[Devel] [PATCH 02/10] memcg: Uncharge all kmem when deleting a cgroup.

[Suleiman Souhlal]

A later patch will also use this to move the accounting to the root
cgroup.

Signed-off-by: Suleiman Souhlal <suleiman at google.com>
---
 mm/memcontrol.c |   30 +++++++++++++++++++++++++++++-
 1 files changed, 29 insertions(+), 1 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 11e31d6..6f44fcb 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -378,6 +378,7 @@ static void mem_cgroup_get(struct mem_cgroup *memcg);
 static void mem_cgroup_put(struct mem_cgroup *memcg);
 static void memcg_kmem_init(struct mem_cgroup *memcg,
     struct mem_cgroup *parent);
+static void memcg_kmem_move(struct mem_cgroup *memcg);
 
 /* Writing them here to avoid exposing memcg's inner layout */
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
@@ -3674,6 +3675,7 @@ static int mem_cgroup_force_empty(struct mem_cgroup *memcg, bool free_all)
 	int ret;
 	int node, zid, shrink;
 	int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
+	unsigned long usage;
 	struct cgroup *cgrp = memcg->css.cgroup;
 
 	css_get(&memcg->css);
@@ -3693,6 +3695,8 @@ move_account:
 		/* This is for making all *used* pages to be on LRU. */
 		lru_add_drain_all();
 		drain_all_stock_sync(memcg);
+		if (!free_all)
+			memcg_kmem_move(memcg);
 		ret = 0;
 		mem_cgroup_start_move(memcg);
 		for_each_node_state(node, N_HIGH_MEMORY) {
@@ -3714,8 +3718,13 @@ move_account:
 		if (ret == -ENOMEM)
 			goto try_to_free;
 		cond_resched();
+		usage = memcg->res.usage;
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+		if (free_all && !memcg->independent_kmem_limit)
+			usage -= memcg->kmem_bytes.usage;
+#endif
 	/* "ret" should also be checked to ensure all lists are empty. */
-	} while (memcg->res.usage > 0 || ret);
+	} while (usage > 0 || ret);
 out:
 	css_put(&memcg->css);
 	return ret;
@@ -5632,9 +5641,28 @@ memcg_kmem_init(struct mem_cgroup *memcg, struct mem_cgroup *parent)
 	res_counter_init(&memcg->kmem_bytes, parent_res);
 	memcg->independent_kmem_limit = 0;
 }
+
+static void
+memcg_kmem_move(struct mem_cgroup *memcg)
+{
+	unsigned long flags;
+	long kmem_bytes;
+
+	spin_lock_irqsave(&memcg->kmem_bytes.lock, flags);
+	kmem_bytes = memcg->kmem_bytes.usage;
+	res_counter_uncharge_locked(&memcg->kmem_bytes, kmem_bytes);
+	spin_unlock_irqrestore(&memcg->kmem_bytes.lock, flags);
+	if (!memcg->independent_kmem_limit)
+		res_counter_uncharge(&memcg->res, kmem_bytes);
+}
 #else /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
 static void
 memcg_kmem_init(struct mem_cgroup *memcg, struct mem_cgroup *parent)
 {
 }
+
+static void
+memcg_kmem_move(struct mem_cgroup *memcg)
+{
+}
 #endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
-- 
1.7.7.3