From: Waiman Long <llong@redhat.com>
To: Tejun Heo <tj@kernel.org>
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 v3 0/9] cgroup/cpuset: Add new cpuset partition type & empty effecitve cpus
Date: Tue, 27 Jul 2021 17:14:27 -0400 [thread overview]
Message-ID: <b2f49b2e-d5a4-1504-bd0c-0bd82943d855@redhat.com> (raw)
In-Reply-To: <YP9ChFvrGrDMGzbe@slm.duckdns.org>
On 7/26/21 7:17 PM, Tejun Heo wrote:
> Hello,
>
> On Tue, Jul 20, 2021 at 10:18:25AM -0400, Waiman Long wrote:
>> v3:
>> - Add two new patches (patches 2 & 3) to fix bugs found during the
>> testing process.
>> - Add a new patch to enable inotify event notification when partition
>> become invalid.
>> - Add a test to test event notification when partition become invalid.
> I applied parts of the series. I think there was a bit of miscommunication.
> I meant that we should use the invalid state as the only way to indicate
> errors as long as the error state is something which can be reached through
> hot unplug or other uncontrollable changes, and require users to monitor the
> state transitions for confirmation and error handling.
Yes, that is the point of adding the event notification patch.
In the current code, direct write to cpuset.cpus.partition are strictly
controlled and invalid transitions are rejected. However, changes to
cpuset.cpus that do not break the cpu exclusivity rule or cpu hot plug
may cause a partition to changed to invalid. What is currently done in
this patchset is to add extra guards to reject those cpuset.cpus change
that cause the partition to become invalid since changes that break cpu
exclusivity rule will be rejected anyway. I can leave out those extra
guards and allow those invalid cpuset.cpus change to go forward and
change the partition to invalid instead if this is what you want.
However, if we have a complicated partition setup with multiple child
partitions. Invalid cpuset.cpus change in a parent partition will cause
all the child partitions to become invalid too. That is the scenario
that I don't want to happen inadvertently. Alternatively, we can
restrict those invalid changes if a child partition exist and let it
pass through and make it invalid if it is a standalone partition.
Please let me know which approach do you want me to take.
Cheers,
Longman
next prev parent reply other threads:[~2021-07-27 21:14 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-20 14:18 [PATCH v3 0/9] cgroup/cpuset: Add new cpuset partition type & empty effecitve cpus Waiman Long
2021-07-20 14:18 ` [PATCH v3 1/9] cgroup/cpuset: Miscellaneous code cleanup Waiman Long
2021-07-20 14:18 ` Waiman Long
2021-07-26 22:56 ` Tejun Heo
2021-07-26 22:56 ` Tejun Heo
2021-07-20 14:18 ` [PATCH v3 2/9] cgroup/cpuset: Fix a partition bug with hotplug Waiman Long
2021-07-20 14:18 ` Waiman Long
2021-07-26 22:59 ` Tejun Heo
2021-07-26 22:59 ` Tejun Heo
2021-07-27 20:16 ` Waiman Long
2021-07-20 14:18 ` [PATCH v3 3/9] cgroup/cpuset: Fix violation of cpuset locking rule Waiman Long
2021-07-26 23:10 ` Tejun Heo
2021-07-20 14:18 ` [PATCH v3 4/9] cgroup/cpuset: Enable event notification when partition become invalid Waiman Long
2021-07-20 14:18 ` Waiman Long
2021-07-26 23:14 ` Tejun Heo
2021-07-27 20:26 ` Waiman Long
2021-07-27 20:26 ` Waiman Long
2021-07-27 20:46 ` Waiman Long
2021-07-27 20:46 ` Waiman Long
2021-07-20 14:18 ` [PATCH v3 5/9] cgroup/cpuset: Clarify the use of invalid partition root Waiman Long
2021-07-20 14:18 ` Waiman Long
2021-07-20 14:18 ` [PATCH v3 6/9] cgroup/cpuset: Add a new isolated cpus.partition type Waiman Long
2021-07-20 14:18 ` Waiman Long
2021-07-27 11:42 ` Frederic Weisbecker
2021-07-27 15:56 ` Waiman Long
2021-07-27 15:56 ` Waiman Long
2021-07-29 11:03 ` Frederic Weisbecker
2021-07-28 16:09 ` Michal Koutný
2021-07-28 16:27 ` Waiman Long
2021-07-28 17:25 ` Michal Koutný
2021-07-28 17:25 ` Michal Koutný
2021-07-20 14:18 ` [PATCH v3 7/9] cgroup/cpuset: Allow non-top parent partition root to distribute out all CPUs Waiman Long
2021-07-20 14:18 ` Waiman Long
2021-07-20 14:18 ` [PATCH v3 8/9] cgroup/cpuset: Update description of cpuset.cpus.partition in cgroup-v2.rst Waiman Long
2021-07-20 14:18 ` Waiman Long
2021-07-20 14:18 ` [PATCH v3 9/9] kselftest/cgroup: Add cpuset v2 partition root state test Waiman Long
2021-07-20 14:18 ` Waiman Long
2021-07-26 23:17 ` [PATCH v3 0/9] cgroup/cpuset: Add new cpuset partition type & empty effecitve cpus Tejun Heo
2021-07-26 23:17 ` Tejun Heo
2021-07-27 21:14 ` Waiman Long [this message]
2021-08-09 22:46 ` Tejun Heo
2021-08-10 1:12 ` Waiman Long
2021-08-10 1:12 ` Waiman Long
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