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Date: Thu, 18 Oct 2012 18:12:18 +0800
From: Bob Liu <lliubbo@...il.com>
To: <akpm@...ux-foundation.org>
CC: <aarcange@...hat.com>, <xiaoguangrong@...ux.vnet.ibm.com>,
<hughd@...gle.com>, <rientjes@...gle.com>,
<linux-kernel@...r.kernel.org>, <kirill.shutemov@...ux.intel.com>,
Bob Liu <lliubbo@...il.com>
Subject: [PATCH 2/4] thp: introduce hugepage_get_pmd()
Introduce hugepage_get_pmd() to simple code.
Signed-off-by: Bob Liu <lliubbo@...il.com>
---
mm/huge_memory.c | 68 ++++++++++++++++++++++--------------------------------
1 file changed, 27 insertions(+), 41 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 462d6ea..e575b29 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1115,6 +1115,25 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
return ret;
}
+static pmd_t *hugepage_get_pmd(struct mm_struct *mm, unsigned long address)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd = NULL;
+
+ pgd = pgd_offset(mm, address);
+ if (!pgd_present(*pgd))
+ goto out;
+
+ pud = pud_offset(pgd, address);
+ if (!pud_present(*pud))
+ goto out;
+
+ pmd = pmd_offset(pud, address);
+out:
+ return pmd;
+}
+
/*
* Returns 1 if a given pmd maps a stable (not under splitting) thp.
* Returns -1 if it maps a thp under splitting. Returns 0 otherwise.
@@ -1145,22 +1164,14 @@ pmd_t *page_check_address_pmd(struct page *page,
unsigned long address,
enum page_check_address_pmd_flag flag)
{
- pgd_t *pgd;
- pud_t *pud;
pmd_t *pmd, *ret = NULL;
if (address & ~HPAGE_PMD_MASK)
goto out;
- pgd = pgd_offset(mm, address);
- if (!pgd_present(*pgd))
- goto out;
-
- pud = pud_offset(pgd, address);
- if (!pud_present(*pud))
+ pmd = hugepage_get_pmd(mm, address);
+ if (!pmd)
goto out;
-
- pmd = pmd_offset(pud, address);
if (pmd_none(*pmd))
goto out;
if (pmd_page(*pmd) != page)
@@ -1908,8 +1919,6 @@ static void collapse_huge_page(struct mm_struct *mm,
struct vm_area_struct *vma,
int node)
{
- pgd_t *pgd;
- pud_t *pud;
pmd_t *pmd, _pmd;
pte_t *pte;
pgtable_t pgtable;
@@ -1955,16 +1964,9 @@ static void collapse_huge_page(struct mm_struct *mm,
goto out;
VM_BUG_ON(vma->vm_flags & VM_NO_THP);
- pgd = pgd_offset(mm, address);
- if (!pgd_present(*pgd))
+ pmd = hugepage_get_pmd(mm, address);
+ if (!pmd)
goto out;
-
- pud = pud_offset(pgd, address);
- if (!pud_present(*pud))
- goto out;
-
- pmd = pmd_offset(pud, address);
- /* pmd can't go away or become huge under us */
if (!pmd_present(*pmd) || pmd_trans_huge(*pmd))
goto out;
@@ -2048,8 +2050,6 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
unsigned long address,
struct page **hpage)
{
- pgd_t *pgd;
- pud_t *pud;
pmd_t *pmd;
pte_t *pte, *_pte;
int ret = 0, referenced = 0, none = 0;
@@ -2060,15 +2060,9 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
- pgd = pgd_offset(mm, address);
- if (!pgd_present(*pgd))
- goto out;
-
- pud = pud_offset(pgd, address);
- if (!pud_present(*pud))
+ pmd = hugepage_get_pmd(mm, address);
+ if (!pmd)
goto out;
-
- pmd = pmd_offset(pud, address);
if (!pmd_present(*pmd) || pmd_trans_huge(*pmd))
goto out;
@@ -2363,21 +2357,13 @@ void __split_huge_page_pmd(struct mm_struct *mm, pmd_t *pmd)
static void split_huge_page_address(struct mm_struct *mm,
unsigned long address)
{
- pgd_t *pgd;
- pud_t *pud;
pmd_t *pmd;
VM_BUG_ON(!(address & ~HPAGE_PMD_MASK));
- pgd = pgd_offset(mm, address);
- if (!pgd_present(*pgd))
- return;
-
- pud = pud_offset(pgd, address);
- if (!pud_present(*pud))
+ pmd = hugepage_get_pmd(mm, address);
+ if (!pmd)
return;
-
- pmd = pmd_offset(pud, address);
if (!pmd_present(*pmd))
return;
/*
--
1.7.9.5
--
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