Re: [PATCH v2] mm/slub: don't wait for high-order page allocation

From: Michal Hocko
Date: Tue Aug 11 2015 - 02:37:07 EST


On Mon 10-08-15 09:40:22, Joonsoo Kim wrote:
> On Fri, Aug 07, 2015 at 05:05:01PM +0200, Michal Hocko wrote:
> > On Fri 07-08-15 11:10:03, Joonsoo Kim wrote:
> > [...]
> > > diff --git a/mm/slub.c b/mm/slub.c
> > > index 257283f..52b9025 100644
> > > --- a/mm/slub.c
> > > +++ b/mm/slub.c
> > > @@ -1364,6 +1364,8 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
> > > * so we fall-back to the minimum order allocation.
> > > */
> > > alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
> > > + if ((alloc_gfp & __GFP_WAIT) && oo_order(oo) > oo_order(s->min))
> > > + alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~__GFP_WAIT;
> >
> > Wouldn't it be preferable to "fix" the __GFP_WAIT behavior than spilling
> > __GFP_NOMEMALLOC around the kernel? GFP flags are getting harder and
> > harder to use right and that is a signal we should thing about it and
> > unclutter the current state.
>
> Maybe, it is preferable. Could you try that?

I will try to cook up something during the week.

> Anyway, it is separate issue so I don't want pending this patch until
> that change.

OK, fair enough, at least this one is in mm proper...
--
Michal Hocko
SUSE Labs
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