memcg: fix reclaimable lru check in memcg
Now, in mem_cgroup_hierarchical_reclaim(), mem_cgroup_local_usage() is
used for checking whether the memcg contains reclaimable pages or not. If
no pages in it, the routine skips it.
But, mem_cgroup_local_usage() contains Unevictable pages and cannot handle
"noswap" condition correctly. This doesn't work on a swapless system.
This patch adds test_mem_cgroup_reclaimable() and replaces
mem_cgroup_local_usage(). test_mem_cgroup_reclaimable() see LRU counter
and returns correct answer to the caller. And this new function has
"noswap" argument and can see only FILE LRU if necessary.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix kerneldoc layout]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Ying Han <yinghan@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
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 ddffc74..a7a5cb1 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -577,15 +577,6 @@
return val;
}
-static long mem_cgroup_local_usage(struct mem_cgroup *mem)
-{
- long ret;
-
- ret = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS);
- ret += mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE);
- return ret;
-}
-
static void mem_cgroup_swap_statistics(struct mem_cgroup *mem,
bool charge)
{
@@ -1129,7 +1120,6 @@
return MEM_CGROUP_ZSTAT(mz, lru);
}
-#ifdef CONFIG_NUMA
static unsigned long mem_cgroup_node_nr_file_lru_pages(struct mem_cgroup *memcg,
int nid)
{
@@ -1141,6 +1131,17 @@
return ret;
}
+static unsigned long mem_cgroup_node_nr_anon_lru_pages(struct mem_cgroup *memcg,
+ int nid)
+{
+ unsigned long ret;
+
+ ret = mem_cgroup_get_zonestat_node(memcg, nid, LRU_INACTIVE_ANON) +
+ mem_cgroup_get_zonestat_node(memcg, nid, LRU_ACTIVE_ANON);
+ return ret;
+}
+
+#if MAX_NUMNODES > 1
static unsigned long mem_cgroup_nr_file_lru_pages(struct mem_cgroup *memcg)
{
u64 total = 0;
@@ -1152,17 +1153,6 @@
return total;
}
-static unsigned long mem_cgroup_node_nr_anon_lru_pages(struct mem_cgroup *memcg,
- int nid)
-{
- unsigned long ret;
-
- ret = mem_cgroup_get_zonestat_node(memcg, nid, LRU_INACTIVE_ANON) +
- mem_cgroup_get_zonestat_node(memcg, nid, LRU_ACTIVE_ANON);
-
- return ret;
-}
-
static unsigned long mem_cgroup_nr_anon_lru_pages(struct mem_cgroup *memcg)
{
u64 total = 0;
@@ -1559,6 +1549,28 @@
return ret;
}
+/**
+ * test_mem_cgroup_node_reclaimable
+ * @mem: the target memcg
+ * @nid: the node ID to be checked.
+ * @noswap : specify true here if the user wants flle only information.
+ *
+ * This function returns whether the specified memcg contains any
+ * reclaimable pages on a node. Returns true if there are any reclaimable
+ * pages in the node.
+ */
+static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *mem,
+ int nid, bool noswap)
+{
+ if (mem_cgroup_node_nr_file_lru_pages(mem, nid))
+ return true;
+ if (noswap || !total_swap_pages)
+ return false;
+ if (mem_cgroup_node_nr_anon_lru_pages(mem, nid))
+ return true;
+ return false;
+
+}
#if MAX_NUMNODES > 1
/*
@@ -1580,15 +1592,8 @@
for_each_node_mask(nid, node_states[N_HIGH_MEMORY]) {
- if (mem_cgroup_get_zonestat_node(mem, nid, LRU_INACTIVE_FILE) ||
- mem_cgroup_get_zonestat_node(mem, nid, LRU_ACTIVE_FILE))
- continue;
-
- if (total_swap_pages &&
- (mem_cgroup_get_zonestat_node(mem, nid, LRU_INACTIVE_ANON) ||
- mem_cgroup_get_zonestat_node(mem, nid, LRU_ACTIVE_ANON)))
- continue;
- node_clear(nid, mem->scan_nodes);
+ if (!test_mem_cgroup_node_reclaimable(mem, nid, false))
+ node_clear(nid, mem->scan_nodes);
}
}
@@ -1627,11 +1632,51 @@
return node;
}
+/*
+ * Check all nodes whether it contains reclaimable pages or not.
+ * For quick scan, we make use of scan_nodes. This will allow us to skip
+ * unused nodes. But scan_nodes is lazily updated and may not cotain
+ * enough new information. We need to do double check.
+ */
+bool mem_cgroup_reclaimable(struct mem_cgroup *mem, bool noswap)
+{
+ int nid;
+
+ /*
+ * quick check...making use of scan_node.
+ * We can skip unused nodes.
+ */
+ if (!nodes_empty(mem->scan_nodes)) {
+ for (nid = first_node(mem->scan_nodes);
+ nid < MAX_NUMNODES;
+ nid = next_node(nid, mem->scan_nodes)) {
+
+ if (test_mem_cgroup_node_reclaimable(mem, nid, noswap))
+ return true;
+ }
+ }
+ /*
+ * Check rest of nodes.
+ */
+ for_each_node_state(nid, N_HIGH_MEMORY) {
+ if (node_isset(nid, mem->scan_nodes))
+ continue;
+ if (test_mem_cgroup_node_reclaimable(mem, nid, noswap))
+ return true;
+ }
+ return false;
+}
+
#else
int mem_cgroup_select_victim_node(struct mem_cgroup *mem)
{
return 0;
}
+
+bool mem_cgroup_reclaimable(struct mem_cgroup *mem, bool noswap)
+{
+ return test_mem_cgroup_node_reclaimable(mem, 0, noswap);
+}
#endif
/*
@@ -1702,7 +1747,7 @@
}
}
}
- if (!mem_cgroup_local_usage(victim)) {
+ if (!mem_cgroup_reclaimable(victim, noswap)) {
/* this cgroup's local usage == 0 */
css_put(&victim->css);
continue;