From 479f0abbfd253d1117a35c1df12755d27a2a0705 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Wed, 12 Dec 2012 13:50:50 -0800 Subject: thp: zap_huge_pmd(): zap huge zero pmd We don't have a mapped page to zap in huge zero page case. Let's just clear pmd and remove it from tlb. Signed-off-by: Kirill A. Shutemov Cc: Andrea Arcangeli Cc: Andi Kleen Cc: "H. Peter Anvin" Cc: Mel Gorman Acked-by: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/huge_memory.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 04eb489a6805..1ee34ddb46ad 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1085,15 +1085,20 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, pmd_t orig_pmd; pgtable = pgtable_trans_huge_withdraw(tlb->mm); orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd); - page = pmd_page(orig_pmd); tlb_remove_pmd_tlb_entry(tlb, pmd, addr); - page_remove_rmap(page); - VM_BUG_ON(page_mapcount(page) < 0); - add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); - VM_BUG_ON(!PageHead(page)); - tlb->mm->nr_ptes--; - spin_unlock(&tlb->mm->page_table_lock); - tlb_remove_page(tlb, page); + if (is_huge_zero_pmd(orig_pmd)) { + tlb->mm->nr_ptes--; + spin_unlock(&tlb->mm->page_table_lock); + } else { + page = pmd_page(orig_pmd); + page_remove_rmap(page); + VM_BUG_ON(page_mapcount(page) < 0); + add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); + VM_BUG_ON(!PageHead(page)); + tlb->mm->nr_ptes--; + spin_unlock(&tlb->mm->page_table_lock); + tlb_remove_page(tlb, page); + } pte_free(tlb->mm, pgtable); ret = 1; } -- cgit v1.2.3