[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
