diff mbox series

[4/6] mm: memory: use a folio in do_cow_page()

Message ID 20231107135216.415926-5-wangkefeng.wang@huawei.com
State New
Headers
Series mm: cleanup and use more folio in page fault |

Commit Message

Kefeng Wang Nov. 7, 2023, 1:52 p.m. UTC 
  Use folio_prealloc() helper and convert to use a folio in
do_cow_page(), which save five compound_head() calls.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 mm/memory.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

Comments

Sidhartha Kumar Nov. 7, 2023, 6:27 p.m. UTC | #1 
On 11/7/23 5:52 AM, Kefeng Wang wrote:
> Use folio_prealloc() helper and convert to use a folio in
> do_cow_page(), which save five compound_head() calls.
> 
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
>   mm/memory.c | 16 ++++++----------
>   1 file changed, 6 insertions(+), 10 deletions(-)
> 
> diff --git a/mm/memory.c b/mm/memory.c
> index 062136d25da3..5ecee3eac29d 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -4648,6 +4648,7 @@ static vm_fault_t do_read_fault(struct vm_fault *vmf)
>   static vm_fault_t do_cow_fault(struct vm_fault *vmf)
>   {
>   	struct vm_area_struct *vma = vmf->vma;
> +	struct folio *folio;
>   	vm_fault_t ret;
>   
>   	ret = vmf_can_call_fault(vmf);
> @@ -4656,16 +4657,11 @@ static vm_fault_t do_cow_fault(struct vm_fault *vmf)
>   	if (ret)
>   		return ret;
>   
> -	vmf->cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vmf->address);
> -	if (!vmf->cow_page)
> +	folio = folio_prealloc(vma->vm_mm, vma, vmf->address, false);
> +	if (!folio)
>   		return VM_FAULT_OOM;
>   
> -	if (mem_cgroup_charge(page_folio(vmf->cow_page), vma->vm_mm,
> -				GFP_KERNEL)) {
> -		put_page(vmf->cow_page);
> -		return VM_FAULT_OOM;
> -	}
> -	folio_throttle_swaprate(page_folio(vmf->cow_page), GFP_KERNEL);

Hi Kefeng,

I was wondering why this block of code is no longer needed after using a 
folio?

Thanks,
Sidhartha Kumar

> +	vmf->cow_page = &folio->page;
>   
>   	ret = __do_fault(vmf);
>   	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
> @@ -4674,7 +4670,7 @@ static vm_fault_t do_cow_fault(struct vm_fault *vmf)
>   		return ret;
>   
>   	copy_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma);
> -	__SetPageUptodate(vmf->cow_page);
> +	__folio_mark_uptodate(folio);
>   
>   	ret |= finish_fault(vmf);
>   	unlock_page(vmf->page);
> @@ -4683,7 +4679,7 @@ static vm_fault_t do_cow_fault(struct vm_fault *vmf)
>   		goto uncharge_out;
>   	return ret;
>   uncharge_out:
> -	put_page(vmf->cow_page);
> +	folio_put(folio);
>   	return ret;
>   }
>
Kefeng Wang Nov. 8, 2023, 1:41 a.m. UTC | #2 
On 2023/11/8 2:27, Sidhartha Kumar wrote:
> On 11/7/23 5:52 AM, Kefeng Wang wrote:
>> Use folio_prealloc() helper and convert to use a folio in
>> do_cow_page(), which save five compound_head() calls.
>>
>> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
>> ---
>>   mm/memory.c | 16 ++++++----------
>>   1 file changed, 6 insertions(+), 10 deletions(-)
>>
>> diff --git a/mm/memory.c b/mm/memory.c
>> index 062136d25da3..5ecee3eac29d 100644
>> --- a/mm/memory.c
>> +++ b/mm/memory.c
>> @@ -4648,6 +4648,7 @@ static vm_fault_t do_read_fault(struct vm_fault 
>> *vmf)
>>   static vm_fault_t do_cow_fault(struct vm_fault *vmf)
>>   {
>>       struct vm_area_struct *vma = vmf->vma;
>> +    struct folio *folio;
>>       vm_fault_t ret;
>>       ret = vmf_can_call_fault(vmf);
>> @@ -4656,16 +4657,11 @@ static vm_fault_t do_cow_fault(struct vm_fault 
>> *vmf)
>>       if (ret)
>>           return ret;
>> -    vmf->cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, 
>> vmf->address);
>> -    if (!vmf->cow_page)
>> +    folio = folio_prealloc(vma->vm_mm, vma, vmf->address, false);
>> +    if (!folio)
>>           return VM_FAULT_OOM;
>> -    if (mem_cgroup_charge(page_folio(vmf->cow_page), vma->vm_mm,
>> -                GFP_KERNEL)) {
>> -        put_page(vmf->cow_page);
>> -        return VM_FAULT_OOM;
>> -    }
>> -    folio_throttle_swaprate(page_folio(vmf->cow_page), GFP_KERNEL);
> 
> Hi Kefeng,
> 
> I was wondering why this block of code is no longer needed after using a 
> folio?

folio_prealloc(previous page_copy_prealloc) already with above code.

> 
> Thanks,
> Sidhartha Kumar
> 
>> +    vmf->cow_page = &folio->page;
>>       ret = __do_fault(vmf);
>>       if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | 
>> VM_FAULT_RETRY)))
>> @@ -4674,7 +4670,7 @@ static vm_fault_t do_cow_fault(struct vm_fault 
>> *vmf)
>>           return ret;
>>       copy_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma);
>> -    __SetPageUptodate(vmf->cow_page);
>> +    __folio_mark_uptodate(folio);
>>       ret |= finish_fault(vmf);
>>       unlock_page(vmf->page);
>> @@ -4683,7 +4679,7 @@ static vm_fault_t do_cow_fault(struct vm_fault 
>> *vmf)
>>           goto uncharge_out;
>>       return ret;
>>   uncharge_out:
>> -    put_page(vmf->cow_page);
>> +    folio_put(folio);
>>       return ret;
>>   }
>
diff mbox series

Patch

diff --git a/mm/memory.c b/mm/memory.c
index 062136d25da3..5ecee3eac29d 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4648,6 +4648,7 @@  static vm_fault_t do_read_fault(struct vm_fault *vmf)
 static vm_fault_t do_cow_fault(struct vm_fault *vmf)
 {
 	struct vm_area_struct *vma = vmf->vma;
+	struct folio *folio;
 	vm_fault_t ret;
 
 	ret = vmf_can_call_fault(vmf);
@@ -4656,16 +4657,11 @@  static vm_fault_t do_cow_fault(struct vm_fault *vmf)
 	if (ret)
 		return ret;
 
-	vmf->cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vmf->address);
-	if (!vmf->cow_page)
+	folio = folio_prealloc(vma->vm_mm, vma, vmf->address, false);
+	if (!folio)
 		return VM_FAULT_OOM;
 
-	if (mem_cgroup_charge(page_folio(vmf->cow_page), vma->vm_mm,
-				GFP_KERNEL)) {
-		put_page(vmf->cow_page);
-		return VM_FAULT_OOM;
-	}
-	folio_throttle_swaprate(page_folio(vmf->cow_page), GFP_KERNEL);
+	vmf->cow_page = &folio->page;
 
 	ret = __do_fault(vmf);
 	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
@@ -4674,7 +4670,7 @@  static vm_fault_t do_cow_fault(struct vm_fault *vmf)
 		return ret;
 
 	copy_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma);
-	__SetPageUptodate(vmf->cow_page);
+	__folio_mark_uptodate(folio);
 
 	ret |= finish_fault(vmf);
 	unlock_page(vmf->page);
@@ -4683,7 +4679,7 @@  static vm_fault_t do_cow_fault(struct vm_fault *vmf)
 		goto uncharge_out;
 	return ret;
 uncharge_out:
-	put_page(vmf->cow_page);
+	folio_put(folio);
 	return ret;
 }