提交 e4b294c2 编写于 作者: K Kirill A. Shutemov 提交者: Linus Torvalds

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: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: NJerome Marchand <jmarchan@redhat.com>
Acked-by: NChristoph Lameter <cl@linux.com>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
上级 aa7ed01f
......@@ -627,29 +627,28 @@ int split_free_page(struct page *page);
* prototype for that function and accessor functions.
* 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,
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)
{
return (compound_page_dtor *)page[1].lru.next;
return page[1].compound_dtor;
}
static inline int compound_order(struct page *page)
{
if (!PageHead(page))
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)
{
page[1].lru.prev = (void *)order;
page[1].compound_order = order;
}
#ifdef CONFIG_MMU
......
......@@ -28,6 +28,8 @@ struct mem_cgroup;
IS_ENABLED(CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK))
#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
* 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
* 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
pgtable_t pmd_huge_pte; /* protected by page->ptl */
#endif
......
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