Commit e880034c authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

mm: introduce page_mapcount_is_type() 

Resolve the awkward "and add one to this opaque constant" test into a
self-documenting inline function.

Link: https://lkml.kernel.org/r/20240821173914.2270383-3-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent e27ad656

fs/proc/internal.h

+1 −2
Original line number Diff line number Diff line
@@ -166,8 +166,7 @@ static inline int folio_precise_page_mapcount(struct folio *folio, 
{

	int mapcount = atomic_read(&page->_mapcount) + 1;



	/* Handle page_has_type() pages */

	if (mapcount < PAGE_MAPCOUNT_RESERVE + 1)

	if (page_mapcount_is_type(mapcount))

		mapcount = 0;

	if (folio_test_large(folio))

		mapcount += folio_entire_mapcount(folio);

include/linux/mm.h

+1 −2
Original line number Diff line number Diff line
@@ -1228,8 +1228,7 @@ static inline int folio_mapcount(const struct folio *folio) 


	if (likely(!folio_test_large(folio))) {

		mapcount = atomic_read(&folio->_mapcount) + 1;

		/* Handle page_has_type() pages */

		if (mapcount < PAGE_MAPCOUNT_RESERVE + 1)

		if (page_mapcount_is_type(mapcount))

			mapcount = 0;

		return mapcount;

	}

include/linux/page-flags.h

+9 −3
Original line number Diff line number Diff line
@@ -956,12 +956,18 @@ enum pagetype { 
#define folio_test_type(folio, flag)					\

	((READ_ONCE(folio->page.page_type) & (PAGE_TYPE_BASE | flag))  == PAGE_TYPE_BASE)



static inline int page_type_has_type(unsigned int page_type)

static inline bool page_type_has_type(int page_type)

{

	return (int)page_type < PAGE_MAPCOUNT_RESERVE;

	return page_type < PAGE_MAPCOUNT_RESERVE;

}



static inline int page_has_type(const struct page *page)

/* This takes a mapcount which is one more than page->_mapcount */

static inline bool page_mapcount_is_type(unsigned int mapcount)

{

	return page_type_has_type(mapcount - 1);

}



static inline bool page_has_type(const struct page *page)

{

	return page_type_has_type(READ_ONCE(page->page_type));

}