Re: [PATCH RFC 1/2] mm, hugetlb: unify core page allocation accounting and initialization

[Michal Hocko]

On Tue 28-11-17 13:34:53, Mike Kravetz wrote:
> On 11/28/2017 06:12 AM, Michal Hocko wrote:
[...]
> > +/*
> > + * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
> > + * manner.
> > + */
> >  static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
> >  {
> >  	struct page *page;
> >  	int nr_nodes, node;
> > -	int ret = 0;
> > +	gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
> >  
> >  	for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
> > -		page = alloc_fresh_huge_page_node(h, node);
> > -		if (page) {
> > -			ret = 1;
> > +		page = __hugetlb_alloc_buddy_huge_page(h, gfp_mask,
> > +				node, nodes_allowed);
> 
> I don't have the greatest understanding of node/nodemasks, but ...
> Since __hugetlb_alloc_buddy_huge_page calls __alloc_pages_nodemask(), do
> we still need to explicitly iterate over nodes with
> for_each_node_mask_to_alloc() here?

Yes we do, because callers depend on the round robin allocation policy
which is implemented by the ugly for_each_node_mask_to_alloc. I am not
saying I like the way this is done but this is user visible thing.

Or maybe I've missunderstood the whole thing...
-- 
Michal Hocko
SUSE Labs