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mm: Add folio_raw_mapping() 

Convert __page_rmapping to folio_raw_mapping and move it to mm/internal.h.
It's only a couple of instructions (load and mask), so it's definitely
going to be cheaper to inline it than call it.  Leave page_rmapping
out of line.  Change page_anon_vma() to not call folio_raw_mapping() --
it's more efficient to do the subtraction than the mask.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
This commit is contained in:
Matthew Wilcox (Oracle) 2021-05-07 11:17:34 -04:00
parent bf6bd276b3
commit 646010009d
2 changed files with 11 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
mm/internal.h
View File

@ -34,6 +34,13 @@
void page_writeback_init(void);
static inline void *folio_raw_mapping(struct folio *folio)
{
unsigned long mapping = (unsigned long)folio->mapping;
return (void *)(mapping & ~PAGE_MAPPING_FLAGS);
}
vm_fault_t do_swap_page(struct vm_fault *vmf);
void folio_rotate_reclaimable(struct folio *folio);

20
mm/util.c
View File

@ -654,21 +654,10 @@ void *kvrealloc(const void *p, size_t oldsize, size_t newsize, gfp_t flags)
}
EXPORT_SYMBOL(kvrealloc);
static inline void *__page_rmapping(struct page *page)
{
unsigned long mapping;
mapping = (unsigned long)page->mapping;
mapping &= ~PAGE_MAPPING_FLAGS;
return (void *)mapping;
}
/* Neutral page->mapping pointer to address_space or anon_vma or other */
void *page_rmapping(struct page *page)
{
page = compound_head(page);
return __page_rmapping(page);
return folio_raw_mapping(page_folio(page));
}
/**
@ -699,13 +688,12 @@ EXPORT_SYMBOL(folio_mapped);
struct anon_vma *page_anon_vma(struct page *page)
{
unsigned long mapping;
struct folio *folio = page_folio(page);
unsigned long mapping = (unsigned long)folio->mapping;
page = compound_head(page);
mapping = (unsigned long)page->mapping;
if ((mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON)
return NULL;
return __page_rmapping(page);
return (void *)(mapping - PAGE_MAPPING_ANON);
}
/**