[PATCH] mm/mmap: introduce vma_range_init()

[PATCH] mm/mmap: introduce vma_range_init()

[Yajun Deng]

There is a lot of code needs to set the range of vma, introduce
vma_range_init() to initialize the range of vma.

Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
---
 include/linux/mm.h |  9 +++++++++
 mm/mmap.c          | 29 +++++++----------------------
 2 files changed, 16 insertions(+), 22 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index f5a97dec5169..abb4534be3cc 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3516,6 +3516,15 @@ static inline bool range_in_vma(struct vm_area_struct *vma,
 	return (vma && vma->vm_start <= start && end <= vma->vm_end);
 }
 
+static inline void vma_range_init(struct vm_area_struct *vma,
+				  unsigned long start, unsigned long end,
+				  pgoff_t pgoff)
+{
+	vma->vm_start = start;
+	vma->vm_end = end;
+	vma->vm_pgoff = pgoff;
+}
+
 #ifdef CONFIG_MMU
 pgprot_t vm_get_page_prot(unsigned long vm_flags);
 void vma_set_page_prot(struct vm_area_struct *vma);
diff --git a/mm/mmap.c b/mm/mmap.c
index 06f1f3e88598..0d3f4612d001 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -663,9 +663,7 @@ int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
 
 	vma_prepare(&vp);
 	vma_adjust_trans_huge(vma, start, end, 0);
-	vma->vm_start = start;
-	vma->vm_end = end;
-	vma->vm_pgoff = pgoff;
+	vma_range_init(vma, start, end, pgoff);
 	vma_iter_store(vmi, vma);
 
 	vma_complete(&vp, vmi, vma->vm_mm);
@@ -708,9 +706,7 @@ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma,
 	vma_adjust_trans_huge(vma, start, end, 0);
 
 	vma_iter_clear(vmi);
-	vma->vm_start = start;
-	vma->vm_end = end;
-	vma->vm_pgoff = pgoff;
+	vma_range_init(vma, start, end, pgoff);
 	vma_complete(&vp, vmi, vma->vm_mm);
 	return 0;
 }
@@ -1015,10 +1011,7 @@ static struct vm_area_struct
 
 	vma_prepare(&vp);
 	vma_adjust_trans_huge(vma, vma_start, vma_end, adj_start);
-
-	vma->vm_start = vma_start;
-	vma->vm_end = vma_end;
-	vma->vm_pgoff = vma_pgoff;
+	vma_range_init(vma, vma_start, vma_end, vma_pgoff);
 
 	if (vma_expanded)
 		vma_iter_store(vmi, vma);
@@ -2811,11 +2804,9 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 	}
 
 	vma_iter_config(&vmi, addr, end);
-	vma->vm_start = addr;
-	vma->vm_end = end;
+	vma_range_init(vma, addr, end, pgoff);
 	vm_flags_init(vma, vm_flags);
 	vma->vm_page_prot = vm_get_page_prot(vm_flags);
-	vma->vm_pgoff = pgoff;
 
 	if (file) {
 		vma->vm_file = get_file(file);
@@ -3165,9 +3156,7 @@ static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma,
 		goto unacct_fail;
 
 	vma_set_anonymous(vma);
-	vma->vm_start = addr;
-	vma->vm_end = addr + len;
-	vma->vm_pgoff = addr >> PAGE_SHIFT;
+	vma_range_init(vma, addr, addr + len, addr >> PAGE_SHIFT);
 	vm_flags_init(vma, flags);
 	vma->vm_page_prot = vm_get_page_prot(flags);
 	vma_start_write(vma);
@@ -3404,9 +3393,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
 		new_vma = vm_area_dup(vma);
 		if (!new_vma)
 			goto out;
-		new_vma->vm_start = addr;
-		new_vma->vm_end = addr + len;
-		new_vma->vm_pgoff = pgoff;
+		vma_range_init(new_vma, addr, addr + len, pgoff);
 		if (vma_dup_policy(vma, new_vma))
 			goto out_free_vma;
 		if (anon_vma_clone(new_vma, vma))
@@ -3574,9 +3561,7 @@ static struct vm_area_struct *__install_special_mapping(
 	if (unlikely(vma == NULL))
 		return ERR_PTR(-ENOMEM);
 
-	vma->vm_start = addr;
-	vma->vm_end = addr + len;
-
+	vma_range_init(vma, addr, addr + len, 0);
 	vm_flags_init(vma, (vm_flags | mm->def_flags |
 		      VM_DONTEXPAND | VM_SOFTDIRTY) & ~VM_LOCKED_MASK);
 	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
-- 
2.25.1

Re: [PATCH] mm/mmap: introduce vma_range_init()

[Liam R. Howlett]

* Yajun Deng <yajun.deng@linux.dev> [240110 21:15]:
> There is a lot of code needs to set the range of vma, introduce
> vma_range_init() to initialize the range of vma.
> 
> Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
> ---
>  include/linux/mm.h |  9 +++++++++
>  mm/mmap.c          | 29 +++++++----------------------
>  2 files changed, 16 insertions(+), 22 deletions(-)

This isn't a whole lot of code, are there others?  We're losing code
clarity in favour of saving 6 lines?

> 
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index f5a97dec5169..abb4534be3cc 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -3516,6 +3516,15 @@ static inline bool range_in_vma(struct vm_area_struct *vma,
>  	return (vma && vma->vm_start <= start && end <= vma->vm_end);
>  }
>  
> +static inline void vma_range_init(struct vm_area_struct *vma,

Any reason this can't be in mm/internal.h ?

vma_range_set(), vma_set_range(), or just vma_range() might be a better
name?  My thinking is that some of these are actually modifying the vma
and not just initializing it, right?

> +				  unsigned long start, unsigned long end,
> +				  pgoff_t pgoff)
> +{
> +	vma->vm_start = start;
> +	vma->vm_end = end;
> +	vma->vm_pgoff = pgoff;
> +}
> +
>  #ifdef CONFIG_MMU
>  pgprot_t vm_get_page_prot(unsigned long vm_flags);
>  void vma_set_page_prot(struct vm_area_struct *vma);
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 06f1f3e88598..0d3f4612d001 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -663,9 +663,7 @@ int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
>  
>  	vma_prepare(&vp);
>  	vma_adjust_trans_huge(vma, start, end, 0);
> -	vma->vm_start = start;
> -	vma->vm_end = end;
> -	vma->vm_pgoff = pgoff;
> +	vma_range_init(vma, start, end, pgoff);
>  	vma_iter_store(vmi, vma);
>  
>  	vma_complete(&vp, vmi, vma->vm_mm);
> @@ -708,9 +706,7 @@ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma,
>  	vma_adjust_trans_huge(vma, start, end, 0);
>  
>  	vma_iter_clear(vmi);
> -	vma->vm_start = start;
> -	vma->vm_end = end;
> -	vma->vm_pgoff = pgoff;
> +	vma_range_init(vma, start, end, pgoff);
>  	vma_complete(&vp, vmi, vma->vm_mm);
>  	return 0;
>  }
> @@ -1015,10 +1011,7 @@ static struct vm_area_struct
>  
>  	vma_prepare(&vp);
>  	vma_adjust_trans_huge(vma, vma_start, vma_end, adj_start);
> -
> -	vma->vm_start = vma_start;
> -	vma->vm_end = vma_end;
> -	vma->vm_pgoff = vma_pgoff;
> +	vma_range_init(vma, vma_start, vma_end, vma_pgoff);
>  
>  	if (vma_expanded)
>  		vma_iter_store(vmi, vma);
> @@ -2811,11 +2804,9 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
>  	}
>  
>  	vma_iter_config(&vmi, addr, end);
> -	vma->vm_start = addr;
> -	vma->vm_end = end;
> +	vma_range_init(vma, addr, end, pgoff);
>  	vm_flags_init(vma, vm_flags);
>  	vma->vm_page_prot = vm_get_page_prot(vm_flags);
> -	vma->vm_pgoff = pgoff;
>  
>  	if (file) {
>  		vma->vm_file = get_file(file);
> @@ -3165,9 +3156,7 @@ static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma,
>  		goto unacct_fail;
>  
>  	vma_set_anonymous(vma);
> -	vma->vm_start = addr;
> -	vma->vm_end = addr + len;
> -	vma->vm_pgoff = addr >> PAGE_SHIFT;
> +	vma_range_init(vma, addr, addr + len, addr >> PAGE_SHIFT);
>  	vm_flags_init(vma, flags);
>  	vma->vm_page_prot = vm_get_page_prot(flags);
>  	vma_start_write(vma);
> @@ -3404,9 +3393,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
>  		new_vma = vm_area_dup(vma);
>  		if (!new_vma)
>  			goto out;
> -		new_vma->vm_start = addr;
> -		new_vma->vm_end = addr + len;
> -		new_vma->vm_pgoff = pgoff;
> +		vma_range_init(new_vma, addr, addr + len, pgoff);
>  		if (vma_dup_policy(vma, new_vma))
>  			goto out_free_vma;
>  		if (anon_vma_clone(new_vma, vma))
> @@ -3574,9 +3561,7 @@ static struct vm_area_struct *__install_special_mapping(
>  	if (unlikely(vma == NULL))
>  		return ERR_PTR(-ENOMEM);
>  
> -	vma->vm_start = addr;
> -	vma->vm_end = addr + len;
> -
> +	vma_range_init(vma, addr, addr + len, 0);
>  	vm_flags_init(vma, (vm_flags | mm->def_flags |
>  		      VM_DONTEXPAND | VM_SOFTDIRTY) & ~VM_LOCKED_MASK);
>  	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
> -- 
> 2.25.1
> 
> 

Re: [PATCH] mm/mmap: introduce vma_range_init()

[Andrew Morton]

On Mon, 22 Jan 2024 17:00:31 -0500 "Liam R. Howlett" <Liam.Howlett@Oracle.com> wrote:

> * Yajun Deng <yajun.deng@linux.dev> [240110 21:15]:
> > There is a lot of code needs to set the range of vma, introduce
> > vma_range_init() to initialize the range of vma.
> > 
> > Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
> > ---
> >  include/linux/mm.h |  9 +++++++++
> >  mm/mmap.c          | 29 +++++++----------------------
> >  2 files changed, 16 insertions(+), 22 deletions(-)
> 
> This isn't a whole lot of code, are there others?  We're losing code
> clarity in favour of saving 6 lines?
> 

Oh.  I thought it was a nice cleanup which made things more clear.

> > diff --git a/include/linux/mm.h b/include/linux/mm.h
> > index f5a97dec5169..abb4534be3cc 100644
> > --- a/include/linux/mm.h
> > +++ b/include/linux/mm.h
> > @@ -3516,6 +3516,15 @@ static inline bool range_in_vma(struct vm_area_struct *vma,
> >  	return (vma && vma->vm_start <= start && end <= vma->vm_end);
> >  }
> >  
> > +static inline void vma_range_init(struct vm_area_struct *vma,
> 
> Any reason this can't be in mm/internal.h ?

That would be good.

> vma_range_set(), vma_set_range(), or just vma_range() might be a better
> name?  My thinking is that some of these are actually modifying the vma
> and not just initializing it, right?

I'd vote for vma_set_range().

Re: [PATCH] mm/mmap: introduce vma_range_init()

[Liam R. Howlett]

* Andrew Morton <akpm@linux-foundation.org> [240122 18:40]:
> On Mon, 22 Jan 2024 17:00:31 -0500 "Liam R. Howlett" <Liam.Howlett@Oracle.com> wrote:
> 
> > * Yajun Deng <yajun.deng@linux.dev> [240110 21:15]:
> > > There is a lot of code needs to set the range of vma, introduce
> > > vma_range_init() to initialize the range of vma.
> > > 
> > > Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
> > > ---
> > >  include/linux/mm.h |  9 +++++++++
> > >  mm/mmap.c          | 29 +++++++----------------------
> > >  2 files changed, 16 insertions(+), 22 deletions(-)
> > 
> > This isn't a whole lot of code, are there others?  We're losing code
> > clarity in favour of saving 6 lines?
> > 
> 
> Oh.  I thought it was a nice cleanup which made things more clear.

I'm not totally against it; that's why I suggested the changes below. I
think a name change would go a long way for clarity. It's not as much as
I though it would be though.

> 
> > > diff --git a/include/linux/mm.h b/include/linux/mm.h
> > > index f5a97dec5169..abb4534be3cc 100644
> > > --- a/include/linux/mm.h
> > > +++ b/include/linux/mm.h
> > > @@ -3516,6 +3516,15 @@ static inline bool range_in_vma(struct vm_area_struct *vma,
> > >  	return (vma && vma->vm_start <= start && end <= vma->vm_end);
> > >  }
> > >  
> > > +static inline void vma_range_init(struct vm_area_struct *vma,
> > 
> > Any reason this can't be in mm/internal.h ?
> 
> That would be good.

One other thing, do we trust this to be inlined correctly by the
compiler or should this be __always_inline?  I'd expect it to be okay as
it is, but I've been proven wrong in a perf trace before..

> 
> > vma_range_set(), vma_set_range(), or just vma_range() might be a better
> > name?  My thinking is that some of these are actually modifying the vma
> > and not just initializing it, right?
> 
> I'd vote for vma_set_range().
> 

Using vma_set_range() leaves vma_range() or vma_size(), which could be
added for the calculations of vma->vm_end - vma->vm_start.  Davidlohr
suggested such a beast a few years ago, but that one would need to live
in the include/linux/mm.h as it occurs a lot more.

$ git grep "vma->vm_end - vma->vm_start" | wc -l
198

.. for just those named vma.

Re: [PATCH] mm/mmap: introduce vma_range_init()

[Yajun Deng]

On 2024/1/23 08:18, Liam R. Howlett wrote:
> * Andrew Morton <akpm@linux-foundation.org> [240122 18:40]:
>> On Mon, 22 Jan 2024 17:00:31 -0500 "Liam R. Howlett" <Liam.Howlett@Oracle.com> wrote:
>>
>>> * Yajun Deng <yajun.deng@linux.dev> [240110 21:15]:
>>>> There is a lot of code needs to set the range of vma, introduce
>>>> vma_range_init() to initialize the range of vma.
>>>>
>>>> Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
>>>> ---
>>>>   include/linux/mm.h |  9 +++++++++
>>>>   mm/mmap.c          | 29 +++++++----------------------
>>>>   2 files changed, 16 insertions(+), 22 deletions(-)
>>> This isn't a whole lot of code, are there others?  We're losing code
>>> clarity in favour of saving 6 lines?
>>>
>> Oh.  I thought it was a nice cleanup which made things more clear.
> I'm not totally against it; that's why I suggested the changes below. I
> think a name change would go a long way for clarity. It's not as much as
> I though it would be though.
>
>>>> diff --git a/include/linux/mm.h b/include/linux/mm.h
>>>> index f5a97dec5169..abb4534be3cc 100644
>>>> --- a/include/linux/mm.h
>>>> +++ b/include/linux/mm.h
>>>> @@ -3516,6 +3516,15 @@ static inline bool range_in_vma(struct vm_area_struct *vma,
>>>>   	return (vma && vma->vm_start <= start && end <= vma->vm_end);
>>>>   }
>>>>   
>>>> +static inline void vma_range_init(struct vm_area_struct *vma,
>>> Any reason this can't be in mm/internal.h ?
>> That would be good.
> One other thing, do we trust this to be inlined correctly by the
> compiler or should this be __always_inline?  I'd expect it to be okay as
> it is, but I've been proven wrong in a perf trace before..
>

Okay, I would take __always_inline and put it in mm/internal.h in v2.

>>> vma_range_set(), vma_set_range(), or just vma_range() might be a better
>>> name?  My thinking is that some of these are actually modifying the vma
>>> and not just initializing it, right?
>> I'd vote for vma_set_range().
>>
> Using vma_set_range() leaves vma_range() or vma_size(), which could be
> added for the calculations of vma->vm_end - vma->vm_start.  Davidlohr
> suggested such a beast a few years ago, but that one would need to live
> in the include/linux/mm.h as it occurs a lot more.
>
> $ git grep "vma->vm_end - vma->vm_start" | wc -l
> 198
>
> .. for just those named vma.
>

Re: [PATCH] mm/mmap: introduce vma_range_init()

[Liam R. Howlett]

* Yajun Deng <yajun.deng@linux.dev> [240122 21:23]:
> 
> On 2024/1/23 08:18, Liam R. Howlett wrote:
> > * Andrew Morton <akpm@linux-foundation.org> [240122 18:40]:
> > > On Mon, 22 Jan 2024 17:00:31 -0500 "Liam R. Howlett" <Liam.Howlett@Oracle.com> wrote:
> > > 
> > > > * Yajun Deng <yajun.deng@linux.dev> [240110 21:15]:
> > > > > There is a lot of code needs to set the range of vma, introduce
> > > > > vma_range_init() to initialize the range of vma.
> > > > > 
> > > > > Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
> > > > > ---
> > > > >   include/linux/mm.h |  9 +++++++++
> > > > >   mm/mmap.c          | 29 +++++++----------------------
> > > > >   2 files changed, 16 insertions(+), 22 deletions(-)
> > > > This isn't a whole lot of code, are there others?  We're losing code
> > > > clarity in favour of saving 6 lines?
> > > > 
> > > Oh.  I thought it was a nice cleanup which made things more clear.
> > I'm not totally against it; that's why I suggested the changes below. I
> > think a name change would go a long way for clarity. It's not as much as
> > I though it would be though.
> > 
> > > > > diff --git a/include/linux/mm.h b/include/linux/mm.h
> > > > > index f5a97dec5169..abb4534be3cc 100644
> > > > > --- a/include/linux/mm.h
> > > > > +++ b/include/linux/mm.h
> > > > > @@ -3516,6 +3516,15 @@ static inline bool range_in_vma(struct vm_area_struct *vma,
> > > > >   	return (vma && vma->vm_start <= start && end <= vma->vm_end);
> > > > >   }
> > > > > +static inline void vma_range_init(struct vm_area_struct *vma,
> > > > Any reason this can't be in mm/internal.h ?
> > > That would be good.
> > One other thing, do we trust this to be inlined correctly by the
> > compiler or should this be __always_inline?  I'd expect it to be okay as
> > it is, but I've been proven wrong in a perf trace before..
> > 
> 
> Okay, I would take __always_inline and put it in mm/internal.h in v2.

I'm not confident in this suggestion as the rest.
Please rename the function when you move it.

> 
> > > > vma_range_set(), vma_set_range(), or just vma_range() might be a better
> > > > name?  My thinking is that some of these are actually modifying the vma
> > > > and not just initializing it, right?
> > > I'd vote for vma_set_range().
                      ^  This part, use vma_set_range() please.

> > Using vma_set_range() leaves vma_range() or vma_size(), which could be
> > added for the calculations of vma->vm_end - vma->vm_start.  Davidlohr
> > suggested such a beast a few years ago, but that one would need to live
> > in the include/linux/mm.h as it occurs a lot more.
> > 
> > $ git grep "vma->vm_end - vma->vm_start" | wc -l
> > 198
> > 
> > .. for just those named vma.
> > 
> 

Re: [PATCH] mm/mmap: introduce vma_range_init()

[Yajun Deng]

On 2024/1/23 11:19, Liam R. Howlett wrote:
> * Yajun Deng <yajun.deng@linux.dev> [240122 21:23]:
>> On 2024/1/23 08:18, Liam R. Howlett wrote:
>>> * Andrew Morton <akpm@linux-foundation.org> [240122 18:40]:
>>>> On Mon, 22 Jan 2024 17:00:31 -0500 "Liam R. Howlett" <Liam.Howlett@Oracle.com> wrote:
>>>>
>>>>> * Yajun Deng <yajun.deng@linux.dev> [240110 21:15]:
>>>>>> There is a lot of code needs to set the range of vma, introduce
>>>>>> vma_range_init() to initialize the range of vma.
>>>>>>
>>>>>> Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
>>>>>> ---
>>>>>>    include/linux/mm.h |  9 +++++++++
>>>>>>    mm/mmap.c          | 29 +++++++----------------------
>>>>>>    2 files changed, 16 insertions(+), 22 deletions(-)
>>>>> This isn't a whole lot of code, are there others?  We're losing code
>>>>> clarity in favour of saving 6 lines?
>>>>>
>>>> Oh.  I thought it was a nice cleanup which made things more clear.
>>> I'm not totally against it; that's why I suggested the changes below. I
>>> think a name change would go a long way for clarity. It's not as much as
>>> I though it would be though.
>>>
>>>>>> diff --git a/include/linux/mm.h b/include/linux/mm.h
>>>>>> index f5a97dec5169..abb4534be3cc 100644
>>>>>> --- a/include/linux/mm.h
>>>>>> +++ b/include/linux/mm.h
>>>>>> @@ -3516,6 +3516,15 @@ static inline bool range_in_vma(struct vm_area_struct *vma,
>>>>>>    	return (vma && vma->vm_start <= start && end <= vma->vm_end);
>>>>>>    }
>>>>>> +static inline void vma_range_init(struct vm_area_struct *vma,
>>>>> Any reason this can't be in mm/internal.h ?
>>>> That would be good.
>>> One other thing, do we trust this to be inlined correctly by the
>>> compiler or should this be __always_inline?  I'd expect it to be okay as
>>> it is, but I've been proven wrong in a perf trace before..
>>>
>> Okay, I would take __always_inline and put it in mm/internal.h in v2.
> I'm not confident in this suggestion as the rest.
> Please rename the function when you move it.

inline is a suggestion, __always_inline is mandatory.
I think __always_inline is better if we're demanding.

>>>>> vma_range_set(), vma_set_range(), or just vma_range() might be a better
>>>>> name?  My thinking is that some of these are actually modifying the vma
>>>>> and not just initializing it, right?
>>>> I'd vote for vma_set_range().
>                        ^  This part, use vma_set_range() please.

Okay.


By the way, I sent another patch with ("mm/mmap: simplify vma_merge()") 
subject a few days ago.

Please comment if you would like.

>>> Using vma_set_range() leaves vma_range() or vma_size(), which could be
>>> added for the calculations of vma->vm_end - vma->vm_start.  Davidlohr
>>> suggested such a beast a few years ago, but that one would need to live
>>> in the include/linux/mm.h as it occurs a lot more.
>>>
>>> $ git grep "vma->vm_end - vma->vm_start" | wc -l
>>> 198
>>>
>>> .. for just those named vma.
>>>

Re: [PATCH] mm/mmap: introduce vma_range_init()

[Liam R. Howlett]

* Yajun Deng <yajun.deng@linux.dev> [240122 22:41]:
> 
> On 2024/1/23 11:19, Liam R. Howlett wrote:
> > * Yajun Deng <yajun.deng@linux.dev> [240122 21:23]:
> > > On 2024/1/23 08:18, Liam R. Howlett wrote:
> > > > * Andrew Morton <akpm@linux-foundation.org> [240122 18:40]:
> > > > > On Mon, 22 Jan 2024 17:00:31 -0500 "Liam R. Howlett" <Liam.Howlett@Oracle.com> wrote:
> > > > > 
> > > > > > * Yajun Deng <yajun.deng@linux.dev> [240110 21:15]:
> > > > > > > There is a lot of code needs to set the range of vma, introduce
> > > > > > > vma_range_init() to initialize the range of vma.
> > > > > > > 
> > > > > > > Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
> > > > > > > ---
> > > > > > >    include/linux/mm.h |  9 +++++++++
> > > > > > >    mm/mmap.c          | 29 +++++++----------------------
> > > > > > >    2 files changed, 16 insertions(+), 22 deletions(-)
> > > > > > This isn't a whole lot of code, are there others?  We're losing code
> > > > > > clarity in favour of saving 6 lines?
> > > > > > 
> > > > > Oh.  I thought it was a nice cleanup which made things more clear.
> > > > I'm not totally against it; that's why I suggested the changes below. I
> > > > think a name change would go a long way for clarity. It's not as much as
> > > > I though it would be though.
> > > > 
> > > > > > > diff --git a/include/linux/mm.h b/include/linux/mm.h
> > > > > > > index f5a97dec5169..abb4534be3cc 100644
> > > > > > > --- a/include/linux/mm.h
> > > > > > > +++ b/include/linux/mm.h
> > > > > > > @@ -3516,6 +3516,15 @@ static inline bool range_in_vma(struct vm_area_struct *vma,
> > > > > > >    	return (vma && vma->vm_start <= start && end <= vma->vm_end);
> > > > > > >    }
> > > > > > > +static inline void vma_range_init(struct vm_area_struct *vma,
> > > > > > Any reason this can't be in mm/internal.h ?
> > > > > That would be good.
> > > > One other thing, do we trust this to be inlined correctly by the
> > > > compiler or should this be __always_inline?  I'd expect it to be okay as
> > > > it is, but I've been proven wrong in a perf trace before..
> > > > 
> > > Okay, I would take __always_inline and put it in mm/internal.h in v2.
> > I'm not confident in this suggestion as the rest.
> > Please rename the function when you move it.
> 
> inline is a suggestion, __always_inline is mandatory.
> I think __always_inline is better if we're demanding.
> 
> > > > > > vma_range_set(), vma_set_range(), or just vma_range() might be a better
> > > > > > name?  My thinking is that some of these are actually modifying the vma
> > > > > > and not just initializing it, right?
> > > > > I'd vote for vma_set_range().
> >                        ^  This part, use vma_set_range() please.
> 
> Okay.
> 
> 
> By the way, I sent another patch with ("mm/mmap: simplify vma_merge()")
> subject a few days ago.
> 
> Please comment if you would like.

Oh, okay.

Can you please Cc people on these?  I almost missed this one and I know
several other people will be interested in the vma_merge() patch
changes.