm-memcg-percpu-per-memcg-percpu-memory-statistics +++ a/mm/percpu.c @@ -1610,6 +1610,11 @@ static void pcpu_memcg_post_alloc_hook(s if (chunk) { chunk->obj_cgroups[off >> PCPU_MIN_ALLOC_SHIFT] = objcg; + + rcu_read_lock(); + mod_memcg_state(obj_cgroup_memcg(objcg), MEMCG_PERCPU_B, + size * num_possible_cpus()); + rcu_read_unlock(); } else { obj_cgroup_uncharge(objcg, size * num_possible_cpus()); obj_cgroup_put(objcg); @@ -1628,6 +1633,11 @@ static void pcpu_memcg_free_hook(struct obj_cgroup_uncharge(objcg, size * num_possible_cpus()); + rcu_read_lock(); + mod_memcg_state(obj_cgroup_memcg(objcg), MEMCG_PERCPU_B, + -(size * num_possible_cpus())); + rcu_read_unlock(); + obj_cgroup_put(objcg); } _
