linux-next: manual merge of the slab tree with the mm-unstable tree

linux-next: manual merge of the slab tree with the mm-unstable tree

[Stephen Rothwell]

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Hi all,

Today's linux-next merge of the slab tree got a conflict in:

  fs/proc/page.c

between commit:

  a602ee331e31 ("fs: stable_page_flags(): use snapshot_page()")

from the mm-unstable tree and commit:

  d8178294c53e ("proc: Remove mention of PG_slab")

from the slab tree.

I fixed it up (I just used the former version) and can carry the fix as
necessary. This is now fixed as far as linux-next is concerned, but any
non trivial conflicts should be mentioned to your upstream maintainer
when your tree is submitted for merging.  You may also want to consider
cooperating with the maintainer of the conflicting tree to minimise any
particularly complex conflicts.

-- 
Cheers,
Stephen Rothwell

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Re: linux-next: manual merge of the slab tree with the mm-unstable tree

[Matthew Wilcox]

On Mon, Jul 21, 2025 at 02:20:01PM +1000, Stephen Rothwell wrote:
> Hi all,
> 
> Today's linux-next merge of the slab tree got a conflict in:
> 
>   fs/proc/page.c
> 
> between commit:
> 
>   a602ee331e31 ("fs: stable_page_flags(): use snapshot_page()")
> 
> from the mm-unstable tree and commit:
> 
>   d8178294c53e ("proc: Remove mention of PG_slab")
> 
> from the slab tree.
> 
> I fixed it up (I just used the former version) and can carry the fix as
> necessary. This is now fixed as far as linux-next is concerned, but any

I think the snapshot_page commit was incorrect in removing this comment.
It is still valuable information.  I think the comment from d8178294c53e
should remain in the tree after the resolution.

Re: linux-next: manual merge of the slab tree with the mm-unstable tree

[Luiz Capitulino]

On 2025-07-21 15:38, Matthew Wilcox wrote:
> On Mon, Jul 21, 2025 at 02:20:01PM +1000, Stephen Rothwell wrote:
>> Hi all,
>>
>> Today's linux-next merge of the slab tree got a conflict in:
>>
>>    fs/proc/page.c
>>
>> between commit:
>>
>>    a602ee331e31 ("fs: stable_page_flags(): use snapshot_page()")
>>
>> from the mm-unstable tree and commit:
>>
>>    d8178294c53e ("proc: Remove mention of PG_slab")
>>
>> from the slab tree.
>>
>> I fixed it up (I just used the former version) and can carry the fix as
>> necessary. This is now fixed as far as linux-next is concerned, but any
> 
> I think the snapshot_page commit was incorrect in removing this comment.
> It is still valuable information.  I think the comment from d8178294c53e
> should remain in the tree after the resolution.

The comment wasn't just dropped, David suggested a new version for the comment
(which is similar to yours). The new comment is now part of set_ps_flags()
which is where we set this flag in the snapshot_page() implementation:

static void set_ps_flags(struct page_snapshot *ps, const struct folio *folio,
                          const struct page *page)
{
         /*
          * Only the first page of a high-order buddy page has PageBuddy() set.
          * So we have to check manually whether this page is part of a high-
          * order buddy page.
          */
         if (PageBuddy(page))
                 ps->flags |= PAGE_SNAPSHOT_PG_BUDDY;
         else if (page_count(page) == 0 && is_free_buddy_page(page))
                 ps->flags |= PAGE_SNAPSHOT_PG_BUDDY;

         if (folio_test_idle(folio))
                 ps->flags |= PAGE_SNAPSHOT_PG_IDLE;
}

Re: linux-next: manual merge of the slab tree with the mm-unstable tree

[Vlastimil Babka]

On 7/21/25 23:35, Luiz Capitulino wrote:
> On 2025-07-21 15:38, Matthew Wilcox wrote:
>> On Mon, Jul 21, 2025 at 02:20:01PM +1000, Stephen Rothwell wrote:
>>> Hi all,
>>>
>>> Today's linux-next merge of the slab tree got a conflict in:
>>>
>>>    fs/proc/page.c
>>>
>>> between commit:
>>>
>>>    a602ee331e31 ("fs: stable_page_flags(): use snapshot_page()")
>>>
>>> from the mm-unstable tree and commit:
>>>
>>>    d8178294c53e ("proc: Remove mention of PG_slab")
>>>
>>> from the slab tree.
>>>
>>> I fixed it up (I just used the former version) and can carry the fix as
>>> necessary. This is now fixed as far as linux-next is concerned, but any
>> 
>> I think the snapshot_page commit was incorrect in removing this comment.
>> It is still valuable information.  I think the comment from d8178294c53e
>> should remain in the tree after the resolution.
> 
> The comment wasn't just dropped, David suggested a new version for the comment
> (which is similar to yours). The new comment is now part of set_ps_flags()
> which is where we set this flag in the snapshot_page() implementation:
> 
> static void set_ps_flags(struct page_snapshot *ps, const struct folio *folio,
>                           const struct page *page)
> {
>          /*
>           * Only the first page of a high-order buddy page has PageBuddy() set.
>           * So we have to check manually whether this page is part of a high-
>           * order buddy page.
>           */
>          if (PageBuddy(page))
>                  ps->flags |= PAGE_SNAPSHOT_PG_BUDDY;

That seems to work. I can therefore simply drop d8178294c53e from the slab tree.

>          else if (page_count(page) == 0 && is_free_buddy_page(page))
>                  ps->flags |= PAGE_SNAPSHOT_PG_BUDDY;
> 
>          if (folio_test_idle(folio))
>                  ps->flags |= PAGE_SNAPSHOT_PG_IDLE;
> }
> 

linux-next: manual merge of the slab tree with the mm-unstable tree

[Stephen Rothwell]

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Hi all,

Today's linux-next merge of the slab tree got a conflict in:

  lib/maple_tree.c

between commit:

  65d011b2bc05 ("maple_tree: remove redundant __GFP_NOWARN")

from the mm-unstable tree and commit:

  1094ea77b180 ("maple_tree: Prefilled sheaf conversion and testing")

from the slab tree.

I fixed it up (I used the latter version) and can carry the fix as
necessary. This is now fixed as far as linux-next is concerned, but any
non trivial conflicts should be mentioned to your upstream maintainer
when your tree is submitted for merging.  You may also want to consider
cooperating with the maintainer of the conflicting tree to minimise any
particularly complex conflicts.

-- 
Cheers,
Stephen Rothwell

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linux-next: manual merge of the slab tree with the mm-unstable tree

[Stephen Rothwell]

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Hi all,

FIXME: Add owner of second tree to To:
       Add author(s)/SOB of conflicting commits.

Today's linux-next merge of the slab tree got a conflict in:

  tools/testing/vma/vma_internal.h

between commit:

  da018ebb7157 ("tools/testing/vma: clean up stubs in vma_internal.h")

from the mm-unstable tree and commits:

  cbb6a30df135 ("tools/testing/vma: Implement vm_refcnt reset")
  6602bcbdfbad ("tools/testing: Add support for changes to slab for sheaves")

from the slab tree.

I fixed it up (I used the latter version) and can carry the fix as
necessary. This is now fixed as far as linux-next is concerned, but any
non trivial conflicts should be mentioned to your upstream maintainer
when your tree is submitted for merging.  You may also want to consider
cooperating with the maintainer of the conflicting tree to minimise any
particularly complex conflicts.

-- 
Cheers,
Stephen Rothwell

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Re: linux-next: manual merge of the slab tree with the mm-unstable tree

[Vlastimil Babka]

On 9/4/25 08:29, Stephen Rothwell wrote:
> Hi all,
> 
> FIXME: Add owner of second tree to To:
>        Add author(s)/SOB of conflicting commits.
> 
> Today's linux-next merge of the slab tree got a conflict in:
> 
>   tools/testing/vma/vma_internal.h
> 
> between commit:
> 
>   da018ebb7157 ("tools/testing/vma: clean up stubs in vma_internal.h")

We can solve it by me taking this and

  65d011b2bc05 ("maple_tree: remove redundant __GFP_NOWARN")

from the other thread and Andrew dropping them in mm-unstable. I tried to
rebase mm-unstable locally while dropping those and there were no conflicts
and they are self-contained cleanups. AFAIR Andrew was fine with such
resolutions in the past.

Thanks.

> from the mm-unstable tree and commits:
> 
>   cbb6a30df135 ("tools/testing/vma: Implement vm_refcnt reset")
>   6602bcbdfbad ("tools/testing: Add support for changes to slab for sheaves")
> 
> from the slab tree.
> 
> I fixed it up (I used the latter version) and can carry the fix as
> necessary. This is now fixed as far as linux-next is concerned, but any
> non trivial conflicts should be mentioned to your upstream maintainer
> when your tree is submitted for merging.  You may also want to consider
> cooperating with the maintainer of the conflicting tree to minimise any
> particularly complex conflicts.
> 

Re: linux-next: manual merge of the slab tree with the mm-unstable tree

[Andrew Morton]

On Thu, 4 Sep 2025 10:39:47 +0200 Vlastimil Babka <vbabka@suse.cz> wrote:

> On 9/4/25 08:29, Stephen Rothwell wrote:
> > Hi all,
> > 
> > FIXME: Add owner of second tree to To:
> >        Add author(s)/SOB of conflicting commits.
> > 
> > Today's linux-next merge of the slab tree got a conflict in:
> > 
> >   tools/testing/vma/vma_internal.h
> > 
> > between commit:
> > 
> >   da018ebb7157 ("tools/testing/vma: clean up stubs in vma_internal.h")
> 
> We can solve it by me taking this and
> 
>   65d011b2bc05 ("maple_tree: remove redundant __GFP_NOWARN")
> 
> from the other thread and Andrew dropping them in mm-unstable. I tried to
> rebase mm-unstable locally while dropping those and there were no conflicts
> and they are self-contained cleanups. AFAIR Andrew was fine with such
> resolutions in the past.

Yep, I generally just drop things when these conflicts occur.