From f535bec883fa41feb786ba4ddbeafe8be864d224 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Mon, 2 Oct 2023 16:29:47 +0200 Subject: [PATCH] mm/rmap: move SetPageAnonExclusive() out of page_move_anon_rmap() Patch series "mm/rmap: convert page_move_anon_rmap() to folio_move_anon_rmap()". Convert page_move_anon_rmap() to folio_move_anon_rmap(), letting the callers handle PageAnonExclusive. I'm including cleanup patch #3 because it fits into the picture and can be done cleaner by the conversion. This patch (of 3): Let's move it into the caller: there is a difference between whether an anon folio can only be mapped by one process (e.g., into one VMA), and whether it is truly exclusive (e.g., no references -- including GUP -- from other processes). Further, for large folios the page might not actually be pointing at the head page of the folio, so it better be handled in the caller. This is a preparation for converting page_move_anon_rmap() to consume a folio. Link: https://lkml.kernel.org/r/20231002142949.235104-1-david@redhat.com Link: https://lkml.kernel.org/r/20231002142949.235104-2-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Suren Baghdasaryan Reviewed-by: Vishal Moola (Oracle) Cc: Mike Kravetz Cc: Muchun Song Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- mm/huge_memory.c | 1 + mm/hugetlb.c | 4 +++- mm/memory.c | 1 + mm/rmap.c | 1 - 4 files changed, 5 insertions(+), 2 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index aa022455613261..76ead290f1c82b 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1377,6 +1377,7 @@ vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) pmd_t entry; page_move_anon_rmap(page, vma); + SetPageAnonExclusive(page); folio_unlock(folio); reuse: if (unlikely(unshare)) { diff --git a/mm/hugetlb.c b/mm/hugetlb.c index bb4428b7355de5..b6b0850be7e852 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5646,8 +5646,10 @@ static vm_fault_t hugetlb_wp(struct mm_struct *mm, struct vm_area_struct *vma, * owner and can reuse this page. */ if (folio_mapcount(old_folio) == 1 && folio_test_anon(old_folio)) { - if (!PageAnonExclusive(&old_folio->page)) + if (!PageAnonExclusive(&old_folio->page)) { page_move_anon_rmap(&old_folio->page, vma); + SetPageAnonExclusive(&old_folio->page); + } if (likely(!unshare)) set_huge_ptep_writable(vma, haddr, ptep); diff --git a/mm/memory.c b/mm/memory.c index 7f42d839076c95..9ac601c591feba 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3484,6 +3484,7 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf) * sunglasses. Hit it. */ page_move_anon_rmap(vmf->page, vma); + SetPageAnonExclusive(vmf->page); folio_unlock(folio); reuse: if (unlikely(unshare)) { diff --git a/mm/rmap.c b/mm/rmap.c index c6bb2339e35b26..6f1ea1491118c5 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1152,7 +1152,6 @@ void page_move_anon_rmap(struct page *page, struct vm_area_struct *vma) * folio_test_anon()) will not see one without the other. */ WRITE_ONCE(folio->mapping, anon_vma); - SetPageAnonExclusive(page); } /**