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mm: Turn head_compound_mapcount() into folio_entire_mapcount()

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Adjust documentation to be more clear.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Matthew Wilcox (Oracle) 2022-01-18 10:50:48 -05:00
parent e20c41b109
commit 74e8ee4708
2 changed files with 15 additions and 8 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

17
include/linux/mm.h
View file

@ -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));
}
/*

6
mm/debug.c
View file

@ -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));
}