mm: add thp_head

This is like compound_head() but compiles away when
CONFIG_TRANSPARENT_HUGEPAGE is not enabled.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Link: http://lkml.kernel.org/r/20200629151959.15779-7-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2020-08-14 17:30:40 -07:00 committed by Linus Torvalds
parent 6c357848b4
commit 2be1d71841

View file

@ -259,6 +259,15 @@ static inline spinlock_t *pud_trans_huge_lock(pud_t *pud,
return NULL;
}
/**
* thp_head - Head page of a transparent huge page.
* @page: Any page (tail, head or regular) found in the page cache.
*/
static inline struct page *thp_head(struct page *page)
{
return compound_head(page);
}
/**
* thp_order - Order of a transparent huge page.
* @page: Head page of a transparent huge page.
@ -335,6 +344,12 @@ static inline struct list_head *page_deferred_list(struct page *page)
#define HPAGE_PUD_MASK ({ BUILD_BUG(); 0; })
#define HPAGE_PUD_SIZE ({ BUILD_BUG(); 0; })
static inline struct page *thp_head(struct page *page)
{
VM_BUG_ON_PGFLAGS(PageTail(page), page);
return page;
}
static inline unsigned int thp_order(struct page *page)
{
VM_BUG_ON_PGFLAGS(PageTail(page), page);