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

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

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

We're adding folio_remove_rmap_ptes() handling right away, as we want to
use that soon for batching rmap operations when unmapping PTE-mapped large
folios.

Link: https://lkml.kernel.org/r/20231220224504.646757-24-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.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>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
David Hildenbrand 2023-12-20 23:44:47 +01:00 committed by Andrew Morton
parent 0cae959e3a
commit b06dc281aa
2 changed files with 71 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/linux/rmap.h
View File

@ -243,6 +243,12 @@ void folio_add_file_rmap_pmd(struct folio *, struct page *,
struct vm_area_struct *);
void page_remove_rmap(struct page *, struct vm_area_struct *,
bool compound);
void folio_remove_rmap_ptes(struct folio *, struct page *, int nr_pages,
struct vm_area_struct *);
#define folio_remove_rmap_pte(folio, page, vma) \
folio_remove_rmap_ptes(folio, page, 1, vma)
void folio_remove_rmap_pmd(struct folio *, struct page *,
struct vm_area_struct *);
void hugetlb_add_anon_rmap(struct folio *, struct vm_area_struct *,
unsigned long address, rmap_t flags);

80
mm/rmap.c
View File

@ -1510,25 +1510,37 @@ void page_remove_rmap(struct page *page, struct vm_area_struct *vma,
bool compound)
{
struct folio *folio = page_folio(page);
if (likely(!compound))
folio_remove_rmap_pte(folio, page, vma);
else
folio_remove_rmap_pmd(folio, page, vma);
}
static __always_inline void __folio_remove_rmap(struct folio *folio,
struct page *page, int nr_pages, struct vm_area_struct *vma,
enum rmap_level level)
{
atomic_t *mapped = &folio->_nr_pages_mapped;
int nr = 0, nr_pmdmapped = 0;
bool last;
int last, nr = 0, nr_pmdmapped = 0;
enum node_stat_item idx;
VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio);
VM_BUG_ON_PAGE(compound && !PageHead(page), page);
__folio_rmap_sanity_checks(folio, page, nr_pages, level);
/* Is page being unmapped by PTE? Is this its last map to be removed? */
if (likely(!compound)) {
last = atomic_add_negative(-1, &page->_mapcount);
nr = last;
if (last && folio_test_large(folio)) {
nr = atomic_dec_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 */
switch (level) {
case RMAP_LEVEL_PTE:
do {
last = atomic_add_negative(-1, &page->_mapcount);
if (last && folio_test_large(folio)) {
last = atomic_dec_return_relaxed(mapped);
last = (last < COMPOUND_MAPPED);
}
if (last)
nr++;
} while (page++, --nr_pages > 0);
break;
case RMAP_LEVEL_PMD:
last = atomic_add_negative(-1, &folio->_entire_mapcount);
if (last) {
nr = atomic_sub_return_relaxed(COMPOUND_MAPPED, mapped);
@ -1543,6 +1555,7 @@ void page_remove_rmap(struct page *page, struct vm_area_struct *vma,
nr = 0;
}
}
break;
}
if (nr_pmdmapped) {
@ -1564,7 +1577,7 @@ void page_remove_rmap(struct page *page, struct vm_area_struct *vma,
* is still mapped.
*/
if (folio_test_large(folio) && folio_test_anon(folio))
if (!compound || nr < nr_pmdmapped)
if (level == RMAP_LEVEL_PTE || nr < nr_pmdmapped)
deferred_split_folio(folio);
}
@ -1579,6 +1592,43 @@ void page_remove_rmap(struct page *page, struct vm_area_struct *vma,
munlock_vma_folio(folio, vma);
}
/**
* folio_remove_rmap_ptes - remove PTE mappings from a page range of a folio
* @folio: The folio to remove the mappings from
* @page: The first page to remove
* @nr_pages: The number of pages that will be removed from the mapping
* @vma: The vm area from which the mappings are removed
*
* The page range of the folio is defined by [page, page + nr_pages)
*
* The caller needs to hold the page table lock.
*/
void folio_remove_rmap_ptes(struct folio *folio, struct page *page,
int nr_pages, struct vm_area_struct *vma)
{
__folio_remove_rmap(folio, page, nr_pages, vma, RMAP_LEVEL_PTE);
}
/**
* folio_remove_rmap_pmd - remove a PMD mapping from a page range of a folio
* @folio: The folio to remove the mapping from
* @page: The first page to remove
* @vma: The vm area from which the mapping is removed
*
* The page range of the folio is defined by [page, page + HPAGE_PMD_NR)
*
* The caller needs to hold the page table lock.
*/
void folio_remove_rmap_pmd(struct folio *folio, struct page *page,
struct vm_area_struct *vma)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
__folio_remove_rmap(folio, page, HPAGE_PMD_NR, vma, RMAP_LEVEL_PMD);
#else
WARN_ON_ONCE(true);
#endif
}
/*
* @arg: enum ttu_flags will be passed to this argument
*/