Re: [PATCH] docs: ABI: sysfs-kernel-slab: mark cpu_partial attributes deprecated

[Harry Yoo]

On 7/2/26 5:28 PM, Vlastimil Babka (SUSE) wrote:
> On 7/2/26 07:18, Harry Yoo wrote:
>>
>>
>> On 7/1/26 11:17 PM, Seongjun Hong wrote:
>>> The per-cpu slab and per-cpu partial slab mechanisms were removed when
>>> SLUB was converted to per-cpu sheaves in Linux 7.0. The cpu_slabs,
>>
>> small nit: sheaves were introduced in v6.18,
>> but the cpu (partial) slabs layer were removed later in v7.0.
> 
> Fixed up when applying by saying "fully converted" :)

Looks good, thanks!

>>> slabs_cpu_partial and cpu_partial sysfs attributes were kept as stubs
>>> that always return 0 for backwards compatibility, but their
>>> documentation still described them as if they were functional.
>>
>> Right, for backward compatibility, because, unlike files that
>> might not exist w/o SLUB_STATS, userspace tools might assume that
>> they always exist.
>>
>>> Update the three descriptions to state that the attributes are
>>> deprecated and always read 0, and note that they are retained only for
>>> compatibility. While here, fix a "partialli" typo in the
>>> slabs_cpu_partial description.
>>>
>>> Signed-off-by: Seongjun Hong <hsj0512@xxxxxxxxx>
>>> ---
>>
>> Overall looks good to me, so:
>> Acked-by: Harry Yoo (Oracle) <harry@xxxxxxxxxx>
> 
> Added to slab/for-next, thanks!

Thanks!

>> By the way.
>>
>> There's still some gap between the documentation
>> and the implementation :)
>>
>> We've dropped a bunch of files that exist only on
>> SLUB_STATS and new files introduced with by
>> sheaves were not documented.
> 
> While we are touching these files, the question is what contact to use
> there. Some have Christoph, some Pekka, some both.
> Seems inflexible to me and should ideally point to the slab MAINTAINERS
> entry.

Agreed.

> But not sure if it's possible. Documentation/ABI/README says:
> 
> Contact:        Primary contact for this interface (may be a mailing list)

Looking at other mm-related sysfs files:

Contact:	Linux memory management mailing list <linux-mm@xxxxxxxxx>

> Maybe we can propose that it can also say
> 
> See the SLAB ALLOCATOR subsystem in MAINTAINERS.

Replacing the contact with linux-mm mailing list and mentioning
SLAB ALLOCATOR subsystem in MAINTAINERS sounds good to me.

-- 
Cheers,
Harry / Hyeonggon

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