Re: [PATCH v5 bpf-next 1/3] bpf: Add kmem_cache iterator

[Namhyung Kim <namhyung@kernel.org>]

Hello Alexei,

On Fri, Oct 11, 2024 at 11:33:31AM -0700, Alexei Starovoitov wrote:
> On Thu, Oct 10, 2024 at 4:25 PM Namhyung Kim <namhyung@kernel.org> wrote:
> >
> > The new "kmem_cache" iterator will traverse the list of slab caches
> > and call attached BPF programs for each entry.  It should check the
> > argument (ctx.s) if it's NULL before using it.
> >
> > Now the iteration grabs the slab_mutex only if it traverse the list and
> 
> traverses
> 
> > releases the mutex when it runs the BPF program.  The kmem_cache entry
> > is protected by a refcount during the execution.
> >
> > It includes the internal "mm/slab.h" header to access kmem_cache,
> > slab_caches and slab_mutex.  Hope it's ok to mm folks.
> 
> What was the reason you dropped Vlastimil's and Roman's acks
> from this patch while keeping them in patch 2 ?

I wanted to make sure the slab maintainers agree with the refcounting and
the locking logic changes.  But I forgot to add back Vlastimil's Acked
for the v4 which is the same in this regard.

> 
> Folks pls Ack again if it looks ok.
> 
> I'm ready to apply, but would like the acks first.
> 
> Also I'd like to remove the above paragraph
> from mm/slab.h from the commit log.
> It was good to ask during v1, but looks odd at v5.

Sure, feel free to make any changes.

Thanks,
Namhyung