[PATCH v2 2/2] mm/cgroup: delay soft limit data allocation
From: Laurent Dufour
Date: Thu Feb 23 2017 - 08:37:09 EST
Until a soft limit is set to a cgroup, the soft limit data are useless
so delay this allocation when a limit is set.
Suggested-by: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Laurent Dufour <ldufour@xxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 67 ++++++++++++++++++++++++++++++++++++++++++++-------------
1 file changed, 52 insertions(+), 15 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a9f10fde44a6..c639c898809d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -142,7 +142,7 @@ struct mem_cgroup_tree {
struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
};
-static struct mem_cgroup_tree soft_limit_tree __read_mostly;
+static struct mem_cgroup_tree *soft_limit_tree __read_mostly;
/* for OOM */
struct mem_cgroup_eventfd_list {
@@ -381,10 +381,52 @@ mem_cgroup_page_nodeinfo(struct mem_cgroup *memcg, struct page *page)
return memcg->nodeinfo[nid];
}
+static bool soft_limit_initialize(void)
+{
+ static DEFINE_MUTEX(soft_limit_mutex);
+ struct mem_cgroup_tree *tree;
+ bool ret = true;
+ int node;
+
+ mutex_lock(&soft_limit_mutex);
+ if (soft_limit_tree)
+ goto bail;
+
+ tree = kmalloc(sizeof(*soft_limit_tree), GFP_KERNEL);
+ if (!tree) {
+ ret = false;
+ goto bail;
+ }
+ for_each_node(node) {
+ struct mem_cgroup_tree_per_node *rtpn;
+
+ rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL,
+ node_online(node) ? node : NUMA_NO_NODE);
+ if (!rtpn)
+ goto cleanup;
+
+ rtpn->rb_root = RB_ROOT;
+ spin_lock_init(&rtpn->lock);
+ tree->rb_tree_per_node[node] = rtpn;
+ }
+ WRITE_ONCE(soft_limit_tree, tree);
+bail:
+ mutex_unlock(&soft_limit_mutex);
+ return ret;
+cleanup:
+ for_each_node(node)
+ kfree(tree->rb_tree_per_node[node]);
+ kfree(tree);
+ ret = false;
+ goto bail;
+}
+
static struct mem_cgroup_tree_per_node *
soft_limit_tree_node(int nid)
{
- return soft_limit_tree.rb_tree_per_node[nid];
+ if (!soft_limit_tree)
+ return NULL;
+ return soft_limit_tree->rb_tree_per_node[nid];
}
static struct mem_cgroup_tree_per_node *
@@ -392,7 +434,9 @@ soft_limit_tree_from_page(struct page *page)
{
int nid = page_to_nid(page);
- return soft_limit_tree.rb_tree_per_node[nid];
+ if (!soft_limit_tree)
+ return NULL;
+ return soft_limit_tree->rb_tree_per_node[nid];
}
static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz,
@@ -3003,6 +3047,10 @@ static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
}
break;
case RES_SOFT_LIMIT:
+ if (!soft_limit_initialize()) {
+ ret = -ENOMEM;
+ break;
+ }
memcg->soft_limit = nr_pages;
ret = 0;
break;
@@ -5777,7 +5825,7 @@ __setup("cgroup.memory=", cgroup_memory);
*/
static int __init mem_cgroup_init(void)
{
- int cpu, node;
+ int cpu;
#ifndef CONFIG_SLOB
/*
@@ -5797,17 +5845,6 @@ static int __init mem_cgroup_init(void)
INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work,
drain_local_stock);
- for_each_node(node) {
- struct mem_cgroup_tree_per_node *rtpn;
-
- rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL,
- node_online(node) ? node : NUMA_NO_NODE);
-
- rtpn->rb_root = RB_ROOT;
- spin_lock_init(&rtpn->lock);
- soft_limit_tree.rb_tree_per_node[node] = rtpn;
- }
-
return 0;
}
subsys_initcall(mem_cgroup_init);
--
2.7.4