Re: [PATCH] xfs: use kmem_cache_free() for kmem_cache objects

Rustam Kovhaev
2021-10-13T16:56:46Z

On Wed, Oct 13, 2021 at 09:38:31AM +0200, Vlastimil Babka wrote:
> On 10/13/21 01:22, Darrick J. Wong wrote:
> > On Tue, Oct 12, 2021 at 11:32:25PM +0200, Vlastimil Babka wrote:
> >> On 10/12/2021 10:43 PM, Darrick J. Wong wrote:
> >> > On Tue, Oct 12, 2021 at 01:43:20PM -0700, Darrick J. Wong wrote:
> >> >> On Sun, Oct 03, 2021 at 06:07:20PM -0700, David Rientjes wrote:
> >> >>
> >> >> I audited the entire xfs (kernel) codebase and didn't find any other
> >> >> usage errors. Thanks for the patch; I'll apply it to for-next.
> >>
> >> Which patch, the one that started this thread and uses kmem_cache_free() instead
> >> of kfree()? I thought we said it's not the best way?
> >
> > It's probably better to fix slob to be able to tell that a kmem_free'd
> > object actually belongs to a cache and should get freed that way, just
> > like its larger sl[ua]b cousins.
>
> Agreed. Rustam, do you still plan to do that?

Yes, I do, thank you.

>
> > However, even if that does come to pass, anybody /else/ who wants to
> > start(?) using XFS on a SLOB system will need this patch to fix the
> > minor papercut. Now that I've checked the rest of the codebase, I don't
> > find it reasonable to make XFS mutually exclusive with SLOB over two
> > instances of slab cache misuse. Hence the RVB. :)
>
> Ok. I was just wondering because Dave's first reply was that actually you'll
> need to expand the use of kfree() instead of kmem_cache_free().
>