mm: memcontrol: report slab usage in cgroup2 memory.stat

Show how much memory is used for storing reclaimable and unreclaimable
in-kernel data structures allocated from slab caches.

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

diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt
index ff49cf9..e4e0c1d 100644 (file)
--- a/Documentation/cgroup-v2.txt
+++ b/Documentation/cgroup-v2.txt
@@ -843,6 +843,11 @@ PAGE_SIZE multiple when read back.
                Amount of memory used to cache filesystem data,
                including tmpfs and shared memory.
 
+         slab
+
+               Amount of memory used for storing in-kernel data
+               structures.
+
          sock
 
                Amount of memory used in network transmission buffers
@@ -871,6 +876,16 @@ PAGE_SIZE multiple when read back.
                on the internal memory management lists used by the
                page reclaim algorithm
 
+         slab_reclaimable
+
+               Part of "slab" that might be reclaimed, such as
+               dentries and inodes.
+
+         slab_unreclaimable
+
+               Part of "slab" that cannot be reclaimed on memory
+               pressure.
+
          pgfault
 
                Total number of page faults incurred

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index f0c4bec..e7af483 100644 (file)
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -53,6 +53,8 @@ enum mem_cgroup_stat_index {
        MEM_CGROUP_STAT_NSTATS,
        /* default hierarchy stats */
        MEMCG_SOCK = MEM_CGROUP_STAT_NSTATS,
+       MEMCG_SLAB_RECLAIMABLE,
+       MEMCG_SLAB_UNRECLAIMABLE,
        MEMCG_NR_STAT,
 };
 
@@ -883,6 +885,20 @@ static __always_inline void memcg_kmem_put_cache(struct kmem_cache *cachep)
        if (memcg_kmem_enabled())
                __memcg_kmem_put_cache(cachep);
 }
+
+/**
+ * memcg_kmem_update_page_stat - update kmem page state statistics
+ * @page: the page
+ * @idx: page state item to account
+ * @val: number of pages (positive or negative)
+ */
+static inline void memcg_kmem_update_page_stat(struct page *page,
+                               enum mem_cgroup_stat_index idx, int val)
+{
+       if (memcg_kmem_enabled() && page->mem_cgroup)
+               this_cpu_add(page->mem_cgroup->stat->count[idx], val);
+}
+
 #else
 #define for_each_memcg_cache_index(_idx)       \
        for (; NULL; )
@@ -928,6 +944,11 @@ memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
 static inline void memcg_kmem_put_cache(struct kmem_cache *cachep)
 {
 }
+
+static inline void memcg_kmem_update_page_stat(struct page *page,
+                               enum mem_cgroup_stat_index idx, int val)
+{
+}
 #endif /* CONFIG_MEMCG && !CONFIG_SLOB */
 
 #endif /* _LINUX_MEMCONTROL_H */

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 4302660..3ad64bf 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5106,6 +5106,9 @@ static int memory_stat_show(struct seq_file *m, void *v)
                   (u64)stat[MEM_CGROUP_STAT_RSS] * PAGE_SIZE);
        seq_printf(m, "file %llu\n",
                   (u64)stat[MEM_CGROUP_STAT_CACHE] * PAGE_SIZE);
+       seq_printf(m, "slab %llu\n",
+                  (u64)(stat[MEMCG_SLAB_RECLAIMABLE] +
+                        stat[MEMCG_SLAB_UNRECLAIMABLE]) * PAGE_SIZE);
        seq_printf(m, "sock %llu\n",
                   (u64)stat[MEMCG_SOCK] * PAGE_SIZE);
 
@@ -5126,6 +5129,11 @@ static int memory_stat_show(struct seq_file *m, void *v)
                           mem_cgroup_lru_names[i], (u64)val * PAGE_SIZE);
        }
 
+       seq_printf(m, "slab_reclaimable %llu\n",
+                  (u64)stat[MEMCG_SLAB_RECLAIMABLE] * PAGE_SIZE);
+       seq_printf(m, "slab_unreclaimable %llu\n",
+                  (u64)stat[MEMCG_SLAB_UNRECLAIMABLE] * PAGE_SIZE);
+
        /* Accumulated memory events */
 
        seq_printf(m, "pgfault %lu\n",

diff --git a/mm/slab.c b/mm/slab.c
index 852fc5c..56dd0df 100644 (file)
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1442,9 +1442,10 @@ static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
  */
 static void kmem_freepages(struct kmem_cache *cachep, struct page *page)
 {
-       const unsigned long nr_freed = (1 << cachep->gfporder);
+       int order = cachep->gfporder;
+       unsigned long nr_freed = (1 << order);
 
-       kmemcheck_free_shadow(page, cachep->gfporder);
+       kmemcheck_free_shadow(page, order);
 
        if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
                sub_zone_page_state(page_zone(page),
@@ -1461,7 +1462,8 @@ static void kmem_freepages(struct kmem_cache *cachep, struct page *page)
 
        if (current->reclaim_state)
                current->reclaim_state->reclaimed_slab += nr_freed;
-       __free_kmem_pages(page, cachep->gfporder);
+       memcg_uncharge_slab(page, order, cachep);
+       __free_pages(page, order);
 }
 
 static void kmem_rcu_free(struct rcu_head *head)

diff --git a/mm/slab.h b/mm/slab.h
index b793436..ff39a8f 100644 (file)
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -246,12 +246,33 @@ static __always_inline int memcg_charge_slab(struct page *page,
                                             gfp_t gfp, int order,
                                             struct kmem_cache *s)
 {
+       int ret;
+
        if (!memcg_kmem_enabled())
                return 0;
        if (is_root_cache(s))
                return 0;
-       return __memcg_kmem_charge_memcg(page, gfp, order,
-                                        s->memcg_params.memcg);
+
+       ret = __memcg_kmem_charge_memcg(page, gfp, order,
+                                       s->memcg_params.memcg);
+       if (ret)
+               return ret;
+
+       memcg_kmem_update_page_stat(page,
+                       (s->flags & SLAB_RECLAIM_ACCOUNT) ?
+                       MEMCG_SLAB_RECLAIMABLE : MEMCG_SLAB_UNRECLAIMABLE,
+                       1 << order);
+       return 0;
+}
+
+static __always_inline void memcg_uncharge_slab(struct page *page, int order,
+                                               struct kmem_cache *s)
+{
+       memcg_kmem_update_page_stat(page,
+                       (s->flags & SLAB_RECLAIM_ACCOUNT) ?
+                       MEMCG_SLAB_RECLAIMABLE : MEMCG_SLAB_UNRECLAIMABLE,
+                       -(1 << order));
+       memcg_kmem_uncharge(page, order);
 }
 
 extern void slab_init_memcg_params(struct kmem_cache *);
@@ -294,6 +315,11 @@ static inline int memcg_charge_slab(struct page *page, gfp_t gfp, int order,
        return 0;
 }
 
+static inline void memcg_uncharge_slab(struct page *page, int order,
+                                      struct kmem_cache *s)
+{
+}
+
 static inline void slab_init_memcg_params(struct kmem_cache *s)
 {
 }

diff --git a/mm/slub.c b/mm/slub.c
index 6c91324..712d534 100644 (file)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1540,7 +1540,8 @@ static void __free_slab(struct kmem_cache *s, struct page *page)
        page_mapcount_reset(page);
        if (current->reclaim_state)
                current->reclaim_state->reclaimed_slab += pages;
-       __free_kmem_pages(page, order);
+       memcg_uncharge_slab(page, order, s);
+       __free_pages(page, order);
 }
 
 #define need_reserve_slab_rcu                                          \