mm: Turn head_compound_mapcount() into folio_entire_mapcount()

Adjust documentation to be more clear.

Matthew Wilcox (Oracle) committed 4 years ago

Commit 74e8ee41 parent e20c41b2 files · +15 −8Browse files

Unified · Split

2 files

@@ -776,21 +776,26 @@ static inline int is_vmalloc_or_module_addr(const void *x) · 775 unmodified lines
776	776	}
777	777	#endif
778	778
779		−static inline int head_compound_mapcount(struct page *head)
	779	+/*
	780	+ * How many times the entire folio is mapped as a single unit (eg by a
	781	+ * PMD or PUD entry). This is probably not what you want, except for
	782	+ * debugging purposes; look at folio_mapcount() or page_mapcount()
	783	+ * instead.
	784	+ */
	785	+static inline int folio_entire_mapcount(struct folio *folio)
780	786	{
781		− return atomic_read(compound_mapcount_ptr(head)) + 1;
	787	+ VM_BUG_ON_FOLIO(!folio_test_large(folio), folio);
	788	+ return atomic_read(folio_mapcount_ptr(folio)) + 1;
782	789	}
783	790
784	791	/*
785	792	* Mapcount of compound page as a whole, does not include mapped sub-pages.
786	793	*
787		− * Must be called only for compound pages or any their tail sub-pages.
	794	+ * Must be called only for compound pages.
788	795	*/
789	796	static inline int compound_mapcount(struct page *page)
790	797	{
791		− VM_BUG_ON_PAGE(!PageCompound(page), page);
792		− page = compound_head(page);
793		− return head_compound_mapcount(page);
	798	+ return folio_entire_mapcount(page_folio(page));
794	799	}
795	800
796	801	/*

@@ -48,7 +48,8 @@ const struct trace_print_flags vmaflag_names[] = { · 47 unmodified lines
48	48
49	49	static void __dump_page(struct page *page)
50	50	{
51		− struct page *head = compound_head(page);
	51	+ struct folio *folio = page_folio(page);
	52	+ struct page *head = &folio->page;
52	53	struct address_space *mapping;
53	54	bool compound = PageCompound(page);
54	55	/*
@@ -76,6 +77,7 @@ static void __dump_page(struct page *page) · 21 unmodified lines
76	77	else
77	78	mapping = (void *)(tmp & ~PAGE_MAPPING_FLAGS);
78	79	head = page;
	80	+ folio = (struct folio *)page;
79	81	compound = false;
80	82	} else {
81	83	mapping = page_mapping(page);
@@ -94,7 +96,7 @@ static void __dump_page(struct page *page) · 12 unmodified lines
94	96	if (compound) {
95	97	pr_warn("head:%p order:%u compound_mapcount:%d compound_pincount:%d\n",
96	98	head, compound_order(head),
97		− head_compound_mapcount(head),
	99	+ folio_entire_mapcount(folio),
98	100	head_compound_pincount(head));
99	101	}
100	102

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