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

From: Joonsoo Kim
Date: Sun Aug 09 2015 - 20:35:03 EST


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?

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

Thanks.
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