On Mon, Sep 14, 2015 at 10:31:45PM +0300, Ebru Akagunduz wrote:
> @@ -2655,6 +2696,8 @@ static void collapse_huge_page(struct mm_struct *mm,
>
> anon_vma_lock_write(vma->anon_vma);
>
> + __collapse_huge_page_swapin(mm, vma, address, pmd, pte);
> +
Do I miss something, or 'pte' is not initialized at this point?
And the value is not really used in __collapse_huge_page_swapin().
> pte = pte_offset_map(pmd, address);
> pte_ptl = pte_lockptr(mm, pmd);
>From 76783e1dfb22cde04cf46903336810df8a632617 Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Date: Thu, 17 Sep 2015 16:23:30 +0300
Subject: [PATCH] khugepaged: __collapse_huge_page_swapin(): drop unused 'pte'
parameter
'pte' dereference is eliminated by compiler, since nobody uses the
pteval until it's overwritten inside the loop.
Value of 'pte' itself is overwritten by pte_offset_map() before first
real use.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 4b057abd8615..5ad5c443cc94 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2628,11 +2628,10 @@ static bool hugepage_vma_check(struct vm_area_struct *vma)
static void __collapse_huge_page_swapin(struct mm_struct *mm,
struct vm_area_struct *vma,
- unsigned long address, pmd_t *pmd,
- pte_t *pte)
+ unsigned long address, pmd_t *pmd)
{
unsigned long _address;
- pte_t pteval = *pte;
+ pte_t *pte, pteval;
int swapped_in = 0, ret = 0;
pte = pte_offset_map(pmd, address);
@@ -2730,7 +2729,7 @@ static void collapse_huge_page(struct mm_struct *mm,
anon_vma_lock_write(vma->anon_vma);
- __collapse_huge_page_swapin(mm, vma, address, pmd, pte);
+ __collapse_huge_page_swapin(mm, vma, address, pmd);
pte = pte_offset_map(pmd, address);
pte_ptl = pte_lockptr(mm, pmd);
--
Kirill A. Shutemov
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