memcg: do not use vmalloc for mem_cgroup allocations

The vmalloc was introduced by 333279 ("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 patch 45cf7e ("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>

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 9615407880ffeb290afceb7dfc3ac4ffc1c48597..b8b35e1798b66169b787214f036e5d2467a5c291 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -48,7 +48,6 @@
 #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>
@@ -335,12 +334,6 @@ 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 */
@@ -6142,14 +6135,12 @@ 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;
 
@@ -6160,10 +6151,7 @@ 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;
 }
 
@@ -6181,7 +6169,6 @@ out_free:
 static void __mem_cgroup_free(struct mem_cgroup *memcg)
 {
        int node;
-       size_t size = memcg_size();
 
        mem_cgroup_remove_from_trees(memcg);
 
@@ -6202,10 +6189,7 @@ 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);
 }
 
 /*