diff mbox series

mm/madvise: minor cleanup for swapin_walk_pmd_entry()

Message ID 20220618090527.37843-1-linmiaohe@huawei.com (mailing list archive)
State New
Headers show
Series mm/madvise: minor cleanup for swapin_walk_pmd_entry() | expand

Commit Message

Miaohe Lin June 18, 2022, 9:05 a.m. UTC
Passing index to pte_offset_map_lock() directly so the below calculation
can be avoided. Rename orig_pte to ptep as it's not changed. Also use
helper is_swap_pte() to improve the readability. No functional change
intended.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
 mm/madvise.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

Comments

Andrew Morton June 18, 2022, 6:59 p.m. UTC | #1
On Sat, 18 Jun 2022 17:05:27 +0800 Miaohe Lin <linmiaohe@huawei.com> wrote:

> Passing index to pte_offset_map_lock() directly so the below calculation
> can be avoided. Rename orig_pte to ptep as it's not changed. Also use
> helper is_swap_pte() to improve the readability. No functional change
> intended.
> 
> ...
>
> --- a/mm/madvise.c
> +++ b/mm/madvise.c
> @@ -195,7 +195,7 @@ static int madvise_update_vma(struct vm_area_struct *vma,
>  static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start,
>  	unsigned long end, struct mm_walk *walk)
>  {
> -	pte_t *orig_pte;
> +	pte_t *ptep;
>  	struct vm_area_struct *vma = walk->private;
>  	unsigned long index;
>  	struct swap_iocb *splug = NULL;
> @@ -209,11 +209,11 @@ static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start,
>  		struct page *page;
>  		spinlock_t *ptl;
>  
> -		orig_pte = pte_offset_map_lock(vma->vm_mm, pmd, start, &ptl);
> -		pte = *(orig_pte + ((index - start) / PAGE_SIZE));
> -		pte_unmap_unlock(orig_pte, ptl);
> +		ptep = pte_offset_map_lock(vma->vm_mm, pmd, index, &ptl);
> +		pte = *ptep;
> +		pte_unmap_unlock(ptep, ptl);
>  
> -		if (pte_present(pte) || pte_none(pte))
> +		if (!is_swap_pte(pte))
>  			continue;
>  		entry = pte_to_swp_entry(pte);
>  		if (unlikely(non_swap_entry(entry)))

Also...

From: Andrew Morton <akpm@linux-foundation.org>
Subject: mm-madvise-minor-cleanup-for-swapin_walk_pmd_entry-fix
Date: Sat Jun 18 11:58:03 AM PDT 2022

reduce scope of `ptep'

Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/madvise.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/madvise.c~mm-madvise-minor-cleanup-for-swapin_walk_pmd_entry-fix
+++ a/mm/madvise.c
@@ -195,7 +195,6 @@ success:
 static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start,
 	unsigned long end, struct mm_walk *walk)
 {
-	pte_t *ptep;
 	struct vm_area_struct *vma = walk->private;
 	unsigned long index;
 	struct swap_iocb *splug = NULL;
@@ -208,6 +207,7 @@ static int swapin_walk_pmd_entry(pmd_t *
 		swp_entry_t entry;
 		struct page *page;
 		spinlock_t *ptl;
+		pte_t *ptep;
 
 		ptep = pte_offset_map_lock(vma->vm_mm, pmd, index, &ptl);
 		pte = *ptep;
Miaohe Lin June 20, 2022, 1:37 a.m. UTC | #2
On 2022/6/19 2:59, Andrew Morton wrote:
> On Sat, 18 Jun 2022 17:05:27 +0800 Miaohe Lin <linmiaohe@huawei.com> wrote:
> 
>> Passing index to pte_offset_map_lock() directly so the below calculation
>> can be avoided. Rename orig_pte to ptep as it's not changed. Also use
>> helper is_swap_pte() to improve the readability. No functional change
>> intended.
>>
>> ...
>>
>> --- a/mm/madvise.c
>> +++ b/mm/madvise.c
>> @@ -195,7 +195,7 @@ static int madvise_update_vma(struct vm_area_struct *vma,
>>  static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start,
>>  	unsigned long end, struct mm_walk *walk)
>>  {
>> -	pte_t *orig_pte;
>> +	pte_t *ptep;
>>  	struct vm_area_struct *vma = walk->private;
>>  	unsigned long index;
>>  	struct swap_iocb *splug = NULL;
>> @@ -209,11 +209,11 @@ static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start,
>>  		struct page *page;
>>  		spinlock_t *ptl;
>>  
>> -		orig_pte = pte_offset_map_lock(vma->vm_mm, pmd, start, &ptl);
>> -		pte = *(orig_pte + ((index - start) / PAGE_SIZE));
>> -		pte_unmap_unlock(orig_pte, ptl);
>> +		ptep = pte_offset_map_lock(vma->vm_mm, pmd, index, &ptl);
>> +		pte = *ptep;
>> +		pte_unmap_unlock(ptep, ptl);
>>  
>> -		if (pte_present(pte) || pte_none(pte))
>> +		if (!is_swap_pte(pte))
>>  			continue;
>>  		entry = pte_to_swp_entry(pte);
>>  		if (unlikely(non_swap_entry(entry)))
> 
> Also...
> 
> From: Andrew Morton <akpm@linux-foundation.org>
> Subject: mm-madvise-minor-cleanup-for-swapin_walk_pmd_entry-fix
> Date: Sat Jun 18 11:58:03 AM PDT 2022
> 
> reduce scope of `ptep'

Looks good to me. Thanks for doing this. :)

> 
> Cc: Miaohe Lin <linmiaohe@huawei.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
> 
>  mm/madvise.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> --- a/mm/madvise.c~mm-madvise-minor-cleanup-for-swapin_walk_pmd_entry-fix
> +++ a/mm/madvise.c
> @@ -195,7 +195,6 @@ success:
>  static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start,
>  	unsigned long end, struct mm_walk *walk)
>  {
> -	pte_t *ptep;
>  	struct vm_area_struct *vma = walk->private;
>  	unsigned long index;
>  	struct swap_iocb *splug = NULL;
> @@ -208,6 +207,7 @@ static int swapin_walk_pmd_entry(pmd_t *
>  		swp_entry_t entry;
>  		struct page *page;
>  		spinlock_t *ptl;
> +		pte_t *ptep;
>  
>  		ptep = pte_offset_map_lock(vma->vm_mm, pmd, index, &ptl);
>  		pte = *ptep;
> _
> 
> .
>
diff mbox series

Patch

diff --git a/mm/madvise.c b/mm/madvise.c
index 7a8af04069b3..cf49e123991c 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -195,7 +195,7 @@  static int madvise_update_vma(struct vm_area_struct *vma,
 static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start,
 	unsigned long end, struct mm_walk *walk)
 {
-	pte_t *orig_pte;
+	pte_t *ptep;
 	struct vm_area_struct *vma = walk->private;
 	unsigned long index;
 	struct swap_iocb *splug = NULL;
@@ -209,11 +209,11 @@  static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start,
 		struct page *page;
 		spinlock_t *ptl;
 
-		orig_pte = pte_offset_map_lock(vma->vm_mm, pmd, start, &ptl);
-		pte = *(orig_pte + ((index - start) / PAGE_SIZE));
-		pte_unmap_unlock(orig_pte, ptl);
+		ptep = pte_offset_map_lock(vma->vm_mm, pmd, index, &ptl);
+		pte = *ptep;
+		pte_unmap_unlock(ptep, ptl);
 
-		if (pte_present(pte) || pte_none(pte))
+		if (!is_swap_pte(pte))
 			continue;
 		entry = pte_to_swp_entry(pte);
 		if (unlikely(non_swap_entry(entry)))