memcg: do not use vmalloc for mem_cgroup allocations

The vmalloc was introduced by 33327948782b ("memcgroup: use vmalloc for
mem_cgroup allocation"), because at that time MAX_NUMNODES was used for
defining the per-node array in the mem_cgroup structure so that the
structure could be huge even if the system had the only NUMA node.

The situation was significantly improved by commit 45cf7ebd5a03 ("memcg:
reduce the size of struct memcg 244-fold"), which made the size of the
mem_cgroup structure calculated dynamically depending on the real number
of NUMA nodes installed on the system (nr_node_ids), so now there is no
point in using vmalloc here: the structure is allocated rarely and on
most systems its size is about 1K.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@openvz.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
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, 6 insertions, 22 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 67dd2a881433..7890ce9d6bd1 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -49,7 +49,6 @@
 #include <linux/sort.h>
 #include <linux/fs.h>
 #include <linux/seq_file.h>
-#include <linux/vmalloc.h>
 #include <linux/vmpressure.h>
 #include <linux/mm_inline.h>
 #include <linux/page_cgroup.h>
@@ -381,12 +380,6 @@ struct mem_cgroup {
         /* WARNING: nodeinfo must be the last member here */
 };
 
-static size_t memcg_size(void)
-{
-        return sizeof(struct mem_cgroup) +
-                nr_node_ids * sizeof(struct mem_cgroup_per_node *);
-}
-
 /* internal only representation about the status of kmem accounting. */
 enum {
         KMEM_ACCOUNTED_ACTIVE = 0, /* accounted by this cgroup itself */
@@ -6405,14 +6398,12 @@ static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
 static struct mem_cgroup *mem_cgroup_alloc(void)
 {
         struct mem_cgroup *memcg;
-        size_t size = memcg_size();
+        size_t size;
 
-        /* Can be very big if nr_node_ids is very big */
-        if (size < PAGE_SIZE)
-                memcg = kzalloc(size, GFP_KERNEL);
-        else
-                memcg = vzalloc(size);
+        size = sizeof(struct mem_cgroup);
+        size += nr_node_ids * sizeof(struct mem_cgroup_per_node *);
 
+        memcg = kzalloc(size, GFP_KERNEL);
         if (!memcg)
                 return NULL;
 
@@ -6423,10 +6414,7 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
         return memcg;
 
 out_free:
-        if (size < PAGE_SIZE)
-                kfree(memcg);
-        else
-                vfree(memcg);
+        kfree(memcg);
         return NULL;
 }
 
@@ -6444,7 +6432,6 @@ out_free:
 static void __mem_cgroup_free(struct mem_cgroup *memcg)
 {
         int node;
-        size_t size = memcg_size();
 
         mem_cgroup_remove_from_trees(memcg);
 
@@ -6465,10 +6452,7 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg)
          * the cgroup_lock.
          */
         disarm_static_keys(memcg);
-        if (size < PAGE_SIZE)
-                kfree(memcg);
-        else
-                vfree(memcg);
+        kfree(memcg);
 }
 
 /*