From 96db66d9c8f3c1547325af01b1f328b85d6ee1b9 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Mon, 11 Dec 2023 16:22:06 +0000 Subject: mm: convert ksm_might_need_to_copy() to work on folios Patch series "Finish two folio conversions". Most callers of page_add_new_anon_rmap() and lru_cache_add_inactive_or_unevictable() have been converted to their folio equivalents, but there are still a few stragglers. There's a bit of preparatory work in ksm and unuse_pte(), but after that it's pretty mechanical. This patch (of 9): Accept a folio as an argument and return a folio result. Removes a call to compound_head() in do_swap_page(), and prevents folio & page from getting out of sync in unuse_pte(). Reviewed-by: David Hildenbrand [willy@infradead.org: fix smatch warning] Link: https://lkml.kernel.org/r/ZXnPtblC6A1IkyAB@casper.infradead.org [david@redhat.com: only adjust the page if the folio changed] Link: https://lkml.kernel.org/r/6a8f2110-fa91-4c10-9eae-88315309a6e3@redhat.com Link: https://lkml.kernel.org/r/20231211162214.2146080-1-willy@infradead.org Link: https://lkml.kernel.org/r/20231211162214.2146080-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: David Hildenbrand Signed-off-by: Andrew Morton --- include/linux/ksm.h | 6 +++--- mm/ksm.c | 21 +++++++++++---------- mm/memory.c | 11 +++++++---- mm/swapfile.c | 8 +++++--- 4 files changed, 26 insertions(+), 20 deletions(-) diff --git a/include/linux/ksm.h b/include/linux/ksm.h index 4643d5244e77..401348e9f92b 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -76,7 +76,7 @@ static inline void ksm_exit(struct mm_struct *mm) * We'd like to make this conditional on vma->vm_flags & VM_MERGEABLE, * but what if the vma was unmerged while the page was swapped out? */ -struct page *ksm_might_need_to_copy(struct page *page, +struct folio *ksm_might_need_to_copy(struct folio *folio, struct vm_area_struct *vma, unsigned long addr); void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc); @@ -129,10 +129,10 @@ static inline int ksm_madvise(struct vm_area_struct *vma, unsigned long start, return 0; } -static inline struct page *ksm_might_need_to_copy(struct page *page, +static inline struct folio *ksm_might_need_to_copy(struct folio *folio, struct vm_area_struct *vma, unsigned long addr) { - return page; + return folio; } static inline void rmap_walk_ksm(struct folio *folio, diff --git a/mm/ksm.c b/mm/ksm.c index c0e1995fb444..e2ce850c2739 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -2873,30 +2873,30 @@ void __ksm_exit(struct mm_struct *mm) trace_ksm_exit(mm); } -struct page *ksm_might_need_to_copy(struct page *page, +struct folio *ksm_might_need_to_copy(struct folio *folio, struct vm_area_struct *vma, unsigned long addr) { - struct folio *folio = page_folio(page); + struct page *page = folio_page(folio, 0); struct anon_vma *anon_vma = folio_anon_vma(folio); struct folio *new_folio; if (folio_test_large(folio)) - return page; + return folio; if (folio_test_ksm(folio)) { if (folio_stable_node(folio) && !(ksm_run & KSM_RUN_UNMERGE)) - return page; /* no need to copy it */ + return folio; /* no need to copy it */ } else if (!anon_vma) { - return page; /* no need to copy it */ + return folio; /* no need to copy it */ } else if (folio->index == linear_page_index(vma, addr) && anon_vma->root == vma->anon_vma->root) { - return page; /* still no need to copy it */ + return folio; /* still no need to copy it */ } if (PageHWPoison(page)) return ERR_PTR(-EHWPOISON); if (!folio_test_uptodate(folio)) - return page; /* let do_swap_page report the error */ + return folio; /* let do_swap_page report the error */ new_folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma, addr, false); if (new_folio && @@ -2905,9 +2905,10 @@ struct page *ksm_might_need_to_copy(struct page *page, new_folio = NULL; } if (new_folio) { - if (copy_mc_user_highpage(&new_folio->page, page, addr, vma)) { + if (copy_mc_user_highpage(folio_page(new_folio, 0), page, + addr, vma)) { folio_put(new_folio); - memory_failure_queue(page_to_pfn(page), 0); + memory_failure_queue(folio_pfn(folio), 0); return ERR_PTR(-EHWPOISON); } folio_set_dirty(new_folio); @@ -2918,7 +2919,7 @@ struct page *ksm_might_need_to_copy(struct page *page, #endif } - return new_folio ? &new_folio->page : NULL; + return new_folio; } void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc) diff --git a/mm/memory.c b/mm/memory.c index b9cc56a75f4b..7649cb9eb7f5 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3942,15 +3942,18 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) * page->index of !PageKSM() pages would be nonlinear inside the * anon VMA -- PageKSM() is lost on actual swapout. */ - page = ksm_might_need_to_copy(page, vma, vmf->address); - if (unlikely(!page)) { + folio = ksm_might_need_to_copy(folio, vma, vmf->address); + if (unlikely(!folio)) { ret = VM_FAULT_OOM; + folio = swapcache; goto out_page; - } else if (unlikely(PTR_ERR(page) == -EHWPOISON)) { + } else if (unlikely(folio == ERR_PTR(-EHWPOISON))) { ret = VM_FAULT_HWPOISON; + folio = swapcache; goto out_page; } - folio = page_folio(page); + if (folio != swapcache) + page = folio_page(folio, 0); /* * If we want to map a page that's in the swapcache writable, we diff --git a/mm/swapfile.c b/mm/swapfile.c index 8be70912e298..0371b7b3cd27 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1749,11 +1749,13 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, int ret = 1; swapcache = page; - page = ksm_might_need_to_copy(page, vma, addr); - if (unlikely(!page)) + folio = ksm_might_need_to_copy(folio, vma, addr); + if (unlikely(!folio)) return -ENOMEM; - else if (unlikely(PTR_ERR(page) == -EHWPOISON)) + else if (unlikely(folio == ERR_PTR(-EHWPOISON))) hwpoisoned = true; + else + page = folio_file_page(folio, swp_offset(entry)); pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); if (unlikely(!pte || !pte_same_as_swp(ptep_get(pte), -- cgit v1.2.3