From: Topi Miettinen <toiwoton@gmail.com>
To: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org, Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>,
"open list:CONTROL GROUP (CGROUP)" <cgroups@vger.kernel.org>
Subject: Re: [RFC 02/18] cgroup_pids: track maximum pids
Date: Mon, 13 Jun 2016 21:29:32 +0000 [thread overview]
Message-ID: <17cb1a37-47b1-dbd4-6835-efad3cf6c12f@gmail.com> (raw)
In-Reply-To: <20160613211227.GG31708@htj.duckdns.org>
On 06/13/16 21:12, Tejun Heo wrote:
> Hello,
>
> On Mon, Jun 13, 2016 at 10:44:09PM +0300, Topi Miettinen wrote:
>> Track maximum pids in the cgroup, present it in cgroup pids.current_max.
>
> "max" is often used for maximum limits in cgroup. I think "watermark"
> or "high_watermark" would be a lot clearer.
OK, I have no preference.
>
>> @@ -236,6 +246,14 @@ static void pids_free(struct task_struct *task)
>> pids_uncharge(pids, 1);
>> }
>>
>> +static void pids_fork(struct task_struct *task)
>> +{
>> + struct pids_cgroup *pids = css_pids(task_css(task, pids_cgrp_id));
>> +
>> + if (atomic64_read(&pids->cur_max) < atomic64_read(&pids->counter))
>> + atomic64_set(&pids->cur_max, atomic64_read(&pids->counter));
>> +}
>
> Wouldn't it make more sense to track high watermark from the charge
> functions instead? I don't get why this requires a separate fork
> callback. Also, racing atomic64_set's are racy. The counter can end
> up with a lower number than it should be.
>
I used fork callback as I don't want to lower the watermark in all cases
where the charge can be lowered, so I'd update the watermark only when
the fork really happens.
Is there a better way to compare and set? I don't think atomic_cmpxchg()
does what's needed,
>> @@ -300,6 +326,11 @@ static struct cftype pids_files[] = {
>> .read_s64 = pids_current_read,
>> .flags = CFTYPE_NOT_ON_ROOT,
>> },
>> + {
>> + .name = "current_max",
>
> Please make this "high_watermark" field in pids.stats file.
>
> Thanks.
>
OK.
-Topi
next prev parent reply other threads:[~2016-06-13 21:29 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 [this message]
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
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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