Commit 74e8ee47 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle)
Browse files

mm: Turn head_compound_mapcount() into folio_entire_mapcount() 



Adjust documentation to be more clear.

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent e20c41b1

include/linux/mm.h

+11 −6
Original line number Diff line number Diff line
@@ -776,21 +776,26 @@ static inline int is_vmalloc_or_module_addr(const void *x) 
}

#endif



static inline int head_compound_mapcount(struct page *head)

/*

 * How many times the entire folio is mapped as a single unit (eg by a

 * PMD or PUD entry).  This is probably not what you want, except for

 * debugging purposes; look at folio_mapcount() or page_mapcount()

 * instead.

 */

static inline int folio_entire_mapcount(struct folio *folio)

{

	return atomic_read(compound_mapcount_ptr(head)) + 1;

	VM_BUG_ON_FOLIO(!folio_test_large(folio), folio);

	return atomic_read(folio_mapcount_ptr(folio)) + 1;

}



/*

 * Mapcount of compound page as a whole, does not include mapped sub-pages.

 *

 * Must be called only for compound pages or any their tail sub-pages.

 * Must be called only for compound pages.

 */

static inline int compound_mapcount(struct page *page)

{

	VM_BUG_ON_PAGE(!PageCompound(page), page);

	page = compound_head(page);

	return head_compound_mapcount(page);

	return folio_entire_mapcount(page_folio(page));

}



/*

mm/debug.c

+4 −2
Original line number Diff line number Diff line
@@ -48,7 +48,8 @@ const struct trace_print_flags vmaflag_names[] = { 


static void __dump_page(struct page *page)

{

	struct page *head = compound_head(page);

	struct folio *folio = page_folio(page);

	struct page *head = &folio->page;

	struct address_space *mapping;

	bool compound = PageCompound(page);

	/*
@@ -76,6 +77,7 @@ static void __dump_page(struct page *page) 
		else

			mapping = (void *)(tmp & ~PAGE_MAPPING_FLAGS);

		head = page;

		folio = (struct folio *)page;

		compound = false;

	} else {

		mapping = page_mapping(page);
@@ -94,7 +96,7 @@ static void __dump_page(struct page *page) 
	if (compound) {

		pr_warn("head:%p order:%u compound_mapcount:%d compound_pincount:%d\n",

				head, compound_order(head),

				head_compound_mapcount(head),

				folio_entire_mapcount(folio),

				head_compound_pincount(head));

	}