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mm: convert total_compound_mapcount() to folio_total_mapcount() 

Instead of enforcing that the argument must be a head page by naming,
enforce it with the compiler by making it a folio.  Also rename the
counter in struct folio from _compound_mapcount to _entire_mapcount.

Link: https://lkml.kernel.org/r/20230111142915.1001531-5-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2023-01-11 14:28:50 +00:00 committed by Andrew Morton
parent 6eee1a0062
commit b14224fbea
3 changed files with 16 additions and 17 deletions
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6
include/linux/mm.h
View File

@ -871,7 +871,7 @@ static inline int page_mapcount(struct page *page)
return head_compound_mapcount(page) + mapcount;
}
int total_compound_mapcount(struct page *head);
int folio_total_mapcount(struct folio *folio);
/**
* folio_mapcount() - Calculate the number of mappings of this folio.
@ -888,14 +888,14 @@ static inline int folio_mapcount(struct folio *folio)
{
if (likely(!folio_test_large(folio)))
return atomic_read(&folio->_mapcount) + 1;
return total_compound_mapcount(&folio->page);
return folio_total_mapcount(folio);
}
static inline int total_mapcount(struct page *page)
{
if (likely(!PageCompound(page)))
return atomic_read(&page->_mapcount) + 1;
return total_compound_mapcount(compound_head(page));
return folio_total_mapcount(page_folio(page));
}
static inline bool folio_large_is_mapped(struct folio *folio)

6
include/linux/mm_types.h
View File

@ -306,7 +306,7 @@ static inline struct page *encoded_page_ptr(struct encoded_page *page)
* @_head_1: Points to the folio. Do not use.
* @_folio_dtor: Which destructor to use for this folio.
* @_folio_order: Do not use directly, call folio_order().
* @_compound_mapcount: Do not use directly, call folio_entire_mapcount().
* @_entire_mapcount: Do not use directly, call folio_entire_mapcount().
* @_nr_pages_mapped: Do not use directly, call folio_mapcount().
* @_pincount: Do not use directly, call folio_maybe_dma_pinned().
* @_folio_nr_pages: Do not use directly, call folio_nr_pages().
@ -360,7 +360,7 @@ struct folio {
unsigned long _head_1;
unsigned char _folio_dtor;
unsigned char _folio_order;
atomic_t _compound_mapcount;
atomic_t _entire_mapcount;
atomic_t _nr_pages_mapped;
atomic_t _pincount;
#ifdef CONFIG_64BIT
@ -403,7 +403,7 @@ FOLIO_MATCH(flags, _flags_1);
FOLIO_MATCH(compound_head, _head_1);
FOLIO_MATCH(compound_dtor, _folio_dtor);
FOLIO_MATCH(compound_order, _folio_order);
FOLIO_MATCH(compound_mapcount, _compound_mapcount);
FOLIO_MATCH(compound_mapcount, _entire_mapcount);
FOLIO_MATCH(subpages_mapcount, _nr_pages_mapped);
FOLIO_MATCH(compound_pincount, _pincount);
#ifdef CONFIG_64BIT

21
mm/rmap.c
View File

@ -1078,27 +1078,26 @@ int pfn_mkclean_range(unsigned long pfn, unsigned long nr_pages, pgoff_t pgoff,
return page_vma_mkclean_one(&pvmw);
}
int total_compound_mapcount(struct page *head)
int folio_total_mapcount(struct folio *folio)
{
struct folio *folio = (struct folio *)head;
int mapcount = head_compound_mapcount(head);
int nr_subpages;
int mapcount = folio_entire_mapcount(folio);
int nr_pages;
int i;
/* In the common case, avoid the loop when no subpages mapped by PTE */
/* In the common case, avoid the loop when no pages mapped by PTE */
if (folio_nr_pages_mapped(folio) == 0)
return mapcount;
/*
* Add all the PTE mappings of those subpages mapped by PTE.
* Limit the loop, knowing that only subpages_mapcount are mapped?
* Add all the PTE mappings of those pages mapped by PTE.
* Limit the loop to folio_nr_pages_mapped()?
* Perhaps: given all the raciness, that may be a good or a bad idea.
*/
nr_subpages = thp_nr_pages(head);
for (i = 0; i < nr_subpages; i++)
mapcount += atomic_read(&head[i]._mapcount);
nr_pages = folio_nr_pages(folio);
for (i = 0; i < nr_pages; i++)
mapcount += atomic_read(&folio_page(folio, i)->_mapcount);
/* But each of those _mapcounts was based on -1 */
mapcount += nr_subpages;
mapcount += nr_pages;
return mapcount;
}