From 5f32b265400de723ab0db23101a75ac073bdd980 Mon Sep 17 00:00:00 2001 From: =?utf8?q?J=C3=A9r=C3=B4me=20Glisse?= Date: Thu, 31 Aug 2017 17:17:38 -0400 Subject: [PATCH] mm/mmu_notifier: kill invalidate_page MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The invalidate_page callback suffered from two pitfalls. First it used to happen after the page table lock was release and thus a new page might have setup before the call to invalidate_page() happened. This is in a weird way fixed by commit c7ab0d2fdc84 ("mm: convert try_to_unmap_one() to use page_vma_mapped_walk()") that moved the callback under the page table lock but this also broke several existing users of the mmu_notifier API that assumed they could sleep inside this callback. The second pitfall was invalidate_page() being the only callback not taking a range of address in respect to invalidation but was giving an address and a page. Lots of the callback implementers assumed this could never be THP and thus failed to invalidate the appropriate range for THP. By killing this callback we unify the mmu_notifier callback API to always take a virtual address range as input. Finally this also simplifies the end user life as there is now two clear choices: - invalidate_range_start()/end() callback (which allow you to sleep) - invalidate_range() where you can not sleep but happen right after page table update under page table lock Signed-off-by: Jérôme Glisse Cc: Bernhard Held Cc: Adam Borowski Cc: Andrea Arcangeli Cc: Radim Krčmář Cc: Wanpeng Li Cc: Paolo Bonzini Cc: Takashi Iwai Cc: Nadav Amit Cc: Mike Galbraith Cc: Kirill A. Shutemov Cc: axie Cc: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mmu_notifier.h | 25 ------------------------- mm/mmu_notifier.c | 14 -------------- 2 files changed, 39 deletions(-) diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h index c91b3bcd158f..7b2e31b1745a 100644 --- a/include/linux/mmu_notifier.h +++ b/include/linux/mmu_notifier.h @@ -94,17 +94,6 @@ struct mmu_notifier_ops { unsigned long address, pte_t pte); - /* - * Before this is invoked any secondary MMU is still ok to - * read/write to the page previously pointed to by the Linux - * pte because the page hasn't been freed yet and it won't be - * freed until this returns. If required set_page_dirty has to - * be called internally to this method. - */ - void (*invalidate_page)(struct mmu_notifier *mn, - struct mm_struct *mm, - unsigned long address); - /* * invalidate_range_start() and invalidate_range_end() must be * paired and are called only when the mmap_sem and/or the @@ -220,8 +209,6 @@ extern int __mmu_notifier_test_young(struct mm_struct *mm, unsigned long address); extern void __mmu_notifier_change_pte(struct mm_struct *mm, unsigned long address, pte_t pte); -extern void __mmu_notifier_invalidate_page(struct mm_struct *mm, - unsigned long address); extern void __mmu_notifier_invalidate_range_start(struct mm_struct *mm, unsigned long start, unsigned long end); extern void __mmu_notifier_invalidate_range_end(struct mm_struct *mm, @@ -268,13 +255,6 @@ static inline void mmu_notifier_change_pte(struct mm_struct *mm, __mmu_notifier_change_pte(mm, address, pte); } -static inline void mmu_notifier_invalidate_page(struct mm_struct *mm, - unsigned long address) -{ - if (mm_has_notifiers(mm)) - __mmu_notifier_invalidate_page(mm, address); -} - static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm, unsigned long start, unsigned long end) { @@ -442,11 +422,6 @@ static inline void mmu_notifier_change_pte(struct mm_struct *mm, { } -static inline void mmu_notifier_invalidate_page(struct mm_struct *mm, - unsigned long address) -{ -} - static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm, unsigned long start, unsigned long end) { diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index 54ca54562928..314285284e6e 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -174,20 +174,6 @@ void __mmu_notifier_change_pte(struct mm_struct *mm, unsigned long address, srcu_read_unlock(&srcu, id); } -void __mmu_notifier_invalidate_page(struct mm_struct *mm, - unsigned long address) -{ - struct mmu_notifier *mn; - int id; - - id = srcu_read_lock(&srcu); - hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) { - if (mn->ops->invalidate_page) - mn->ops->invalidate_page(mn, mm, address); - } - srcu_read_unlock(&srcu, id); -} - void __mmu_notifier_invalidate_range_start(struct mm_struct *mm, unsigned long start, unsigned long end) { -- 2.20.1