memcg: use [kv]zalloc[_node] rather than [kv]malloc+memset (17295c88) · Commits · 戴 / test

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 <jj@chaosbits.net> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/memcontrol.c

+3 −6

Original line number	Diff line number	Diff line
		@@ -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;

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