diff options
| -rw-r--r-- | kernel/sched/topology.c | 91 |
1 files changed, 61 insertions, 30 deletions
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 09d35044bd88..12f80587e127 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -723,35 +723,6 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) for (tmp = sd; tmp; tmp = tmp->parent) numa_distance += !!(tmp->flags & SD_NUMA); - /* - * FIXME: Diameter >=3 is misrepresented. - * - * Smallest diameter=3 topology is: - * - * node 0 1 2 3 - * 0: 10 20 30 40 - * 1: 20 10 20 30 - * 2: 30 20 10 20 - * 3: 40 30 20 10 - * - * 0 --- 1 --- 2 --- 3 - * - * NUMA-3 0-3 N/A N/A 0-3 - * groups: {0-2},{1-3} {1-3},{0-2} - * - * NUMA-2 0-2 0-3 0-3 1-3 - * groups: {0-1},{1-3} {0-2},{2-3} {1-3},{0-1} {2-3},{0-2} - * - * NUMA-1 0-1 0-2 1-3 2-3 - * groups: {0},{1} {1},{2},{0} {2},{3},{1} {3},{2} - * - * NUMA-0 0 1 2 3 - * - * The NUMA-2 groups for nodes 0 and 3 are obviously buggered, as the - * group span isn't a subset of the domain span. - */ - WARN_ONCE(numa_distance > 2, "Shortest NUMA path spans too many nodes\n"); - sched_domain_debug(sd, cpu); rq_attach_root(rq, rd); @@ -982,6 +953,31 @@ static void init_overlap_sched_group(struct sched_domain *sd, sg->sgc->max_capacity = SCHED_CAPACITY_SCALE; } +static struct sched_domain * +find_descended_sibling(struct sched_domain *sd, struct sched_domain *sibling) +{ + /* + * The proper descendant would be the one whose child won't span out + * of sd + */ + while (sibling->child && + !cpumask_subset(sched_domain_span(sibling->child), + sched_domain_span(sd))) + sibling = sibling->child; + + /* + * As we are referencing sgc across different topology level, we need + * to go down to skip those sched_domains which don't contribute to + * scheduling because they will be degenerated in cpu_attach_domain + */ + while (sibling->child && + cpumask_equal(sched_domain_span(sibling->child), + sched_domain_span(sibling))) + sibling = sibling->child; + + return sibling; +} + static int build_overlap_sched_groups(struct sched_domain *sd, int cpu) { @@ -1015,6 +1011,41 @@ build_overlap_sched_groups(struct sched_domain *sd, int cpu) if (!cpumask_test_cpu(i, sched_domain_span(sibling))) continue; + /* + * Usually we build sched_group by sibling's child sched_domain + * But for machines whose NUMA diameter are 3 or above, we move + * to build sched_group by sibling's proper descendant's child + * domain because sibling's child sched_domain will span out of + * the sched_domain being built as below. + * + * Smallest diameter=3 topology is: + * + * node 0 1 2 3 + * 0: 10 20 30 40 + * 1: 20 10 20 30 + * 2: 30 20 10 20 + * 3: 40 30 20 10 + * + * 0 --- 1 --- 2 --- 3 + * + * NUMA-3 0-3 N/A N/A 0-3 + * groups: {0-2},{1-3} {1-3},{0-2} + * + * NUMA-2 0-2 0-3 0-3 1-3 + * groups: {0-1},{1-3} {0-2},{2-3} {1-3},{0-1} {2-3},{0-2} + * + * NUMA-1 0-1 0-2 1-3 2-3 + * groups: {0},{1} {1},{2},{0} {2},{3},{1} {3},{2} + * + * NUMA-0 0 1 2 3 + * + * The NUMA-2 groups for nodes 0 and 3 are obviously buggered, as the + * group span isn't a subset of the domain span. + */ + if (sibling->child && + !cpumask_subset(sched_domain_span(sibling->child), span)) + sibling = find_descended_sibling(sd, sibling); + sg = build_group_from_child_sched_domain(sibling, cpu); if (!sg) goto fail; @@ -1022,7 +1053,7 @@ build_overlap_sched_groups(struct sched_domain *sd, int cpu) sg_span = sched_group_span(sg); cpumask_or(covered, covered, sg_span); - init_overlap_sched_group(sd, sg); + init_overlap_sched_group(sibling, sg); if (!first) first = sg; |