memcg: add memcg sanity checks at allocating and freeing pages
Add checks at allocating or freeing a page whether the page is used (iow,
charged) from the view point of memcg.
This check may be useful in debugging a problem and we did similar checks
before the commit 52d4b9ac(memcg: allocate all page_cgroup at boot).
This patch adds some overheads at allocating or freeing memory, so it's
enabled only when CONFIG_DEBUG_VM is enabled.
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Minchan Kim <minchan.kim@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 3a2d54b..0356cb6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3046,6 +3046,52 @@
return ret;
}
+#ifdef CONFIG_DEBUG_VM
+static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
+{
+ struct page_cgroup *pc;
+
+ pc = lookup_page_cgroup(page);
+ if (likely(pc) && PageCgroupUsed(pc))
+ return pc;
+ return NULL;
+}
+
+bool mem_cgroup_bad_page_check(struct page *page)
+{
+ if (mem_cgroup_disabled())
+ return false;
+
+ return lookup_page_cgroup_used(page) != NULL;
+}
+
+void mem_cgroup_print_bad_page(struct page *page)
+{
+ struct page_cgroup *pc;
+
+ pc = lookup_page_cgroup_used(page);
+ if (pc) {
+ int ret = -1;
+ char *path;
+
+ printk(KERN_ALERT "pc:%p pc->flags:%lx pc->mem_cgroup:%p",
+ pc, pc->flags, pc->mem_cgroup);
+
+ path = kmalloc(PATH_MAX, GFP_KERNEL);
+ if (path) {
+ rcu_read_lock();
+ ret = cgroup_path(pc->mem_cgroup->css.cgroup,
+ path, PATH_MAX);
+ rcu_read_unlock();
+ }
+
+ printk(KERN_CONT "(%s)\n",
+ (ret < 0) ? "cannot get the path" : path);
+ kfree(path);
+ }
+}
+#endif
+
static DEFINE_MUTEX(set_limit_mutex);
static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,