From: Waiman Long <llong@redhat.com>
To: "Michal Koutný" <mkoutny@suse.com>, "Tejun Heo" <tj@kernel.org>
Cc: cgroups@vger.kernel.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, Josef Bacik <josef@toxicpanda.com>,
Jens Axboe <axboe@kernel.dk>,
Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH 4/9] cgroup: Print warning when /proc/cgroups is read on v2-only system
Date: Wed, 5 Mar 2025 11:27:33 -0500 [thread overview]
Message-ID: <9c24f14f-c7a8-490e-9077-0d977d175d89@redhat.com> (raw)
In-Reply-To: <t35nwno7wwwq43psp7cumpqco3zmi5n5y2czh3m4nj72qw2udp@ha3g6qnwkzh7>
On 3/5/25 5:17 AM, Michal Koutný wrote:
> On Tue, Mar 04, 2025 at 06:55:02AM -1000, Tejun Heo <tj@kernel.org> wrote:
>> I'm hoping that we could deprecate /proc/cgroups entirely. Maybe we can just
>> warn whenever the file is accessed?
> I added the guard with legacy systems (i.e. make this backportable) in
> mind which start with no cgroupfs mounted at all and until they decide
> to continue either v1 or v2 way, looking at /proc/cgroups is fine.
> It should warn users that look at /proc/cgroups in cases when it bears
> no valid information.
I like the idea of warning users about using /etc/cgroups if no v1
filesystem is mounted. It makes sense to make it backportable to older
kernel. We can always add a follow-up patch later to always warn about it.
Acked-by: Waiman Long <longman@redhat.com>
next prev parent reply other threads:[~2025-03-05 16:27 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-04 15:37 [PATCH 0/9] cgroup v1 deprecation warnings Michal Koutný
2025-03-04 15:37 ` [PATCH 1/9] cgroup/cpuset-v1: Add deprecation warnings to sched_load_balance and memory_pressure_enabled Michal Koutný
2025-03-04 16:19 ` Waiman Long
2025-03-04 16:52 ` Tejun Heo
2025-03-04 17:10 ` Michal Koutný
2025-03-04 17:33 ` Waiman Long
2025-03-04 18:04 ` Tejun Heo
2025-03-05 10:12 ` Michal Koutný
2025-03-05 18:39 ` Tejun Heo
2025-03-04 15:37 ` [PATCH 2/9] cgroup/cpuset-v1: Add deprecation warnings to memory_spread_page and memory_spread_slab Michal Koutný
2025-03-04 15:37 ` [PATCH 3/9] cgroup/blkio: Add deprecation warnings to reset_stats Michal Koutný
2025-03-04 15:37 ` [PATCH 4/9] cgroup: Print warning when /proc/cgroups is read on v2-only system Michal Koutný
2025-03-04 16:55 ` Tejun Heo
2025-03-05 10:17 ` Michal Koutný
2025-03-05 16:27 ` Waiman Long [this message]
2025-03-04 15:37 ` [PATCH 5/9] RFC cgroup/cpuset-v1: Add deprecation warnings to mem_exclusive and mem_hardwall Michal Koutný
2025-03-04 15:37 ` [PATCH 6/9] RFC cgroup/cpuset-v1: Add deprecation warnings to memory_migrate Michal Koutný
2025-03-04 15:37 ` [PATCH 7/9] RFC cgroup/cpuset-v1: Add deprecation warnings to sched_relax_domain_level Michal Koutný
2025-03-04 15:38 ` [PATCH 8/9] cgroup: Update file naming comment Michal Koutný
2025-03-04 15:38 ` [PATCH 9/9] blk-cgroup: Simplify policy files registration Michal Koutný
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