Re: [PATCH 3/3] mm/mmap.c: extract __vma_unlink_list as counter part for __vma_link_list
On Tue, Aug 20, 2019 at 06:59:39PM -0700, Matthew Wilcox wrote:
>On Wed, Aug 21, 2019 at 09:22:44AM +0800, Wei Yang wrote:
>> On Tue, Aug 20, 2019 at 05:54:17PM -0700, Matthew Wilcox wrote:
>> >On Wed, Aug 21, 2019 at 08:52:34AM +0800, Wei Yang wrote:
>> >> On Tue, Aug 20, 2019 at 10:26:29AM -0700, Matthew Wilcox wrote:
>> >> >On Wed, Aug 14, 2019 at 11:19:37AM +0200, Vlastimil Babka wrote:
>> >> >> On 8/14/19 8:57 AM, Wei Yang wrote:
>> >> >> > On Tue, Aug 13, 2019 at 10:16:11PM -0700, Christoph Hellwig wrote:
>> >> >> >>Btw, is there any good reason we don't use a list_head for vma
>> >> >> >>linkage?
>> >> >> >
>> >> >> > Not sure, maybe there is some historical reason?
>> >> >>
>> >> >> Seems it was single-linked until 2010 commit 297c5eee3724 ("mm: make
>> >> >> the vma
>> >> >> list be doubly linked") and I guess it was just simpler to add the
>> >> >> vm_prev link.
>> >> >>
>> >> >> Conversion to list_head might be an interesting project for some
>> >> >> "advanced
>> >> >> beginner" in the kernel :)
>> >> >
>> >> >I'm working to get rid of vm_prev and vm_next, so it would probably be
>> >> >wasted effort.
>> >>
>> >> You mean replace it with list_head?
>> >
>> >No, replace the rbtree with a new tree. https://lwn.net/Articles/787629/
>>
>> Sounds interesting.
>>
>> While I am not sure the plan is settled down, and how long it would take to
>> replace the rb_tree with maple tree. I guess it would probably take some time
>> to get merged upstream.
>>
>> IMHO, it would be good to have this cleanup in current kernel. Do you agree?
>
>The three cleanups you've posted are fine. Doing more work (ie the
>list_head) seems like wasted effort to me.
Ah, got your point. I misunderstand it.
--
Wei Yang
Help you, Help me
Re: [PATCH 3/3] mm/mmap.c: extract __vma_unlink_list as counter part for __vma_link_list
On Wed, Aug 21, 2019 at 09:22:44AM +0800, Wei Yang wrote:
> On Tue, Aug 20, 2019 at 05:54:17PM -0700, Matthew Wilcox wrote:
> >On Wed, Aug 21, 2019 at 08:52:34AM +0800, Wei Yang wrote:
> >> On Tue, Aug 20, 2019 at 10:26:29AM -0700, Matthew Wilcox wrote:
> >> >On Wed, Aug 14, 2019 at 11:19:37AM +0200, Vlastimil Babka wrote:
> >> >> On 8/14/19 8:57 AM, Wei Yang wrote:
> >> >> > On Tue, Aug 13, 2019 at 10:16:11PM -0700, Christoph Hellwig wrote:
> >> >> >>Btw, is there any good reason we don't use a list_head for vma
> >> >> >>linkage?
> >> >> >
> >> >> > Not sure, maybe there is some historical reason?
> >> >>
> >> >> Seems it was single-linked until 2010 commit 297c5eee3724 ("mm: make
> >> >> the vma
> >> >> list be doubly linked") and I guess it was just simpler to add the
> >> >> vm_prev link.
> >> >>
> >> >> Conversion to list_head might be an interesting project for some
> >> >> "advanced
> >> >> beginner" in the kernel :)
> >> >
> >> >I'm working to get rid of vm_prev and vm_next, so it would probably be
> >> >wasted effort.
> >>
> >> You mean replace it with list_head?
> >
> >No, replace the rbtree with a new tree. https://lwn.net/Articles/787629/
>
> Sounds interesting.
>
> While I am not sure the plan is settled down, and how long it would take to
> replace the rb_tree with maple tree. I guess it would probably take some time
> to get merged upstream.
>
> IMHO, it would be good to have this cleanup in current kernel. Do you agree?
The three cleanups you've posted are fine. Doing more work (ie the
list_head) seems like wasted effort to me.
Re: [PATCH 3/3] mm/mmap.c: extract __vma_unlink_list as counter part for __vma_link_list
On Tue, Aug 20, 2019 at 05:54:17PM -0700, Matthew Wilcox wrote:
>On Wed, Aug 21, 2019 at 08:52:34AM +0800, Wei Yang wrote:
>> On Tue, Aug 20, 2019 at 10:26:29AM -0700, Matthew Wilcox wrote:
>> >On Wed, Aug 14, 2019 at 11:19:37AM +0200, Vlastimil Babka wrote:
>> >> On 8/14/19 8:57 AM, Wei Yang wrote:
>> >> > On Tue, Aug 13, 2019 at 10:16:11PM -0700, Christoph Hellwig wrote:
>> >> >>Btw, is there any good reason we don't use a list_head for vma linkage?
>> >> >
>> >> > Not sure, maybe there is some historical reason?
>> >>
>> >> Seems it was single-linked until 2010 commit 297c5eee3724 ("mm: make the
>> >> vma
>> >> list be doubly linked") and I guess it was just simpler to add the
>> >> vm_prev link.
>> >>
>> >> Conversion to list_head might be an interesting project for some "advanced
>> >> beginner" in the kernel :)
>> >
>> >I'm working to get rid of vm_prev and vm_next, so it would probably be
>> >wasted effort.
>>
>> You mean replace it with list_head?
>
>No, replace the rbtree with a new tree. https://lwn.net/Articles/787629/
Sounds interesting.
While I am not sure the plan is settled down, and how long it would take to
replace the rb_tree with maple tree. I guess it would probably take some time
to get merged upstream.
IMHO, it would be good to have this cleanup in current kernel. Do you agree?
--
Wei Yang
Help you, Help me
Re: [PATCH 3/3] mm/mmap.c: extract __vma_unlink_list as counter part for __vma_link_list
On Wed, Aug 21, 2019 at 08:52:34AM +0800, Wei Yang wrote:
> On Tue, Aug 20, 2019 at 10:26:29AM -0700, Matthew Wilcox wrote:
> >On Wed, Aug 14, 2019 at 11:19:37AM +0200, Vlastimil Babka wrote:
> >> On 8/14/19 8:57 AM, Wei Yang wrote:
> >> > On Tue, Aug 13, 2019 at 10:16:11PM -0700, Christoph Hellwig wrote:
> >> >>Btw, is there any good reason we don't use a list_head for vma linkage?
> >> >
> >> > Not sure, maybe there is some historical reason?
> >>
> >> Seems it was single-linked until 2010 commit 297c5eee3724 ("mm: make the
> >> vma
> >> list be doubly linked") and I guess it was just simpler to add the vm_prev
> >> link.
> >>
> >> Conversion to list_head might be an interesting project for some "advanced
> >> beginner" in the kernel :)
> >
> >I'm working to get rid of vm_prev and vm_next, so it would probably be
> >wasted effort.
>
> You mean replace it with list_head?
No, replace the rbtree with a new tree. https://lwn.net/Articles/787629/
Re: [PATCH 3/3] mm/mmap.c: extract __vma_unlink_list as counter part for __vma_link_list
On Tue, Aug 20, 2019 at 10:26:29AM -0700, Matthew Wilcox wrote:
>On Wed, Aug 14, 2019 at 11:19:37AM +0200, Vlastimil Babka wrote:
>> On 8/14/19 8:57 AM, Wei Yang wrote:
>> > On Tue, Aug 13, 2019 at 10:16:11PM -0700, Christoph Hellwig wrote:
>> >>Btw, is there any good reason we don't use a list_head for vma linkage?
>> >
>> > Not sure, maybe there is some historical reason?
>>
>> Seems it was single-linked until 2010 commit 297c5eee3724 ("mm: make the vma
>> list be doubly linked") and I guess it was just simpler to add the vm_prev
>> link.
>>
>> Conversion to list_head might be an interesting project for some "advanced
>> beginner" in the kernel :)
>
>I'm working to get rid of vm_prev and vm_next, so it would probably be
>wasted effort.
You mean replace it with list_head?
--
Wei Yang
Help you, Help me
Re: [PATCH 3/3] mm/mmap.c: extract __vma_unlink_list as counter part for __vma_link_list
On Wed, Aug 14, 2019 at 11:19:37AM +0200, Vlastimil Babka wrote:
> On 8/14/19 8:57 AM, Wei Yang wrote:
> > On Tue, Aug 13, 2019 at 10:16:11PM -0700, Christoph Hellwig wrote:
> >>Btw, is there any good reason we don't use a list_head for vma linkage?
> >
> > Not sure, maybe there is some historical reason?
>
> Seems it was single-linked until 2010 commit 297c5eee3724 ("mm: make the vma
> list be doubly linked") and I guess it was just simpler to add the vm_prev
> link.
>
> Conversion to list_head might be an interesting project for some "advanced
> beginner" in the kernel :)
I'm working to get rid of vm_prev and vm_next, so it would probably be
wasted effort.
Re: [PATCH 3/3] mm/mmap.c: extract __vma_unlink_list as counter part for __vma_link_list
On Wed, Aug 14, 2019 at 11:19:37AM +0200, Vlastimil Babka wrote:
>On 8/14/19 8:57 AM, Wei Yang wrote:
>> On Tue, Aug 13, 2019 at 10:16:11PM -0700, Christoph Hellwig wrote:
>>>Btw, is there any good reason we don't use a list_head for vma linkage?
>>
>> Not sure, maybe there is some historical reason?
>
>Seems it was single-linked until 2010 commit 297c5eee3724 ("mm: make the vma
>list be doubly linked") and I guess it was just simpler to add the vm_prev
>link.
>
>Conversion to list_head might be an interesting project for some "advanced
>beginner" in the kernel :)
Seems it will touch many code ...
--
Wei Yang
Help you, Help me
Re: [PATCH 3/3] mm/mmap.c: extract __vma_unlink_list as counter part for __vma_link_list
On 8/14/19 8:57 AM, Wei Yang wrote:
> On Tue, Aug 13, 2019 at 10:16:11PM -0700, Christoph Hellwig wrote:
>>Btw, is there any good reason we don't use a list_head for vma linkage?
>
> Not sure, maybe there is some historical reason?
Seems it was single-linked until 2010 commit 297c5eee3724 ("mm: make the vma
list be doubly linked") and I guess it was just simpler to add the vm_prev link.
Conversion to list_head might be an interesting project for some "advanced
beginner" in the kernel :)
Re: [PATCH 3/3] mm/mmap.c: extract __vma_unlink_list as counter part for __vma_link_list
On Tue, Aug 13, 2019 at 10:16:11PM -0700, Christoph Hellwig wrote: >Btw, is there any good reason we don't use a list_head for vma linkage? Not sure, maybe there is some historical reason? -- Wei Yang Help you, Help me
Re: [PATCH 3/3] mm/mmap.c: extract __vma_unlink_list as counter part for __vma_link_list
Btw, is there any good reason we don't use a list_head for vma linkage?
