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 <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kirill A. Shutemov 2012-12-12 13:50:50 -08:00 committed by Linus Torvalds
parent 4a6c129726
commit 479f0abbfd

View file

@ -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;
}