On 02.10.2024 17:25, Matthew Wilcox (Oracle) wrote:
> Check that this anonymous page is really anonymous, not
> anonymous-or-KSM. This optimises the debug check, but its real purpose
> is to remove the last two users of PageKsm().
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> ---
> include/linux/page-flags.h | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
> index 4c2dfe289046..157c4ffc2fdc 100644
> --- a/include/linux/page-flags.h
> +++ b/include/linux/page-flags.h
> @@ -689,6 +689,13 @@ static __always_inline bool folio_test_anon(const struct folio *folio)
> return ((unsigned long)folio->mapping & PAGE_MAPPING_ANON) != 0;
> }
>
> +static __always_inline bool PageAnonNotKsm(const struct page *page)
> +{
> + unsigned long flags = (unsigned long)page_folio(page)->mapping;
> +
> + return (flags & PAGE_MAPPING_FLAGS) == PAGE_MAPPING_ANON;
> +}
> +
> static __always_inline bool PageAnon(const struct page *page)
> {
> return folio_test_anon(page_folio(page));
> @@ -1129,14 +1136,14 @@ static __always_inline int PageAnonExclusive(const struct page *page)
>
> static __always_inline void SetPageAnonExclusive(struct page *page)
> {
> - VM_BUG_ON_PGFLAGS(!PageAnon(page) || PageKsm(page), page);
> + VM_BUG_ON_PGFLAGS(PageAnonNotKsm(page), page);
!PageAnonNotKsm(page) ?
At least such change fixes booting of today's linux-next with debug
enabled on RISC-V based boards.
> VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
> set_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
> }
>
> static __always_inline void ClearPageAnonExclusive(struct page *page)
> {
> - VM_BUG_ON_PGFLAGS(!PageAnon(page) || PageKsm(page), page);
> + VM_BUG_ON_PGFLAGS(PageAnonNotKsm(page), page);
ditto
> VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
> clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
> }
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
