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Commit e4b294c2 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Linus Torvalds
Browse files

mm: add fields for compound destructor and order into struct page 



Currently, we use lru.next/lru.prev plus cast to access or set
destructor and order of compound page.

Let's replace it with explicit fields in struct page.

Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
Acked-by: default avatarChristoph Lameter <cl@linux.com>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent aa7ed01f

include/linux/mm.h

+4 −5
Original line number Original line Diff line number Diff line
@@ -627,29 +627,28 @@ int split_free_page(struct page *page); 
 * prototype for that function and accessor functions.

 * prototype for that function and accessor functions.

 * These are _only_ valid on the head of a PG_compound page.

 * These are _only_ valid on the head of a PG_compound page.

 */

 */

typedef void compound_page_dtor(struct page *);





static inline void set_compound_page_dtor(struct page *page,

static inline void set_compound_page_dtor(struct page *page,

						compound_page_dtor *dtor)

						compound_page_dtor *dtor)

{

{

	page[1].lru.next = (void *)dtor;

	page[1].compound_dtor = dtor;

}

}





static inline compound_page_dtor *get_compound_page_dtor(struct page *page)

static inline compound_page_dtor *get_compound_page_dtor(struct page *page)

{

{

	return (compound_page_dtor *)page[1].lru.next;

	return page[1].compound_dtor;

}

}





static inline int compound_order(struct page *page)

static inline int compound_order(struct page *page)

{

{

	if (!PageHead(page))

	if (!PageHead(page))

		return 0;

		return 0;

	return (unsigned long)page[1].lru.prev;

	return page[1].compound_order;

}

}





static inline void set_compound_order(struct page *page, unsigned long order)

static inline void set_compound_order(struct page *page, unsigned long order)

{

{

	page[1].lru.prev = (void *)order;

	page[1].compound_order = order;

}

}





#ifdef CONFIG_MMU

#ifdef CONFIG_MMU

include/linux/mm_types.h

+8 −0
Original line number Original line Diff line number Diff line
@@ -28,6 +28,8 @@ struct mem_cgroup; 
		IS_ENABLED(CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK))

		IS_ENABLED(CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK))

#define ALLOC_SPLIT_PTLOCKS	(SPINLOCK_SIZE > BITS_PER_LONG/8)

#define ALLOC_SPLIT_PTLOCKS	(SPINLOCK_SIZE > BITS_PER_LONG/8)





typedef void compound_page_dtor(struct page *);



/*

/*

 * Each physical page in the system has a struct page associated with

 * Each physical page in the system has a struct page associated with

 * it to keep track of whatever it is we are using the page for at the

 * it to keep track of whatever it is we are using the page for at the
@@ -142,6 +144,12 @@ struct page { 
		struct rcu_head rcu_head;	/* Used by SLAB

		struct rcu_head rcu_head;	/* Used by SLAB

						 * when destroying via RCU

						 * when destroying via RCU

						 */

						 */

		/* First tail page of compound page */

		struct {

			compound_page_dtor *compound_dtor;

			unsigned long compound_order;

		};



#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS

#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && USE_SPLIT_PMD_PTLOCKS

		pgtable_t pmd_huge_pte; /* protected by page->ptl */

		pgtable_t pmd_huge_pte; /* protected by page->ptl */

#endif

#endif