[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH 4/33] mm: add utility functions for ptdesc
On Wed, Apr 19, 2023 at 6:34 AM Vernon Yang <vernon2gm@xxxxxxxxx> wrote: > > On Mon, Apr 17, 2023 at 01:50:19PM -0700, Vishal Moola wrote: > > Introduce utility functions setting the foundation for ptdescs. These > > will also assist in the splitting out of ptdesc from struct page. > > > > ptdesc_alloc() is defined to allocate new ptdesc pages as compound > > pages. This is to standardize ptdescs by allowing for one allocation > > and one free function, in contrast to 2 allocation and 2 free functions. > > > > Signed-off-by: Vishal Moola (Oracle) <vishal.moola@xxxxxxxxx> > > --- > > include/asm-generic/tlb.h | 11 ++++++++++ > > include/linux/mm.h | 44 +++++++++++++++++++++++++++++++++++++++ > > include/linux/pgtable.h | 13 ++++++++++++ > > 3 files changed, 68 insertions(+) > > > > diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h > > index b46617207c93..6bade9e0e799 100644 > > --- a/include/asm-generic/tlb.h > > +++ b/include/asm-generic/tlb.h > > @@ -481,6 +481,17 @@ static inline void tlb_remove_page(struct mmu_gather > > *tlb, struct page *page) > > return tlb_remove_page_size(tlb, page, PAGE_SIZE); > > } > > > > +static inline void tlb_remove_ptdesc(struct mmu_gather *tlb, void *pt) > > +{ > > + tlb_remove_table(tlb, pt); > > +} > > + > > +/* Like tlb_remove_ptdesc, but for page-like page directories. */ > > +static inline void tlb_remove_page_ptdesc(struct mmu_gather *tlb, struct > > ptdesc *pt) > > +{ > > + tlb_remove_page(tlb, ptdesc_page(pt)); > > +} > > + > > static inline void tlb_change_page_size(struct mmu_gather *tlb, > > unsigned int page_size) > > { > > diff --git a/include/linux/mm.h b/include/linux/mm.h > > index b18848ae7e22..ec3cbe2fa665 100644 > > --- a/include/linux/mm.h > > +++ b/include/linux/mm.h > > @@ -2744,6 +2744,45 @@ static inline pmd_t *pmd_alloc(struct mm_struct *mm, > > pud_t *pud, unsigned long a > > } > > #endif /* CONFIG_MMU */ > > > > +static inline struct ptdesc *virt_to_ptdesc(const void *x) > > +{ > > + return page_ptdesc(virt_to_head_page(x)); > > +} > > + > > +static inline void *ptdesc_to_virt(struct ptdesc *pt) > > +{ > > + return page_to_virt(ptdesc_page(pt)); > > +} > > + > > +static inline void *ptdesc_address(struct ptdesc *pt) > > +{ > > + return folio_address(ptdesc_folio(pt)); > > +} > > + > > +static inline bool ptdesc_is_reserved(struct ptdesc *pt) > > +{ > > + return folio_test_reserved(ptdesc_folio(pt)); > > +} > > + > > +static inline struct ptdesc *ptdesc_alloc(gfp_t gfp, unsigned int order) > > +{ > > + struct page *page = alloc_pages(gfp | __GFP_COMP, order); > > + > > + return page_ptdesc(page); > > +} > > + > > +static inline void ptdesc_free(struct ptdesc *pt) > > +{ > > + struct page *page = ptdesc_page(pt); > > + > > + __free_pages(page, compound_order(page)); > > +} > > + > > +static inline void ptdesc_clear(void *x) > > +{ > > + clear_page(x); > > +} > > + > > #if USE_SPLIT_PTE_PTLOCKS > > #if ALLOC_SPLIT_PTLOCKS > > void __init ptlock_cache_init(void); > > @@ -2970,6 +3009,11 @@ static inline void mark_page_reserved(struct page > > *page) > > adjust_managed_page_count(page, -1); > > } > > > > +static inline void free_reserved_ptdesc(struct ptdesc *pt) > > +{ > > + free_reserved_page(ptdesc_page(pt)); > > +} > > + > > /* > > * Default method to free all the __init memory into the buddy system. > > * The freed pages will be poisoned with pattern "poison" if it's within > > diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h > > index 7cc6ea057ee9..7cd803aa38eb 100644 > > --- a/include/linux/pgtable.h > > +++ b/include/linux/pgtable.h > > @@ -97,6 +97,19 @@ TABLE_MATCH(ptl, ptl); > > #undef TABLE_MATCH > > static_assert(sizeof(struct ptdesc) <= sizeof(struct page)); > > > > +#define ptdesc_page(pt) (_Generic((pt), > > \ > > + const struct ptdesc *: (const struct page *)(pt), \ > > + struct ptdesc *: (struct page *)(pt))) > > + > > +#define ptdesc_folio(pt) (_Generic((pt), \ > > + const struct ptdesc *: (const struct folio *)(pt), \ > > + struct ptdesc *: (struct folio *)(pt))) > > + > > +static inline struct ptdesc *page_ptdesc(struct page *page) > > +{ > > + return (struct ptdesc *)page; > > +} > > Hi Vishal, > > I'm a little curious, why is the page_ptdesc() using inline functions instead > of macro? > If this is any magic, please tell me, thank you very much. No magic here, I was mainly basing it off Matthew's netmem series. I'm not too clear on when to use macros vs inlines myself :/. If there's a benefit to having it be a macro let me know and I can make that change in v2.
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