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authorQuentin Perret <quentin.perret@arm.com>2018-12-03 09:56:23 +0000
committerIngo Molnar <mingo@kernel.org>2019-01-27 12:29:37 +0100
commit8d5d0cfb63cbcb4005e19a332b31d687b1d01e58 (patch)
treee2a84b9053e709df25352a1ab4a07b83d464f1c1 /kernel/sched
parent62a8ddc93a8526eafbdc26e5ee3830e2e9f639e8 (diff)
sched/topology: Introduce a sysctl for Energy Aware Scheduling
In its current state, Energy Aware Scheduling (EAS) starts automatically on asymmetric platforms having an Energy Model (EM). However, there are users who want to have an EM (for thermal management for example), but don't want EAS with it. In order to let users disable EAS explicitly, introduce a new sysctl called 'sched_energy_aware'. It is enabled by default so that EAS can start automatically on platforms where it makes sense. Flipping it to 0 rebuilds the scheduling domains and disables EAS. Signed-off-by: Quentin Perret <quentin.perret@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: adharmap@codeaurora.org Cc: chris.redpath@arm.com Cc: currojerez@riseup.net Cc: dietmar.eggemann@arm.com Cc: edubezval@gmail.com Cc: gregkh@linuxfoundation.org Cc: javi.merino@kernel.org Cc: joel@joelfernandes.org Cc: juri.lelli@redhat.com Cc: morten.rasmussen@arm.com Cc: patrick.bellasi@arm.com Cc: pkondeti@codeaurora.org Cc: rjw@rjwysocki.net Cc: skannan@codeaurora.org Cc: smuckle@google.com Cc: srinivas.pandruvada@linux.intel.com Cc: thara.gopinath@linaro.org Cc: tkjos@google.com Cc: valentin.schneider@arm.com Cc: vincent.guittot@linaro.org Cc: viresh.kumar@linaro.org Link: https://lkml.kernel.org/r/20181203095628.11858-11-quentin.perret@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/topology.c29
1 files changed, 29 insertions, 0 deletions
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 3f35ba1d8fde..50c3fc316c54 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -203,9 +203,35 @@ sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
DEFINE_STATIC_KEY_FALSE(sched_energy_present);
#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
+unsigned int sysctl_sched_energy_aware = 1;
DEFINE_MUTEX(sched_energy_mutex);
bool sched_energy_update;
+#ifdef CONFIG_PROC_SYSCTL
+int sched_energy_aware_handler(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ int ret, state;
+
+ if (write && !capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+ if (!ret && write) {
+ state = static_branch_unlikely(&sched_energy_present);
+ if (state != sysctl_sched_energy_aware) {
+ mutex_lock(&sched_energy_mutex);
+ sched_energy_update = 1;
+ rebuild_sched_domains();
+ sched_energy_update = 0;
+ mutex_unlock(&sched_energy_mutex);
+ }
+ }
+
+ return ret;
+}
+#endif
+
static void free_pd(struct perf_domain *pd)
{
struct perf_domain *tmp;
@@ -322,6 +348,9 @@ static bool build_perf_domains(const struct cpumask *cpu_map)
struct cpufreq_policy *policy;
struct cpufreq_governor *gov;
+ if (!sysctl_sched_energy_aware)
+ goto free;
+
/* EAS is enabled for asymmetric CPU capacity topologies. */
if (!per_cpu(sd_asym_cpucapacity, cpu)) {
if (sched_debug()) {