Re: [PATCH v3 07/10] thp: implement splitting pmd for huge zero page
From: Ni zhan Chen
Date: Fri Oct 12 2012 - 01:00:45 EST
On 10/12/2012 12:13 PM, Kirill A. Shutemov wrote:
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
Oh, thanks!
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