sched: convert struct sched_group/sched_domain cpumask_ts to variable bitmaps
Impact: (future) size reduction for large NR_CPUS.
We move the 'cpumask' member of sched_group to the end, so when we
kmalloc it we can do a minimal allocation: saves space for small
nr_cpu_ids but big CONFIG_NR_CPUS. Similar trick for 'span' in
sched_domain.
This isn't quite as good as converting to a cpumask_var_t, as some
sched_groups are actually static, but it's safer: we don't have to
figure out where to call alloc_cpumask_var/free_cpumask_var.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched.c b/kernel/sched.c
index 575f38a..6b9606a 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -7006,18 +7006,33 @@
int sched_smt_power_savings = 0, sched_mc_power_savings = 0;
/*
+ * The cpus mask in sched_group and sched_domain hangs off the end.
+ * FIXME: use cpumask_var_t or dynamic percpu alloc to avoid wasting space
+ * for nr_cpu_ids < CONFIG_NR_CPUS.
+ */
+struct static_sched_group {
+ struct sched_group sg;
+ DECLARE_BITMAP(cpus, CONFIG_NR_CPUS);
+};
+
+struct static_sched_domain {
+ struct sched_domain sd;
+ DECLARE_BITMAP(span, CONFIG_NR_CPUS);
+};
+
+/*
* SMT sched-domains:
*/
#ifdef CONFIG_SCHED_SMT
-static DEFINE_PER_CPU(struct sched_domain, cpu_domains);
-static DEFINE_PER_CPU(struct sched_group, sched_group_cpus);
+static DEFINE_PER_CPU(struct static_sched_domain, cpu_domains);
+static DEFINE_PER_CPU(struct static_sched_group, sched_group_cpus);
static int
cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
cpumask_t *unused)
{
if (sg)
- *sg = &per_cpu(sched_group_cpus, cpu);
+ *sg = &per_cpu(sched_group_cpus, cpu).sg;
return cpu;
}
#endif /* CONFIG_SCHED_SMT */
@@ -7026,8 +7041,8 @@
* multi-core sched-domains:
*/
#ifdef CONFIG_SCHED_MC
-static DEFINE_PER_CPU(struct sched_domain, core_domains);
-static DEFINE_PER_CPU(struct sched_group, sched_group_core);
+static DEFINE_PER_CPU(struct static_sched_domain, core_domains);
+static DEFINE_PER_CPU(struct static_sched_group, sched_group_core);
#endif /* CONFIG_SCHED_MC */
#if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
@@ -7041,7 +7056,7 @@
cpus_and(*mask, *mask, *cpu_map);
group = first_cpu(*mask);
if (sg)
- *sg = &per_cpu(sched_group_core, group);
+ *sg = &per_cpu(sched_group_core, group).sg;
return group;
}
#elif defined(CONFIG_SCHED_MC)
@@ -7050,13 +7065,13 @@
cpumask_t *unused)
{
if (sg)
- *sg = &per_cpu(sched_group_core, cpu);
+ *sg = &per_cpu(sched_group_core, cpu).sg;
return cpu;
}
#endif
-static DEFINE_PER_CPU(struct sched_domain, phys_domains);
-static DEFINE_PER_CPU(struct sched_group, sched_group_phys);
+static DEFINE_PER_CPU(struct static_sched_domain, phys_domains);
+static DEFINE_PER_CPU(struct static_sched_group, sched_group_phys);
static int
cpu_to_phys_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
@@ -7075,7 +7090,7 @@
group = cpu;
#endif
if (sg)
- *sg = &per_cpu(sched_group_phys, group);
+ *sg = &per_cpu(sched_group_phys, group).sg;
return group;
}
@@ -7089,7 +7104,7 @@
static struct sched_group ***sched_group_nodes_bycpu;
static DEFINE_PER_CPU(struct sched_domain, allnodes_domains);
-static DEFINE_PER_CPU(struct sched_group, sched_group_allnodes);
+static DEFINE_PER_CPU(struct static_sched_group, sched_group_allnodes);
static int cpu_to_allnodes_group(int cpu, const cpumask_t *cpu_map,
struct sched_group **sg, cpumask_t *nodemask)
@@ -7101,7 +7116,7 @@
group = first_cpu(*nodemask);
if (sg)
- *sg = &per_cpu(sched_group_allnodes, group);
+ *sg = &per_cpu(sched_group_allnodes, group).sg;
return group;
}
@@ -7116,7 +7131,7 @@
for_each_cpu(j, sched_group_cpus(sg)) {
struct sched_domain *sd;
- sd = &per_cpu(phys_domains, j);
+ sd = &per_cpu(phys_domains, j).sd;
if (j != cpumask_first(sched_group_cpus(sd->groups))) {
/*
* Only add "power" once for each
@@ -7385,7 +7400,7 @@
#endif
p = sd;
- sd = &per_cpu(phys_domains, i);
+ sd = &per_cpu(phys_domains, i).sd;
SD_INIT(sd, CPU);
set_domain_attribute(sd, attr);
cpumask_copy(sched_domain_span(sd), nodemask);
@@ -7396,7 +7411,7 @@
#ifdef CONFIG_SCHED_MC
p = sd;
- sd = &per_cpu(core_domains, i);
+ sd = &per_cpu(core_domains, i).sd;
SD_INIT(sd, MC);
set_domain_attribute(sd, attr);
*sched_domain_span(sd) = cpu_coregroup_map(i);
@@ -7409,7 +7424,7 @@
#ifdef CONFIG_SCHED_SMT
p = sd;
- sd = &per_cpu(cpu_domains, i);
+ sd = &per_cpu(cpu_domains, i).sd;
SD_INIT(sd, SIBLING);
set_domain_attribute(sd, attr);
cpumask_and(sched_domain_span(sd),
@@ -7485,7 +7500,8 @@
sched_domain_node_span(i, domainspan);
cpus_and(*domainspan, *domainspan, *cpu_map);
- sg = kmalloc_node(sizeof(struct sched_group), GFP_KERNEL, i);
+ sg = kmalloc_node(sizeof(struct sched_group) + cpumask_size(),
+ GFP_KERNEL, i);
if (!sg) {
printk(KERN_WARNING "Can not alloc domain group for "
"node %d\n", i);
@@ -7518,7 +7534,8 @@
if (cpus_empty(*tmpmask))
continue;
- sg = kmalloc_node(sizeof(struct sched_group),
+ sg = kmalloc_node(sizeof(struct sched_group) +
+ cpumask_size(),
GFP_KERNEL, i);
if (!sg) {
printk(KERN_WARNING
@@ -7538,21 +7555,21 @@
/* Calculate CPU power for physical packages and nodes */
#ifdef CONFIG_SCHED_SMT
for_each_cpu(i, cpu_map) {
- struct sched_domain *sd = &per_cpu(cpu_domains, i);
+ struct sched_domain *sd = &per_cpu(cpu_domains, i).sd;
init_sched_groups_power(i, sd);
}
#endif
#ifdef CONFIG_SCHED_MC
for_each_cpu(i, cpu_map) {
- struct sched_domain *sd = &per_cpu(core_domains, i);
+ struct sched_domain *sd = &per_cpu(core_domains, i).sd;
init_sched_groups_power(i, sd);
}
#endif
for_each_cpu(i, cpu_map) {
- struct sched_domain *sd = &per_cpu(phys_domains, i);
+ struct sched_domain *sd = &per_cpu(phys_domains, i).sd;
init_sched_groups_power(i, sd);
}
@@ -7574,11 +7591,11 @@
for_each_cpu(i, cpu_map) {
struct sched_domain *sd;
#ifdef CONFIG_SCHED_SMT
- sd = &per_cpu(cpu_domains, i);
+ sd = &per_cpu(cpu_domains, i).sd;
#elif defined(CONFIG_SCHED_MC)
- sd = &per_cpu(core_domains, i);
+ sd = &per_cpu(core_domains, i).sd;
#else
- sd = &per_cpu(phys_domains, i);
+ sd = &per_cpu(phys_domains, i).sd;
#endif
cpu_attach_domain(sd, rd, i);
}