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Commit f55e1014 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Revert "mm, thp: Do not make pmd/pud dirty without a reason" 



This reverts commit 152e93af.

It was a nice cleanup in theory, but as Nicolai Stange points out, we do
need to make the page dirty for the copy-on-write case even when we
didn't end up making it writable, since the dirty bit is what we use to
check that we've gone through a COW cycle.

Reported-by: default avatarMichal Hocko <mhocko@kernel.org>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 43570f03

mm/huge_memory.c

+12 −19
Original line number Original line Diff line number Diff line
@@ -474,13 +474,10 @@ static int __init setup_transparent_hugepage(char *str) 
}

}

__setup("transparent_hugepage=", setup_transparent_hugepage);

__setup("transparent_hugepage=", setup_transparent_hugepage);





pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma, bool dirty)

pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)

{

{

	if (likely(vma->vm_flags & VM_WRITE)) {

	if (likely(vma->vm_flags & VM_WRITE))

		pmd = pmd_mkwrite(pmd);

		pmd = pmd_mkwrite(pmd);

		if (dirty)

			pmd = pmd_mkdirty(pmd);

	}

	return pmd;

	return pmd;

}

}
@@ -602,7 +599,7 @@ static int __do_huge_pmd_anonymous_page(struct vm_fault *vmf, struct page *page, 
		}

		}





		entry = mk_huge_pmd(page, vma->vm_page_prot);

		entry = mk_huge_pmd(page, vma->vm_page_prot);

		entry = maybe_pmd_mkwrite(entry, vma, true);

		entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);

		page_add_new_anon_rmap(page, vma, haddr, true);

		page_add_new_anon_rmap(page, vma, haddr, true);

		mem_cgroup_commit_charge(page, memcg, false, true);

		mem_cgroup_commit_charge(page, memcg, false, true);

		lru_cache_add_active_or_unevictable(page, vma);

		lru_cache_add_active_or_unevictable(page, vma);
@@ -744,8 +741,8 @@ static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, 
	if (pfn_t_devmap(pfn))

	if (pfn_t_devmap(pfn))

		entry = pmd_mkdevmap(entry);

		entry = pmd_mkdevmap(entry);

	if (write) {

	if (write) {

		entry = pmd_mkyoung(entry);

		entry = pmd_mkyoung(pmd_mkdirty(entry));

		entry = maybe_pmd_mkwrite(entry, vma, true);

		entry = maybe_pmd_mkwrite(entry, vma);

	}

	}





	if (pgtable) {

	if (pgtable) {
@@ -791,14 +788,10 @@ int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, 
EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd);

EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd);





#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD

#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD

static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma,

static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma)

		bool dirty)

{

{

	if (likely(vma->vm_flags & VM_WRITE)) {

	if (likely(vma->vm_flags & VM_WRITE))

		pud = pud_mkwrite(pud);

		pud = pud_mkwrite(pud);

		if (dirty)

			pud = pud_mkdirty(pud);

	}

	return pud;

	return pud;

}

}
@@ -814,8 +807,8 @@ static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, 
	if (pfn_t_devmap(pfn))

	if (pfn_t_devmap(pfn))

		entry = pud_mkdevmap(entry);

		entry = pud_mkdevmap(entry);

	if (write) {

	if (write) {

		entry = pud_mkyoung(entry);

		entry = pud_mkyoung(pud_mkdirty(entry));

		entry = maybe_pud_mkwrite(entry, vma, true);

		entry = maybe_pud_mkwrite(entry, vma);

	}

	}

	set_pud_at(mm, addr, pud, entry);

	set_pud_at(mm, addr, pud, entry);

	update_mmu_cache_pud(vma, addr, pud);

	update_mmu_cache_pud(vma, addr, pud);
@@ -1286,7 +1279,7 @@ int do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) 
	if (reuse_swap_page(page, NULL)) {

	if (reuse_swap_page(page, NULL)) {

		pmd_t entry;

		pmd_t entry;

		entry = pmd_mkyoung(orig_pmd);

		entry = pmd_mkyoung(orig_pmd);

		entry = maybe_pmd_mkwrite(entry, vma, true);

		entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);

		if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry,  1))

		if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry,  1))

			update_mmu_cache_pmd(vma, vmf->address, vmf->pmd);

			update_mmu_cache_pmd(vma, vmf->address, vmf->pmd);

		ret |= VM_FAULT_WRITE;

		ret |= VM_FAULT_WRITE;
@@ -1356,7 +1349,7 @@ int do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) 
	} else {

	} else {

		pmd_t entry;

		pmd_t entry;

		entry = mk_huge_pmd(new_page, vma->vm_page_prot);

		entry = mk_huge_pmd(new_page, vma->vm_page_prot);

		entry = maybe_pmd_mkwrite(entry, vma, true);

		entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);

		pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd);

		pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd);

		page_add_new_anon_rmap(new_page, vma, haddr, true);

		page_add_new_anon_rmap(new_page, vma, haddr, true);

		mem_cgroup_commit_charge(new_page, memcg, false, true);

		mem_cgroup_commit_charge(new_page, memcg, false, true);
@@ -2935,7 +2928,7 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) 
	if (pmd_swp_soft_dirty(*pvmw->pmd))

	if (pmd_swp_soft_dirty(*pvmw->pmd))

		pmde = pmd_mksoft_dirty(pmde);

		pmde = pmd_mksoft_dirty(pmde);

	if (is_write_migration_entry(entry))

	if (is_write_migration_entry(entry))

		pmde = maybe_pmd_mkwrite(pmde, vma, false);

		pmde = maybe_pmd_mkwrite(pmde, vma);





	flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE);

	flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE);

	page_add_anon_rmap(new, vma, mmun_start, true);

	page_add_anon_rmap(new, vma, mmun_start, true);

mm/internal.h

+1 −2
Original line number Original line Diff line number Diff line
@@ -328,8 +328,7 @@ static inline void mlock_migrate_page(struct page *newpage, struct page *page) 
	}

	}

}

}





extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma,

extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);

		bool dirty);





/*

/*

 * At what user virtual address is page expected in @vma?

 * At what user virtual address is page expected in @vma?

mm/khugepaged.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -1057,7 +1057,7 @@ static void collapse_huge_page(struct mm_struct *mm, 
	pgtable = pmd_pgtable(_pmd);

	pgtable = pmd_pgtable(_pmd);





	_pmd = mk_huge_pmd(new_page, vma->vm_page_prot);

	_pmd = mk_huge_pmd(new_page, vma->vm_page_prot);

	_pmd = maybe_pmd_mkwrite(_pmd, vma, false);

	_pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma);





	/*

	/*

	 * spin_lock() below is not the equivalent of smp_wmb(), so

	 * spin_lock() below is not the equivalent of smp_wmb(), so

mm/memory.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -3335,7 +3335,7 @@ static int do_set_pmd(struct vm_fault *vmf, struct page *page) 




	entry = mk_huge_pmd(page, vma->vm_page_prot);

	entry = mk_huge_pmd(page, vma->vm_page_prot);

	if (write)

	if (write)

		entry = maybe_pmd_mkwrite(entry, vma, true);

		entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);





	add_mm_counter(vma->vm_mm, MM_FILEPAGES, HPAGE_PMD_NR);

	add_mm_counter(vma->vm_mm, MM_FILEPAGES, HPAGE_PMD_NR);

	page_add_file_rmap(page, true);

	page_add_file_rmap(page, true);

mm/migrate.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -2068,7 +2068,7 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm, 
	}

	}





	entry = mk_huge_pmd(new_page, vma->vm_page_prot);

	entry = mk_huge_pmd(new_page, vma->vm_page_prot);

	entry = maybe_pmd_mkwrite(entry, vma, false);

	entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);





	/*

	/*

	 * Clear the old entry under pagetable lock and establish the new PTE.

	 * Clear the old entry under pagetable lock and establish the new PTE.