From: Waiman Long <longman@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-doc@vger.kernel.org, linux-mm@kvack.org,
kernel-team@fb.com, pjt@google.com, luto@amacapital.net,
efault@gmx.de
Subject: Re: [RFC PATCH v2 13/17] cgroup: Allow fine-grained controllers control in cgroup v2
Date: Wed, 24 May 2017 13:49:46 -0400 [thread overview]
Message-ID: <29bc746d-f89b-3385-fd5c-314bcd22f9f7@redhat.com> (raw)
In-Reply-To: <20170524173144.GI24798@htj.duckdns.org>
On 05/24/2017 01:31 PM, Tejun Heo wrote:
> Hello, Waiman.
>
> On Fri, May 19, 2017 at 05:20:01PM -0400, Waiman Long wrote:
>>> This breaks the invariant that in a cgroup its resource control knobs
>>> control distribution of resources from its parent. IOW, the resource
>>> control knobs of a cgroup always belong to the parent. This is also
>>> reflected in how delegation is done. The delegatee assumes ownership
>>> of the cgroup itself and the ability to manage sub-cgroups but doesn't
>>> get the ownership of the resource control knobs as otherwise the
>>> parent would lose control over how it distributes its resources.
>> One twist that I am thinking is to have a controller enabled by the
>> parent in subtree_control, but then allow the child to either disable it
>> or set it in pass-through mode by writing to controllers file. IOW, a
>> child cannot enable a controller without parent's permission. Once a
>> child has permission, it can do whatever it wants. A parent cannot force
>> a child to have a controller enabled.
> Heh, I think I need more details to follow your proposal. Anyways,
> what we need to guarantee is that a descendant is never allowed to
> pull in more resources than its ancestors want it to.
What I am saying is as follows:
/ A
P - B
\ C
# echo +memory > P/cgroups.subtree_control
# echo -memory > P/A/cgroup.controllers
# echo "#memory" > P/B/cgroup.controllers
The parent grants the memory controller to its children - A, B and C.
Child A has the memory controller explicitly disabled. Child B has the
memory controller in pass-through mode, while child C has the memory
controller enabled by default. "echo +memory > cgroup.controllers" is
not allowed. There are 2 possible choices with regard to the '-' or '#'
prefixes. We can allow them before the grant from the parent or only
after that. In the former case, the state remains dormant until after
the grant from the parent.
Cheers,
Longman
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-05-24 17:49 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-15 13:33 [RFC PATCH v2 00/17] cgroup: Major changes to cgroup v2 core Waiman Long
2017-05-15 13:34 ` [RFC PATCH v2 01/17] cgroup: reorganize cgroup.procs / task write path Waiman Long
2017-05-15 13:34 ` [RFC PATCH v2 02/17] cgroup: add @flags to css_task_iter_start() and implement CSS_TASK_ITER_PROCS Waiman Long
2017-05-15 13:34 ` [RFC PATCH v2 03/17] cgroup: introduce cgroup->proc_cgrp and threaded css_set handling Waiman Long
2017-05-15 13:34 ` [RFC PATCH v2 04/17] cgroup: implement CSS_TASK_ITER_THREADED Waiman Long
2017-05-15 13:34 ` [RFC PATCH v2 05/17] cgroup: implement cgroup v2 thread support Waiman Long
2017-05-15 13:34 ` [RFC PATCH v2 06/17] cgroup: Fix reference counting bug in cgroup_procs_write() Waiman Long
2017-05-17 19:20 ` Tejun Heo
2017-05-15 13:34 ` [RFC PATCH v2 07/17] cgroup: Prevent kill_css() from being called more than once Waiman Long
2017-05-17 19:23 ` Tejun Heo
2017-05-17 20:24 ` Waiman Long
2017-05-17 21:34 ` Tejun Heo
2017-05-15 13:34 ` [RFC PATCH v2 08/17] cgroup: Move debug cgroup to its own file Waiman Long
2017-05-17 21:36 ` Tejun Heo
2017-05-18 15:29 ` Waiman Long
2017-05-18 15:52 ` Waiman Long
2017-05-19 19:21 ` Tejun Heo
2017-05-19 19:33 ` Waiman Long
2017-05-19 20:28 ` Tejun Heo
2017-05-15 13:34 ` [RFC PATCH v2 09/17] cgroup: Keep accurate count of tasks in each css_set Waiman Long
2017-05-17 21:40 ` Tejun Heo
2017-05-18 15:56 ` Waiman Long
2017-05-15 13:34 ` [RFC PATCH v2 10/17] cgroup: Make debug cgroup support v2 and thread mode Waiman Long
2017-05-17 21:43 ` Tejun Heo
2017-05-18 15:58 ` Waiman Long
2017-05-15 13:34 ` [RFC PATCH v2 11/17] cgroup: Implement new thread mode semantics Waiman Long
2017-05-17 21:47 ` Tejun Heo
2017-05-18 17:21 ` Waiman Long
2017-05-19 20:26 ` Tejun Heo
2017-05-19 20:58 ` Tejun Heo
2017-05-22 17:13 ` Waiman Long
2017-05-22 17:32 ` Waiman Long
2017-05-24 20:36 ` Tejun Heo
2017-05-24 21:17 ` Waiman Long
2017-05-24 21:27 ` Tejun Heo
2017-06-01 14:50 ` Tejun Heo
2017-06-01 15:10 ` Peter Zijlstra
2017-06-01 15:35 ` Tejun Heo
2017-06-01 18:44 ` Waiman Long
2017-06-01 18:47 ` Tejun Heo
2017-06-01 19:27 ` Waiman Long
2017-06-01 20:38 ` Tejun Heo
2017-06-01 20:48 ` Waiman Long
2017-06-01 20:52 ` Tejun Heo
2017-06-01 21:12 ` Waiman Long
2017-06-01 21:18 ` Tejun Heo
2017-06-02 20:36 ` Waiman Long
2017-06-03 10:33 ` Tejun Heo
2017-06-01 19:55 ` Waiman Long
2017-06-01 20:15 ` Waiman Long
2017-06-01 18:41 ` Waiman Long
2017-05-15 13:34 ` [RFC PATCH v2 12/17] cgroup: Remove cgroup v2 no internal process constraint Waiman Long
2017-05-19 20:38 ` Tejun Heo
2017-05-20 2:10 ` Mike Galbraith
2017-05-24 17:01 ` Tejun Heo
2017-05-22 16:56 ` Waiman Long
2017-05-24 17:05 ` Tejun Heo
2017-05-24 18:09 ` Waiman Long
2017-05-24 18:19 ` Waiman Long
2017-05-15 13:34 ` [RFC PATCH v2 13/17] cgroup: Allow fine-grained controllers control in cgroup v2 Waiman Long
2017-05-19 20:55 ` Tejun Heo
2017-05-19 21:20 ` Waiman Long
2017-05-24 17:31 ` Tejun Heo
2017-05-24 17:49 ` Waiman Long [this message]
2017-05-24 17:56 ` Tejun Heo
2017-05-24 18:17 ` Waiman Long
2017-05-15 13:34 ` [RFC PATCH v2 14/17] cgroup: Enable printing of v2 controllers' cgroup hierarchy Waiman Long
2017-05-15 13:34 ` [RFC PATCH v2 15/17] sched: Misc preps for cgroup unified hierarchy interface Waiman Long
2017-05-15 13:34 ` [RFC PATCH v2 16/17] sched: Implement interface for cgroup unified hierarchy Waiman Long
2017-05-15 13:34 ` [RFC PATCH v2 17/17] sched: Make cpu/cpuacct threaded controllers Waiman Long
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=29bc746d-f89b-3385-fd5c-314bcd22f9f7@redhat.com \
--to=longman@redhat.com \
--cc=cgroups@vger.kernel.org \
--cc=efault@gmx.de \
--cc=hannes@cmpxchg.org \
--cc=kernel-team@fb.com \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=lizefan@huawei.com \
--cc=luto@amacapital.net \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=pjt@google.com \
--cc=tj@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).