* [PATCH] mm/madvise: minor cleanup for swapin_walk_pmd_entry()
@ 2022-06-18 9:05 Miaohe Lin
2022-06-18 18:59 ` Andrew Morton
0 siblings, 1 reply; 3+ messages in thread
From: Miaohe Lin @ 2022-06-18 9:05 UTC (permalink / raw)
To: akpm; +Cc: linux-mm, linux-kernel, linmiaohe
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(-)
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)))
--
2.23.0
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] mm/madvise: minor cleanup for swapin_walk_pmd_entry()
2022-06-18 9:05 [PATCH] mm/madvise: minor cleanup for swapin_walk_pmd_entry() Miaohe Lin
@ 2022-06-18 18:59 ` Andrew Morton
2022-06-20 1:37 ` Miaohe Lin
0 siblings, 1 reply; 3+ messages in thread
From: Andrew Morton @ 2022-06-18 18:59 UTC (permalink / raw)
To: Miaohe Lin; +Cc: linux-mm, linux-kernel
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;
_
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] mm/madvise: minor cleanup for swapin_walk_pmd_entry()
2022-06-18 18:59 ` Andrew Morton
@ 2022-06-20 1:37 ` Miaohe Lin
0 siblings, 0 replies; 3+ messages in thread
From: Miaohe Lin @ 2022-06-20 1:37 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-mm, linux-kernel
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;
> _
>
> .
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-06-18 9:05 [PATCH] mm/madvise: minor cleanup for swapin_walk_pmd_entry() Miaohe Lin
2022-06-18 18:59 ` Andrew Morton
2022-06-20 1:37 ` Miaohe Lin
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