[PATCH v4 02/10] thp: zap_huge_pmd(): zap huge zero pmd
From: Kirill A. Shutemov <hidden>
Date: 2012-10-15 06:00:16
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 | 21 +++++++++++++-------- 1 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 438adbf..680c27f 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c@@ -1057,15 +1057,20 @@ 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; }
--
1.7.7.6
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