[PATCH v2 02/10] thp: zap_huge_pmd(): zap huge zero pmd
From: Kirill A. Shutemov <hidden>
Date: 2012-09-10 13:15:30
Also in:
lkml
Subsystem:
memory management, memory management - thp (transparent huge page), the rest · Maintainers:
Andrew Morton, David Hildenbrand, Lorenzo Stoakes, Linus Torvalds
From: "Kirill A. Shutemov" <redacted> We don't have a real page to zap in huge zero page case. Let's just clear pmd and remove it from tlb. Signed-off-by: Kirill A. Shutemov <redacted> --- mm/huge_memory.c | 27 +++++++++++++++++---------- 1 files changed, 17 insertions(+), 10 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 88e0a7a..9dcb9e6 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c@@ -1071,16 +1071,23 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, struct page *page; pgtable_t pgtable; pgtable = get_pmd_huge_pte(tlb->mm); - page = pmd_page(*pmd); - pmd_clear(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(*pmd)) { + pmd_clear(pmd); + tlb_remove_pmd_tlb_entry(tlb, pmd, addr); + tlb->mm->nr_ptes--; + spin_unlock(&tlb->mm->page_table_lock); + } else { + page = pmd_page(*pmd); + pmd_clear(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); + } pte_free(tlb->mm, pgtable); ret = 1; }
--
1.7.7.6
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