Re: [External] Re: [PATCH v9 03/11] mm/hugetlb: Free the vmemmap pages associated with each HugeTLB page

[Muchun Song]

On Wed, Dec 16, 2020 at 9:06 PM Oscar Salvador <osalvador@xxxxxxx> wrote:
>
> On Sun, Dec 13, 2020 at 11:45:26PM +0800, Muchun Song wrote:
> > +
> > +/*
> > + * vmemmap_rmap_walk - walk vmemmap page table
> > + *
> > + * @rmap_pte:                called for each non-empty PTE (lowest-level) entry.
> > + * @reuse:           the page which is reused for the tail vmemmap pages.
> > + * @vmemmap_pages:   the list head of the vmemmap pages that can be freed.
> > + */
> > +struct vmemmap_rmap_walk {
> > +     void (*rmap_pte)(pte_t *pte, unsigned long addr,
> > +                      struct vmemmap_rmap_walk *walk);
> > +     struct page *reuse;
> > +     struct list_head *vmemmap_pages;
> > +};
>
> Why did you chose this approach in this version?
> Earlier versions of this patchset had a single vmemmap_to_pmd() function
> which returned the PMD, and now we have serveral vmemmap_{levels}_range
> and a vmemmap_rmap_walk.

This approach will be more universal. :-)

> A brief explanation about why this change was introduced would have been nice.
>
> I guess it is because ealier versions were too oriented for the usecase
> this patchset presents, while the new versions tries to be more broad
> about future re-uses of the interface?

Yeah, you are right. I plan to reuse those interfaces in the feature.

Thanks.

>
>
> --
> Oscar Salvador
> SUSE L3



-- 
Yours,
Muchun