From: Steve Muckle Date: Fri, 11 Nov 2016 22:04:43 +0000 (-0800) Subject: sched: backport cpufreq hooks from 4.9-rc4 X-Git-Tag: release-20171130_firefly~4^2~100^2~86 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=dee8fa15529f1ce843764d5c1dd2033e2e4154b0;p=firefly-linux-kernel-4.4.55.git sched: backport cpufreq hooks from 4.9-rc4 The scheduler cpufreq hooks are required by the schedutil cpufreq governor. Change-Id: Ied6c46262bb33b7e81bbb3d3d2761124e0c676b7 Signed-off-by: Steve Muckle [trivial cherry-picking fixes] Signed-off-by: Juri Lelli Signed-off-by: Chris Redpath --- diff --git a/include/linux/sched.h b/include/linux/sched.h index 79f70e5bae08..bc23d15244db 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -3291,4 +3291,21 @@ static inline unsigned long rlimit_max(unsigned int limit) return task_rlimit_max(current, limit); } +#define SCHED_CPUFREQ_RT (1U << 0) +#define SCHED_CPUFREQ_DL (1U << 1) +#define SCHED_CPUFREQ_IOWAIT (1U << 2) + +#define SCHED_CPUFREQ_RT_DL (SCHED_CPUFREQ_RT | SCHED_CPUFREQ_DL) + +#ifdef CONFIG_CPU_FREQ +struct update_util_data { + void (*func)(struct update_util_data *data, u64 time, unsigned int flags); +}; + +void cpufreq_add_update_util_hook(int cpu, struct update_util_data *data, + void (*func)(struct update_util_data *data, u64 time, + unsigned int flags)); +void cpufreq_remove_update_util_hook(int cpu); +#endif /* CONFIG_CPU_FREQ */ + #endif diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile index 623ce4bde0d5..f2d49474aab1 100644 --- a/kernel/sched/Makefile +++ b/kernel/sched/Makefile @@ -21,4 +21,5 @@ obj-$(CONFIG_SCHEDSTATS) += stats.o obj-$(CONFIG_SCHED_DEBUG) += debug.o obj-$(CONFIG_SCHED_TUNE) += tune.o obj-$(CONFIG_CGROUP_CPUACCT) += cpuacct.o +obj-$(CONFIG_CPU_FREQ) += cpufreq.o obj-$(CONFIG_CPU_FREQ_GOV_SCHED) += cpufreq_sched.o diff --git a/kernel/sched/cpufreq.c b/kernel/sched/cpufreq.c new file mode 100644 index 000000000000..dbc51442ecbc --- /dev/null +++ b/kernel/sched/cpufreq.c @@ -0,0 +1,63 @@ +/* + * Scheduler code and data structures related to cpufreq. + * + * Copyright (C) 2016, Intel Corporation + * Author: Rafael J. Wysocki + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "sched.h" + +DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data); + +/** + * cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer. + * @cpu: The CPU to set the pointer for. + * @data: New pointer value. + * @func: Callback function to set for the CPU. + * + * Set and publish the update_util_data pointer for the given CPU. + * + * The update_util_data pointer of @cpu is set to @data and the callback + * function pointer in the target struct update_util_data is set to @func. + * That function will be called by cpufreq_update_util() from RCU-sched + * read-side critical sections, so it must not sleep. @data will always be + * passed to it as the first argument which allows the function to get to the + * target update_util_data structure and its container. + * + * The update_util_data pointer of @cpu must be NULL when this function is + * called or it will WARN() and return with no effect. + */ +void cpufreq_add_update_util_hook(int cpu, struct update_util_data *data, + void (*func)(struct update_util_data *data, u64 time, + unsigned int flags)) +{ + if (WARN_ON(!data || !func)) + return; + + if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu))) + return; + + data->func = func; + rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), data); +} +EXPORT_SYMBOL_GPL(cpufreq_add_update_util_hook); + +/** + * cpufreq_remove_update_util_hook - Clear the CPU's update_util_data pointer. + * @cpu: The CPU to clear the pointer for. + * + * Clear the update_util_data pointer for the given CPU. + * + * Callers must use RCU-sched callbacks to free any memory that might be + * accessed via the old update_util_data pointer or invoke synchronize_sched() + * right after this function to avoid use-after-free. + */ +void cpufreq_remove_update_util_hook(int cpu) +{ + rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), NULL); +} +EXPORT_SYMBOL_GPL(cpufreq_remove_update_util_hook); diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index f10b1cb255b2..9ec7f19b5020 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -753,6 +753,9 @@ static void update_curr_dl(struct rq *rq) if (unlikely((s64)delta_exec <= 0)) return; + /* kick cpufreq (see the comment in kernel/sched/sched.h). */ + cpufreq_update_this_cpu(rq, SCHED_CPUFREQ_DL); + schedstat_set(curr->se.statistics.exec_max, max(curr->se.statistics.exec_max, delta_exec)); diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 6f353de3f390..baba2d34c34e 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2711,6 +2711,29 @@ static inline void update_tg_load_avg(struct cfs_rq *cfs_rq, int force) static inline void update_tg_load_avg(struct cfs_rq *cfs_rq, int force) {} #endif /* CONFIG_FAIR_GROUP_SCHED */ +static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq) +{ + if (&this_rq()->cfs == cfs_rq) { + /* + * There are a few boundary cases this might miss but it should + * get called often enough that that should (hopefully) not be + * a real problem -- added to that it only calls on the local + * CPU, so if we enqueue remotely we'll miss an update, but + * the next tick/schedule should update. + * + * It will not get called when we go idle, because the idle + * thread is a different class (!fair), nor will the utilization + * number include things like RT tasks. + * + * As is, the util number is not freq-invariant (we'd have to + * implement arch_scale_freq_capacity() for that). + * + * See cpu_util(). + */ + cpufreq_update_util(rq_of(cfs_rq), 0); + } +} + static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq); /* @@ -2731,10 +2754,11 @@ static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq); } while (0) /* Group cfs_rq's load_avg is used for task_h_load and update_cfs_share */ -static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) +static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, + bool update_freq) { struct sched_avg *sa = &cfs_rq->avg; - int decayed, removed = 0; + int decayed, removed = 0, removed_util = 0; if (atomic_long_read(&cfs_rq->removed_load_avg)) { s64 r = atomic_long_xchg(&cfs_rq->removed_load_avg, 0); @@ -2747,6 +2771,7 @@ static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) long r = atomic_long_xchg(&cfs_rq->removed_util_avg, 0); sub_positive(&sa->util_avg, r); sub_positive(&sa->util_sum, r * LOAD_AVG_MAX); + removed_util = 1; } decayed = __update_load_avg(now, cpu_of(rq_of(cfs_rq)), sa, @@ -2761,6 +2786,9 @@ static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) if (cfs_rq == &rq_of(cfs_rq)->cfs) trace_sched_load_avg_cpu(cpu_of(rq_of(cfs_rq)), cfs_rq); + if (update_freq && (decayed || removed_util)) + cfs_rq_util_change(cfs_rq); + return decayed || removed; } @@ -2779,7 +2807,7 @@ static inline void update_load_avg(struct sched_entity *se, int update_tg) se->on_rq * scale_load_down(se->load.weight), cfs_rq->curr == se, NULL); - if (update_cfs_rq_load_avg(now, cfs_rq) && update_tg) + if (update_cfs_rq_load_avg(now, cfs_rq, true) && update_tg) update_tg_load_avg(cfs_rq, 0); if (entity_is_task(se)) @@ -2811,6 +2839,8 @@ skip_aging: cfs_rq->avg.load_sum += se->avg.load_sum; cfs_rq->avg.util_avg += se->avg.util_avg; cfs_rq->avg.util_sum += se->avg.util_sum; + + cfs_rq_util_change(cfs_rq); } static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) @@ -2823,6 +2853,8 @@ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s sub_positive(&cfs_rq->avg.load_sum, se->avg.load_sum); sub_positive(&cfs_rq->avg.util_avg, se->avg.util_avg); sub_positive(&cfs_rq->avg.util_sum, se->avg.util_sum); + + cfs_rq_util_change(cfs_rq); } /* Add the load generated by se into cfs_rq's load average */ @@ -2840,7 +2872,7 @@ enqueue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) cfs_rq->curr == se, NULL); } - decayed = update_cfs_rq_load_avg(now, cfs_rq); + decayed = update_cfs_rq_load_avg(now, cfs_rq, !migrated); cfs_rq->runnable_load_avg += sa->load_avg; cfs_rq->runnable_load_sum += sa->load_sum; @@ -2940,7 +2972,11 @@ static int idle_balance(struct rq *this_rq); #else /* CONFIG_SMP */ -static inline void update_load_avg(struct sched_entity *se, int update_tg) {} +static inline void update_load_avg(struct sched_entity *se, int update_tg) +{ + cpufreq_update_util(rq_of(cfs_rq_of(se)), 0); +} + static inline void enqueue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {} static inline void @@ -4257,6 +4293,14 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) int task_wakeup = flags & ENQUEUE_WAKEUP; #endif + /* + * If in_iowait is set, the code below may not trigger any cpufreq + * utilization updates, so do it here explicitly with the IOWAIT flag + * passed. + */ + if (p->in_iowait) + cpufreq_update_this_cpu(rq, SCHED_CPUFREQ_IOWAIT); + for_each_sched_entity(se) { if (se->on_rq) break; @@ -6923,7 +6967,8 @@ static void update_blocked_averages(int cpu) if (throttled_hierarchy(cfs_rq)) continue; - if (update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq)) + if (update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq, + true)) update_tg_load_avg(cfs_rq, 0); } raw_spin_unlock_irqrestore(&rq->lock, flags); @@ -6984,7 +7029,7 @@ static inline void update_blocked_averages(int cpu) raw_spin_lock_irqsave(&rq->lock, flags); update_rq_clock(rq); - update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq); + update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq, true); raw_spin_unlock_irqrestore(&rq->lock, flags); } diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 541b8494450e..6bb51d62dca4 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1002,6 +1002,9 @@ static void update_curr_rt(struct rq *rq) if (unlikely((s64)delta_exec <= 0)) return; + /* Kick cpufreq (see the comment in kernel/sched/sched.h). */ + cpufreq_update_this_cpu(rq, SCHED_CPUFREQ_RT); + schedstat_set(curr->se.statistics.exec_max, max(curr->se.statistics.exec_max, delta_exec)); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 0386a2cdb008..237b0bcdd304 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2038,3 +2038,55 @@ static inline void account_reset_rq(struct rq *rq) rq->prev_steal_time_rq = 0; #endif } + +#ifdef CONFIG_CPU_FREQ +DECLARE_PER_CPU(struct update_util_data *, cpufreq_update_util_data); + +/** + * cpufreq_update_util - Take a note about CPU utilization changes. + * @rq: Runqueue to carry out the update for. + * @flags: Update reason flags. + * + * This function is called by the scheduler on the CPU whose utilization is + * being updated. + * + * It can only be called from RCU-sched read-side critical sections. + * + * The way cpufreq is currently arranged requires it to evaluate the CPU + * performance state (frequency/voltage) on a regular basis to prevent it from + * being stuck in a completely inadequate performance level for too long. + * That is not guaranteed to happen if the updates are only triggered from CFS, + * though, because they may not be coming in if RT or deadline tasks are active + * all the time (or there are RT and DL tasks only). + * + * As a workaround for that issue, this function is called by the RT and DL + * sched classes to trigger extra cpufreq updates to prevent it from stalling, + * but that really is a band-aid. Going forward it should be replaced with + * solutions targeted more specifically at RT and DL tasks. + */ +static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) +{ + struct update_util_data *data; + + data = rcu_dereference_sched(*this_cpu_ptr(&cpufreq_update_util_data)); + if (data) + data->func(data, rq_clock(rq), flags); +} + +static inline void cpufreq_update_this_cpu(struct rq *rq, unsigned int flags) +{ + if (cpu_of(rq) == smp_processor_id()) + cpufreq_update_util(rq, flags); +} +#else +static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {} +static inline void cpufreq_update_this_cpu(struct rq *rq, unsigned int flags) {} +#endif /* CONFIG_CPU_FREQ */ + +#ifdef arch_scale_freq_capacity +#ifndef arch_scale_freq_invariant +#define arch_scale_freq_invariant() (true) +#endif +#else /* arch_scale_freq_capacity */ +#define arch_scale_freq_invariant() (false) +#endif