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-rw-r--r--kernel/sched/topology.c113
1 files changed, 70 insertions, 43 deletions
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 09d35044bd88..55a0a243e871 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -14,15 +14,15 @@ static cpumask_var_t sched_domains_tmpmask2;
static int __init sched_debug_setup(char *str)
{
- sched_debug_enabled = true;
+ sched_debug_verbose = true;
return 0;
}
-early_param("sched_debug", sched_debug_setup);
+early_param("sched_verbose", sched_debug_setup);
static inline bool sched_debug(void)
{
- return sched_debug_enabled;
+ return sched_debug_verbose;
}
#define SD_FLAG(_name, mflags) [__##_name] = { .meta_flags = mflags, .name = #_name },
@@ -131,7 +131,7 @@ static void sched_domain_debug(struct sched_domain *sd, int cpu)
{
int level = 0;
- if (!sched_debug_enabled)
+ if (!sched_debug_verbose)
return;
if (!sd) {
@@ -152,7 +152,7 @@ static void sched_domain_debug(struct sched_domain *sd, int cpu)
}
#else /* !CONFIG_SCHED_DEBUG */
-# define sched_debug_enabled 0
+# define sched_debug_verbose 0
# define sched_domain_debug(sd, cpu) do { } while (0)
static inline bool sched_debug(void)
{
@@ -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);
@@ -963,7 +934,7 @@ static void init_overlap_sched_group(struct sched_domain *sd,
int cpu;
build_balance_mask(sd, sg, mask);
- cpu = cpumask_first_and(sched_group_span(sg), mask);
+ cpu = cpumask_first(mask);
sg->sgc = *per_cpu_ptr(sdd->sgc, cpu);
if (atomic_inc_return(&sg->sgc->ref) == 1)
@@ -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;
@@ -2110,7 +2141,7 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att
if (has_asym)
static_branch_inc_cpuslocked(&sched_asym_cpucapacity);
- if (rq && sched_debug_enabled) {
+ if (rq && sched_debug_verbose) {
pr_info("root domain span: %*pbl (max cpu_capacity = %lu)\n",
cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity);
}
@@ -2128,7 +2159,7 @@ static cpumask_var_t *doms_cur;
/* Number of sched domains in 'doms_cur': */
static int ndoms_cur;
-/* Attribues of custom domains in 'doms_cur' */
+/* Attributes of custom domains in 'doms_cur' */
static struct sched_domain_attr *dattr_cur;
/*
@@ -2192,7 +2223,6 @@ int sched_init_domains(const struct cpumask *cpu_map)
doms_cur = &fallback_doms;
cpumask_and(doms_cur[0], cpu_map, housekeeping_cpumask(HK_FLAG_DOMAIN));
err = build_sched_domains(doms_cur[0], NULL);
- register_sched_domain_sysctl();
return err;
}
@@ -2267,9 +2297,6 @@ void partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[],
lockdep_assert_held(&sched_domains_mutex);
- /* Always unregister in case we don't destroy any domains: */
- unregister_sched_domain_sysctl();
-
/* Let the architecture update CPU core mappings: */
new_topology = arch_update_cpu_topology();
@@ -2358,7 +2385,7 @@ match3:
dattr_cur = dattr_new;
ndoms_cur = ndoms_new;
- register_sched_domain_sysctl();
+ update_sched_domain_debugfs();
}
/*