On Wed 25-11-15 12:57:08, David Rientjes wrote:
> On Wed, 25 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. __GFP_NOFAIL should be
relatively rare and nodes are rarely depeleted so much that
ALLOC_NO_WATERMARKS wouldn't be able to allocate from the first zone in
the zone list. I mean I have no problem to do the above it just sounds
overcomplicating the situation without making practical difference.
If you and others insist I can resping the patch though.
--
Michal Hocko
SUSE Labs
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