On Wed, 10 Aug 2011 12:00:42 +0200
Michal Hocko [off-list ref] wrote:

On Tue 09-08-11 19:08:24, KAMEZAWA Hiroyuki wrote:

quoted

Making memcg numa's scanning information update by schedule_work().

Now, memcg's numa information is updated under a thread doing
memory reclaim. It's not very heavy weight now. But upcoming updates
around numa scanning will add more works. This patch makes
the update be done by schedule_work() and reduce latency caused
by this updates.

I am not sure whether this pays off. Anyway, I think it would be better
to place this patch somewhere at the end of the series so that we can
measure its impact separately.

I'll consider reordering when I come back from vacation.

quoted

Signed-off-by: KAMEZAWA Hiroyuki <redacted>

Otherwise looks good to me.
Reviewed-by: Michal Hocko <redacted>

Thanks.

Just a minor nit bellow.

quoted

---
 mm/memcontrol.c |   42 ++++++++++++++++++++++++++++++------------
 1 file changed, 30 insertions(+), 12 deletions(-)

Index: mmotm-Aug3/mm/memcontrol.c
===================================================================

--- mmotm-Aug3.orig/mm/memcontrol.c
+++ mmotm-Aug3/mm/memcontrol.c

@@ -285,6 +285,7 @@ struct mem_cgroup {
 	nodemask_t	scan_nodes;
 	atomic_t	numainfo_events;
 	atomic_t	numainfo_updating;
+	struct work_struct	numainfo_update_work;
 #endif
 	/*
 	 * Should the accounting and control be hierarchical, per subtree?

@@ -1567,6 +1568,23 @@ static bool test_mem_cgroup_node_reclaim
 }
 #if MAX_NUMNODES > 1
 
+static void mem_cgroup_numainfo_update_work(struct work_struct *work)
+{
+	struct mem_cgroup *memcg;
+	int nid;
+
+	memcg = container_of(work, struct mem_cgroup, numainfo_update_work);
+
+	memcg->scan_nodes = node_states[N_HIGH_MEMORY];
+	for_each_node_mask(nid, node_states[N_HIGH_MEMORY]) {
+		if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
+			node_clear(nid, memcg->scan_nodes);
+	}
+	atomic_set(&memcg->numainfo_updating, 0);
+	css_put(&memcg->css);
+}
+
+
 /*
  * Always updating the nodemask is not very good - even if we have an empty
  * list or the wrong list here, we can start from some node and traverse all

@@ -1575,7 +1593,6 @@ static bool test_mem_cgroup_node_reclaim
  */

Would be good to update the function comment as well (we still have 10s
period there).

ok.

Thanks,
-Kame


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