Re: [patch 2/9] mm: memcontrol: rearrange charging fast path

From: Michal Hocko
Date: Mon May 12 2014 - 03:59:44 EST


On Thu 08-05-14 14:22:24, Johannes Weiner wrote:
> On Wed, May 07, 2014 at 04:33:34PM +0200, Michal Hocko wrote:
> > On Wed 30-04-14 16:25:36, Johannes Weiner wrote:
[...]
> > > - if (unlikely(task_in_memcg_oom(current)))
> > > - goto nomem;
> > > -
> > > - if (gfp_mask & __GFP_NOFAIL)
> > > - oom = false;
> > > retry:
> > > if (consume_stock(memcg, nr_pages))
> > > goto done;
> > [...]
> > > @@ -2662,6 +2660,9 @@ retry:
> > > if (mem_cgroup_wait_acct_move(mem_over_limit))
> > > goto retry;
> > >
> > > + if (gfp_mask & __GFP_NOFAIL)
> > > + goto bypass;
> > > +
> >
> > This is a behavior change because we have returned ENOMEM previously
>
> __GFP_NOFAIL must never return -ENOMEM, or we'd have to rename it ;-)
> It just looks like this in the patch, but this is the label code:
>
> nomem:
> if (!(gfp_mask & __GFP_NOFAIL))
> return -ENOMEM;
> bypass:
> ...

Ouch. Brain fart. Sorry...

--
Michal Hocko
SUSE Labs
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