Re: [PATCH v2 3/6] mm, page_alloc: pass preferred nid instead of zonelist to allocator

[Christoph Lameter]

On Wed, 17 May 2017, Vlastimil Babka wrote:

>  struct page *
> -__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
> -		       struct zonelist *zonelist, nodemask_t *nodemask);
> +__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, int preferred_nid,
> +							nodemask_t *nodemask);
>
>  static inline struct page *
> -__alloc_pages(gfp_t gfp_mask, unsigned int order,
> -		struct zonelist *zonelist)
> +__alloc_pages(gfp_t gfp_mask, unsigned int order, int preferred_nid)
>  {
> -	return __alloc_pages_nodemask(gfp_mask, order, zonelist, NULL);
> +	return __alloc_pages_nodemask(gfp_mask, order, preferred_nid, NULL);
>  }

Maybe use nid instead of preferred_nid like in __alloc_pages? Otherwise
there may be confusion with the MPOL_PREFER policy.

> @@ -1963,8 +1960,8 @@ alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
>  {
>  	struct mempolicy *pol;
>  	struct page *page;
> +	int preferred_nid;
>  	unsigned int cpuset_mems_cookie;
> -	struct zonelist *zl;
>  	nodemask_t *nmask;

Same here.

> @@ -4012,8 +4012,8 @@ static inline void finalise_ac(gfp_t gfp_mask,
>   * This is the 'heart' of the zoned buddy allocator.
>   */
>  struct page *
> -__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
> -			struct zonelist *zonelist, nodemask_t *nodemask)
> +__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, int preferred_nid,
> +							nodemask_t *nodemask)
>  {

and here

This looks clean to me. Still feel a bit uneasy about this since I do
remember that we had a reason to use zonelists instead of nodes back then
but cannot remember what that reason was....

CCing Dimitri at SGI. This may break a lot of legacy SGIapps. If you read
this Dimitri then please review this patchset and the discussions around
it.

Reviewed-by: Christoph Lameter <cl@xxxxxxxxx>