[RESEND] [PATCH v1 2/3] Move from all possible nodes to online nodes

[Balbir Singh <bsingharora@gmail.com>]

Move routines that do operations on all nodes to
just the online nodes. Most of the changes are
very obvious (like the ones related to soft limit tree
per node)

Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org> 
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
---
 mm/memcontrol.c | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 5585fce..cc49fa2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -497,7 +497,7 @@ static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
 	struct mem_cgroup_per_node *mz;
 	int nid;
 
-	for_each_node(nid) {
+	for_each_online_node(nid) {
 		mz = mem_cgroup_nodeinfo(memcg, nid);
 		mctz = soft_limit_tree_node(nid);
 		mem_cgroup_remove_exceeded(mz, mctz);
@@ -895,7 +895,7 @@ static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
 	int i;
 
 	while ((memcg = parent_mem_cgroup(memcg))) {
-		for_each_node(nid) {
+		for_each_online_node(nid) {
 			mz = mem_cgroup_nodeinfo(memcg, nid);
 			for (i = 0; i <= DEF_PRIORITY; i++) {
 				iter = &mz->iter[i];
@@ -4146,7 +4146,7 @@ static void mem_cgroup_free(struct mem_cgroup *memcg)
 	int node;
 
 	memcg_wb_domain_exit(memcg);
-	for_each_node(node)
+	for_each_online_node(node)
 		free_mem_cgroup_per_node_info(memcg, node);
 	free_percpu(memcg->stat);
 	kfree(memcg);
@@ -4175,7 +4175,7 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
 	if (!memcg->stat)
 		goto fail;
 
-	for_each_node(node)
+	for_each_online_node(node)
 		if (alloc_mem_cgroup_per_node_info(memcg, node))
 			goto fail;
 
@@ -5774,11 +5774,21 @@ __setup("cgroup.memory=", cgroup_memory);
 static void memcg_node_offline(int node)
 {
 	struct mem_cgroup *memcg;
+	struct mem_cgroup_tree_per_node *rtpn;
+	struct mem_cgroup_tree_per_node *mctz;
+	struct mem_cgroup_per_node *mz;
 
 	if (node < 0)
 		return;
 
+	rtpn = soft_limit_tree.rb_tree_per_node[node];
+	kfree(rtpn);
+
 	for_each_mem_cgroup(memcg) {
+		mz = mem_cgroup_nodeinfo(memcg, node);
+		mctz = soft_limit_tree_node(node);
+		mem_cgroup_remove_exceeded(mz, mctz);
+
 		free_mem_cgroup_per_node_info(memcg, node);
 		mem_cgroup_may_update_nodemask(memcg);
 	}
@@ -5787,10 +5797,18 @@ static void memcg_node_offline(int node)
 static void memcg_node_online(int node)
 {
 	struct mem_cgroup *memcg;
+	struct mem_cgroup_tree_per_node *rtpn;
 
 	if (node < 0)
 		return;
 
+	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;
+
 	for_each_mem_cgroup(memcg) {
 		alloc_mem_cgroup_per_node_info(memcg, node);
 		mem_cgroup_may_update_nodemask(memcg);
@@ -5854,7 +5872,7 @@ static int __init mem_cgroup_init(void)
 		INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work,
 			  drain_local_stock);
 
-	for_each_node(node) {
+	for_each_online_node(node) {
 		struct mem_cgroup_tree_per_node *rtpn;
 
 		rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL,
-- 
2.5.5