Re: [PATCH v6 1/6] mm/mempolicy: Add MPOL_PREFERRED_MANY for multiple preferred nodes

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



[Sorry for a late review]

On Mon 12-07-21 16:09:29, Feng Tang wrote:
[...]
> @@ -1887,7 +1909,8 @@ nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
>  /* Return the node id preferred by the given mempolicy, or the given id */
>  static int policy_node(gfp_t gfp, struct mempolicy *policy, int nd)
>  {
> -	if (policy->mode == MPOL_PREFERRED) {
> +	if (policy->mode == MPOL_PREFERRED ||
> +	    policy->mode == MPOL_PREFERRED_MANY) {
>  		nd = first_node(policy->nodes);
>  	} else {
>  		/*

Do we really want to have the preferred node to be always the first node
in the node mask? Shouldn't that strive for a locality as well? Existing
callers already prefer numa_node_id() - aka local node - and I belive we
shouldn't just throw that away here.

> @@ -1931,6 +1954,7 @@ unsigned int mempolicy_slab_node(void)
>  
>  	switch (policy->mode) {
>  	case MPOL_PREFERRED:
> +	case MPOL_PREFERRED_MANY:
>  		return first_node(policy->nodes);

Similarly here but I am not really familiar with the slab numa code
enough to have strong opinions here.

> @@ -2173,10 +2198,12 @@ struct page *alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
>  		 * node and don't fall back to other nodes, as the cost of
>  		 * remote accesses would likely offset THP benefits.
>  		 *
> -		 * If the policy is interleave, or does not allow the current
> -		 * node in its nodemask, we allocate the standard way.
> +		 * If the policy is interleave or multiple preferred nodes, or
> +		 * does not allow the current node in its nodemask, we allocate
> +		 * the standard way.
>  		 */
> -		if (pol->mode == MPOL_PREFERRED)
> +		if ((pol->mode == MPOL_PREFERRED ||
> +		     pol->mode == MPOL_PREFERRED_MANY))
>  			hpage_node = first_node(pol->nodes);

Same here.

> @@ -2451,6 +2479,9 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long
>  		break;
>  
>  	case MPOL_PREFERRED:
> +	case MPOL_PREFERRED_MANY:
> +		if (node_isset(curnid, pol->nodes))
> +			goto out;
>  		polnid = first_node(pol->nodes);
>  		break;

I do not follow what is the point of using first_node here. Either the
node is in the mask or it is misplaced. What are you trying to achieve
here?
-- 
Michal Hocko
SUSE Labs




[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux