Re: [PATCH v2] slub: clarify kmem_cache_refill_sheaf() comments

Hao Li
2026-04-07T11:53:02Z

On Tue, Apr 07, 2026 at 07:49:39PM +0900, Harry Yoo (Oracle) wrote:
> On Tue, Apr 07, 2026 at 05:59:10PM +0800, Hao Li wrote:
> > In the in-place refill case, some objects may already have been added
> > before the function returns -ENOMEM.
> > Clarify this behavior and polish the rest of the comment for readability.
> >
> > Signed-off-by: Hao Li <hao.li@linux.dev>
> > ---
> > Thanks Harry for suggestions on v1!
>
> You're welcome!
>
> Overall looks good to me, so:
> Acked-by: Harry Yoo (Oracle) <harry@kernel.org>
>
> With some small nitpicking :)

Thanks for pointing that out :)

>
> > ---
> > mm/slub.c | 13 ++++++++-----
> > 1 file changed, 8 insertions(+), 5 deletions(-)
> >
> > diff --git a/mm/slub.c b/mm/slub.c
> > index 4927407c9699..a45eb1bd2ce5 100644
> > --- a/mm/slub.c
> > +++ b/mm/slub.c
> > @@ -5120,12 +5120,15 @@ void kmem_cache_return_sheaf(struct kmem_cache *s, gfp_t gfp,
> > }
> >
> > /*
> > - * refill a sheaf previously returned by kmem_cache_prefill_sheaf to at least
> > - * the given size
> > + * Refill a sheaf previously returned by kmem_cache_prefill_sheaf to at least
> > + * the given size.
> > *
> > - * the sheaf might be replaced by a new one when requesting more than
> > - * s->sheaf_capacity objects if such replacement is necessary, but the refill
> > - * fails (returning -ENOMEM), the existing sheaf is left intact
> > + * Return: 0 on success. The sheaf will contain at least @size objects.
> > + * The sheaf might be replaced with a new one if more than sheaf->capacity
>
> nit: "The sheaf might have been replaced with a new one" ...

Yes, the perfect tense would be better.
>
> > + * objects are requested.
> > + *
> > + * Return: -ENOMEM on failure. The refill might partially fill the existing
> nit: ..."Some objects might have been added to the sheaf,
> but the sheaf will not be replaced."

Great! this is less ambiguous than "leave it unchanged."

>
> sounds a little bit more clear (tm).
>
> > + * sheaf or leave it unchanged, but it will not replace the existing sheaf.
> > *
> > * In practice we always refill to full sheaf's capacity.
> > */
> > --
> > 2.50.1
> >
>

--
Thanks,
Hao