From 62beb906ef644b0f0555b2b9f9626c27e2038d84 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Wed, 11 Jan 2023 14:28:51 +0000 Subject: [PATCH] mm: convert page_remove_rmap() to use a folio internally The API for page_remove_rmap() needs to be page-based, because we can remove mappings of pages individually. But inside the function, we want to only call compound_head() once and then use the folio APIs instead of the page APIs that each call compound_head(). Link: https://lkml.kernel.org/r/20230111142915.1001531-6-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton --- mm/rmap.c | 47 ++++++++++++++++++++++++++--------------------- 1 file changed, 26 insertions(+), 21 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index 1418efc80027..7762ab8371c0 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1365,19 +1365,21 @@ void page_add_file_rmap(struct page *page, * * The caller needs to hold the pte lock. */ -void page_remove_rmap(struct page *page, - struct vm_area_struct *vma, bool compound) +void page_remove_rmap(struct page *page, struct vm_area_struct *vma, + bool compound) { - atomic_t *mapped; + struct folio *folio = page_folio(page); + atomic_t *mapped = &folio->_nr_pages_mapped; int nr = 0, nr_pmdmapped = 0; bool last; + enum node_stat_item idx; VM_BUG_ON_PAGE(compound && !PageHead(page), page); /* Hugetlb pages are not counted in NR_*MAPPED */ - if (unlikely(PageHuge(page))) { + if (unlikely(folio_test_hugetlb(folio))) { /* hugetlb pages are always mapped with pmds */ - atomic_dec(compound_mapcount_ptr(page)); + atomic_dec(&folio->_entire_mapcount); return; } @@ -1385,20 +1387,18 @@ void page_remove_rmap(struct page *page, if (likely(!compound)) { last = atomic_add_negative(-1, &page->_mapcount); nr = last; - if (last && PageCompound(page)) { - mapped = subpages_mapcount_ptr(compound_head(page)); + if (last && folio_test_large(folio)) { nr = atomic_dec_return_relaxed(mapped); nr = (nr < COMPOUND_MAPPED); } - } else if (PageTransHuge(page)) { + } else if (folio_test_pmd_mappable(folio)) { /* That test is redundant: it's for safety or to optimize out */ - last = atomic_add_negative(-1, compound_mapcount_ptr(page)); + last = atomic_add_negative(-1, &folio->_entire_mapcount); if (last) { - mapped = subpages_mapcount_ptr(page); nr = atomic_sub_return_relaxed(COMPOUND_MAPPED, mapped); if (likely(nr < COMPOUND_MAPPED)) { - nr_pmdmapped = thp_nr_pages(page); + nr_pmdmapped = folio_nr_pages(folio); nr = nr_pmdmapped - (nr & FOLIO_PAGES_MAPPED); /* Raced ahead of another remove and an add? */ if (unlikely(nr < 0)) @@ -1411,21 +1411,26 @@ void page_remove_rmap(struct page *page, } if (nr_pmdmapped) { - __mod_lruvec_page_state(page, PageAnon(page) ? NR_ANON_THPS : - (PageSwapBacked(page) ? NR_SHMEM_PMDMAPPED : - NR_FILE_PMDMAPPED), -nr_pmdmapped); + if (folio_test_anon(folio)) + idx = NR_ANON_THPS; + else if (folio_test_swapbacked(folio)) + idx = NR_SHMEM_PMDMAPPED; + else + idx = NR_FILE_PMDMAPPED; + __lruvec_stat_mod_folio(folio, idx, -nr_pmdmapped); } if (nr) { - __mod_lruvec_page_state(page, PageAnon(page) ? NR_ANON_MAPPED : - NR_FILE_MAPPED, -nr); + idx = folio_test_anon(folio) ? NR_ANON_MAPPED : NR_FILE_MAPPED; + __lruvec_stat_mod_folio(folio, idx, -nr); + /* - * Queue anon THP for deferred split if at least one small - * page of the compound page is unmapped, but at least one - * small page is still mapped. + * Queue anon THP for deferred split if at least one + * page of the folio is unmapped and at least one page + * is still mapped. */ - if (PageTransCompound(page) && PageAnon(page)) + if (folio_test_pmd_mappable(folio) && folio_test_anon(folio)) if (!compound || nr < nr_pmdmapped) - deferred_split_huge_page(compound_head(page)); + deferred_split_huge_page(&folio->page); } /* -- 2.11.0