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Commit 2cb378c8 authored by Paul Menage's avatar Paul Menage Committed by Linus Torvalds
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cgroups: use hierarchy_mutex in memory controller 



Update the memory controller to use its hierarchy_mutex rather than
calling cgroup_lock() to protected against cgroup_mkdir()/cgroup_rmdir()
from occurring in its hierarchy.

Signed-off-by: default avatarPaul Menage <menage@google.com>
Tested-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 999cd8a4

mm/memcontrol.c

+6 −8
Original line number Diff line number Diff line
@@ -154,7 +154,7 @@ struct mem_cgroup { 


	/*

	 * While reclaiming in a hiearchy, we cache the last child we

	 * reclaimed from. Protected by cgroup_lock()

	 * reclaimed from. Protected by hierarchy_mutex

	 */

	struct mem_cgroup *last_scanned_child;

	/*
@@ -615,7 +615,7 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, 


/*

 * This routine finds the DFS walk successor. This routine should be

 * called with cgroup_mutex held

 * called with hierarchy_mutex held

 */

static struct mem_cgroup *

mem_cgroup_get_next_node(struct mem_cgroup *curr, struct mem_cgroup *root_mem)
@@ -685,7 +685,7 @@ mem_cgroup_get_first_node(struct mem_cgroup *root_mem) 
	/*

	 * Scan all children under the mem_cgroup mem

	 */

	cgroup_lock();

	mutex_lock(&mem_cgroup_subsys.hierarchy_mutex);

	if (list_empty(&root_mem->css.cgroup->children)) {

		ret = root_mem;

		goto done;
@@ -706,7 +706,7 @@ mem_cgroup_get_first_node(struct mem_cgroup *root_mem) 


done:

	root_mem->last_scanned_child = ret;

	cgroup_unlock();

	mutex_unlock(&mem_cgroup_subsys.hierarchy_mutex);

	return ret;

}
@@ -770,18 +770,16 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem, 
	while (next_mem != root_mem) {

		if (mem_cgroup_is_obsolete(next_mem)) {

			mem_cgroup_put(next_mem);

			cgroup_lock();

			next_mem = mem_cgroup_get_first_node(root_mem);

			cgroup_unlock();

			continue;

		}

		ret = try_to_free_mem_cgroup_pages(next_mem, gfp_mask, noswap,

						   get_swappiness(next_mem));

		if (mem_cgroup_check_under_limit(root_mem))

			return 0;

		cgroup_lock();

		mutex_lock(&mem_cgroup_subsys.hierarchy_mutex);

		next_mem = mem_cgroup_get_next_node(next_mem, root_mem);

		cgroup_unlock();

		mutex_unlock(&mem_cgroup_subsys.hierarchy_mutex);

	}

	return ret;

}