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>
This commit is contained in:
Paul Menage 2009-01-07 18:08:37 -08:00 committed by Linus Torvalds
parent 999cd8a450
commit 2cb378c862

View file

@ -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;
}