mm, memcg: add rss_huge stat to memory.stat

This exports the amount of anonymous transparent hugepages for each
memcg via the new "rss_huge" stat in memory.stat.  The units are in
bytes.

This is helpful to determine the hugepage utilization for individual
jobs on the system in comparison to rss and opportunities where
MADV_HUGEPAGE may be helpful.

The amount of anonymous transparent hugepages is also included in "rss"
for backwards compatibility.

Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 26 insertions, 10 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 0f1d92163f30..cb1c9dedf9b6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -92,16 +92,18 @@ enum mem_cgroup_stat_index {
         /*
          * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
          */
-        MEM_CGROUP_STAT_CACHE,     /* # of pages charged as cache */
-        MEM_CGROUP_STAT_RSS,       /* # of pages charged as anon rss */
-        MEM_CGROUP_STAT_FILE_MAPPED,  /* # of pages charged as file rss */
-        MEM_CGROUP_STAT_SWAP, /* # of pages, swapped out */
+        MEM_CGROUP_STAT_CACHE,          /* # of pages charged as cache */
+        MEM_CGROUP_STAT_RSS,            /* # of pages charged as anon rss */
+        MEM_CGROUP_STAT_RSS_HUGE,       /* # of pages charged as anon huge */
+        MEM_CGROUP_STAT_FILE_MAPPED,    /* # of pages charged as file rss */
+        MEM_CGROUP_STAT_SWAP,           /* # of pages, swapped out */
         MEM_CGROUP_STAT_NSTATS,
 };
 
 static const char * const mem_cgroup_stat_names[] = {
         "cache",
         "rss",
+        "rss_huge",
         "mapped_file",
         "swap",
 };
@@ -917,6 +919,7 @@ static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
 }
 
 static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
+                                         struct page *page,
                                          bool anon, int nr_pages)
 {
         preempt_disable();
@@ -932,6 +935,10 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
                 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE],
                                 nr_pages);
 
+        if (PageTransHuge(page))
+                __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
+                                nr_pages);
+
         /* pagein of a big page is an event. So, ignore page size */
         if (nr_pages > 0)
                 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
@@ -2914,7 +2921,7 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg,
         else
                 anon = false;
 
-        mem_cgroup_charge_statistics(memcg, anon, nr_pages);
+        mem_cgroup_charge_statistics(memcg, page, anon, nr_pages);
         unlock_page_cgroup(pc);
 
         /*
@@ -3708,16 +3715,21 @@ void mem_cgroup_split_huge_fixup(struct page *head)
 {
         struct page_cgroup *head_pc = lookup_page_cgroup(head);
         struct page_cgroup *pc;
+        struct mem_cgroup *memcg;
         int i;
 
         if (mem_cgroup_disabled())
                 return;
+
+        memcg = head_pc->mem_cgroup;
         for (i = 1; i < HPAGE_PMD_NR; i++) {
                 pc = head_pc + i;
-                pc->mem_cgroup = head_pc->mem_cgroup;
+                pc->mem_cgroup = memcg;
                 smp_wmb();/* see __commit_charge() */
                 pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
         }
+        __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
+                       HPAGE_PMD_NR);
 }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
@@ -3773,11 +3785,11 @@ static int mem_cgroup_move_account(struct page *page,
                 __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
                 preempt_enable();
         }
-        mem_cgroup_charge_statistics(from, anon, -nr_pages);
+        mem_cgroup_charge_statistics(from, page, anon, -nr_pages);
 
         /* caller should have done css_get */
         pc->mem_cgroup = to;
-        mem_cgroup_charge_statistics(to, anon, nr_pages);
+        mem_cgroup_charge_statistics(to, page, anon, nr_pages);
         move_unlock_mem_cgroup(from, &flags);
         ret = 0;
 unlock:
@@ -4152,7 +4164,7 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype,
                 break;
         }
 
-        mem_cgroup_charge_statistics(memcg, anon, -nr_pages);
+        mem_cgroup_charge_statistics(memcg, page, anon, -nr_pages);
 
         ClearPageCgroupUsed(pc);
         /*
@@ -4502,7 +4514,7 @@ void mem_cgroup_replace_page_cache(struct page *oldpage,
         lock_page_cgroup(pc);
         if (PageCgroupUsed(pc)) {
                 memcg = pc->mem_cgroup;
-                mem_cgroup_charge_statistics(memcg, false, -1);
+                mem_cgroup_charge_statistics(memcg, oldpage, false, -1);
                 ClearPageCgroupUsed(pc);
         }
         unlock_page_cgroup(pc);
@@ -5030,6 +5042,10 @@ static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
                         return res_counter_read_u64(&memcg->memsw, RES_USAGE);
         }
 
+        /*
+         * Transparent hugepages are still accounted for in MEM_CGROUP_STAT_RSS
+         * as well as in MEM_CGROUP_STAT_RSS_HUGE.
+         */
         val = mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_CACHE);
         val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_RSS);