[RFC PATCH 04/16] sched: Allocate and initialize sched energy

From: Morten Rasmussen
Date: Fri May 23 2014 - 14:20:53 EST


From: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>

The per sg struct sched_group_energy structure plus the related struct
capacity_state array are allocated like the other sd hierarchy data
structures (e.g. struct sched_group). This includes the freeing of
struct sched_group_energy structures which are not used.
One problem is that the sd energy information consists of two structures
per sg, the actual struct sched_group_energy and the related
capacity_state array and that the number of elements of this array can be
configured (see struct sched_group_energy.nr_cap_states). That means
that the number of capacity states has to be figured out in __sdt_alloc()
and since both data structures are allocated at the same time, struct
sched_group_energy.cap_states is initialized to point to the start of the
capacity state array memory.

The new function init_sched_energy() initializes the per sg struct
sched_group_energy and the struct capacity_state array in case the struct
sched_domain_topology_level contains sd energy information.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
---
kernel/sched/core.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++
kernel/sched/sched.h | 30 ++++++++++++++++++
2 files changed, 116 insertions(+)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 851cbd8..785b61d 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5438,6 +5438,9 @@ static void free_sched_domain(struct rcu_head *rcu)
free_sched_groups(sd->groups, 1);
} else if (atomic_dec_and_test(&sd->groups->ref)) {
kfree(sd->groups->sgp);
+#ifdef CONFIG_SCHED_ENERGY
+ kfree(sd->groups->sge);
+#endif
kfree(sd->groups);
}
kfree(sd);
@@ -5698,6 +5701,10 @@ static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg)
*sg = *per_cpu_ptr(sdd->sg, cpu);
(*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu);
atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */
+#ifdef CONFIG_SCHED_ENERGY
+ (*sg)->sge = *per_cpu_ptr(sdd->sge, cpu);
+ atomic_set(&(*sg)->sge->ref, 1); /* for claim_allocations */
+#endif
}

return cpu;
@@ -5789,6 +5796,31 @@ static void init_sched_groups_power(int cpu, struct sched_domain *sd)
atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight);
}

+#ifdef CONFIG_SCHED_ENERGY
+static void init_sched_energy(int cpu, struct sched_domain *sd,
+ struct sched_domain_topology_level *tl)
+{
+ struct sched_group *sg = sd->groups;
+ struct sched_energy *energy = &sg->sge->data;
+ sched_domain_energy_f fn = tl->energy;
+ struct cpumask *mask = sched_group_cpus(sg);
+
+ if (!fn || !fn(cpu))
+ return;
+
+ if (cpumask_weight(mask) > 1)
+ check_sched_energy_data(cpu, fn, mask);
+
+ energy->max_capacity = fn(cpu)->max_capacity;
+ energy->idle_power = fn(cpu)->idle_power;
+ energy->wakeup_energy = fn(cpu)->wakeup_energy;
+ energy->nr_cap_states = fn(cpu)->nr_cap_states;
+
+ memcpy(energy->cap_states, fn(cpu)->cap_states,
+ energy->nr_cap_states*sizeof(struct capacity_state));
+}
+#endif
+
/*
* Initializers for schedule domains
* Non-inlined to reduce accumulated stack pressure in build_sched_domains()
@@ -5879,6 +5911,11 @@ static void claim_allocations(int cpu, struct sched_domain *sd)

if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref))
*per_cpu_ptr(sdd->sgp, cpu) = NULL;
+
+#ifdef CONFIG_SCHED_ENERGY
+ if (atomic_read(&(*per_cpu_ptr(sdd->sge, cpu))->ref))
+ *per_cpu_ptr(sdd->sge, cpu) = NULL;
+#endif
}

#ifdef CONFIG_NUMA
@@ -6284,10 +6321,29 @@ static int __sdt_alloc(const struct cpumask *cpu_map)
if (!sdd->sgp)
return -ENOMEM;

+#ifdef CONFIG_SCHED_ENERGY
+ sdd->sge = alloc_percpu(struct sched_group_energy *);
+ if (!sdd->sge)
+ return -ENOMEM;
+#endif
for_each_cpu(j, cpu_map) {
struct sched_domain *sd;
struct sched_group *sg;
struct sched_group_power *sgp;
+#ifdef CONFIG_SCHED_ENERGY
+ struct sched_group_energy *sge;
+ sched_domain_energy_f fn = tl->energy;
+
+ /*
+ * Figure out how many elements the cap state array has
+ * to contain.
+ * In case tl->info.energy(j)->nr_cap_states is 0, we
+ * still allocate struct sched_group_energy XXX which is
+ * not used but will be freed later XXX.
+ */
+ unsigned int nr_cap_states = !fn || !fn(j) ? 0 :
+ fn(j)->nr_cap_states;
+#endif

sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
GFP_KERNEL, cpu_to_node(j));
@@ -6311,6 +6367,20 @@ static int __sdt_alloc(const struct cpumask *cpu_map)
return -ENOMEM;

*per_cpu_ptr(sdd->sgp, j) = sgp;
+
+#ifdef CONFIG_SCHED_ENERGY
+ sge = kzalloc_node(sizeof(struct sched_group_energy) +
+ nr_cap_states*sizeof(struct capacity_state),
+ GFP_KERNEL, cpu_to_node(j));
+
+ if (!sge)
+ return -ENOMEM;
+
+ sge->data.cap_states = (struct capacity_state *)((void *)sge +
+ sizeof(struct sched_group_energy));
+
+ *per_cpu_ptr(sdd->sge, j) = sge;
+#endif
}
}

@@ -6339,6 +6409,10 @@ static void __sdt_free(const struct cpumask *cpu_map)
kfree(*per_cpu_ptr(sdd->sg, j));
if (sdd->sgp)
kfree(*per_cpu_ptr(sdd->sgp, j));
+#ifdef CONFIG_SCHED_ENERGY
+ if (sdd->sge)
+ kfree(*per_cpu_ptr(sdd->sge, j));
+#endif
}
free_percpu(sdd->sd);
sdd->sd = NULL;
@@ -6346,6 +6420,10 @@ static void __sdt_free(const struct cpumask *cpu_map)
sdd->sg = NULL;
free_percpu(sdd->sgp);
sdd->sgp = NULL;
+#ifdef CONFIG_SCHED_ENERGY
+ free_percpu(sdd->sge);
+ sdd->sge = NULL;
+#endif
}
}

@@ -6417,10 +6495,18 @@ static int build_sched_domains(const struct cpumask *cpu_map,

/* Calculate CPU power for physical packages and nodes */
for (i = nr_cpumask_bits-1; i >= 0; i--) {
+#ifdef CONFIG_SCHED_ENERGY
+ struct sched_domain_topology_level *tl = sched_domain_topology;
+#endif
if (!cpumask_test_cpu(i, cpu_map))
continue;

+#ifdef CONFIG_SCHED_ENERGY
+ for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent, tl++) {
+ init_sched_energy(i, sd, tl);
+#else
for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
+#endif
claim_allocations(i, sd);
init_sched_groups_power(i, sd);
}
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index c566f5e..6726437 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -807,6 +807,36 @@ static inline unsigned int group_first_cpu(struct sched_group *group)

extern int group_balance_cpu(struct sched_group *sg);

+/*
+ * Check that the per-cpu provided sd energy data is consistent for all cpus
+ * within the mask.
+ */
+#ifdef CONFIG_SCHED_ENERGY
+static inline void check_sched_energy_data(int cpu, sched_domain_energy_f fn,
+ const struct cpumask *cpumask)
+{
+ struct cpumask mask;
+ int i;
+
+ cpumask_xor(&mask, cpumask, get_cpu_mask(cpu));
+
+ for_each_cpu(i, &mask) {
+ int y = 0;
+
+ BUG_ON(fn(i)->max_capacity != fn(cpu)->max_capacity);
+ BUG_ON(fn(i)->idle_power != fn(cpu)->idle_power);
+ BUG_ON(fn(i)->wakeup_energy != fn(cpu)->wakeup_energy);
+ BUG_ON(fn(i)->nr_cap_states != fn(cpu)->nr_cap_states);
+
+ for (; y < (fn(i)->nr_cap_states); y++) {
+ BUG_ON(fn(i)->cap_states[y].cap !=
+ fn(cpu)->cap_states[y].cap);
+ BUG_ON(fn(i)->cap_states[y].power !=
+ fn(cpu)->cap_states[y].power);
+ }
+ }
+}
+#endif
#endif /* CONFIG_SMP */

#include "stats.h"
--
1.7.9.5


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