1. Patchew
  2. linux
  3. [PATCH v2 0/8] mm/gup: Unify hugetlb, speed up thp
  4. View patch

[PATCH v2 3/8] mm/hugetlb: Add page_mask for hugetlb_follow_page_mask()

Peter Xu posted 8 patches 2 years, 7 months ago
There is a newer version of this series
[PATCH v2 3/8] mm/hugetlb: Add page_mask for hugetlb_follow_page_mask()
Posted by Peter Xu 2 years, 7 months ago 
follow_page() doesn't need it, but we'll start to need it when unifying gup
for hugetlb.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 include/linux/hugetlb.h | 8 +++++---
 mm/gup.c                | 3 ++-
 mm/hugetlb.c            | 5 ++++-
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index beb7c63d2871..2e2d89e79d6c 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -131,7 +131,8 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma,
 int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *,
 			    struct vm_area_struct *, struct vm_area_struct *);
 struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
-				unsigned long address, unsigned int flags);
+				      unsigned long address, unsigned int flags,
+				      unsigned int *page_mask);
 long follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *,
 			 struct page **, unsigned long *, unsigned long *,
 			 long, unsigned int, int *);
@@ -297,8 +298,9 @@ static inline void adjust_range_if_pmd_sharing_possible(
 {
 }
 
-static inline struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
-				unsigned long address, unsigned int flags)
+static inline struct page *hugetlb_follow_page_mask(
+    struct vm_area_struct *vma, unsigned long address, unsigned int flags,
+    unsigned int *page_mask)
 {
 	BUILD_BUG(); /* should never be compiled in if !CONFIG_HUGETLB_PAGE*/
 }
diff --git a/mm/gup.c b/mm/gup.c
index abcd841d94b7..9fc9271cba8d 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -780,7 +780,8 @@ static struct page *follow_page_mask(struct vm_area_struct *vma,
 	 * Ordinary GUP uses follow_hugetlb_page for hugetlb processing.
 	 */
 	if (is_vm_hugetlb_page(vma))
-		return hugetlb_follow_page_mask(vma, address, flags);
+		return hugetlb_follow_page_mask(vma, address, flags,
+						&ctx->page_mask);
 
 	pgd = pgd_offset(mm, address);
 
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 9a6918c4250a..fbf6a09c0ec4 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6454,7 +6454,8 @@ static inline bool __follow_hugetlb_must_fault(struct vm_area_struct *vma,
 }
 
 struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
-				unsigned long address, unsigned int flags)
+				      unsigned long address, unsigned int flags,
+				      unsigned int *page_mask)
 {
 	struct hstate *h = hstate_vma(vma);
 	struct mm_struct *mm = vma->vm_mm;
@@ -6499,6 +6500,8 @@ struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
 			page = NULL;
 			goto out;
 		}
+
+		*page_mask = ~huge_page_mask(h) >> PAGE_SHIFT;
 	}
 out:
 	spin_unlock(ptl);
-- 
2.40.1
Re: [PATCH v2 3/8] mm/hugetlb: Add page_mask for hugetlb_follow_page_mask()
Posted by David Hildenbrand 2 years, 7 months ago 
On 20.06.23 01:10, Peter Xu wrote:
> follow_page() doesn't need it, but we'll start to need it when unifying gup
> for hugetlb.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>   include/linux/hugetlb.h | 8 +++++---
>   mm/gup.c                | 3 ++-
>   mm/hugetlb.c            | 5 ++++-
>   3 files changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index beb7c63d2871..2e2d89e79d6c 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
> @@ -131,7 +131,8 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma,
>   int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *,
>   			    struct vm_area_struct *, struct vm_area_struct *);
>   struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
> -				unsigned long address, unsigned int flags);
> +				      unsigned long address, unsigned int flags,
> +				      unsigned int *page_mask);
>   long follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *,
>   			 struct page **, unsigned long *, unsigned long *,
>   			 long, unsigned int, int *);
> @@ -297,8 +298,9 @@ static inline void adjust_range_if_pmd_sharing_possible(
>   {
>   }
>   
> -static inline struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
> -				unsigned long address, unsigned int flags)
> +static inline struct page *hugetlb_follow_page_mask(
> +    struct vm_area_struct *vma, unsigned long address, unsigned int flags,
> +    unsigned int *page_mask)
>   {
>   	BUILD_BUG(); /* should never be compiled in if !CONFIG_HUGETLB_PAGE*/
>   }
> diff --git a/mm/gup.c b/mm/gup.c
> index abcd841d94b7..9fc9271cba8d 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -780,7 +780,8 @@ static struct page *follow_page_mask(struct vm_area_struct *vma,
>   	 * Ordinary GUP uses follow_hugetlb_page for hugetlb processing.
>   	 */
>   	if (is_vm_hugetlb_page(vma))
> -		return hugetlb_follow_page_mask(vma, address, flags);
> +		return hugetlb_follow_page_mask(vma, address, flags,
> +						&ctx->page_mask);
>   
>   	pgd = pgd_offset(mm, address);
>   
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 9a6918c4250a..fbf6a09c0ec4 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -6454,7 +6454,8 @@ static inline bool __follow_hugetlb_must_fault(struct vm_area_struct *vma,
>   }
>   
>   struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
> -				unsigned long address, unsigned int flags)
> +				      unsigned long address, unsigned int flags,
> +				      unsigned int *page_mask)
>   {
>   	struct hstate *h = hstate_vma(vma);
>   	struct mm_struct *mm = vma->vm_mm;
> @@ -6499,6 +6500,8 @@ struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
>   			page = NULL;
>   			goto out;
>   		}
> +
> +		*page_mask = ~huge_page_mask(h) >> PAGE_SHIFT;

As discussed, can be simplified. But can be done on top (or not at all, 
but it is confusing code).

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 
Cheers,

David / dhildenb
Re: [PATCH v2 3/8] mm/hugetlb: Add page_mask for hugetlb_follow_page_mask()
Posted by Peter Xu 2 years, 7 months ago 
On Tue, Jun 20, 2023 at 05:23:09PM +0200, David Hildenbrand wrote:
> On 20.06.23 01:10, Peter Xu wrote:
> > follow_page() doesn't need it, but we'll start to need it when unifying gup
> > for hugetlb.
> > 
> > Signed-off-by: Peter Xu <peterx@redhat.com>
> > ---
> >   include/linux/hugetlb.h | 8 +++++---
> >   mm/gup.c                | 3 ++-
> >   mm/hugetlb.c            | 5 ++++-
> >   3 files changed, 11 insertions(+), 5 deletions(-)
> > 
> > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> > index beb7c63d2871..2e2d89e79d6c 100644
> > --- a/include/linux/hugetlb.h
> > +++ b/include/linux/hugetlb.h
> > @@ -131,7 +131,8 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma,
> >   int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *,
> >   			    struct vm_area_struct *, struct vm_area_struct *);
> >   struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
> > -				unsigned long address, unsigned int flags);
> > +				      unsigned long address, unsigned int flags,
> > +				      unsigned int *page_mask);
> >   long follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *,
> >   			 struct page **, unsigned long *, unsigned long *,
> >   			 long, unsigned int, int *);
> > @@ -297,8 +298,9 @@ static inline void adjust_range_if_pmd_sharing_possible(
> >   {
> >   }
> > -static inline struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
> > -				unsigned long address, unsigned int flags)
> > +static inline struct page *hugetlb_follow_page_mask(
> > +    struct vm_area_struct *vma, unsigned long address, unsigned int flags,
> > +    unsigned int *page_mask)
> >   {
> >   	BUILD_BUG(); /* should never be compiled in if !CONFIG_HUGETLB_PAGE*/
> >   }
> > diff --git a/mm/gup.c b/mm/gup.c
> > index abcd841d94b7..9fc9271cba8d 100644
> > --- a/mm/gup.c
> > +++ b/mm/gup.c
> > @@ -780,7 +780,8 @@ static struct page *follow_page_mask(struct vm_area_struct *vma,
> >   	 * Ordinary GUP uses follow_hugetlb_page for hugetlb processing.
> >   	 */
> >   	if (is_vm_hugetlb_page(vma))
> > -		return hugetlb_follow_page_mask(vma, address, flags);
> > +		return hugetlb_follow_page_mask(vma, address, flags,
> > +						&ctx->page_mask);
> >   	pgd = pgd_offset(mm, address);
> > diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> > index 9a6918c4250a..fbf6a09c0ec4 100644
> > --- a/mm/hugetlb.c
> > +++ b/mm/hugetlb.c
> > @@ -6454,7 +6454,8 @@ static inline bool __follow_hugetlb_must_fault(struct vm_area_struct *vma,
> >   }
> >   struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
> > -				unsigned long address, unsigned int flags)
> > +				      unsigned long address, unsigned int flags,
> > +				      unsigned int *page_mask)
> >   {
> >   	struct hstate *h = hstate_vma(vma);
> >   	struct mm_struct *mm = vma->vm_mm;
> > @@ -6499,6 +6500,8 @@ struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
> >   			page = NULL;
> >   			goto out;
> >   		}
> > +
> > +		*page_mask = ~huge_page_mask(h) >> PAGE_SHIFT;
> 
> As discussed, can be simplified. But can be done on top (or not at all, but
> it is confusing code).

Since we decided to make this prettier..  At last I decided to go with this:

		*page_mask = (1U << huge_page_order(h)) - 1;

The previous suggestion of PHYS_PFN() will do two shifts over PAGE_SIZE
(the other one in huge_page_size()) which might be unnecessary, also, PHYS_
can be slightly misleading too as prefix.

> 
> Reviewed-by: David Hildenbrand <david@redhat.com>

I'll take this with above change, please shoot if not applicable.  Thanks,

-- 
Peter Xu
Re: [PATCH v2 3/8] mm/hugetlb: Add page_mask for hugetlb_follow_page_mask()
Posted by David Hildenbrand 2 years, 7 months ago 
On 20.06.23 18:28, Peter Xu wrote:
> On Tue, Jun 20, 2023 at 05:23:09PM +0200, David Hildenbrand wrote:
>> On 20.06.23 01:10, Peter Xu wrote:
>>> follow_page() doesn't need it, but we'll start to need it when unifying gup
>>> for hugetlb.
>>>
>>> Signed-off-by: Peter Xu <peterx@redhat.com>
>>> ---
>>>    include/linux/hugetlb.h | 8 +++++---
>>>    mm/gup.c                | 3 ++-
>>>    mm/hugetlb.c            | 5 ++++-
>>>    3 files changed, 11 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
>>> index beb7c63d2871..2e2d89e79d6c 100644
>>> --- a/include/linux/hugetlb.h
>>> +++ b/include/linux/hugetlb.h
>>> @@ -131,7 +131,8 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma,
>>>    int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *,
>>>    			    struct vm_area_struct *, struct vm_area_struct *);
>>>    struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
>>> -				unsigned long address, unsigned int flags);
>>> +				      unsigned long address, unsigned int flags,
>>> +				      unsigned int *page_mask);
>>>    long follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *,
>>>    			 struct page **, unsigned long *, unsigned long *,
>>>    			 long, unsigned int, int *);
>>> @@ -297,8 +298,9 @@ static inline void adjust_range_if_pmd_sharing_possible(
>>>    {
>>>    }
>>> -static inline struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
>>> -				unsigned long address, unsigned int flags)
>>> +static inline struct page *hugetlb_follow_page_mask(
>>> +    struct vm_area_struct *vma, unsigned long address, unsigned int flags,
>>> +    unsigned int *page_mask)
>>>    {
>>>    	BUILD_BUG(); /* should never be compiled in if !CONFIG_HUGETLB_PAGE*/
>>>    }
>>> diff --git a/mm/gup.c b/mm/gup.c
>>> index abcd841d94b7..9fc9271cba8d 100644
>>> --- a/mm/gup.c
>>> +++ b/mm/gup.c
>>> @@ -780,7 +780,8 @@ static struct page *follow_page_mask(struct vm_area_struct *vma,
>>>    	 * Ordinary GUP uses follow_hugetlb_page for hugetlb processing.
>>>    	 */
>>>    	if (is_vm_hugetlb_page(vma))
>>> -		return hugetlb_follow_page_mask(vma, address, flags);
>>> +		return hugetlb_follow_page_mask(vma, address, flags,
>>> +						&ctx->page_mask);
>>>    	pgd = pgd_offset(mm, address);
>>> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
>>> index 9a6918c4250a..fbf6a09c0ec4 100644
>>> --- a/mm/hugetlb.c
>>> +++ b/mm/hugetlb.c
>>> @@ -6454,7 +6454,8 @@ static inline bool __follow_hugetlb_must_fault(struct vm_area_struct *vma,
>>>    }
>>>    struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
>>> -				unsigned long address, unsigned int flags)
>>> +				      unsigned long address, unsigned int flags,
>>> +				      unsigned int *page_mask)
>>>    {
>>>    	struct hstate *h = hstate_vma(vma);
>>>    	struct mm_struct *mm = vma->vm_mm;
>>> @@ -6499,6 +6500,8 @@ struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
>>>    			page = NULL;
>>>    			goto out;
>>>    		}
>>> +
>>> +		*page_mask = ~huge_page_mask(h) >> PAGE_SHIFT;
>>
>> As discussed, can be simplified. But can be done on top (or not at all, but
>> it is confusing code).
> 
> Since we decided to make this prettier..  At last I decided to go with this:
> 
> 		*page_mask = (1U << huge_page_order(h)) - 1;
> 
> The previous suggestion of PHYS_PFN() will do two shifts over PAGE_SIZE
> (the other one in huge_page_size()) which might be unnecessary, also, PHYS_
> can be slightly misleading too as prefix.
> 
>>
>> Reviewed-by: David Hildenbrand <david@redhat.com>
> 
> I'll take this with above change, please shoot if not applicable.  Thanks,
> 

Perfectly fine :)

-- 
Cheers,

David / dhildenb

Patchew 2.1-devel-b67e4c2

© 2016 - 2026 Red Hat, Inc.