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mm: add folio_add_new_anon_rmap()

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In contrast to other rmap functions, page_add_new_anon_rmap() is always
called with a freshly allocated page.  That means it can't be called with
a tail page.  Turn page_add_new_anon_rmap() into folio_add_new_anon_rmap()
and add a page_add_new_anon_rmap() wrapper.  Callers can be converted
individually.

[akpm@linux-foundation.org: fix NOMMU build.  page_add_new_anon_rmap() requires CONFIG_MMU]
[willy@infradead.org: folio-compat.c needs rmap.h]
Link: https://lkml.kernel.org/r/20230111142915.1001531-9-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 14:28:54 +00:00 committed by Andrew Morton
parent eb01a2ad7e
commit 4d510f3da4
3 changed files with 31 additions and 19 deletions
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2
include/linux/rmap.h
View file

@ -194,6 +194,8 @@ void page_add_anon_rmap(struct page *, struct vm_area_struct *,
unsigned long address, rmap_t flags);
void page_add_new_anon_rmap(struct page *, struct vm_area_struct *,
unsigned long address);
void folio_add_new_anon_rmap(struct folio *, struct vm_area_struct *,
unsigned long address);
void page_add_file_rmap(struct page *, struct vm_area_struct *,
bool compound);
void page_remove_rmap(struct page *, struct vm_area_struct *,

11
mm/folio-compat.c
View file

@ -6,6 +6,7 @@
#include <linux/migrate.h>
#include <linux/pagemap.h>
#include <linux/rmap.h>
#include <linux/swap.h>
#include "internal.h"
@ -123,3 +124,13 @@ void putback_lru_page(struct page *page)
{
folio_putback_lru(page_folio(page));
}
#ifdef CONFIG_MMU
void page_add_new_anon_rmap(struct page *page, struct vm_area_struct *vma,
unsigned long address)
{
VM_BUG_ON_PAGE(PageTail(page), page);
return folio_add_new_anon_rmap((struct folio *)page, vma, address);
}
#endif

37
mm/rmap.c
View file

@ -1264,41 +1264,40 @@ void page_add_anon_rmap(struct page *page, struct vm_area_struct *vma,
}
/**
* page_add_new_anon_rmap - add mapping to a new anonymous page
* @page: the page to add the mapping to
* folio_add_new_anon_rmap - Add mapping to a new anonymous folio.
* @folio: The folio to add the mapping to.
* @vma: the vm area in which the mapping is added
* @address: the user virtual address mapped
*
* If it's a compound page, it is accounted as a compound page. As the page
* is new, it's assume to get mapped exclusively by a single process.
*
* Same as page_add_anon_rmap but must only be called on *new* pages.
* Like page_add_anon_rmap() but must only be called on *new* folios.
* This means the inc-and-test can be bypassed.
* Page does not have to be locked.
* The folio does not have to be locked.
*
* If the folio is large, it is accounted as a THP. As the folio
* is new, it's assumed to be mapped exclusively by a single process.
*/
void page_add_new_anon_rmap(struct page *page,
struct vm_area_struct *vma, unsigned long address)
void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
unsigned long address)
{
int nr;
VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma);
__SetPageSwapBacked(page);
__folio_set_swapbacked(folio);
if (likely(!PageCompound(page))) {
if (likely(!folio_test_pmd_mappable(folio))) {
/* increment count (starts at -1) */
atomic_set(&page->_mapcount, 0);
atomic_set(&folio->_mapcount, 0);
nr = 1;
} else {
VM_BUG_ON_PAGE(!PageTransHuge(page), page);
/* increment count (starts at -1) */
atomic_set(compound_mapcount_ptr(page), 0);
atomic_set(subpages_mapcount_ptr(page), COMPOUND_MAPPED);
nr = thp_nr_pages(page);
__mod_lruvec_page_state(page, NR_ANON_THPS, nr);
atomic_set(&folio->_entire_mapcount, 0);
atomic_set(&folio->_nr_pages_mapped, COMPOUND_MAPPED);
nr = folio_nr_pages(folio);
__lruvec_stat_mod_folio(folio, NR_ANON_THPS, nr);
}
__mod_lruvec_page_state(page, NR_ANON_MAPPED, nr);
__page_set_anon_rmap(page, vma, address, 1);
__lruvec_stat_mod_folio(folio, NR_ANON_MAPPED, nr);
__page_set_anon_rmap(&folio->page, vma, address, 1);
}
/**