Re: [PATCH 3/4] memcg: get rid of percpu_charge_mutex lock

On Fri 22-07-11 08:49:27, KAMEZAWA Hiroyuki wrote:

On Thu, 21 Jul 2011 14:42:23 +0200
Michal Hocko [off-list ref] wrote:

quoted

On Thu 21-07-11 13:47:04, Michal Hocko wrote:

quoted

On Thu 21-07-11 19:30:51, KAMEZAWA Hiroyuki wrote:

quoted

On Thu, 21 Jul 2011 09:58:24 +0200
Michal Hocko [off-list ref] wrote:

[...]

quoted

quoted

quoted

--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c

@@ -2166,7 +2165,8 @@ static void drain_all_stock(struct mem_cgroup *root_mem, bool sync)
 
 	for_each_online_cpu(cpu) {
 		struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
-		if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
+		if (root_mem == stock->cached &&
+				test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
 			flush_work(&stock->work);

Doesn't this new check handle hierarchy ?
css_is_ancestor() will be required if you do this check.

Yes you are right. Will fix it. I will add a helper for the check.

Here is the patch with the helper. The above will then read 
	if (mem_cgroup_same_or_subtree(root_mem, stock->cached))

---
From b963a9f4dac61044daac49700f84b7819d7c2f53 Mon Sep 17 00:00:00 2001
From: Michal Hocko <redacted>
Date: Thu, 21 Jul 2011 13:54:13 +0200
Subject: [PATCH] memcg: add mem_cgroup_same_or_subtree helper

We are checking whether a given two groups are same or at least in the
same subtree of a hierarchy at several places. Let's make a helper for
it to make code easier to read.

Signed-off-by: Michal Hocko <redacted>

Acked-by: KAMEZAWA Hiroyuki <redacted>

Thanks

-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic

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