On Thu, 26 Nov 2015, Michal Hocko wrote:
> > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> > > index 8034909faad2..94b04c1e894a 100644
> > > --- a/mm/page_alloc.c
> > > +++ b/mm/page_alloc.c
> > > @@ -2766,8 +2766,13 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int
> > > order,
> > > goto out;
> > > }
> > > /* Exhausted what can be done so it's blamo time */
> > > - if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL))
> > > + if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) {
> > > *did_some_progress = 1;
> > > +
> > > + if (gfp_mask & __GFP_NOFAIL)
> > > + page = get_page_from_freelist(gfp_mask, order,
> > > + ALLOC_NO_WATERMARKS, ac);
> > > + }
> > > out:
> > > mutex_unlock(&oom_lock);
> > > return page;
> >
> > Well, sure, that's one way to do it, but for cpuset users, wouldn't this
> > lead to a depletion of the first system zone since you've dropped
> > ALLOC_CPUSET and are doing ALLOC_NO_WATERMARKS in the same call?
>
> Are you suggesting to do?
> if (gfp_mask & __GFP_NOFAIL) {
> page = get_page_from_freelist(gfp_mask, order,
> ALLOC_NO_WATERMARKS|ALLOC_CPUSET, ac);
> /*
> * fallback to ignore cpuset if our nodes are
> * depleted
> */
> if (!page)
> get_page_from_freelist(gfp_mask, order,
> ALLOC_NO_WATERMARKS, ac);
> }
>
> I am not really sure this worth complication.
I'm objecting to the ability of a process that is doing a __GFP_NOFAIL
allocation, which has been disallowed access from allocating on certain
mems through cpusets, to cause an oom condition on those disallowed nodes,
yes.
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