On 04/18/2018 08:49 PM, Matthew Wilcox wrote:
> From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
>
> Since the LRU is two words, this does not affect the double-word
> alignment of SLUB's freelist.
>
> Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
> ---
> include/linux/mm_types.h | 102 +++++++++++++++++++--------------------
> 1 file changed, 51 insertions(+), 51 deletions(-)
>
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index 39521b8385c1..230d473f16da 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -72,6 +72,57 @@ struct hmm;
> struct page {
> unsigned long flags; /* Atomic flags, some possibly
> * updated asynchronously */
> + /*
> + * WARNING: bit 0 of the first word encode PageTail(). That means
> + * the rest users of the storage space MUST NOT use the bit to
> + * avoid collision and false-positive PageTail().
> + */
> + union {
> + struct list_head lru; /* Pageout list, eg. active_list
> + * protected by zone_lru_lock !
> + * Can be used as a generic list
> + * by the page owner.
> + */
> + struct dev_pagemap *pgmap; /* ZONE_DEVICE pages are never on an
> + * lru or handled by a slab
> + * allocator, this points to the
> + * hosting device page map.
> + */
> + struct { /* slub per cpu partial pages */
> + struct page *next; /* Next partial slab */
> +#ifdef CONFIG_64BIT
> + int pages; /* Nr of partial slabs left */
> + int pobjects; /* Approximate # of objects */
> +#else
> + short int pages;
> + short int pobjects;
> +#endif
> + };
> +
> + struct rcu_head rcu_head; /* Used by SLAB
> + * when destroying via RCU
> + */
> + /* Tail pages of compound page */
> + struct {
> + unsigned long compound_head; /* If bit zero is set */
> +
> + /* First tail page only */
> + unsigned char compound_dtor;
> + unsigned char compound_order;
> + /* two/six bytes available here */
> + };
> +
> +#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS
> + struct {
> + unsigned long __pad; /* do not overlay pmd_huge_pte
> + * with compound_head to avoid
> + * possible bit 0 collision.
> + */
> + pgtable_t pmd_huge_pte; /* protected by page->ptl */
> + };
> +#endif
> + };
> +
> union { /* This union is three words (12/24 bytes) in size */
> struct { /* Page cache and anonymous pages */
> /* See page-flags.h for PAGE_MAPPING_FLAGS */
> @@ -133,57 +184,6 @@ struct page {
> /* Usage count. *DO NOT USE DIRECTLY*. See page_ref.h */
> atomic_t _refcount;
>
> - /*
> - * WARNING: bit 0 of the first word encode PageTail(). That means
> - * the rest users of the storage space MUST NOT use the bit to
> - * avoid collision and false-positive PageTail().
> - */
> - union {
> - struct list_head lru; /* Pageout list, eg. active_list
> - * protected by zone_lru_lock !
> - * Can be used as a generic list
> - * by the page owner.
> - */
> - struct dev_pagemap *pgmap; /* ZONE_DEVICE pages are never on an
> - * lru or handled by a slab
> - * allocator, this points to the
> - * hosting device page map.
> - */
> - struct { /* slub per cpu partial pages */
> - struct page *next; /* Next partial slab */
> -#ifdef CONFIG_64BIT
> - int pages; /* Nr of partial slabs left */
> - int pobjects; /* Approximate # of objects */
> -#else
> - short int pages;
> - short int pobjects;
> -#endif
> - };
> -
> - struct rcu_head rcu_head; /* Used by SLAB
> - * when destroying via RCU
> - */
> - /* Tail pages of compound page */
> - struct {
> - unsigned long compound_head; /* If bit zero is set */
> -
> - /* First tail page only */
> - unsigned char compound_dtor;
> - unsigned char compound_order;
> - /* two/six bytes available here */
> - };
> -
> -#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS
> - struct {
> - unsigned long __pad; /* do not overlay pmd_huge_pte
> - * with compound_head to avoid
> - * possible bit 0 collision.
> - */
> - pgtable_t pmd_huge_pte; /* protected by page->ptl */
> - };
> -#endif
> - };
> -
> #ifdef CONFIG_MEMCG
> struct mem_cgroup *mem_cgroup;
> #endif
>
