Re: [PATCH 1/2] mm/slub: wake up kswapd for initial high order allocation

From: Christopher Lameter
Date: Wed Sep 06 2017 - 11:59:17 EST


On Wed, 6 Sep 2017, js1304@xxxxxxxxx wrote:

> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -1578,8 +1578,12 @@ 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_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
> - alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~(__GFP_RECLAIM|__GFP_NOFAIL);
> + if (oo_order(oo) > oo_order(s->min)) {
> + if (alloc_gfp & __GFP_DIRECT_RECLAIM) {
> + alloc_gfp |= __GFP_NOMEMALLOC;
> + alloc_gfp &= ~__GFP_DIRECT_RECLAIM;
> + }
> + }
>

Can we come up with another inline function in gfp.h for this as well?

Well and needing these functions to manipulate flags actually indicates
that we may need a cleanup of the GFP flags at some point. There is a buch
of flags that disable things and some that enable things.