Commit 8ff69e2c authored by Vladimir Davydov's avatar Vladimir Davydov Committed by Linus Torvalds
Browse files

memcg: do not use vmalloc for mem_cgroup allocations 



The vmalloc was introduced by 33327948 ("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 45cf7ebd ("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: default avatarVladimir Davydov <vdavydov@parallels.com>
Acked-by: default avatarMichal 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 01cc2e58

mm/memcontrol.c

+6 −22
Original line number Diff line number Diff line
@@ -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);

	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);

}



/*

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