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From: Topi Miettinen <toiwoton@gmail.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: linux-kernel@vger.kernel.org,
	Johannes Weiner <hannes@cmpxchg.org>,
	Vladimir Davydov <vdavydov@virtuozzo.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)" 
	<cgroups@vger.kernel.org>,
	"open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)" 
	<linux-mm@kvack.org>
Subject: Re: [RFC 03/18] memcontrol: present maximum used memory also for cgroup-v2
Date: Tue, 14 Jun 2016 15:47:20 +0000	[thread overview]
Message-ID: <b9d04ccd-28d2-993a-2a40-bbed7b6289d4@gmail.com> (raw)
In-Reply-To: <20160614070130.GB5681@dhcp22.suse.cz>

On 06/14/16 07:01, Michal Hocko wrote:
> On Mon 13-06-16 22:44:10, Topi Miettinen wrote:
>> Present maximum used memory in cgroup memory.current_max.
> 
> It would be really much more preferable to present the usecase in the
> patch description. It is true that this information is presented in the
> v1 API but the current policy is to export new knobs only when there is
> a reasonable usecase for it.
> 

This was stated in the cover letter:
https://lkml.org/lkml/2016/6/13/857

"There are many basic ways to control processes, including capabilities,
cgroups and resource limits. However, there are far fewer ways to find out
useful values for the limits, except blind trial and error.

This patch series attempts to fix that by giving at least a nice starting
point from the actual maximum values. I looked where each limit is checked
and added a call to limit bump nearby."

"Cgroups
[RFC 02/18] cgroup_pids: track maximum pids
[RFC 03/18] memcontrol: present maximum used memory also for
[RFC 04/18] device_cgroup: track and present accessed devices

For tasks and memory cgroup limits the situation is somewhat better as the
current tasks and memory status can be easily seen with ps(1). However, any
transient tasks or temporary higher memory use might slip from the view.
Device use may be seen with advanced MAC tools, like TOMOYO, but there is no
universal method. Program sources typically give no useful indication about
memory use or how many tasks there could be."

I can add some of this to the commit message, is that sufficient for you?

>> Signed-off-by: Topi Miettinen <toiwoton@gmail.com>
>> ---
>>  include/linux/page_counter.h |  7 ++++++-
>>  mm/memcontrol.c              | 13 +++++++++++++
>>  2 files changed, 19 insertions(+), 1 deletion(-)
>>
>> diff --git a/include/linux/page_counter.h b/include/linux/page_counter.h
>> index 7e62920..be4de17 100644
>> --- a/include/linux/page_counter.h
>> +++ b/include/linux/page_counter.h
>> @@ -9,9 +9,9 @@ struct page_counter {
>>  	atomic_long_t count;
>>  	unsigned long limit;
>>  	struct page_counter *parent;
>> +	unsigned long watermark;
>>  
>>  	/* legacy */
>> -	unsigned long watermark;
>>  	unsigned long failcnt;
>>  };
>>  
>> @@ -34,6 +34,11 @@ static inline unsigned long page_counter_read(struct page_counter *counter)
>>  	return atomic_long_read(&counter->count);
>>  }
>>  
>> +static inline unsigned long page_counter_read_watermark(struct page_counter *counter)
>> +{
>> +	return counter->watermark;
>> +}
>> +
>>  void page_counter_cancel(struct page_counter *counter, unsigned long nr_pages);
>>  void page_counter_charge(struct page_counter *counter, unsigned long nr_pages);
>>  bool page_counter_try_charge(struct page_counter *counter,
>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
>> index 75e7440..5513771 100644
>> --- a/mm/memcontrol.c
>> +++ b/mm/memcontrol.c
>> @@ -4966,6 +4966,14 @@ static u64 memory_current_read(struct cgroup_subsys_state *css,
>>  	return (u64)page_counter_read(&memcg->memory) * PAGE_SIZE;
>>  }
>>  
>> +static u64 memory_current_max_read(struct cgroup_subsys_state *css,
>> +				   struct cftype *cft)
>> +{
>> +	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
>> +
>> +	return (u64)page_counter_read_watermark(&memcg->memory) * PAGE_SIZE;
>> +}
>> +
>>  static int memory_low_show(struct seq_file *m, void *v)
>>  {
>>  	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
>> @@ -5179,6 +5187,11 @@ static struct cftype memory_files[] = {
>>  		.read_u64 = memory_current_read,
>>  	},
>>  	{
>> +		.name = "current_max",
>> +		.flags = CFTYPE_NOT_ON_ROOT,
>> +		.read_u64 = memory_current_max_read,
>> +	},
>> +	{
>>  		.name = "low",
>>  		.flags = CFTYPE_NOT_ON_ROOT,
>>  		.seq_show = memory_low_show,
>> -- 
>> 2.8.1
> 

  reply	other threads:[~2016-06-14 15:47 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-13 19:44 [RFC 00/18] Present useful limits to user Topi Miettinen
2016-06-13 19:44 ` [RFC 01/18] capabilities: track actually used capabilities Topi Miettinen
2016-06-13 20:32   ` Andy Lutomirski
2016-06-13 20:45     ` Topi Miettinen
2016-06-13 21:12       ` Andy Lutomirski
2016-06-13 21:48         ` Topi Miettinen
2016-06-13 19:44 ` [RFC 02/18] cgroup_pids: track maximum pids Topi Miettinen
2016-06-13 21:12   ` Tejun Heo
2016-06-13 21:29     ` Topi Miettinen
2016-06-13 21:33       ` Tejun Heo
2016-06-13 21:59         ` Topi Miettinen
2016-06-13 22:09           ` Tejun Heo
2016-07-17 20:11         ` Topi Miettinen
2016-07-19  1:09           ` Tejun Heo
2016-07-19 16:59             ` Topi Miettinen
2016-07-19 18:13               ` Tejun Heo
2016-06-13 19:44 ` [RFC 03/18] memcontrol: present maximum used memory also for cgroup-v2 Topi Miettinen
2016-06-14  7:01   ` Michal Hocko
2016-06-14 15:47     ` Topi Miettinen [this message]
2016-06-14 16:04       ` Johannes Weiner
2016-06-14 17:15         ` Topi Miettinen
2016-06-16 10:27           ` Michal Hocko
2016-06-13 19:44 ` [RFC 04/18] device_cgroup: track and present accessed devices Topi Miettinen
2016-06-17 15:22   ` Serge E. Hallyn
2016-06-13 19:44 ` [RFC 05/18] limits: track and present RLIMIT_NOFILE actual max Topi Miettinen
2016-06-13 20:40   ` Andy Lutomirski
2016-06-13 21:13     ` Topi Miettinen
2016-06-13 21:16       ` Andy Lutomirski
2016-06-14 15:21         ` Topi Miettinen
2016-06-13 19:44 ` [RFC 06/18] limits: present RLIMIT_CPU and RLIMIT_RTTIMER current status Topi Miettinen
2016-06-14  9:14   ` Alexey Dobriyan
2016-06-13 19:44 ` [RFC 07/18] limits: track RLIMIT_FSIZE actual max Topi Miettinen
2016-06-13 19:44 ` [RFC 08/18] limits: track RLIMIT_DATA " Topi Miettinen
2016-06-13 19:44 ` [RFC 09/18] limits: track RLIMIT_CORE " Topi Miettinen
2016-06-13 19:44 ` [RFC 10/18] limits: track RLIMIT_STACK " Topi Miettinen
2016-06-13 19:44 ` [RFC 11/18] limits: track and present RLIMIT_NPROC " Topi Miettinen
2016-06-13 22:27   ` Jann Horn
2016-06-14 15:40     ` Topi Miettinen
2016-06-14 23:15       ` Jann Horn
2016-06-13 19:44 ` [RFC 13/18] limits: track RLIMIT_AS " Topi Miettinen
2016-06-13 19:44 ` [RFC 14/18] limits: track RLIMIT_SIGPENDING " Topi Miettinen
2016-06-14 14:50   ` Oleg Nesterov
2016-06-14 15:51     ` Topi Miettinen
2016-06-13 19:44 ` [RFC 15/18] limits: track RLIMIT_MSGQUEUE " Topi Miettinen
2016-06-17 19:52   ` Doug Ledford
2016-06-13 19:44 ` [RFC 16/18] limits: track RLIMIT_NICE " Topi Miettinen
2016-06-13 19:44 ` [RFC 17/18] limits: track RLIMIT_RTPRIO " Topi Miettinen
2016-06-13 19:44 ` [RFC 18/18] proc: present VM_LOCKED memory in /proc/self/maps Topi Miettinen
2016-06-13 20:43   ` Kees Cook
2016-06-13 20:52     ` Topi Miettinen
2016-06-14 19:03 ` [RFC 00/18] Present useful limits to user Konstantin Khlebnikov
2016-06-14 19:46   ` Topi Miettinen
2016-06-15 14:47   ` Austin S. Hemmelgarn
2016-06-18 14:45     ` Konstantin Khlebnikov
2016-06-19  6:38       ` Topi Miettinen
2016-06-20 17:37       ` Austin S. Hemmelgarn

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