On 28.04.22 10:34, David Hildenbrand wrote: > This is roughly what we have in -mm and -next, however, includes one > additional patch and some minor differences, especially minor fixes in the > patch descriptions. > > v4 is located at: > https://github.com/davidhildenbrand/linux/tree/cow_fixes_part_2_v4 > > Please refer to to v3 cover letter: > https://lkml.kernel.org/r/20220329160440.193848-1-david@xxxxxxxxxx > > Essential diff to v3: diff --git a/include/linux/swapops.h b/include/linux/swapops.h index 06280fc1c99b..8b6e4cd1fab8 100644 --- a/include/linux/swapops.h +++ b/include/linux/swapops.h @@ -299,7 +299,7 @@ static inline bool is_pfn_swap_entry(swp_entry_t entry) struct page_vma_mapped_walk; #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION -extern void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, +extern int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, struct page *page); extern void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, @@ -332,7 +332,7 @@ static inline int is_pmd_migration_entry(pmd_t pmd) return !pmd_present(pmd) && is_migration_entry(pmd_to_swp_entry(pmd)); } #else -static inline void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, +static inline int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, struct page *page) { BUILD_BUG(); diff --git a/mm/gup.c b/mm/gup.c index 5c17d4816441..46ffd8c51c6e 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -564,8 +564,8 @@ static struct page *follow_page_pte(struct vm_area_struct *vma, goto out; } - VM_BUG_ON((flags & FOLL_PIN) && PageAnon(page) && - !PageAnonExclusive(page)); + VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) && + !PageAnonExclusive(page), page); /* try_grab_page() does nothing unless FOLL_GET or FOLL_PIN is set. */ if (unlikely(!try_grab_page(page, flags))) { diff --git a/mm/huge_memory.c b/mm/huge_memory.c index c7ac1b462543..a2f44d8d3d47 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1392,8 +1392,8 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, if (!pmd_write(*pmd) && gup_must_unshare(flags, page)) return ERR_PTR(-EMLINK); - VM_BUG_ON((flags & FOLL_PIN) && PageAnon(page) && - !PageAnonExclusive(page)); + VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) && + !PageAnonExclusive(page), page); if (!try_grab_page(page, flags)) return ERR_PTR(-ENOMEM); @@ -3080,7 +3080,7 @@ late_initcall(split_huge_pages_debugfs); #endif #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION -void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, +int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, struct page *page) { struct vm_area_struct *vma = pvmw->vma; @@ -3092,7 +3092,7 @@ void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, pmd_t pmdswp; if (!(pvmw->pmd && !pvmw->pte)) - return; + return 0; flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); pmdval = pmdp_invalidate(vma, address, pvmw->pmd); @@ -3100,7 +3100,7 @@ void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, anon_exclusive = PageAnon(page) && PageAnonExclusive(page); if (anon_exclusive && page_try_share_anon_rmap(page)) { set_pmd_at(mm, address, pvmw->pmd, pmdval); - return; + return -EBUSY; } if (pmd_dirty(pmdval)) @@ -3118,6 +3118,8 @@ void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, page_remove_rmap(page, vma, true); put_page(page); trace_set_migration_pmd(address, pmd_val(pmdswp)); + + return 0; } void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index ee0542f77130..534747d661dd 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -6100,8 +6100,8 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; page = pte_page(huge_ptep_get(pte)); - VM_BUG_ON((flags & FOLL_PIN) && PageAnon(page) && - !PageAnonExclusive(page)); + VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) && + !PageAnonExclusive(page), page); /* * If subpage information not requested, update counters diff --git a/mm/memory.c b/mm/memory.c index 2046de391da2..1a25d28ee5d9 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3132,7 +3132,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) free_swap_cache(old_page); put_page(old_page); } - return page_copied && !unshare ? VM_FAULT_WRITE : 0; + return (page_copied && !unshare) ? VM_FAULT_WRITE : 0; oom_free_new: put_page(new_page); oom: @@ -4557,7 +4557,7 @@ static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf) const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; if (vma_is_anonymous(vmf->vma)) { - if (unlikely(unshare) && + if (likely(!unshare) && userfaultfd_huge_pmd_wp(vmf->vma, vmf->orig_pmd)) return handle_userfault(vmf, VM_UFFD_WP); return do_huge_pmd_wp_page(vmf); diff --git a/mm/rmap.c b/mm/rmap.c index 00418faaf4ce..12f54fbdb920 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1217,8 +1217,6 @@ void page_add_new_anon_rmap(struct page *page, __mod_lruvec_page_state(page, NR_ANON_THPS, nr); } else { - /* Anon THP always mapped first with PMD */ - VM_BUG_ON_PAGE(PageTransCompound(page), page); /* increment count (starts at -1) */ atomic_set(&page->_mapcount, 0); } @@ -1814,7 +1812,11 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, VM_BUG_ON_FOLIO(folio_test_hugetlb(folio) || !folio_test_pmd_mappable(folio), folio); - set_pmd_migration_entry(&pvmw, subpage); + if (set_pmd_migration_entry(&pvmw, subpage)) { + ret = false; + page_vma_mapped_walk_done(&pvmw); + break; + } continue; } #endif -- Thanks, David / dhildenb
