Re: [PATCH v3 0/8] mm/page_owner: Add PID/TGID/COMM and cgroup filtering

[Zi Yan]

On 19 Sep 2026, at 22:11, zhen.ni wrote:

> 在 2026/9/11 19:32, Lorenzo Stoakes (ARM) 写道:
>> On Fri, Sep 11, 2026 at 01:06:46PM +0200, David Hildenbrand (Arm) wrote:
>>> On 9/11/26 09:58, zhen.ni wrote:
>>>>
>>>>
>>>> 在 2026/9/9 23:54, Zi Yan 写道:
>>>>> On 9 Sep 2026, at 6:28, David Hildenbrand (Arm) wrote:
>>>>>
>>>>>>
>>>>>> Because it results in less kernel code  :)
>>>>>>
>>>>>> And less kernel code is good. Unless unavoidable.
>>>>>
>>>>> An alternative is to add BPF hooks like bpf_iter to do the filtering
>>>>> and by default, when no BPF program is attached, everything is printed.
>>>>>
>>>>>
>>>>
>>>> I’ve also thought about a similar approach—perhaps a new bpf_iter type
>>>> that could iterate over all pages by PFN. The advantage would be that
>>>> you can fully customize what you want to print and what you want to
>>>> filter. However, doing so would require refactoring the entire
>>>> page_owner, and I’m not sure whether it’s worth pursuing in this
>>>> direction.I’d also like to hear everyone’s thoughts on this.
>>>
>>> Certainly better than having more and more manual filters added to the code base.
>>
>> Agreed.
>>
>> bpf seems the ideal fit here I think?
>>
>> Means that those who want this information can get it and those who don't are
>> unaffected.
>>
>
> I have prototyped page_owner bpf_iter and confirmed it is a viable and
> valuable direction:
>
> 1.Most parameter parsing is offloaded to the existing BPF verifier,
> keeping the page_owner kernel-side logic simple.
>
> 2.Filtering and printing are delegated to the BPF program, providing
> greater flexibility and enabling more complex composite filtering.

Without attaching a BPF program, page_owner could still print to
the console, right? Otherwise, it will break existing users without a
BPF program. You could add a hook to decide where to print the results.

>
> I plan to further refine this patch series, but it will likely be
> submitted as a separate series, as it represents a different direction.
>
>
> Thanks,
> Zhen


Best Regards,
Yan, Zi