On 18 Jun 2025, at 13:40, David Hildenbrand wrote:
> Instead, let's use a page flag. As the page flag can result in
> false-positives, glue it to the page types for which we
> support/implement movable_ops page migration.
>
> Signed-off-by: David Hildenbrand <da...@redhat.com>
> ---
> include/linux/balloon_compaction.h | 2 +-
> include/linux/migrate.h | 8 -----
> include/linux/page-flags.h | 52 ++++++++++++++++++++++++------
> mm/compaction.c | 6 ----
> mm/zpdesc.h | 2 +-
> 5 files changed, 44 insertions(+), 26 deletions(-)
>
<snip>
> +
> +/**
> + * page_has_movable_ops - test for a movable_ops page
> + * @page The page to test.
> + *
> + * Test whether this is a movable_ops page. Such pages will stay that
> + * way until freed.
> + *
> + * Returns true if this is a movable_ops page, otherwise false.
> + */
> +static inline bool page_has_movable_ops(const struct page *page)
> +{
> + return PageMovableOps(page) &&
> + (PageOffline(page) || PageZsmalloc(page));
> +}
> +
Should we do the code below in case PageMovableOps is set on pages
other than PageOffline and PageZsmalloc?
return PageMovableOps(page) &&
!VM_WARN_ON_ONCE_PAGE(!(PageOffline(page) || PageZsmalloc(page)),
page);
> static __always_inline int PageAnonExclusive(const struct page *page)
> {
> VM_BUG_ON_PGFLAGS(!PageAnon(page), page);
> diff --git a/mm/compaction.c b/mm/compaction.c
> index a10f23df9396e..86d671a520e91 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -114,12 +114,6 @@ static unsigned long release_free_list(struct list_head
> *freepages)
> }
>
> #ifdef CONFIG_COMPACTION
> -void __SetPageMovable(struct page *page)
> -{
> - VM_BUG_ON_PAGE(!PageLocked(page), page);
> - page->mapping = (void *)(PAGE_MAPPING_MOVABLE);
> -}
> -EXPORT_SYMBOL(__SetPageMovable);
>
> /* Do not skip compaction more than 64 times */
> #define COMPACT_MAX_DEFER_SHIFT 6
> diff --git a/mm/zpdesc.h b/mm/zpdesc.h
> index 6855d9e2732d8..25bf5ea0beb83 100644
> --- a/mm/zpdesc.h
> +++ b/mm/zpdesc.h
> @@ -154,7 +154,7 @@ static inline struct zpdesc *pfn_zpdesc(unsigned long pfn)
>
> static inline void __zpdesc_set_movable(struct zpdesc *zpdesc)
> {
> - __SetPageMovable(zpdesc_page(zpdesc));
> + SetPageMovableOps(zpdesc_page(zpdesc));
> }
>
> static inline void __zpdesc_set_zsmalloc(struct zpdesc *zpdesc)
> --
> 2.49.0
Otherwise, LGTM. Reviewed-by: Zi Yan <z...@nvidia.com>
--
Best Regards,
Yan, Zi
