From 8d5d0cfb63cbcb4005e19a332b31d687b1d01e58 Mon Sep 17 00:00:00 2001 From: Quentin Perret Date: Mon, 3 Dec 2018 09:56:23 +0000 Subject: 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 Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner 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 --- kernel/sched/topology.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) (limited to 'kernel/sched/topology.c') 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()) { -- cgit v1.2.3 From f8a696f25ba09a1821dc6ca3db56f41c264fb896 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 5 Dec 2018 11:23:56 +0100 Subject: sched/core: Give DCE a fighting chance All that fancy new Energy-Aware scheduling foo is hidden behind a static_key, which is awesome if you have the stuff enabled in your config. However, when you lack all the prerequisites it doesn't make any sense to pretend we'll ever actually run this, so provide a little more clue to the compiler so it can more agressively delete the code. text data bss dec hex filename 50297 976 96 51369 c8a9 defconfig-build/kernel/sched/fair.o 49227 944 96 50267 c45b defconfig-build/kernel/sched/fair.o Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 4 ++-- kernel/sched/sched.h | 18 +++++++++++++----- kernel/sched/topology.c | 2 +- 3 files changed, 16 insertions(+), 8 deletions(-) (limited to 'kernel/sched/topology.c') diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 50aa2aba69bd..b1374fbddd0d 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6607,7 +6607,7 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f if (sd_flag & SD_BALANCE_WAKE) { record_wakee(p); - if (static_branch_unlikely(&sched_energy_present)) { + if (sched_energy_enabled()) { new_cpu = find_energy_efficient_cpu(p, prev_cpu); if (new_cpu >= 0) return new_cpu; @@ -8635,7 +8635,7 @@ static struct sched_group *find_busiest_group(struct lb_env *env) */ update_sd_lb_stats(env, &sds); - if (static_branch_unlikely(&sched_energy_present)) { + if (sched_energy_enabled()) { struct root_domain *rd = env->dst_rq->rd; if (rcu_dereference(rd->pd) && !READ_ONCE(rd->overutilized)) diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index d04530bf251f..d27c1a5d4e25 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2299,11 +2299,19 @@ unsigned long scale_irq_capacity(unsigned long util, unsigned long irq, unsigned #endif #if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) + #define perf_domain_span(pd) (to_cpumask(((pd)->em_pd->cpus))) -#else + +DECLARE_STATIC_KEY_FALSE(sched_energy_present); + +static inline bool sched_energy_enabled(void) +{ + return static_branch_unlikely(&sched_energy_present); +} + +#else /* ! (CONFIG_ENERGY_MODEL && CONFIG_CPU_FREQ_GOV_SCHEDUTIL) */ + #define perf_domain_span(pd) NULL -#endif +static inline bool sched_energy_enabled(void) { return false; } -#ifdef CONFIG_SMP -extern struct static_key_false sched_energy_present; -#endif +#endif /* CONFIG_ENERGY_MODEL && CONFIG_CPU_FREQ_GOV_SCHEDUTIL */ diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 50c3fc316c54..4ae9403420ed 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -201,8 +201,8 @@ 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_STATIC_KEY_FALSE(sched_energy_present); unsigned int sysctl_sched_energy_aware = 1; DEFINE_MUTEX(sched_energy_mutex); bool sched_energy_update; -- cgit v1.2.3 From 99687cdbb3f6c8e32bcc7f37496e811f30460e48 Mon Sep 17 00:00:00 2001 From: Luc Van Oostenryck Date: Fri, 18 Jan 2019 15:49:36 +0100 Subject: sched/topology: Fix percpu data types in struct sd_data & struct s_data The percpu members of struct sd_data and s_data are declared as: struct ... ** __percpu member; So their type is: __percpu pointer to pointer to struct ... But looking at how they're used, their type should be: pointer to __percpu pointer to struct ... and they should thus be declared as: struct ... * __percpu *member; So fix the placement of '__percpu' in the definition of these structures. This addresses a bunch of Sparse's warnings like: warning: incorrect type in initializer (different address spaces) expected void const [noderef] *__vpp_verify got struct sched_domain ** Signed-off-by: Luc Van Oostenryck Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20190118144936.79158-1-luc.vanoostenryck@gmail.com Signed-off-by: Ingo Molnar --- include/linux/sched/topology.h | 8 ++++---- kernel/sched/topology.c | 2 +- 2 files changed, 5 insertions(+), 5 deletions(-) (limited to 'kernel/sched/topology.c') diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h index c31d3a47a47c..57c7ed3fe465 100644 --- a/include/linux/sched/topology.h +++ b/include/linux/sched/topology.h @@ -176,10 +176,10 @@ typedef int (*sched_domain_flags_f)(void); #define SDTL_OVERLAP 0x01 struct sd_data { - struct sched_domain **__percpu sd; - struct sched_domain_shared **__percpu sds; - struct sched_group **__percpu sg; - struct sched_group_capacity **__percpu sgc; + struct sched_domain *__percpu *sd; + struct sched_domain_shared *__percpu *sds; + struct sched_group *__percpu *sg; + struct sched_group_capacity *__percpu *sgc; }; struct sched_domain_topology_level { diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 4ae9403420ed..93ff526e77b0 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -705,7 +705,7 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) } struct s_data { - struct sched_domain ** __percpu sd; + struct sched_domain * __percpu *sd; struct root_domain *rd; }; -- cgit v1.2.3