On Wed, 23 Oct 2024 10:07:58 -0700 Suren Baghdasaryan <surenb@xxxxxxxxxx> wrote:
> To simplify later changes to page tag references, introduce new
> pgtag_ref_handle type. This allows easy replacement of page_ext
> as a storage of page allocation tags.
>
> ...
>
> static inline void pgalloc_tag_copy(struct folio *new, struct folio *old)
> {
> + union pgtag_ref_handle handle;
> + union codetag_ref ref;
> struct alloc_tag *tag;
> - union codetag_ref *ref;
>
> tag = pgalloc_tag_get(&old->page);
> if (!tag)
> return;
>
> - ref = get_page_tag_ref(&new->page);
> - if (!ref)
> + if (!get_page_tag_ref(&new->page, &ref, &handle))
> return;
>
> /* Clear the old ref to the original allocation tag. */
> clear_page_tag_ref(&old->page);
> /* Decrement the counters of the tag on get_new_folio. */
> - alloc_tag_sub(ref, folio_nr_pages(new));
> -
> - __alloc_tag_ref_set(ref, tag);
> -
> - put_page_tag_ref(ref);
> + alloc_tag_sub(&ref, folio_nr_pages(new));
mm-stable has folio_size(new) here, fixed up.
I think we aleady discussed this, but there's a crazy amount of
inlining here. pgalloc_tag_split() is huge, and has four callsites.
