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mm/rmap: introduce folio_add_anon_rmap_[pte|ptes|pmd]()

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Let's mimic what we did with folio_add_file_rmap_*() so we can similarly
replace page_add_anon_rmap() next.

Make the compiler always special-case on the granularity by using
__always_inline.

For the PageAnonExclusive sanity checks, when adding a PMD mapping, we're
now also checking each individual subpage covered by that PMD, instead of
only the head page.

Note that the new functions ignore the RMAP_COMPOUND flag, which we will
remove as soon as page_add_anon_rmap() is gone.

Link: https://lkml.kernel.org/r/20231220224504.646757-15-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
David Hildenbrand 2023-12-20 23:44:38 +01:00 committed by Andrew Morton
parent 96fd74958c
commit 8bd5130070
2 changed files with 88 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/linux/rmap.h
View File

@ -233,6 +233,12 @@ static inline void __folio_rmap_sanity_checks(struct folio *folio,
* rmap interfaces called when adding or removing pte of page
*/
void folio_move_anon_rmap(struct folio *, struct vm_area_struct *);
void folio_add_anon_rmap_ptes(struct folio *, struct page *, int nr_pages,
struct vm_area_struct *, unsigned long address, rmap_t flags);
#define folio_add_anon_rmap_pte(folio, page, vma, address, flags) \
folio_add_anon_rmap_ptes(folio, page, 1, vma, address, flags)
void folio_add_anon_rmap_pmd(struct folio *, struct page *,
struct vm_area_struct *, unsigned long address, rmap_t flags);
void page_add_anon_rmap(struct page *, struct vm_area_struct *,
unsigned long address, rmap_t flags);
void folio_add_new_anon_rmap(struct folio *, struct vm_area_struct *,

120
mm/rmap.c
View File

@ -1299,40 +1299,20 @@ void page_add_anon_rmap(struct page *page, struct vm_area_struct *vma,
unsigned long address, rmap_t flags)
{
struct folio *folio = page_folio(page);
atomic_t *mapped = &folio->_nr_pages_mapped;
int nr = 0, nr_pmdmapped = 0;
bool compound = flags & RMAP_COMPOUND;
bool first;
VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio);
if (likely(!(flags & RMAP_COMPOUND)))
folio_add_anon_rmap_pte(folio, page, vma, address, flags);
else
folio_add_anon_rmap_pmd(folio, page, vma, address, flags);
}
/* Is page being mapped by PTE? Is this its first map to be added? */
if (likely(!compound)) {
first = atomic_inc_and_test(&page->_mapcount);
nr = first;
if (first && folio_test_large(folio)) {
nr = atomic_inc_return_relaxed(mapped);
nr = (nr < COMPOUND_MAPPED);
}
} else if (folio_test_pmd_mappable(folio)) {
/* That test is redundant: it's for safety or to optimize out */
first = atomic_inc_and_test(&folio->_entire_mapcount);
if (first) {
nr = atomic_add_return_relaxed(COMPOUND_MAPPED, mapped);
if (likely(nr < COMPOUND_MAPPED + COMPOUND_MAPPED)) {
nr_pmdmapped = folio_nr_pages(folio);
nr = nr_pmdmapped - (nr & FOLIO_PAGES_MAPPED);
/* Raced ahead of a remove and another add? */
if (unlikely(nr < 0))
nr = 0;
} else {
/* Raced ahead of a remove of COMPOUND_MAPPED */
nr = 0;
}
}
}
static __always_inline void __folio_add_anon_rmap(struct folio *folio,
struct page *page, int nr_pages, struct vm_area_struct *vma,
unsigned long address, rmap_t flags, enum rmap_level level)
{
int i, nr, nr_pmdmapped = 0;
nr = __folio_add_rmap(folio, page, nr_pages, level, &nr_pmdmapped);
if (nr_pmdmapped)
__lruvec_stat_mod_folio(folio, NR_ANON_THPS, nr_pmdmapped);
if (nr)
@ -1346,18 +1326,34 @@ void page_add_anon_rmap(struct page *page, struct vm_area_struct *vma,
* folio->index right when not given the address of the head
* page.
*/
VM_WARN_ON_FOLIO(folio_test_large(folio) && !compound, folio);
VM_WARN_ON_FOLIO(folio_test_large(folio) &&
level != RMAP_LEVEL_PMD, folio);
__folio_set_anon(folio, vma, address,
!!(flags & RMAP_EXCLUSIVE));
} else if (likely(!folio_test_ksm(folio))) {
__page_check_anon_rmap(folio, page, vma, address);
}
if (flags & RMAP_EXCLUSIVE)
SetPageAnonExclusive(page);
/* While PTE-mapping a THP we have a PMD and a PTE mapping. */
VM_WARN_ON_FOLIO((atomic_read(&page->_mapcount) > 0 ||
(folio_test_large(folio) && folio_entire_mapcount(folio) > 1)) &&
PageAnonExclusive(page), folio);
if (flags & RMAP_EXCLUSIVE) {
switch (level) {
case RMAP_LEVEL_PTE:
for (i = 0; i < nr_pages; i++)
SetPageAnonExclusive(page + i);
break;
case RMAP_LEVEL_PMD:
SetPageAnonExclusive(page);
break;
}
}
for (i = 0; i < nr_pages; i++) {
struct page *cur_page = page + i;
/* While PTE-mapping a THP we have a PMD and a PTE mapping. */
VM_WARN_ON_FOLIO((atomic_read(&cur_page->_mapcount) > 0 ||
(folio_test_large(folio) &&
folio_entire_mapcount(folio) > 1)) &&
PageAnonExclusive(cur_page), folio);
}
/*
* For large folio, only mlock it if it's fully mapped to VMA. It's
@ -1369,6 +1365,54 @@ void page_add_anon_rmap(struct page *page, struct vm_area_struct *vma,
mlock_vma_folio(folio, vma);
}
/**
* folio_add_anon_rmap_ptes - add PTE mappings to a page range of an anon folio
* @folio: The folio to add the mappings to
* @page: The first page to add
* @nr_pages: The number of pages which will be mapped
* @vma: The vm area in which the mappings are added
* @address: The user virtual address of the first page to map
* @flags: The rmap flags
*
* The page range of folio is defined by [first_page, first_page + nr_pages)
*
* The caller needs to hold the page table lock, and the page must be locked in
* the anon_vma case: to serialize mapping,index checking after setting,
* and to ensure that an anon folio is not being upgraded racily to a KSM folio
* (but KSM folios are never downgraded).
*/
void folio_add_anon_rmap_ptes(struct folio *folio, struct page *page,
int nr_pages, struct vm_area_struct *vma, unsigned long address,
rmap_t flags)
{
__folio_add_anon_rmap(folio, page, nr_pages, vma, address, flags,
RMAP_LEVEL_PTE);
}
/**
* folio_add_anon_rmap_pmd - add a PMD mapping to a page range of an anon folio
* @folio: The folio to add the mapping to
* @page: The first page to add
* @vma: The vm area in which the mapping is added
* @address: The user virtual address of the first page to map
* @flags: The rmap flags
*
* The page range of folio is defined by [first_page, first_page + HPAGE_PMD_NR)
*
* The caller needs to hold the page table lock, and the page must be locked in
* the anon_vma case: to serialize mapping,index checking after setting.
*/
void folio_add_anon_rmap_pmd(struct folio *folio, struct page *page,
struct vm_area_struct *vma, unsigned long address, rmap_t flags)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
__folio_add_anon_rmap(folio, page, HPAGE_PMD_NR, vma, address, flags,
RMAP_LEVEL_PMD);
#else
WARN_ON_ONCE(true);
#endif
}
/**
* folio_add_new_anon_rmap - Add mapping to a new anonymous folio.
* @folio: The folio to add the mapping to.