[RESEND PATCH v2] thp: Remove unused vma parameter from khugepaged_alloc_page

[RESEND PATCH v2] thp: Remove unused vma parameter from khugepaged_alloc_page

[Aaron Tomlin]

Resending due to incomplete subject.

Changes since v2:

 - Fixed incorrect commit message

The "vma" parameter to khugepaged_alloc_page() is unused.
It has to remain unused or the drop read lock 'map_sem' optimisation
introduce by commit 8b1645685acf ("mm, THP: don't hold mmap_sem in
khugepaged when allocating THP") wouldn't be safe. So let's remove it.

Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
---
 mm/huge_memory.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index bbac913..490fa81 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2413,8 +2413,7 @@ static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
 
 static struct page *
 khugepaged_alloc_page(struct page **hpage, gfp_t gfp, struct mm_struct *mm,
-		       struct vm_area_struct *vma, unsigned long address,
-		       int node)
+		       unsigned long address, int node)
 {
 	VM_BUG_ON_PAGE(*hpage, *hpage);
 
@@ -2481,8 +2480,7 @@ static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
 
 static struct page *
 khugepaged_alloc_page(struct page **hpage, gfp_t gfp, struct mm_struct *mm,
-		       struct vm_area_struct *vma, unsigned long address,
-		       int node)
+		       unsigned long address, int node)
 {
 	up_read(&mm->mmap_sem);
 	VM_BUG_ON(!*hpage);
@@ -2530,7 +2528,7 @@ static void collapse_huge_page(struct mm_struct *mm,
 		__GFP_THISNODE;
 
 	/* release the mmap_sem read lock. */
-	new_page = khugepaged_alloc_page(hpage, gfp, mm, vma, address, node);
+	new_page = khugepaged_alloc_page(hpage, gfp, mm, address, node);
 	if (!new_page)
 		return;
 
-- 
2.4.3

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [RESEND PATCH v2] thp: Remove unused vma parameter from khugepaged_alloc_page

[Vlastimil Babka]

On 11/04/2015 01:48 PM, Aaron Tomlin wrote:
> Resending due to incomplete subject.
>
> Changes since v2:
>
>   - Fixed incorrect commit message
>
> The "vma" parameter to khugepaged_alloc_page() is unused.
> It has to remain unused or the drop read lock 'map_sem' optimisation
> introduce by commit 8b1645685acf ("mm, THP: don't hold mmap_sem in
> khugepaged when allocating THP") wouldn't be safe. So let's remove it.
>
> Signed-off-by: Aaron Tomlin <atomlin@redhat.com>

Pretty sure the compiler inlines it away anyway, but sure, why not.
Acked-by: Vlastimil Babka <vbabka@suse.cz>

> ---
>   mm/huge_memory.c | 8 +++-----
>   1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index bbac913..490fa81 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -2413,8 +2413,7 @@ static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
>
>   static struct page *
>   khugepaged_alloc_page(struct page **hpage, gfp_t gfp, struct mm_struct *mm,
> -		       struct vm_area_struct *vma, unsigned long address,
> -		       int node)
> +		       unsigned long address, int node)
>   {
>   	VM_BUG_ON_PAGE(*hpage, *hpage);
>
> @@ -2481,8 +2480,7 @@ static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
>
>   static struct page *
>   khugepaged_alloc_page(struct page **hpage, gfp_t gfp, struct mm_struct *mm,
> -		       struct vm_area_struct *vma, unsigned long address,
> -		       int node)
> +		       unsigned long address, int node)
>   {
>   	up_read(&mm->mmap_sem);
>   	VM_BUG_ON(!*hpage);
> @@ -2530,7 +2528,7 @@ static void collapse_huge_page(struct mm_struct *mm,
>   		__GFP_THISNODE;
>
>   	/* release the mmap_sem read lock. */
> -	new_page = khugepaged_alloc_page(hpage, gfp, mm, vma, address, node);
> +	new_page = khugepaged_alloc_page(hpage, gfp, mm, address, node);
>   	if (!new_page)
>   		return;
>
>

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>