Commit 21a000fe authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

mm: reimplement compound_nr() 

Turn compound_nr() into a wrapper around folio_nr_pages().  Similarly to
compound_order(), casting the struct page directly to struct folio
preserves the existing behaviour, while calling page_folio() would change
the behaviour.  Move thp_nr_pages() down in the file so that compound_nr()
can be after folio_nr_pages().

[willy@infradead.org: fix assertion triggering]
  Link: https://lkml.kernel.org/r/Y8AFgZEEjnUIaCbf@casper.infradead.org
Link: https://lkml.kernel.org/r/20230111142915.1001531-18-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 5eb5cea1

include/linux/mm.h

+27 −22
Original line number Diff line number Diff line
@@ -1005,18 +1005,6 @@ static inline void set_compound_order(struct page *page, unsigned int order) 
#endif

}



/* Returns the number of pages in this potentially compound page. */

static inline unsigned long compound_nr(struct page *page)

{

	if (!PageHead(page))

		return 1;

#ifdef CONFIG_64BIT

	return page[1].compound_nr;

#else

	return 1UL << compound_order(page);

#endif

}



/* Returns the number of bytes in this potentially compound page. */

static inline unsigned long page_size(struct page *page)

{
@@ -1039,16 +1027,6 @@ static inline unsigned int thp_order(struct page *page) 
	return compound_order(page);

}



/**

 * thp_nr_pages - The number of regular pages in this huge page.

 * @page: The head page of a huge page.

 */

static inline int thp_nr_pages(struct page *page)

{

	VM_BUG_ON_PGFLAGS(PageTail(page), page);

	return compound_nr(page);

}



/**

 * thp_size - Size of a transparent huge page.

 * @page: Head page of a transparent huge page.
@@ -1758,6 +1736,33 @@ static inline long folio_nr_pages(struct folio *folio) 
#endif

}



/*

 * compound_nr() returns the number of pages in this potentially compound

 * page.  compound_nr() can be called on a tail page, and is defined to

 * return 1 in that case.

 */

static inline unsigned long compound_nr(struct page *page)

{

	struct folio *folio = (struct folio *)page;



	if (!test_bit(PG_head, &folio->flags))

		return 1;

#ifdef CONFIG_64BIT

	return folio->_folio_nr_pages;

#else

	return 1L << folio->_folio_order;

#endif

}



/**

 * thp_nr_pages - The number of regular pages in this huge page.

 * @page: The head page of a huge page.

 */

static inline int thp_nr_pages(struct page *page)

{

	return folio_nr_pages((struct folio *)page);

}



/**

 * folio_next - Move to the next physical folio.

 * @folio: The folio we're currently operating on.