[RFC][PATCH] memcg: show real limit under hierarchy

[RFC][PATCH] memcg: show real limit under hierarchy

[KAMEZAWA Hiroyuki]

I wonder other people who debugs memcg's hierarchy may use similar patches.
this is my one.
comments ?
==
From:KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

Show "real" limit of memcg.
This helps my debugging and maybe useful for users.

While testing hierarchy like this

	mount -t cgroup none /cgroup -t memory
	mkdir /cgroup/A
	set use_hierarchy==1 to "A"
	mkdir /cgroup/A/01
	mkdir /cgroup/A/01/02
	mkdir /cgroup/A/01/03
	mkdir /cgroup/A/01/03/04
	mkdir /cgroup/A/08
	mkdir /cgroup/A/08/01
	....
and set each own limit to them, "real" limit of each memcg is unclear.
This patch shows real limit by checking all ancestors in memory.stat.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
---
 mm/memcontrol.c |   37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

Index: mmotm-2.6.28-Dec09/mm/memcontrol.c
===================================================================
--- mmotm-2.6.28-Dec09.orig/mm/memcontrol.c
+++ mmotm-2.6.28-Dec09/mm/memcontrol.c
@@ -1758,6 +1758,36 @@ static int mem_cgroup_write(struct cgrou
 	return ret;
 }
 
+static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
+		unsigned long long *mem_limit, unsigned long long *memsw_limit)
+{
+	struct cgroup *cgroup;
+	unsigned long long min_limit, min_memsw_limit, tmp;
+
+	min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
+	min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
+	cgroup = memcg->css.cgroup;
+	if (!memcg->use_hierarchy)
+		goto out;
+
+	while (cgroup->parent) {
+		cgroup = cgroup->parent;
+		memcg = mem_cgroup_from_cont(cgroup);
+		if (!memcg->use_hierarchy)
+			break;
+		tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
+		if (tmp < min_limit)
+			min_limit = tmp;
+		tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
+		if (tmp < min_memsw_limit)
+			min_memsw_limit = tmp;
+	}
+out:
+	*mem_limit = min_limit;
+	*memsw_limit = min_memsw_limit;
+	return;
+}
+
 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
 {
 	struct mem_cgroup *mem;
@@ -1831,6 +1861,13 @@ static int mem_control_stat_show(struct 
 		cb->fill(cb, "unevictable", unevictable * PAGE_SIZE);
 
 	}
+	{
+		unsigned long long limit, memsw_limit;
+		memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
+		cb->fill(cb, "hierarchical_memory_limit", limit);
+		if (do_swap_account)
+			cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
+	}
 
 #ifdef CONFIG_DEBUG_VM
 	cb->fill(cb, "inactive_ratio", mem_cont->inactive_ratio);

Re: [RFC][PATCH] memcg: show real limit under hierarchy

[KOSAKI Motohiro]

> I wonder other people who debugs memcg's hierarchy may use similar patches.
> this is my one.
> comments ?
> ==
> From:KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> 
> Show "real" limit of memcg.
> This helps my debugging and maybe useful for users.
> 
> While testing hierarchy like this
> 
> 	mount -t cgroup none /cgroup -t memory
> 	mkdir /cgroup/A
> 	set use_hierarchy==1 to "A"
> 	mkdir /cgroup/A/01
> 	mkdir /cgroup/A/01/02
> 	mkdir /cgroup/A/01/03
> 	mkdir /cgroup/A/01/03/04
> 	mkdir /cgroup/A/08
> 	mkdir /cgroup/A/08/01
> 	....
> and set each own limit to them, "real" limit of each memcg is unclear.
> This patch shows real limit by checking all ancestors in memory.stat.
> 
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

Great!

I hoped to use this patch at hierarchy inactive_ratio debugging ;)

Re: [RFC][PATCH] memcg: show real limit under hierarchy

[Balbir Singh]

On Thu, Dec 11, 2008 at 8:54 AM, KOSAKI Motohiro
<kosaki.motohiro@jp.fujitsu.com> wrote:
>> I wonder other people who debugs memcg's hierarchy may use similar patches.
>> this is my one.
>> comments ?
>> ==
>> From:KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
>>
>> Show "real" limit of memcg.
>> This helps my debugging and maybe useful for users.
>>
>> While testing hierarchy like this
>>
>>       mount -t cgroup none /cgroup -t memory
>>       mkdir /cgroup/A
>>       set use_hierarchy==1 to "A"
>>       mkdir /cgroup/A/01
>>       mkdir /cgroup/A/01/02
>>       mkdir /cgroup/A/01/03
>>       mkdir /cgroup/A/01/03/04
>>       mkdir /cgroup/A/08
>>       mkdir /cgroup/A/08/01
>>       ....
>> and set each own limit to them, "real" limit of each memcg is unclear.
>> This patch shows real limit by checking all ancestors in memory.stat.
>>
>> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
>
> Great!
>
> I hoped to use this patch at hierarchy inactive_ratio debugging ;)

I like this very much too

I would prefer to use

min_limit = min(tmp, min_limit); and similarly for min_memsw_limit

Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>

Balbir

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Re: [RFC][PATCH] memcg: show real limit under hierarchy

[KAMEZAWA Hiroyuki]

On Thu, 11 Dec 2008 19:30:46 +0530
"Balbir Singh" <balbir@linux.vnet.ibm.com> wrote:

> On Thu, Dec 11, 2008 at 8:54 AM, KOSAKI Motohiro
> <kosaki.motohiro@jp.fujitsu.com> wrote:
> >> I wonder other people who debugs memcg's hierarchy may use similar patches.
> >> this is my one.
> >> comments ?
> >> ==
> >> From:KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> >>
> >> Show "real" limit of memcg.
> >> This helps my debugging and maybe useful for users.
> >>
> >> While testing hierarchy like this
> >>
> >>       mount -t cgroup none /cgroup -t memory
> >>       mkdir /cgroup/A
> >>       set use_hierarchy==1 to "A"
> >>       mkdir /cgroup/A/01
> >>       mkdir /cgroup/A/01/02
> >>       mkdir /cgroup/A/01/03
> >>       mkdir /cgroup/A/01/03/04
> >>       mkdir /cgroup/A/08
> >>       mkdir /cgroup/A/08/01
> >>       ....
> >> and set each own limit to them, "real" limit of each memcg is unclear.
> >> This patch shows real limit by checking all ancestors in memory.stat.
> >>
> >> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> >
> > Great!
> >
> > I hoped to use this patch at hierarchy inactive_ratio debugging ;)
> 
> I like this very much too
> 
> I would prefer to use
> 
> min_limit = min(tmp, min_limit); and similarly for min_memsw_limit
> 
> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
> 
Thanks, I'll upadte this and forward to Andrew.

-Kame


> Balbir
>