LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Tejun Heo <tj@kernel.org>
To: Waiman Long <longman@redhat.com>
Cc: "Zefan Li" <lizefan.x@bytedance.com>,
	"Johannes Weiner" <hannes@cmpxchg.org>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Shuah Khan" <shuah@kernel.org>,
	cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Roman Gushchin" <guro@fb.com>, "Phil Auld" <pauld@redhat.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Juri Lelli" <juri.lelli@redhat.com>,
	"Frederic Weisbecker" <frederic@kernel.org>,
	"Marcelo Tosatti" <mtosatti@redhat.com>,
	"Michal Koutný" <mkoutny@suse.com>
Subject: Re: [PATCH v4 2/6] cgroup/cpuset: Properly handle partition root tree
Date: Wed, 11 Aug 2021 08:08:41 -1000	[thread overview]
Message-ID: <YRQSKZB8rQUsfF2K@slm.duckdns.org> (raw)
In-Reply-To: <20210811030607.13824-3-longman@redhat.com>

Hello,

On Tue, Aug 10, 2021 at 11:06:03PM -0400, Waiman Long wrote:
> For a partition root tree with parent and child partition roots, this
> patch will now prohibit changing parent partition root back to member
> as changes to "cpuset.cpus.partition" should not cause those child
> partition roots to become invalid.

So, the general rule is that a descendant should never be able to affect or
restrict what an ancestor can do in terms of configuration. This is because
descendant cgroups can be delegated and a system manager sitting at a higher
level in the hierarchy may not have much control over what happens under
delegated subtrees.

Given that we're promoting the error state as the first class citizen in the
interface anyway, wouldn't it be better to keep this in line too?

Thanks.

-- 
tejun

  reply	other threads:[~2021-08-11 18:08 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-11  3:06 [PATCH-cgroup v4 0/6] cgroup/cpuset: Add new cpuset partition type & empty effecitve cpus Waiman Long
2021-08-11  3:06 ` [PATCH v4 1/6] cgroup/cpuset: Enable event notification when partition state changes Waiman Long
2021-08-11 18:04   ` Tejun Heo
2021-08-11  3:06 ` [PATCH v4 2/6] cgroup/cpuset: Properly handle partition root tree Waiman Long
2021-08-11 18:08   ` Tejun Heo [this message]
2021-08-11 19:27     ` Waiman Long
2021-08-12 22:18       ` Tejun Heo
2021-08-12 22:56         ` Waiman Long
2021-08-13 16:07           ` Tejun Heo
2021-08-11  3:06 ` [PATCH v4 3/6] cgroup/cpuset: Add a new isolated cpus.partition type Waiman Long
2021-08-11  3:06 ` [PATCH v4 4/6] cgroup/cpuset: Allow non-top parent partition root to distribute out all CPUs Waiman Long
2021-08-11 18:13   ` Tejun Heo
2021-08-11 18:18     ` Waiman Long
2021-08-11 18:21       ` Tejun Heo
2021-08-11 18:46         ` Waiman Long
2021-08-12 21:51           ` Tejun Heo
2021-08-11  3:06 ` [PATCH v4 5/6] cgroup/cpuset: Update description of cpuset.cpus.partition in cgroup-v2.rst Waiman Long
2021-08-11 18:15   ` Tejun Heo
2021-08-11 18:19     ` Waiman Long
2021-08-11  3:06 ` [PATCH v4 6/6] kselftest/cgroup: Add cpuset v2 partition root state test 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=YRQSKZB8rQUsfF2K@slm.duckdns.org \
    --to=tj@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=cgroups@vger.kernel.org \
    --cc=corbet@lwn.net \
    --cc=frederic@kernel.org \
    --cc=guro@fb.com \
    --cc=hannes@cmpxchg.org \
    --cc=juri.lelli@redhat.com \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-kselftest@vger.kernel.org \
    --cc=lizefan.x@bytedance.com \
    --cc=longman@redhat.com \
    --cc=mkoutny@suse.com \
    --cc=mtosatti@redhat.com \
    --cc=pauld@redhat.com \
    --cc=peterz@infradead.org \
    --cc=shuah@kernel.org \
    --subject='Re: [PATCH v4 2/6] cgroup/cpuset: Properly handle partition root tree' \
    /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

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).