memcg: use [kv]zalloc[_node] rather than [kv]malloc+memset

In mem_cgroup_alloc() we currently do either kmalloc() or vmalloc() then
followed by memset() to zero the memory.  This can be more efficiently
achieved by using kzalloc() and vzalloc().  There's also one situation
where we can use kzalloc_node() - this is what's new in this version of
the patch.

Signed-off-by: Jesper Juhl <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Wu Fengguang <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: Li Zefan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 3 insertions, 6 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c339d7431bda..6424ba0fce83 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4216,13 +4216,11 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
 	 */
 	if (!node_state(node, N_NORMAL_MEMORY))
 		tmp = -1;
-	pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
+	pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
 	if (!pn)
 		return 1;
 
 	mem->info.nodeinfo[node] = pn;
-	memset(pn, 0, sizeof(*pn));
-
 	for (zone = 0; zone < MAX_NR_ZONES; zone++) {
 		mz = &pn->zoneinfo[zone];
 		for_each_lru(l)
@@ -4246,14 +4244,13 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
 
 	/* Can be very big if MAX_NUMNODES is very big */
 	if (size < PAGE_SIZE)
-		mem = kmalloc(size, GFP_KERNEL);
+		mem = kzalloc(size, GFP_KERNEL);
 	else
-		mem = vmalloc(size);
+		mem = vzalloc(size);
 
 	if (!mem)
 		return NULL;
 
-	memset(mem, 0, size);
 	mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
 	if (!mem->stat)
 		goto out_free;