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

[zhen.ni]

在 2026/9/22 00:25, Zi Yan 写道:
> 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.

The existing console/debugfs path is untouched -- the BPF iterator is a
new, opt-in channel that coexists with it. Without a program attached,
page_owner behaves exactly as before.

> > 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

Thanks,
Zhen