From: Quentin Perret <quentin.perret@arm.com>
To: peterz@infradead.org, rjw@rjwysocki.net,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org
Cc: gregkh@linuxfoundation.org, mingo@redhat.com,
dietmar.eggemann@arm.com, morten.rasmussen@arm.com,
chris.redpath@arm.com, patrick.bellasi@arm.com,
valentin.schneider@arm.com, vincent.guittot@linaro.org,
thara.gopinath@linaro.org, viresh.kumar@linaro.org,
tkjos@google.com, joel@joelfernandes.org, smuckle@google.com,
adharmap@codeaurora.org, skannan@codeaurora.org,
pkondeti@codeaurora.org, juri.lelli@redhat.com,
edubezval@gmail.com, srinivas.pandruvada@linux.intel.com,
currojerez@riseup.net, javi.merino@kernel.org,
quentin.perret@arm.com
Subject: [PATCH v10 09/15] sched: Introduce sched_energy_present static key
Date: Mon, 3 Dec 2018 09:56:22 +0000 [thread overview]
Message-ID: <20181203095628.11858-10-quentin.perret@arm.com> (raw)
In-Reply-To: <20181203095628.11858-1-quentin.perret@arm.com>
In order to make sure Energy Aware Scheduling (EAS) will not impact
systems where no Energy Model is available, introduce a static key
guarding the access to EAS code. Since EAS is enabled on a
per-root-domain basis, the static key is enabled when at least one root
domain meets all conditions for EAS.
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
---
kernel/sched/sched.h | 4 ++++
kernel/sched/topology.c | 28 ++++++++++++++++++++++++----
2 files changed, 28 insertions(+), 4 deletions(-)
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 6236081d68bf..8decb3bc0e3f 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2298,3 +2298,7 @@ unsigned long scale_irq_capacity(unsigned long util, unsigned long irq, unsigned
#else
#define perf_domain_span(pd) NULL
#endif
+
+#ifdef CONFIG_SMP
+extern struct static_key_false sched_energy_present;
+#endif
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 70492d4bfed6..24d211ca384d 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -201,6 +201,7 @@ sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
return 1;
}
+DEFINE_STATIC_KEY_FALSE(sched_energy_present);
#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
DEFINE_MUTEX(sched_energy_mutex);
bool sched_energy_update;
@@ -273,6 +274,19 @@ static void destroy_perf_domain_rcu(struct rcu_head *rp)
free_pd(pd);
}
+static void sched_energy_set(bool has_eas)
+{
+ if (!has_eas && static_branch_unlikely(&sched_energy_present)) {
+ if (sched_debug())
+ pr_info("%s: stopping EAS\n", __func__);
+ static_branch_disable_cpuslocked(&sched_energy_present);
+ } else if (has_eas && !static_branch_unlikely(&sched_energy_present)) {
+ if (sched_debug())
+ pr_info("%s: starting EAS\n", __func__);
+ static_branch_enable_cpuslocked(&sched_energy_present);
+ }
+}
+
/*
* EAS can be used on a root domain if it meets all the following conditions:
* 1. an Energy Model (EM) is available;
@@ -299,7 +313,7 @@ static void destroy_perf_domain_rcu(struct rcu_head *rp)
#define EM_MAX_COMPLEXITY 2048
extern struct cpufreq_governor schedutil_gov;
-static void build_perf_domains(const struct cpumask *cpu_map)
+static bool build_perf_domains(const struct cpumask *cpu_map)
{
int i, nr_pd = 0, nr_cs = 0, nr_cpus = cpumask_weight(cpu_map);
struct perf_domain *pd = NULL, *tmp;
@@ -365,7 +379,7 @@ static void build_perf_domains(const struct cpumask *cpu_map)
if (tmp)
call_rcu(&tmp->rcu, destroy_perf_domain_rcu);
- return;
+ return !!pd;
free:
free_pd(pd);
@@ -373,6 +387,8 @@ static void build_perf_domains(const struct cpumask *cpu_map)
rcu_assign_pointer(rd->pd, NULL);
if (tmp)
call_rcu(&tmp->rcu, destroy_perf_domain_rcu);
+
+ return false;
}
#else
static void free_pd(struct perf_domain *pd) { }
@@ -2116,6 +2132,7 @@ static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
struct sched_domain_attr *dattr_new)
{
+ bool __maybe_unused has_eas = false;
int i, j, n;
int new_topology;
@@ -2179,14 +2196,17 @@ void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
for (i = 0; i < ndoms_new; i++) {
for (j = 0; j < n && !sched_energy_update; j++) {
if (cpumask_equal(doms_new[i], doms_cur[j]) &&
- cpu_rq(cpumask_first(doms_cur[j]))->rd->pd)
+ cpu_rq(cpumask_first(doms_cur[j]))->rd->pd) {
+ has_eas = true;
goto match3;
+ }
}
/* No match - add perf. domains for a new rd */
- build_perf_domains(doms_new[i]);
+ has_eas |= build_perf_domains(doms_new[i]);
match3:
;
}
+ sched_energy_set(has_eas);
#endif
/* Remember the new sched domains: */
--
2.19.2
next prev parent reply other threads:[~2018-12-03 9:57 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-03 9:56 [PATCH v10 00/15] Energy Aware Scheduling Quentin Perret
2018-12-03 9:56 ` [PATCH v10 01/15] sched: Relocate arch_scale_cpu_capacity Quentin Perret
2018-12-11 15:32 ` [tip:sched/core] sched/topology: Relocate arch_scale_cpu_capacity() to the internal header tip-bot for Quentin Perret
2018-12-03 9:56 ` [PATCH v10 02/15] sched/cpufreq: Prepare schedutil for Energy Aware Scheduling Quentin Perret
2018-12-11 12:01 ` Rafael J. Wysocki
2018-12-11 12:17 ` Quentin Perret
2018-12-11 12:22 ` Rafael J. Wysocki
2018-12-11 12:24 ` Quentin Perret
2018-12-11 15:33 ` [tip:sched/core] " tip-bot for Quentin Perret
2018-12-03 9:56 ` [PATCH v10 03/15] PM: Introduce an Energy Model management framework Quentin Perret
2018-12-11 15:33 ` [tip:sched/core] " tip-bot for Quentin Perret
2018-12-03 9:56 ` [PATCH v10 04/15] PM / EM: Expose the Energy Model in sysfs Quentin Perret
2018-12-11 14:18 ` Ingo Molnar
2018-12-11 15:04 ` Quentin Perret
2018-12-03 9:56 ` [PATCH v10 05/15] sched/topology: Reference the Energy Model of CPUs when available Quentin Perret
2018-12-11 15:34 ` [tip:sched/core] " tip-bot for Quentin Perret
2018-12-03 9:56 ` [PATCH v10 06/15] sched/topology: Lowest CPU asymmetry sched_domain level pointer Quentin Perret
2018-12-11 15:34 ` [tip:sched/core] sched/topology: Add lowest " tip-bot for Quentin Perret
2018-12-03 9:56 ` [PATCH v10 07/15] sched/topology: Disable EAS on inappropriate platforms Quentin Perret
2018-12-11 15:35 ` [tip:sched/core] " tip-bot for Quentin Perret
2018-12-03 9:56 ` [PATCH v10 08/15] sched/topology: Make Energy Aware Scheduling depend on schedutil Quentin Perret
2018-12-11 15:36 ` [tip:sched/core] " tip-bot for Quentin Perret
2018-12-03 9:56 ` Quentin Perret [this message]
2018-12-11 15:36 ` [tip:sched/core] sched/toplogy: Introduce the 'sched_energy_present' static key tip-bot for Quentin Perret
2018-12-13 13:56 ` Quentin Perret
2018-12-03 9:56 ` [PATCH v10 10/15] sched: Introduce a sysctl for Energy Aware Scheduling Quentin Perret
2018-12-11 14:15 ` Ingo Molnar
2018-12-11 14:49 ` Quentin Perret
2018-12-13 14:03 ` Peter Zijlstra
2019-01-21 11:35 ` [tip:sched/core] sched/topology: " tip-bot for Quentin Perret
2019-01-21 13:51 ` tip-bot for Quentin Perret
2019-01-27 11:34 ` tip-bot for Quentin Perret
2018-12-03 9:56 ` [PATCH v10 11/15] sched/fair: Clean-up update_sg_lb_stats parameters Quentin Perret
2018-12-11 15:37 ` [tip:sched/core] " tip-bot for Quentin Perret
2018-12-03 9:56 ` [PATCH v10 12/15] sched: Add over-utilization/tipping point indicator Quentin Perret
2018-12-11 15:37 ` [tip:sched/core] sched/fair: " tip-bot for Morten Rasmussen
2018-12-03 9:56 ` [PATCH v10 13/15] sched/fair: Introduce an energy estimation helper function Quentin Perret
2018-12-11 15:38 ` [tip:sched/core] " tip-bot for Quentin Perret
2018-12-03 9:56 ` [PATCH v10 14/15] sched/fair: Select an energy-efficient CPU on task wake-up Quentin Perret
2018-12-11 15:39 ` [tip:sched/core] " tip-bot for Quentin Perret
2018-12-03 9:56 ` [PATCH v10 15/15] OPTIONAL: cpufreq: dt: Register an Energy Model Quentin Perret
2019-01-08 20:38 ` Matthias Kaehlcke
2019-01-09 10:57 ` Quentin Perret
2019-01-09 18:14 ` Matthias Kaehlcke
2019-01-10 9:08 ` Quentin Perret
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