mm/rmap: factor out adding folio mappings into __folio_add_rmap()

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.

Link: https://lkml.kernel.org/r/20231220224504.646757-14-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>

diff --git a/mm/rmap.c b/mm/rmap.c
index 5ab5ef10fbf5e5cd567d3f3b5e7f80abb8f272c0..895a8534a935d7c8e446c661d720dfd74512c129 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1157,6 +1157,48 @@ 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_level level,
+               int *nr_pmdmapped)
+{
+       atomic_t *mapped = &folio->_nr_pages_mapped;
+       int first, nr = 0;
+
+       __folio_rmap_sanity_checks(folio, page, nr_pages, level);
+
+       switch (level) {
+       case RMAP_LEVEL_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_LEVEL_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
@@ -1382,43 +1424,11 @@ static __always_inline void __folio_add_file_rmap(struct folio *folio,
                struct page *page, int nr_pages, struct vm_area_struct *vma,
                enum rmap_level level)
 {
-       atomic_t *mapped = &folio->_nr_pages_mapped;
-       int nr = 0, nr_pmdmapped = 0, first;
+       int nr, nr_pmdmapped = 0;
 
        VM_WARN_ON_FOLIO(folio_test_anon(folio), folio);
-       __folio_rmap_sanity_checks(folio, page, nr_pages, level);
-
-       switch (level) {
-       case RMAP_LEVEL_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_LEVEL_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, level, &nr_pmdmapped);
        if (nr_pmdmapped)
                __lruvec_stat_mod_folio(folio, folio_test_swapbacked(folio) ?
                        NR_SHMEM_PMDMAPPED : NR_FILE_PMDMAPPED, nr_pmdmapped);