memcg: reduce size of mem_cgroup by using nr_cpu_ids
As Jan Blunck <jblunck@suse.de> pointed out, allocating per-cpu stat for
memcg to the size of NR_CPUS is not good.
This patch changes mem_cgroup's cpustat allocation not based on NR_CPUS
but based on nr_cpu_ids.
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 49234d9..e00f25e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -60,7 +60,7 @@
} ____cacheline_aligned_in_smp;
struct mem_cgroup_stat {
- struct mem_cgroup_stat_cpu cpustat[NR_CPUS];
+ struct mem_cgroup_stat_cpu cpustat[0];
};
/*
@@ -129,11 +129,10 @@
int prev_priority; /* for recording reclaim priority */
/*
- * statistics.
+ * statistics. This must be placed at the end of memcg.
*/
struct mem_cgroup_stat stat;
};
-static struct mem_cgroup init_mem_cgroup;
enum charge_type {
MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
@@ -1293,23 +1292,30 @@
kfree(mem->info.nodeinfo[node]);
}
+static int mem_cgroup_size(void)
+{
+ int cpustat_size = nr_cpu_ids * sizeof(struct mem_cgroup_stat_cpu);
+ return sizeof(struct mem_cgroup) + cpustat_size;
+}
+
static struct mem_cgroup *mem_cgroup_alloc(void)
{
struct mem_cgroup *mem;
+ int size = mem_cgroup_size();
- if (sizeof(*mem) < PAGE_SIZE)
- mem = kmalloc(sizeof(*mem), GFP_KERNEL);
+ if (size < PAGE_SIZE)
+ mem = kmalloc(size, GFP_KERNEL);
else
- mem = vmalloc(sizeof(*mem));
+ mem = vmalloc(size);
if (mem)
- memset(mem, 0, sizeof(*mem));
+ memset(mem, 0, size);
return mem;
}
static void mem_cgroup_free(struct mem_cgroup *mem)
{
- if (sizeof(*mem) < PAGE_SIZE)
+ if (mem_cgroup_size() < PAGE_SIZE)
kfree(mem);
else
vfree(mem);
@@ -1322,13 +1328,9 @@
struct mem_cgroup *mem;
int node;
- if (unlikely((cont->parent) == NULL)) {
- mem = &init_mem_cgroup;
- } else {
- mem = mem_cgroup_alloc();
- if (!mem)
- return ERR_PTR(-ENOMEM);
- }
+ mem = mem_cgroup_alloc();
+ if (!mem)
+ return ERR_PTR(-ENOMEM);
res_counter_init(&mem->res);
@@ -1340,8 +1342,7 @@
free_out:
for_each_node_state(node, N_POSSIBLE)
free_mem_cgroup_per_zone_info(mem, node);
- if (cont->parent != NULL)
- mem_cgroup_free(mem);
+ mem_cgroup_free(mem);
return ERR_PTR(-ENOMEM);
}