From e135826b2da0cf25305086dc9ac1e91718a148e1 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Wed, 20 Dec 2023 23:44:26 +0100 Subject: mm/rmap: introduce and use hugetlb_remove_rmap() hugetlb rmap handling differs quite a lot from "ordinary" rmap code. For example, hugetlb currently only supports entire mappings, and treats any mapping as mapped using a single "logical PTE". Let's move it out of the way so we can overhaul our "ordinary" rmap. implementation/interface. Let's introduce and use hugetlb_remove_rmap() and remove the hugetlb code from page_remove_rmap(). This effectively removes one check on the small-folio path as well. Add sanity checks that we end up with the right folios in the right functions. Note: all possible candidates that need care are page_remove_rmap() that pass compound=true. Link: https://lkml.kernel.org/r/20231220224504.646757-3-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Yin Fengwei Reviewed-by: Ryan Roberts Reviewed-by: Matthew Wilcox (Oracle) Reviewed-by: Muchun Song Cc: Hugh Dickins Cc: Muchun Song Cc: Peter Xu Signed-off-by: Andrew Morton --- mm/rmap.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) (limited to 'mm/rmap.c') diff --git a/mm/rmap.c b/mm/rmap.c index 9845499b22f8..261e1af0d254 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1480,15 +1480,9 @@ void page_remove_rmap(struct page *page, struct vm_area_struct *vma, bool last; enum node_stat_item idx; + VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio); VM_BUG_ON_PAGE(compound && !PageHead(page), page); - /* Hugetlb pages are not counted in NR_*MAPPED */ - if (unlikely(folio_test_hugetlb(folio))) { - /* hugetlb pages are always mapped with pmds */ - atomic_dec(&folio->_entire_mapcount); - return; - } - /* Is page being unmapped by PTE? Is this its last map to be removed? */ if (likely(!compound)) { last = atomic_add_negative(-1, &page->_mapcount); @@ -1846,7 +1840,10 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, dec_mm_counter(mm, mm_counter_file(&folio->page)); } discard: - page_remove_rmap(subpage, vma, folio_test_hugetlb(folio)); + if (unlikely(folio_test_hugetlb(folio))) + hugetlb_remove_rmap(folio); + else + page_remove_rmap(subpage, vma, false); if (vma->vm_flags & VM_LOCKED) mlock_drain_local(); folio_put(folio); @@ -2199,7 +2196,10 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, */ } - page_remove_rmap(subpage, vma, folio_test_hugetlb(folio)); + if (unlikely(folio_test_hugetlb(folio))) + hugetlb_remove_rmap(folio); + else + page_remove_rmap(subpage, vma, false); if (vma->vm_flags & VM_LOCKED) mlock_drain_local(); folio_put(folio); -- cgit v1.2.3