Re: A path forward to cleaning up dying cgroups?

[Waiman Long <llong@redhat.com>]

On 2/5/25 10:30 PM, Muchun Song wrote:
>
>> On Feb 6, 2025, at 02:46, Shakeel Butt <shakeel.butt@linux.dev> wrote:
>>
>> On Wed, Feb 05, 2025 at 01:08:42PM -0500, Johannes Weiner wrote:
>>> On Wed, Feb 05, 2025 at 12:50:19PM -0500, Hamza Mahfooz wrote:
>>>> Cc: Shakeel Butt <shakeel.butt@linux.dev>
>>>>
>>>> On 2/5/25 12:48, Hamza Mahfooz wrote:
>>>>> I was just curious as to what the status of the issue described in [1]
>>>>> is. It appears that the last time someone took a stab at it was in [2].
>>> If memory serves, the sticking point was whether pages should indeed
>>> be reparented on cgroup death, or whether they could be moved
>>> arbitrarily to other cgroups that are still using them.
>>>
>>> It's a bit unfortunate, because the reparenting patches were tested
>>> and reviewed, and the arbitrary recharging was just an idea that
>>> ttbomk nobody seriously followed up on afterwards.
>>>
>>> We also recently removed the charge moving code from cgroup1, along
>>> with the subtle page access/locking/accounting rules it imposed on the
>>> rest of the MM. I'm doubtful there is much appetite in either camp for
>>> bringing this back.
>>>
>>> So I would still love to see Muchun's patches merged. They fix a
>>> seemingly universally experienced operational issue in memcg, and we
>>> shouldn't hold it up unless somebody actually posts alternative code.
>>>
>>> Thoughts?
>> I think the recharging (or whatever the alternative) can be a followup
>> to this. I agree this is a good change.
> I agree with you. We've been encountering dying memory issues for years
> on our servers. As Roman said, I need to refresh my patches. So I need
> some time for refreshing.

Glad to hear that. I have been waiting for a resolution of the dying 
memory cgroup problems for years :-)

Cheers,
Longman