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: Paul Menage <menage@google.com>
Tested-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
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 93a7928..e2996b8 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -154,7 +154,7 @@
/*
* 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 @@
/*
* 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 @@
/*
* 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 @@
done:
root_mem->last_scanned_child = ret;
- cgroup_unlock();
+ mutex_unlock(&mem_cgroup_subsys.hierarchy_mutex);
return ret;
}
@@ -770,18 +770,16 @@
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;
}
