[PATCH v1 13/39] mm/rmap: factor out adding folio mappings into __folio_add_rmap()

David Hildenbrand
2023-12-11T15:57:42Z

Let's factor it out to prepare for reuse as we convert
page_add_anon_rmap() to folio_add_anon_rmap_[pte|ptes|pmd]().

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

Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
mm/rmap.c | 81 ++++++++++++++++++++++++++++++-------------------------
1 file changed, 45 insertions(+), 36 deletions(-)

diff --git a/mm/rmap.c b/mm/rmap.c
index 2ff2f11275e5..c5761986a411 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1157,6 +1157,49 @@ int folio_total_mapcount(struct folio *folio)
return mapcount;
}

+static __always_inline unsigned int __folio_add_rmap(struct folio *folio,
+ struct page *page, int nr_pages, enum rmap_mode mode,
+ unsigned int *nr_pmdmapped)
+{
+ atomic_t *mapped = &folio->_nr_pages_mapped;
+ int first, nr = 0;
+
+ __folio_rmap_sanity_checks(folio, page, nr_pages, mode);
+
+ /* Is page being mapped by PTE? Is this its first map to be added? */
+ switch (mode) {
+ case RMAP_MODE_PTE:
+ do {
+ first = atomic_inc_and_test(&page->_mapcount);
+ if (first && folio_test_large(folio)) {
+ first = atomic_inc_return_relaxed(mapped);
+ first = (first < COMPOUND_MAPPED);
+ }
+
+ if (first)
+ nr++;
+ } while (page++, --nr_pages > 0);
+ break;
+ case RMAP_MODE_PMD:
+ 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;
+ }
+ }
+ break;
+ }
+ return nr;
+}
+
/**
* folio_move_anon_rmap - move a folio to our anon_vma
* @folio: The folio to move to our anon_vma
@@ -1380,45 +1423,11 @@ static __always_inline void __folio_add_file_rmap(struct folio *folio,
struct page *page, int nr_pages, struct vm_area_struct *vma,
enum rmap_mode mode)
{
- atomic_t *mapped = &folio->_nr_pages_mapped;
- unsigned int nr_pmdmapped = 0, first;
- int nr = 0;
+ unsigned int nr, nr_pmdmapped = 0;

VM_WARN_ON_FOLIO(folio_test_anon(folio), folio);
- __folio_rmap_sanity_checks(folio, page, nr_pages, mode);
-
- /* Is page being mapped by PTE? Is this its first map to be added? */
- switch (mode) {
- case RMAP_MODE_PTE:
- do {
- first = atomic_inc_and_test(&page->_mapcount);
- if (first && folio_test_large(folio)) {
- first = atomic_inc_return_relaxed(mapped);
- first = (first < COMPOUND_MAPPED);
- }
-
- if (first)
- nr++;
- } while (page++, --nr_pages > 0);
- break;
- case RMAP_MODE_PMD:
- 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;
- }
- }
- break;
- }

+ nr = __folio_add_rmap(folio, page, nr_pages, mode, &nr_pmdmapped);
if (nr_pmdmapped)
__lruvec_stat_mod_folio(folio, folio_test_swapbacked(folio) ?
NR_SHMEM_PMDMAPPED : NR_FILE_PMDMAPPED, nr_pmdmapped);
--
2.43.0