Re: [RFC PATCH 2/2] slab: implement bulk free in SLAB allocator

[Jesper Dangaard Brouer <brouer@redhat.com>]

(To Vladimir can you comment on memcg?)


On Mon, 7 Dec 2015 08:59:25 -0600 (CST) Christoph Lameter <cl@linux.com> wrote:

> On Mon, 7 Dec 2015, Jesper Dangaard Brouer wrote:
> 
> > > > +
> > > > +	local_irq_disable();
> > > > +	for (i = 0; i < size; i++) {
> > > > +		void *objp = p[i];
> > > > +
> > > > +		s = cache_from_obj(orig_s, objp);
> > >
> > > Does this support freeing objects from a set of different caches?
> >
> > This is for supporting memcg (CONFIG_MEMCG_KMEM).
> >
> > Quoting from commit 033745189b1b ("slub: add missing kmem cgroup
> > support to kmem_cache_free_bulk"):
> >
> >    Incoming bulk free objects can belong to different kmem cgroups, and
> >    object free call can happen at a later point outside memcg context.  Thus,
> >    we need to keep the orig kmem_cache, to correctly verify if a memcg object
> >    match against its "root_cache" (s->memcg_params.root_cache).
> 
> Where is that verification? This looks like SLAB would support freeing
> objects from different caches.

This is for supporting CONFIG_MEMCG_KMEM, thus I would like Vladimir
input on this, as I don't know enough about memcg....

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  Author of http://www.iptv-analyzer.org
  LinkedIn: http://www.linkedin.com/in/brouer

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