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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