On Fri, Oct 12, 2012 at 11:23:37AM +0800, Ni zhan Chen wrote: > On 10/02/2012 11:19 PM, Kirill A. Shutemov wrote: > >From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> > > > >We can't split huge zero page itself, but we can split the pmd which > >points to it. > > > >On splitting the pmd we create a table with all ptes set to normal zero > >page. > > > >Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> > >Reviewed-by: Andrea Arcangeli <aarcange@xxxxxxxxxx> > >--- > > mm/huge_memory.c | 32 ++++++++++++++++++++++++++++++++ > > 1 files changed, 32 insertions(+), 0 deletions(-) > > > >diff --git a/mm/huge_memory.c b/mm/huge_memory.c > >index 95032d3..3f1c59c 100644 > >--- a/mm/huge_memory.c > >+++ b/mm/huge_memory.c > >@@ -1600,6 +1600,7 @@ int split_huge_page(struct page *page) > > struct anon_vma *anon_vma; > > int ret = 1; > >+ BUG_ON(is_huge_zero_pfn(page_to_pfn(page))); > > BUG_ON(!PageAnon(page)); > > anon_vma = page_lock_anon_vma(page); > > if (!anon_vma) > >@@ -2503,6 +2504,32 @@ static int khugepaged(void *none) > > return 0; > > } > >+static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, > >+ unsigned long haddr, pmd_t *pmd) > >+{ > >+ pgtable_t pgtable; > >+ pmd_t _pmd; > >+ int i; > >+ > >+ pmdp_clear_flush_notify(vma, haddr, pmd); > > why I can't find function pmdp_clear_flush_notify in kernel source > code? Do you mean pmdp_clear_flush_young_notify or something like > that? It was changed recently. See commit 2ec74c3 mm: move all mmu notifier invocations to be done outside the PT lock -- Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>