mm: memcontrol: basic memory statistics in cgroup2 memory controller

Provide a cgroup2 memory.stat that provides statistics on LRU memory
and fault event counters. More consumers and breakdowns will follow.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 68 insertions, 0 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index bf35bff282fc..98f4109bff6c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2767,6 +2767,18 @@ static unsigned long tree_stat(struct mem_cgroup *memcg,
         return val;
 }
 
+static unsigned long tree_events(struct mem_cgroup *memcg,
+                                 enum mem_cgroup_events_index idx)
+{
+        struct mem_cgroup *iter;
+        unsigned long val = 0;
+
+        for_each_mem_cgroup_tree(iter, memcg)
+                val += mem_cgroup_read_events(iter, idx);
+
+        return val;
+}
+
 static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
 {
         unsigned long val;
@@ -5096,6 +5108,57 @@ static int memory_events_show(struct seq_file *m, void *v)
         return 0;
 }
 
+static int memory_stat_show(struct seq_file *m, void *v)
+{
+        struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
+        int i;
+
+        /*
+         * Provide statistics on the state of the memory subsystem as
+         * well as cumulative event counters that show past behavior.
+         *
+         * This list is ordered following a combination of these gradients:
+         * 1) generic big picture -> specifics and details
+         * 2) reflecting userspace activity -> reflecting kernel heuristics
+         *
+         * Current memory state:
+         */
+
+        seq_printf(m, "anon %llu\n",
+                   (u64)tree_stat(memcg, MEM_CGROUP_STAT_RSS) * PAGE_SIZE);
+        seq_printf(m, "file %llu\n",
+                   (u64)tree_stat(memcg, MEM_CGROUP_STAT_CACHE) * PAGE_SIZE);
+
+        seq_printf(m, "file_mapped %llu\n",
+                   (u64)tree_stat(memcg, MEM_CGROUP_STAT_FILE_MAPPED) *
+                   PAGE_SIZE);
+        seq_printf(m, "file_dirty %llu\n",
+                   (u64)tree_stat(memcg, MEM_CGROUP_STAT_DIRTY) *
+                   PAGE_SIZE);
+        seq_printf(m, "file_writeback %llu\n",
+                   (u64)tree_stat(memcg, MEM_CGROUP_STAT_WRITEBACK) *
+                   PAGE_SIZE);
+
+        for (i = 0; i < NR_LRU_LISTS; i++) {
+                struct mem_cgroup *mi;
+                unsigned long val = 0;
+
+                for_each_mem_cgroup_tree(mi, memcg)
+                        val += mem_cgroup_nr_lru_pages(mi, BIT(i));
+                seq_printf(m, "%s %llu\n",
+                           mem_cgroup_lru_names[i], (u64)val * PAGE_SIZE);
+        }
+
+        /* Accumulated memory events */
+
+        seq_printf(m, "pgfault %lu\n",
+                   tree_events(memcg, MEM_CGROUP_EVENTS_PGFAULT));
+        seq_printf(m, "pgmajfault %lu\n",
+                   tree_events(memcg, MEM_CGROUP_EVENTS_PGMAJFAULT));
+
+        return 0;
+}
+
 static struct cftype memory_files[] = {
         {
                 .name = "current",
@@ -5126,6 +5189,11 @@ static struct cftype memory_files[] = {
                 .file_offset = offsetof(struct mem_cgroup, events_file),
                 .seq_show = memory_events_show,
         },
+        {
+                .name = "stat",
+                .flags = CFTYPE_NOT_ON_ROOT,
+                .seq_show = memory_stat_show,
+        },
         { }     /* terminate */
 };