memcg: add mem_cgroup_same_or_subtree() helper
We are checking whether a given two groups are same or at least in the
same subtree of a hierarchy at several places. Let's make a helper for
it to make code easier to read.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <bsingharora@gmail.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 af920d0..79f23a1 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1108,6 +1108,21 @@
mem_cgroup_add_lru_list(page, to);
}
+/*
+ * Checks whether given mem is same or in the root_mem's
+ * hierarchy subtree
+ */
+static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_mem,
+ struct mem_cgroup *mem)
+{
+ if (root_mem != mem) {
+ return (root_mem->use_hierarchy &&
+ css_is_ancestor(&mem->css, &root_mem->css));
+ }
+
+ return true;
+}
+
int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
{
int ret;
@@ -1127,10 +1142,7 @@
* enabled in "curr" and "curr" is a child of "mem" in *cgroup*
* hierarchy(even if use_hierarchy is disabled in "mem").
*/
- if (mem->use_hierarchy)
- ret = css_is_ancestor(&curr->css, &mem->css);
- else
- ret = (curr == mem);
+ ret = mem_cgroup_same_or_subtree(mem, curr);
css_put(&curr->css);
return ret;
}
@@ -1369,10 +1381,9 @@
to = mc.to;
if (!from)
goto unlock;
- if (from == mem || to == mem
- || (mem->use_hierarchy && css_is_ancestor(&from->css, &mem->css))
- || (mem->use_hierarchy && css_is_ancestor(&to->css, &mem->css)))
- ret = true;
+
+ ret = mem_cgroup_same_or_subtree(mem, from)
+ || mem_cgroup_same_or_subtree(mem, to);
unlock:
spin_unlock(&mc.lock);
return ret;
@@ -1915,25 +1926,20 @@
static int memcg_oom_wake_function(wait_queue_t *wait,
unsigned mode, int sync, void *arg)
{
- struct mem_cgroup *wake_mem = (struct mem_cgroup *)arg;
+ struct mem_cgroup *wake_mem = (struct mem_cgroup *)arg,
+ *oom_wait_mem;
struct oom_wait_info *oom_wait_info;
oom_wait_info = container_of(wait, struct oom_wait_info, wait);
+ oom_wait_mem = oom_wait_info->mem;
- if (oom_wait_info->mem == wake_mem)
- goto wakeup;
- /* if no hierarchy, no match */
- if (!oom_wait_info->mem->use_hierarchy || !wake_mem->use_hierarchy)
- return 0;
/*
* Both of oom_wait_info->mem and wake_mem are stable under us.
* Then we can use css_is_ancestor without taking care of RCU.
*/
- if (!css_is_ancestor(&oom_wait_info->mem->css, &wake_mem->css) &&
- !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css))
+ if (!mem_cgroup_same_or_subtree(oom_wait_mem, wake_mem)
+ && !mem_cgroup_same_or_subtree(wake_mem, oom_wait_mem))
return 0;
-
-wakeup:
return autoremove_wake_function(wait, mode, sync, arg);
}
@@ -2178,13 +2184,8 @@
mem = stock->cached;
if (!mem || !stock->nr_pages)
continue;
- if (mem != root_mem) {
- if (!root_mem->use_hierarchy)
- continue;
- /* check whether "mem" is under tree of "root_mem" */
- if (!css_is_ancestor(&mem->css, &root_mem->css))
- continue;
- }
+ if (!mem_cgroup_same_or_subtree(root_mem, mem))
+ continue;
if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
if (cpu == curcpu)
drain_local_stock(&stock->work);
