diff options
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/Makefile | 2 | ||||
| -rw-r--r-- | kernel/sched/clock.c | 57 | ||||
| -rw-r--r-- | kernel/sched/completion.c | 8 | ||||
| -rw-r--r-- | kernel/sched/core.c | 174 | ||||
| -rw-r--r-- | kernel/sched/cpufreq_schedutil.c | 103 | ||||
| -rw-r--r-- | kernel/sched/deadline.c | 8 | ||||
| -rw-r--r-- | kernel/sched/debug.c | 37 | ||||
| -rw-r--r-- | kernel/sched/fair.c | 664 | ||||
| -rw-r--r-- | kernel/sched/pelt.c | 399 | ||||
| -rw-r--r-- | kernel/sched/pelt.h | 72 | ||||
| -rw-r--r-- | kernel/sched/rt.c | 15 | ||||
| -rw-r--r-- | kernel/sched/sched.h | 87 | ||||
| -rw-r--r-- | kernel/sched/swait.c | 32 | ||||
| -rw-r--r-- | kernel/sched/wait.c | 55 |
14 files changed, 956 insertions, 757 deletions
diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile index d9a02b318108..7fe183404c38 100644 --- a/kernel/sched/Makefile +++ b/kernel/sched/Makefile @@ -20,7 +20,7 @@ obj-y += core.o loadavg.o clock.o cputime.o obj-y += idle.o fair.o rt.o deadline.o obj-y += wait.o wait_bit.o swait.o completion.o -obj-$(CONFIG_SMP) += cpupri.o cpudeadline.o topology.o stop_task.o +obj-$(CONFIG_SMP) += cpupri.o cpudeadline.o topology.o stop_task.o pelt.o obj-$(CONFIG_SCHED_AUTOGROUP) += autogroup.o obj-$(CONFIG_SCHEDSTATS) += stats.o obj-$(CONFIG_SCHED_DEBUG) += debug.o diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c index 10c83e73837a..e3e3b979f9bd 100644 --- a/kernel/sched/clock.c +++ b/kernel/sched/clock.c @@ -53,6 +53,7 @@ * */ #include "sched.h" +#include <linux/sched_clock.h> /* * Scheduler clock - returns current time in nanosec units. @@ -66,12 +67,7 @@ unsigned long long __weak sched_clock(void) } EXPORT_SYMBOL_GPL(sched_clock); -__read_mostly int sched_clock_running; - -void sched_clock_init(void) -{ - sched_clock_running = 1; -} +static DEFINE_STATIC_KEY_FALSE(sched_clock_running); #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK /* @@ -195,17 +191,40 @@ void clear_sched_clock_stable(void) smp_mb(); /* matches sched_clock_init_late() */ - if (sched_clock_running == 2) + if (static_key_count(&sched_clock_running.key) == 2) __clear_sched_clock_stable(); } +static void __sched_clock_gtod_offset(void) +{ + struct sched_clock_data *scd = this_scd(); + + __scd_stamp(scd); + __gtod_offset = (scd->tick_raw + __sched_clock_offset) - scd->tick_gtod; +} + +void __init sched_clock_init(void) +{ + /* + * Set __gtod_offset such that once we mark sched_clock_running, + * sched_clock_tick() continues where sched_clock() left off. + * + * Even if TSC is buggered, we're still UP at this point so it + * can't really be out of sync. + */ + local_irq_disable(); + __sched_clock_gtod_offset(); + local_irq_enable(); + + static_branch_inc(&sched_clock_running); +} /* * We run this as late_initcall() such that it runs after all built-in drivers, * notably: acpi_processor and intel_idle, which can mark the TSC as unstable. */ static int __init sched_clock_init_late(void) { - sched_clock_running = 2; + static_branch_inc(&sched_clock_running); /* * Ensure that it is impossible to not do a static_key update. * @@ -350,8 +369,8 @@ u64 sched_clock_cpu(int cpu) if (sched_clock_stable()) return sched_clock() + __sched_clock_offset; - if (unlikely(!sched_clock_running)) - return 0ull; + if (!static_branch_unlikely(&sched_clock_running)) + return sched_clock(); preempt_disable_notrace(); scd = cpu_sdc(cpu); @@ -373,7 +392,7 @@ void sched_clock_tick(void) if (sched_clock_stable()) return; - if (unlikely(!sched_clock_running)) + if (!static_branch_unlikely(&sched_clock_running)) return; lockdep_assert_irqs_disabled(); @@ -385,8 +404,6 @@ void sched_clock_tick(void) void sched_clock_tick_stable(void) { - u64 gtod, clock; - if (!sched_clock_stable()) return; @@ -398,9 +415,7 @@ void sched_clock_tick_stable(void) * TSC to be unstable, any computation will be computing crap. */ local_irq_disable(); - gtod = ktime_get_ns(); - clock = sched_clock(); - __gtod_offset = (clock + __sched_clock_offset) - gtod; + __sched_clock_gtod_offset(); local_irq_enable(); } @@ -434,9 +449,17 @@ EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event); #else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */ +void __init sched_clock_init(void) +{ + static_branch_inc(&sched_clock_running); + local_irq_disable(); + generic_sched_clock_init(); + local_irq_enable(); +} + u64 sched_clock_cpu(int cpu) { - if (unlikely(!sched_clock_running)) + if (!static_branch_unlikely(&sched_clock_running)) return 0; return sched_clock(); diff --git a/kernel/sched/completion.c b/kernel/sched/completion.c index e426b0cb9ac6..a1ad5b7d5521 100644 --- a/kernel/sched/completion.c +++ b/kernel/sched/completion.c @@ -22,8 +22,8 @@ * * See also complete_all(), wait_for_completion() and related routines. * - * It may be assumed that this function implies a write memory barrier before - * changing the task state if and only if any tasks are woken up. + * If this function wakes up a task, it executes a full memory barrier before + * accessing the task state. */ void complete(struct completion *x) { @@ -44,8 +44,8 @@ EXPORT_SYMBOL(complete); * * This will wake up all threads waiting on this particular completion event. * - * It may be assumed that this function implies a write memory barrier before - * changing the task state if and only if any tasks are woken up. + * If this function wakes up a task, it executes a full memory barrier before + * accessing the task state. * * Since complete_all() sets the completion of @x permanently to done * to allow multiple waiters to finish, a call to reinit_completion() diff --git a/kernel/sched/core.c b/kernel/sched/core.c index fe365c9a08e9..454adf9f8180 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -17,6 +17,8 @@ #include "../workqueue_internal.h" #include "../smpboot.h" +#include "pelt.h" + #define CREATE_TRACE_POINTS #include <trace/events/sched.h> @@ -45,14 +47,6 @@ const_debug unsigned int sysctl_sched_features = const_debug unsigned int sysctl_sched_nr_migrate = 32; /* - * period over which we average the RT time consumption, measured - * in ms. - * - * default: 1s - */ -const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC; - -/* * period over which we measure -rt task CPU usage in us. * default: 1s */ @@ -183,9 +177,9 @@ static void update_rq_clock_task(struct rq *rq, s64 delta) rq->clock_task += delta; -#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) +#ifdef HAVE_SCHED_AVG_IRQ if ((irq_delta + steal) && sched_feat(NONTASK_CAPACITY)) - sched_rt_avg_update(rq, irq_delta + steal); + update_irq_load_avg(rq, irq_delta + steal); #endif } @@ -412,8 +406,8 @@ void wake_q_add(struct wake_q_head *head, struct task_struct *task) * its already queued (either by us or someone else) and will get the * wakeup due to that. * - * This cmpxchg() implies a full barrier, which pairs with the write - * barrier implied by the wakeup in wake_up_q(). + * This cmpxchg() executes a full barrier, which pairs with the full + * barrier executed by the wakeup in wake_up_q(). */ if (cmpxchg(&node->next, NULL, WAKE_Q_TAIL)) return; @@ -441,8 +435,8 @@ void wake_up_q(struct wake_q_head *head) task->wake_q.next = NULL; /* - * wake_up_process() implies a wmb() to pair with the queueing - * in wake_q_add() so as not to miss wakeups. + * wake_up_process() executes a full barrier, which pairs with + * the queueing in wake_q_add() so as not to miss wakeups. */ wake_up_process(task); put_task_struct(task); @@ -649,23 +643,6 @@ bool sched_can_stop_tick(struct rq *rq) return true; } #endif /* CONFIG_NO_HZ_FULL */ - -void sched_avg_update(struct rq *rq) -{ - s64 period = sched_avg_period(); - - while ((s64)(rq_clock(rq) - rq->age_stamp) > period) { - /* - * Inline assembly required to prevent the compiler - * optimising this loop into a divmod call. - * See __iter_div_u64_rem() for another example of this. - */ - asm("" : "+rm" (rq->age_stamp)); - rq->age_stamp += period; - rq->rt_avg /= 2; - } -} - #endif /* CONFIG_SMP */ #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \ @@ -1199,6 +1176,7 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu) __set_task_cpu(p, new_cpu); } +#ifdef CONFIG_NUMA_BALANCING static void __migrate_swap_task(struct task_struct *p, int cpu) { if (task_on_rq_queued(p)) { @@ -1280,16 +1258,17 @@ unlock: /* * Cross migrate two tasks */ -int migrate_swap(struct task_struct *cur, struct task_struct *p) +int migrate_swap(struct task_struct *cur, struct task_struct *p, + int target_cpu, int curr_cpu) { struct migration_swap_arg arg; int ret = -EINVAL; arg = (struct migration_swap_arg){ .src_task = cur, - .src_cpu = task_cpu(cur), + .src_cpu = curr_cpu, .dst_task = p, - .dst_cpu = task_cpu(p), + .dst_cpu = target_cpu, }; if (arg.src_cpu == arg.dst_cpu) @@ -1314,6 +1293,7 @@ int migrate_swap(struct task_struct *cur, struct task_struct *p) out: return ret; } +#endif /* CONFIG_NUMA_BALANCING */ /* * wait_task_inactive - wait for a thread to unschedule. @@ -1879,8 +1859,7 @@ static void ttwu_queue(struct task_struct *p, int cpu, int wake_flags) * rq(c1)->lock (if not at the same time, then in that order). * C) LOCK of the rq(c1)->lock scheduling in task * - * Transitivity guarantees that B happens after A and C after B. - * Note: we only require RCpc transitivity. + * Release/acquire chaining guarantees that B happens after A and C after B. * Note: the CPU doing B need not be c0 or c1 * * Example: @@ -1942,16 +1921,9 @@ static void ttwu_queue(struct task_struct *p, int cpu, int wake_flags) * UNLOCK rq(0)->lock * * - * However; for wakeups there is a second guarantee we must provide, namely we - * must observe the state that lead to our wakeup. That is, not only must our - * task observe its own prior state, it must also observe the stores prior to - * its wakeup. - * - * This means that any means of doing remote wakeups must order the CPU doing - * the wakeup against the CPU the task is going to end up running on. This, - * however, is already required for the regular Program-Order guarantee above, - * since the waking CPU is the one issueing the ACQUIRE (smp_cond_load_acquire). - * + * However, for wakeups there is a second guarantee we must provide, namely we + * must ensure that CONDITION=1 done by the caller can not be reordered with + * accesses to the task state; see try_to_wake_up() and set_current_state(). */ /** @@ -1967,6 +1939,9 @@ static void ttwu_queue(struct task_struct *p, int cpu, int wake_flags) * Atomic against schedule() which would dequeue a task, also see * set_current_state(). * + * This function executes a full memory barrier before accessing the task + * state; see set_current_state(). + * * Return: %true if @p->state changes (an actual wakeup was done), * %false otherwise. */ @@ -1998,21 +1973,20 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) * be possible to, falsely, observe p->on_rq == 0 and get stuck * in smp_cond_load_acquire() below. * - * sched_ttwu_pending() try_to_wake_up() - * [S] p->on_rq = 1; [L] P->state - * UNLOCK rq->lock -----. - * \ - * +--- RMB - * schedule() / - * LOCK rq->lock -----' - * UNLOCK rq->lock + * sched_ttwu_pending() try_to_wake_up() + * STORE p->on_rq = 1 LOAD p->state + * UNLOCK rq->lock + * + * __schedule() (switch to task 'p') + * LOCK rq->lock smp_rmb(); + * smp_mb__after_spinlock(); + * UNLOCK rq->lock * * [task p] - * [S] p->state = UNINTERRUPTIBLE [L] p->on_rq + * STORE p->state = UNINTERRUPTIBLE LOAD p->on_rq * - * Pairs with the UNLOCK+LOCK on rq->lock from the - * last wakeup of our task and the schedule that got our task - * current. + * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in + * __schedule(). See the comment for smp_mb__after_spinlock(). */ smp_rmb(); if (p->on_rq && ttwu_remote(p, wake_flags)) @@ -2026,15 +2000,17 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) * One must be running (->on_cpu == 1) in order to remove oneself * from the runqueue. * - * [S] ->on_cpu = 1; [L] ->on_rq - * UNLOCK rq->lock - * RMB - * LOCK rq->lock - * [S] ->on_rq = 0; [L] ->on_cpu + * __schedule() (switch to task 'p') try_to_wake_up() + * STORE p->on_cpu = 1 LOAD p->on_rq + * UNLOCK rq->lock + * + * __schedule() (put 'p' to sleep) + * LOCK rq->lock smp_rmb(); + * smp_mb__after_spinlock(); + * STORE p->on_rq = 0 LOAD p->on_cpu * - * Pairs with the full barrier implied in the UNLOCK+LOCK on rq->lock - * from the consecutive calls to schedule(); the first switching to our - * task, the second putting it to sleep. + * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in + * __schedule(). See the comment for smp_mb__after_spinlock(). */ smp_rmb(); @@ -2140,8 +2116,7 @@ out: * * Return: 1 if the process was woken up, 0 if it was already running. * - * It may be assumed that this function implies a write memory barrier before - * changing the task state if and only if any tasks are woken up. + * This function executes a full memory barrier before accessing the task state. */ int wake_up_process(struct task_struct *p) { @@ -2317,7 +2292,6 @@ static inline void init_schedstats(void) {} int sched_fork(unsigned long clone_flags, struct task_struct *p) { unsigned long flags; - int cpu = get_cpu(); __sched_fork(clone_flags, p); /* @@ -2353,14 +2327,12 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p) p->sched_reset_on_fork = 0; } - if (dl_prio(p->prio)) { - put_cpu(); + if (dl_prio(p->prio)) return -EAGAIN; - } else if (rt_prio(p->prio)) { + else if (rt_prio(p->prio)) p->sched_class = &rt_sched_class; - } else { + else p->sched_class = &fair_sched_class; - } init_entity_runnable_average(&p->se); @@ -2376,7 +2348,7 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p) * We're setting the CPU for the first time, we don't migrate, * so use __set_task_cpu(). */ - __set_task_cpu(p, cpu); + __set_task_cpu(p, smp_processor_id()); if (p->sched_class->task_fork) p->sched_class->task_fork(p); raw_spin_unlock_irqrestore(&p->pi_lock, flags); @@ -2393,8 +2365,6 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p) plist_node_init(&p->pushable_tasks, MAX_PRIO); RB_CLEAR_NODE(&p->pushable_dl_tasks); #endif - - put_cpu(); return 0; } @@ -5714,13 +5684,6 @@ void set_rq_offline(struct rq *rq) } } -static void set_cpu_rq_start_time(unsigned int cpu) -{ - struct rq *rq = cpu_rq(cpu); - - rq->age_stamp = sched_clock_cpu(cpu); -} - /* * used to mark begin/end of suspend/resume: */ @@ -5774,6 +5737,18 @@ int sched_cpu_activate(unsigned int cpu) struct rq *rq = cpu_rq(cpu); struct rq_flags rf; +#ifdef CONFIG_SCHED_SMT + /* + * The sched_smt_present static key needs to be evaluated on every + * hotplug event because at boot time SMT might be disabled when + * the number of booted CPUs is limited. + * + * If then later a sibling gets hotplugged, then the key would stay + * off and SMT scheduling would never be functional. + */ + if (cpumask_weight(cpu_smt_mask(cpu)) > 1) + static_branch_enable_cpuslocked(&sched_smt_present); +#endif set_cpu_active(cpu, true); if (sched_smp_initialized) { @@ -5838,7 +5813,6 @@ static void sched_rq_cpu_starting(unsigned int cpu) int sched_cpu_starting(unsigned int cpu) { - set_cpu_rq_start_time(cpu); sched_rq_cpu_starting(cpu); sched_tick_start(cpu); return 0; @@ -5871,22 +5845,6 @@ int sched_cpu_dying(unsigned int cpu) } #endif -#ifdef CONFIG_SCHED_SMT -DEFINE_STATIC_KEY_FALSE(sched_smt_present); - -static void sched_init_smt(void) -{ - /* - * We've enumerated all CPUs and will assume that if any CPU - * has SMT siblings, CPU0 will too. - */ - if (cpumask_weight(cpu_smt_mask(0)) > 1) - static_branch_enable(&sched_smt_present); -} -#else -static inline void sched_init_smt(void) { } -#endif - void __init sched_init_smp(void) { sched_init_numa(); @@ -5908,8 +5866,6 @@ void __init sched_init_smp(void) init_sched_rt_class(); init_sched_dl_class(); - sched_init_smt(); - sched_smp_initialized = true; } @@ -5954,7 +5910,6 @@ void __init sched_init(void) int i, j; unsigned long alloc_size = 0, ptr; - sched_clock_init(); wait_bit_init(); #ifdef CONFIG_FAIR_GROUP_SCHED @@ -6106,7 +6061,6 @@ void __init sched_init(void) #ifdef CONFIG_SMP idle_thread_set_boot_cpu(); - set_cpu_rq_start_time(smp_processor_id()); #endif init_sched_fair_class(); @@ -6785,6 +6739,16 @@ static int cpu_cfs_stat_show(struct seq_file *sf, void *v) seq_printf(sf, "nr_throttled %d\n", cfs_b->nr_throttled); seq_printf(sf, "throttled_time %llu\n", cfs_b->throttled_time); + if (schedstat_enabled() && tg != &root_task_group) { + u64 ws = 0; + int i; + + for_each_possible_cpu(i) + ws += schedstat_val(tg->se[i]->statistics.wait_sum); + + seq_printf(sf, "wait_sum %llu\n", ws); + } + return 0; } #endif /* CONFIG_CFS_BANDWIDTH */ diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index c907fde01eaa..3fffad3bc8a8 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -53,9 +53,7 @@ struct sugov_cpu { unsigned int iowait_boost_max; u64 last_update; - /* The fields below are only needed when sharing a policy: */ - unsigned long util_cfs; - unsigned long util_dl; + unsigned long bw_dl; unsigned long max; /* The field below is for single-CPU policies only: */ @@ -179,33 +177,90 @@ static unsigned int get_next_freq(struct sugov_policy *sg_policy, return cpufreq_driver_resolve_freq(policy, freq); } -static void sugov_get_util(struct sugov_cpu *sg_cpu) +/* + * This function computes an effective utilization for the given CPU, to be + * used for frequency selection given the linear relation: f = u * f_max. + * + * The scheduler tracks the following metrics: + * + * cpu_util_{cfs,rt,dl,irq}() + * cpu_bw_dl() + * + * Where the cfs,rt and dl util numbers are tracked with the same metric and + * synchronized windows and are thus directly comparable. + * + * The cfs,rt,dl utilization are the running times measured with rq->clock_task + * which excludes things like IRQ and steal-time. These latter are then accrued + * in the irq utilization. + * + * The DL bandwidth number otoh is not a measured metric but a value computed + * based on the task model parameters and gives the minimal utilization + * required to meet deadlines. + */ +static unsigned long sugov_get_util(struct sugov_cpu *sg_cpu) { struct rq *rq = cpu_rq(sg_cpu->cpu); + unsigned long util, irq, max; - sg_cpu->max = arch_scale_cpu_capacity(NULL, sg_cpu->cpu); - sg_cpu->util_cfs = cpu_util_cfs(rq); - sg_cpu->util_dl = cpu_util_dl(rq); -} - -static unsigned long sugov_aggregate_util(struct sugov_cpu *sg_cpu) -{ - struct rq *rq = cpu_rq(sg_cpu->cpu); + sg_cpu->max = max = arch_scale_cpu_capacity(NULL, sg_cpu->cpu); + sg_cpu->bw_dl = cpu_bw_dl(rq); if (rt_rq_is_runnable(&rq->rt)) - return sg_cpu->max; + return max; + + /* + * Early check to see if IRQ/steal time saturates the CPU, can be + * because of inaccuracies in how we track these -- see + * update_irq_load_avg(). + */ + irq = cpu_util_irq(rq); + if (unlikely(irq >= max)) + return max; + + /* + * Because the time spend on RT/DL tasks is visible as 'lost' time to + * CFS tasks and we use the same metric to track the effective + * utilization (PELT windows are synchronized) we can directly add them + * to obtain the CPU's actual utilization. + */ + util = cpu_util_cfs(rq); + util += cpu_util_rt(rq); + + /* + * We do not make cpu_util_dl() a permanent part of this sum because we + * want to use cpu_bw_dl() later on, but we need to check if the + * CFS+RT+DL sum is saturated (ie. no idle time) such that we select + * f_max when there is no idle time. + * + * NOTE: numerical errors or stop class might cause us to not quite hit + * saturation when we should -- something for later. + */ + if ((util + cpu_util_dl(rq)) >= max) + return max; + + /* + * There is still idle time; further improve the number by using the + * irq metric. Because IRQ/steal time is hidden from the task clock we + * need to scale the task numbers: + * + * 1 - irq + * U' = irq + ------- * U + * max + */ + util = scale_irq_capacity(util, irq, max); + util += irq; /* - * Utilization required by DEADLINE must always be granted while, for - * FAIR, we use blocked utilization of IDLE CPUs as a mechanism to - * gracefully reduce the frequency when no tasks show up for longer + * Bandwidth required by DEADLINE must always be granted while, for + * FAIR and RT, we use blocked utilization of IDLE CPUs as a mechanism + * to gracefully reduce the frequency when no tasks show up for longer * periods of time. * - * Ideally we would like to set util_dl as min/guaranteed freq and - * util_cfs + util_dl as requested freq. However, cpufreq is not yet - * ready for such an interface. So, we only do the latter for now. + * Ideally we would like to set bw_dl as min/guaranteed freq and util + + * bw_dl as requested freq. However, cpufreq is not yet ready for such + * an interface. So, we only do the latter for now. */ - return min(sg_cpu->max, (sg_cpu->util_dl + sg_cpu->util_cfs)); + return min(max, util + sg_cpu->bw_dl); } /** @@ -360,7 +415,7 @@ static inline bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) { return false; } */ static inline void ignore_dl_rate_limit(struct sugov_cpu *sg_cpu, struct sugov_policy *sg_policy) { - if (cpu_util_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->util_dl) + if (cpu_bw_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->bw_dl) sg_policy->need_freq_update = true; } @@ -383,9 +438,8 @@ static void sugov_update_single(struct update_util_data *hook, u64 time, busy = sugov_cpu_is_busy(sg_cpu); - sugov_get_util(sg_cpu); + util = sugov_get_util(sg_cpu); max = sg_cpu->max; - util = sugov_aggregate_util(sg_cpu); sugov_iowait_apply(sg_cpu, time, &util, &max); next_f = get_next_freq(sg_policy, util, max); /* @@ -424,9 +478,8 @@ static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time) struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j); unsigned long j_util, j_max; - sugov_get_util(j_sg_cpu); + j_util = sugov_get_util(j_sg_cpu); j_max = j_sg_cpu->max; - j_util = sugov_aggregate_util(j_sg_cpu); sugov_iowait_apply(j_sg_cpu, time, &j_util, &j_max); if (j_util * max > j_max * util) { diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index b5fbdde6afa9..997ea7b839fa 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -16,6 +16,7 @@ * Fabio Checconi <fchecconi@gmail.com> */ #include "sched.h" +#include "pelt.h" struct dl_bandwidth def_dl_bandwidth; @@ -1179,8 +1180,6 @@ static void update_curr_dl(struct rq *rq) curr->se.exec_start = now; cgroup_account_cputime(curr, delta_exec); - sched_rt_avg_update(rq, delta_exec); - if (dl_entity_is_special(dl_se)) return; @@ -1761,6 +1760,9 @@ pick_next_task_dl(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) deadline_queue_push_tasks(rq); + if (rq->curr->sched_class != &dl_sched_class) + update_dl_rq_load_avg(rq_clock_task(rq), rq, 0); + return p; } @@ -1768,6 +1770,7 @@ static void put_prev_task_dl(struct rq *rq, struct task_struct *p) { update_curr_dl(rq); + update_dl_rq_load_avg(rq_clock_task(rq), rq, 1); if (on_dl_rq(&p->dl) && p->nr_cpus_allowed > 1) enqueue_pushable_dl_task(rq, p); } @@ -1784,6 +1787,7 @@ static void task_tick_dl(struct rq *rq, struct task_struct *p, int queued) { update_curr_dl(rq); + update_dl_rq_load_avg(rq_clock_task(rq), rq, 1); /* * Even when we have runtime, update_curr_dl() might have resulted in us * not being the leftmost task anymore. In that case NEED_RESCHED will diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index e593b4118578..60caf1fb94e0 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -111,20 +111,19 @@ static int sched_feat_set(char *cmp) cmp += 3; } - for (i = 0; i < __SCHED_FEAT_NR; i++) { - if (strcmp(cmp, sched_feat_names[i]) == 0) { - if (neg) { - sysctl_sched_features &= ~(1UL << i); - sched_feat_disable(i); - } else { - sysctl_sched_features |= (1UL << i); - sched_feat_enable(i); - } - break; - } + i = match_string(sched_feat_names, __SCHED_FEAT_NR, cmp); + if (i < 0) + return i; + + if (neg) { + sysctl_sched_features &= ~(1UL << i); + sched_feat_disable(i); + } else { + sysctl_sched_features |= (1UL << i); + sched_feat_enable(i); } - return i; + return 0; } static ssize_t @@ -133,7 +132,7 @@ sched_feat_write(struct file *filp, const char __user *ubuf, { char buf[64]; char *cmp; - int i; + int ret; struct inode *inode; if (cnt > 63) @@ -148,10 +147,10 @@ sched_feat_write(struct file *filp, const char __user *ubuf, /* Ensure the static_key remains in a consistent state */ inode = file_inode(filp); inode_lock(inode); - i = sched_feat_set(cmp); + ret = sched_feat_set(cmp); inode_unlock(inode); - if (i == __SCHED_FEAT_NR) - return -EINVAL; + if (ret < 0) + return ret; *ppos += cnt; @@ -623,8 +622,6 @@ void print_dl_rq(struct seq_file *m, int cpu, struct dl_rq *dl_rq) #undef PU } -extern __read_mostly int sched_clock_running; - static void print_cpu(struct seq_file *m, int cpu) { struct rq *rq = cpu_rq(cpu); @@ -843,8 +840,8 @@ void print_numa_stats(struct seq_file *m, int node, unsigned long tsf, unsigned long tpf, unsigned long gsf, unsigned long gpf) { SEQ_printf(m, "numa_faults node=%d ", node); - SEQ_printf(m, "task_private=%lu task_shared=%lu ", tsf, tpf); - SEQ_printf(m, "group_private=%lu group_shared=%lu\n", gsf, gpf); + SEQ_printf(m, "task_private=%lu task_shared=%lu ", tpf, tsf); + SEQ_printf(m, "group_private=%lu group_shared=%lu\n", gpf, gsf); } #endif diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 2f0a0be4d344..b39fb596f6c1 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -255,9 +255,6 @@ static inline struct rq *rq_of(struct cfs_rq *cfs_rq) return cfs_rq->rq; } -/* An entity is a task if it doesn't "own" a runqueue */ -#define entity_is_task(se) (!se->my_q) - static inline struct task_struct *task_of(struct sched_entity *se) { SCHED_WARN_ON(!entity_is_task(se)); @@ -419,7 +416,6 @@ static inline struct rq *rq_of(struct cfs_rq *cfs_rq) return container_of(cfs_rq, struct rq, cfs); } -#define entity_is_task(se) 1 #define for_each_sched_entity(se) \ for (; se; se = NULL) @@ -692,7 +688,7 @@ static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se) } #ifdef CONFIG_SMP - +#include "pelt.h" #include "sched-pelt.h" static int select_idle_sibling(struct task_struct *p, int prev_cpu, int cpu); @@ -735,11 +731,12 @@ static void attach_entity_cfs_rq(struct sched_entity *se); * To solve this problem, we also cap the util_avg of successive tasks to * only 1/2 of the left utilization budget: * - * util_avg_cap = (1024 - cfs_rq->avg.util_avg) / 2^n + * util_avg_cap = (cpu_scale - cfs_rq->avg.util_avg) / 2^n * - * where n denotes the nth task. + * where n denotes the nth task and cpu_scale the CPU capacity. * - * For example, a simplest series from the beginning would be like: + * For example, for a CPU with 1024 of capacity, a simplest series from + * the beginning would be like: * * task util_avg: 512, 256, 128, 64, 32, 16, 8, ... * cfs_rq util_avg: 512, 768, 896, 960, 992, 1008, 1016, ... @@ -751,7 +748,8 @@ void post_init_entity_util_avg(struct sched_entity *se) { struct cfs_rq *cfs_rq = cfs_rq_of(se); struct sched_avg *sa = &se->avg; - long cap = (long)(SCHED_CAPACITY_SCALE - cfs_rq->avg.util_avg) / 2; + long cpu_scale = arch_scale_cpu_capacity(NULL, cpu_of(rq_of(cfs_rq))); + long cap = (long)(cpu_scale - cfs_rq->avg.util_avg) / 2; if (cap > 0) { if (cfs_rq->avg.util_avg != 0) { @@ -1314,7 +1312,7 @@ static unsigned long score_nearby_nodes(struct task_struct *p, int nid, * of each group. Skip other nodes. */ if (sched_numa_topology_type == NUMA_BACKPLANE && - dist > maxdist) + dist >= maxdist) continue; /* Add up the faults from nearby nodes. */ @@ -1452,15 +1450,12 @@ static unsigned long capacity_of(int cpu); /* Cached statistics for all CPUs within a node */ struct numa_stats { - unsigned long nr_running; unsigned long load; /* Total compute capacity of CPUs on a node */ unsigned long compute_capacity; - /* Approximate capacity in terms of runnable tasks on a node */ - unsigned long task_capacity; - int has_free_capacity; + unsigned int nr_running; }; /* @@ -1487,8 +1482,7 @@ static void update_numa_stats(struct numa_stats *ns, int nid) * the @ns structure is NULL'ed and task_numa_compare() will * not find this node attractive. * - * We'll either bail at !has_free_capacity, or we'll detect a huge - * imbalance and bail there. + * We'll detect a huge imbalance and bail there. */ if (!cpus) return; @@ -1497,9 +1491,8 @@ static void update_numa_stats(struct numa_stats *ns, int nid) smt = DIV_ROUND_UP(SCHED_CAPACITY_SCALE * cpus, ns->compute_capacity); capacity = cpus / smt; /* cores */ - ns->task_capacity = min_t(unsigned, capacity, + capacity = min_t(unsigned, capacity, DIV_ROUND_CLOSEST(ns->compute_capacity, SCHED_CAPACITY_SCALE)); - ns->has_free_capacity = (ns->nr_running < ns->task_capacity); } struct task_numa_env { @@ -1548,28 +1541,12 @@ static bool load_too_imbalanced(long src_load, long dst_load, src_capacity = env->src_stats.compute_capacity; dst_capacity = env->dst_stats.compute_capacity; - /* We care about the slope of the imbalance, not the direction. */ - if (dst_load < src_load) - swap(dst_load, src_load); + imb = abs(dst_load * src_capacity - src_load * dst_capacity); - /* Is the difference below the threshold? */ - imb = dst_load * src_capacity * 100 - - src_load * dst_capacity * env->imbalance_pct; - if (imb <= 0) - return false; - - /* - * The imbalance is above the allowed threshold. - * Compare it with the old imbalance. - */ orig_src_load = env->src_stats.load; orig_dst_load = env->dst_stats.load; - if (orig_dst_load < orig_src_load) - swap(orig_dst_load, orig_src_load); - - old_imb = orig_dst_load * src_capacity * 100 - - orig_src_load * dst_capacity * env->imbalance_pct; + old_imb = abs(orig_dst_load * src_capacity - orig_src_load * dst_capacity); /* Would this change make things worse? */ return (imb > old_imb); @@ -1582,9 +1559,8 @@ static bool load_too_imbalanced(long src_load, long dst_load, * be exchanged with the source task */ static void task_numa_compare(struct task_numa_env *env, - long taskimp, long groupimp) + long taskimp, long groupimp, bool maymove) { - struct rq *src_rq = cpu_rq(env->src_cpu); struct rq *dst_rq = cpu_rq(env->dst_cpu); struct task_struct *cur; long src_load, dst_load; @@ -1605,97 +1581,73 @@ static void task_numa_compare(struct task_numa_env *env, if (cur == env->p) goto unlock; + if (!cur) { + if (maymove || imp > env->best_imp) + goto assign; + else + goto unlock; + } + /* * "imp" is the fault differential for the source task between the * source and destination node. Calculate the total differential for * the source task and potential destination task. The more negative - * the value is, the more rmeote accesses that would be expected to + * the value is, the more remote accesses that would be expected to * be incurred if the tasks were swapped. */ - if (cur) { - /* Skip this swap candidate if cannot move to the source CPU: */ - if (!cpumask_test_cpu(env->src_cpu, &cur->cpus_allowed)) - goto unlock; + /* Skip this swap candidate if cannot move to the source cpu */ + if (!cpumask_test_cpu(env->src_cpu, &cur->cpus_allowed)) + goto unlock; + /* + * If dst and source tasks are in the same NUMA group, or not + * in any group then look only at task weights. + */ + if (cur->numa_group == env->p->numa_group) { + imp = taskimp + task_weight(cur, env->src_nid, dist) - + task_weight(cur, env->dst_nid, dist); /* - * If dst and source tasks are in the same NUMA group, or not - * in any group then look only at task weights. + * Add some hysteresis to prevent swapping the + * tasks within a group over tiny differences. */ - if (cur->numa_group == env->p->numa_group) { - imp = taskimp + task_weight(cur, env->src_nid, dist) - - task_weight(cur, env->dst_nid, dist); - /* - * Add some hysteresis to prevent swapping the - * tasks within a group over tiny differences. - */ - if (cur->numa_group) - imp -= imp/16; - } else { - /* - * Compare the group weights. If a task is all by - * itself (not part of a group), use the task weight - * instead. - */ - if (cur->numa_group) - imp += group_weight(cur, env->src_nid, dist) - - group_weight(cur, env->dst_nid, dist); - else - imp += task_weight(cur, env->src_nid, dist) - - task_weight(cur, env->dst_nid, dist); - } + if (cur->numa_group) + imp -= imp / 16; + } else { + /* + * Compare the group weights. If a task is all by itself + * (not part of a group), use the task weight instead. + */ + if (cur->numa_group && env->p->numa_group) + imp += group_weight(cur, env->src_nid, dist) - + group_weight(cur, env->dst_nid, dist); + else + imp += task_weight(cur, env->src_nid, dist) - + task_weight(cur, env->dst_nid, dist); } - if (imp <= env->best_imp && moveimp <= env->best_imp) + if (imp <= env->best_imp) goto unlock; - if (!cur) { - /* Is there capacity at our destination? */ - if (env->src_stats.nr_running <= env->src_stats.task_capacity && - !env->dst_stats.has_free_capacity) - goto unlock; - - goto balance; - } - - /* Balance doesn't matter much if we're running a task per CPU: */ - if (imp > env->best_imp && src_rq->nr_running == 1 && - dst_rq->nr_running == 1) + if (maymove && moveimp > imp && moveimp > env->best_imp) { + imp = moveimp - 1; + cur = NULL; goto assign; + } /* * In the overloaded case, try and keep the load balanced. */ -balance: - load = task_h_load(env->p); + load = task_h_load(env->p) - task_h_load(cur); + if (!load) + goto assign; + dst_load = env->dst_stats.load + load; src_load = env->src_stats.load - load; - if (moveimp > imp && moveimp > env->best_imp) { - /* - * If the improvement from just moving env->p direction is - * better than swapping tasks around, check if a move is - * possible. Store a slightly smaller score than moveimp, - * so an actually idle CPU will win. - */ - if (!load_too_imbalanced(src_load, dst_load, env)) { - imp = moveimp - 1; - cur = NULL; - goto assign; - } - } - - if (imp <= env->best_imp) - goto unlock; - - if (cur) { - load = task_h_load(cur); - dst_load -= load; - src_load += load; - } - if (load_too_imbalanced(src_load, dst_load, env)) goto unlock; +assign: /* * One idle CPU per node is evaluated for a task numa move. * Call select_idle_sibling to maybe find a better one. @@ -1711,7 +1663,6 @@ balance: local_irq_enable(); } -assign: task_numa_assign(env, cur, imp); unlock: rcu_read_unlock(); @@ -1720,43 +1671,30 @@ unlock: static void task_numa_find_cpu(struct task_numa_env *env, long taskimp, long groupimp) { + long src_load, dst_load, load; + bool maymove = false; int cpu; + load = task_h_load(env->p); + dst_load = env->dst_stats.load + load; + src_load = env->src_stats.load - load; + + /* + * If the improvement from just moving env->p direction is better + * than swapping tasks around, check if a move is possible. + */ + maymove = !load_too_imbalanced(src_load, dst_load, env); + for_each_cpu(cpu, cpumask_of_node(env->dst_nid)) { /* Skip this CPU if the source task cannot migrate */ if (!cpumask_test_cpu(cpu, &env->p->cpus_allowed)) continue; env->dst_cpu = cpu; - task_numa_compare(env, taskimp, groupimp); + task_numa_compare(env, taskimp, groupimp, maymove); } } -/* Only move tasks to a NUMA node less busy than the current node. */ -static bool numa_has_capacity(struct task_numa_env *env) -{ - struct numa_stats *src = &env->src_stats; - struct numa_stats *dst = &env->dst_stats; - - if (src->has_free_capacity && !dst->has_free_capacity) - return false; - - /* - * Only consider a task move if the source has a higher load - * than the destination, corrected for CPU capacity on each node. - * - * src->load dst->load - * --------------------- vs --------------------- - * src->compute_capacity dst->compute_capacity - */ - if (src->load * dst->compute_capacity * env->imbalance_pct > - - dst->load * src->compute_capacity * 100) - return true; - - return false; -} - static int task_numa_migrate(struct task_struct *p) { struct task_numa_env env = { @@ -1797,7 +1735,7 @@ static int task_numa_migrate(struct task_struct *p) * elsewhere, so there is no point in (re)trying. */ if (unlikely(!sd)) { - p->numa_preferred_nid = task_node(p); + sched_setnuma(p, task_node(p)); return -EINVAL; } @@ -1811,8 +1749,7 @@ static int task_numa_migrate(struct task_struct *p) update_numa_stats(&env.dst_stats, env.dst_nid); /* Try to find a spot on the preferred nid. */ - if (numa_has_capacity(&env)) - task_numa_find_cpu(&env, taskimp, groupimp); + task_numa_find_cpu(&env, taskimp, groupimp); /* * Look at other nodes in these cases: @@ -1842,8 +1779,7 @@ static int task_numa_migrate(struct task_struct *p) env.dist = dist; env.dst_nid = nid; update_numa_stats(&env.dst_stats, env.dst_nid); - if (numa_has_capacity(&env)) - task_numa_find_cpu(&env, taskimp, groupimp); + task_numa_find_cpu(&env, taskimp, groupimp); } } @@ -1856,15 +1792,13 @@ static int task_numa_migrate(struct task_struct *p) * trying for a better one later. Do not set the preferred node here. */ if (p->numa_group) { - struct numa_group *ng = p->numa_group; - if (env.best_cpu == -1) nid = env.src_nid; else - nid = env.dst_nid; + nid = cpu_to_node(env.best_cpu); - if (ng->active_nodes > 1 && numa_is_active_node(env.dst_nid, ng)) - sched_setnuma(p, env.dst_nid); + if (nid != p->numa_preferred_nid) + sched_setnuma(p, nid); } /* No better CPU than the current one was found. */ @@ -1884,7 +1818,8 @@ static int task_numa_migrate(struct task_struct *p) return ret; } - ret = migrate_swap(p, env.best_task); + ret = migrate_swap(p, env.best_task, env.best_cpu, env.src_cpu); + if (ret != 0) trace_sched_stick_numa(p, env.src_cpu, task_cpu(env.best_task)); put_task_struct(env.best_task); @@ -2144,8 +2079,8 @@ static int preferred_group_nid(struct task_struct *p, int nid) static void task_numa_placement(struct task_struct *p) { - int seq, nid, max_nid = -1, max_group_nid = -1; - unsigned long max_faults = 0, max_group_faults = 0; + int seq, nid, max_nid = -1; + unsigned long max_faults = 0; unsigned long fault_types[2] = { 0, 0 }; unsigned long total_faults; u64 runtime, period; @@ -2224,33 +2159,30 @@ static void task_numa_placement(struct task_struct *p) } } - if (faults > max_faults) { - max_faults = faults; + if (!p->numa_group) { + if (faults > max_faults) { + max_faults = faults; + max_nid = nid; + } + } else if (group_faults > max_faults) { + max_faults = group_faults; max_nid = nid; } - - if (group_faults > max_group_faults) { - max_group_faults = group_faults; - max_group_nid = nid; - } } - update_task_scan_period(p, fault_types[0], fault_types[1]); - if (p->numa_group) { numa_group_count_active_nodes(p->numa_group); spin_unlock_irq(group_lock); - max_nid = preferred_group_nid(p, max_group_nid); + max_nid = preferred_group_nid(p, max_nid); } if (max_faults) { /* Set the new preferred node */ if (max_nid != p->numa_preferred_nid) sched_setnuma(p, max_nid); - - if (task_node(p) != p->numa_preferred_nid) - numa_migrate_preferred(p); } + + update_task_scan_period(p, fault_types[0], fault_types[1]); } static inline int get_numa_group(struct numa_group *grp) @@ -2450,14 +2382,14 @@ void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags) numa_is_active_node(mem_node, ng)) local = 1; - task_numa_placement(p); - /* * Retry task to preferred node migration periodically, in case it * case it previously failed, or the scheduler moved us. */ - if (time_after(jiffies, p->numa_migrate_retry)) + if (time_after(jiffies, p->numa_migrate_retry)) { + task_numa_placement(p); numa_migrate_preferred(p); + } if (migrated) p->numa_pages_migrated += pages; @@ -2749,19 +2681,6 @@ account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) } while (0) #ifdef CONFIG_SMP -/* - * XXX we want to get rid of these helpers and use the full load resolution. - */ -static inline long se_weight(struct sched_entity *se) -{ - return scale_load_down(se->load.weight); -} - -static inline long se_runnable(struct sched_entity *se) -{ - return scale_load_down(se->runnable_weight); -} - static inline void enqueue_runnable_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { @@ -3062,314 +2981,6 @@ static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq, int flags) } #ifdef CONFIG_SMP -/* - * Approximate: - * val * y^n, where y^32 ~= 0.5 (~1 scheduling period) - */ -static u64 decay_load(u64 val, u64 n) -{ - unsigned int local_n; - - if (unlikely(n > LOAD_AVG_PERIOD * 63)) - return 0; - - /* after bounds checking we can collapse to 32-bit */ - local_n = n; - - /* - * As y^PERIOD = 1/2, we can combine - * y^n = 1/2^(n/PERIOD) * y^(n%PERIOD) - * With a look-up table which covers y^n (n<PERIOD) - * - * To achieve constant time decay_load. - */ - if (unlikely(local_n >= LOAD_AVG_PERIOD)) { - val >>= local_n / LOAD_AVG_PERIOD; - local_n %= LOAD_AVG_PERIOD; - } - - val = mul_u64_u32_shr(val, runnable_avg_yN_inv[local_n], 32); - return val; -} - -static u32 __accumulate_pelt_segments(u64 periods, u32 d1, u32 d3) -{ - u32 c1, c2, c3 = d3; /* y^0 == 1 */ - - /* - * c1 = d1 y^p - */ - c1 = decay_load((u64)d1, periods); - - /* - * p-1 - * c2 = 1024 \Sum y^n - * n=1 - * - * inf inf - * = 1024 ( \Sum y^n - \Sum y^n - y^0 ) - * n=0 n=p - */ - c2 = LOAD_AVG_MAX - decay_load(LOAD_AVG_MAX, periods) - 1024; - - return c1 + c2 + c3; -} - -/* - * Accumulate the three separate parts of the sum; d1 the remainder - * of the last (incomplete) period, d2 the span of full periods and d3 - * the remainder of the (incomplete) current period. - * - * d1 d2 d3 - * ^ ^ ^ - * | | | - * |<->|<----------------->|<--->| - * ... |---x---|------| ... |------|-----x (now) - * - * p-1 - * u' = (u + d1) y^p + 1024 \Sum y^n + d3 y^0 - * n=1 - * - * = u y^p + (Step 1) - * - * p-1 - * d1 y^p + 1024 \Sum y^n + d3 y^0 (Step 2) - * n=1 - */ -static __always_inline u32 -accumulate_sum(u64 delta, int cpu, struct sched_avg *sa, - unsigned long load, unsigned long runnable, int running) -{ - unsigned long scale_freq, scale_cpu; - u32 contrib = (u32)delta; /* p == 0 -> delta < 1024 */ - u64 periods; - - scale_freq = arch_scale_freq_capacity(cpu); - scale_cpu = arch_scale_cpu_capacity(NULL, cpu); - - delta += sa->period_contrib; - periods = delta / 1024; /* A period is 1024us (~1ms) */ - - /* - * Step 1: decay old *_sum if we crossed period boundaries. - */ - if (periods) { - sa->load_sum = decay_load(sa->load_sum, periods); - sa->runnable_load_sum = - decay_load(sa->runnable_load_sum, periods); - sa->util_sum = decay_load((u64)(sa->util_sum), periods); - - /* - * Step 2 - */ - delta %= 1024; - contrib = __accumulate_pelt_segments(periods, - 1024 - sa->period_contrib, delta); - } - sa->period_contrib = delta; - - contrib = cap_scale(contrib, scale_freq); - if (load) - sa->load_sum += load * contrib; - if (runnable) - sa->runnable_load_sum += runnable * contrib; - if (running) - sa->util_sum += contrib * scale_cpu; - - return periods; -} - -/* - * We can represent the historical contribution to runnable average as the - * coefficients of a geometric series. To do this we sub-divide our runnable - * history into segments of approximately 1ms (1024us); label the segment that - * occurred N-ms ago p_N, with p_0 corresponding to the current period, e.g. - * - * [<- 1024us ->|<- 1024us ->|<- 1024us ->| ... - * p0 p1 p2 - * (now) (~1ms ago) (~2ms ago) - * - * Let u_i denote the fraction of p_i that the entity was runnable. - * - * We then designate the fractions u_i as our co-efficients, yielding the - * following representation of historical load: - * u_0 + u_1*y + u_2*y^2 + u_3*y^3 + ... - * - * We choose y based on the with of a reasonably scheduling period, fixing: - * y^32 = 0.5 - * - * This means that the contribution to load ~32ms ago (u_32) will be weighted - * approximately half as much as the contribution to load within the last ms - * (u_0). - * - * When a period "rolls over" and we have new u_0`, multiplying the previous - * sum again by y is sufficient to update: - * load_avg = u_0` + y*(u_0 + u_1*y + u_2*y^2 + ... ) - * = u_0 + u_1*y + u_2*y^2 + ... [re-labeling u_i --> u_{i+1}] - */ -static __always_inline int -___update_load_sum(u64 now, int cpu, struct sched_avg *sa, - unsigned long load, unsigned long runnable, int running) -{ - u64 delta; - - delta = now - sa->last_update_time; - /* - * This should only happen when time goes backwards, which it - * unfortunately does during sched clock init when we swap over to TSC. - */ - if ((s64)delta < 0) { - sa->last_update_time = now; - return 0; - } - - /* - * Use 1024ns as the unit of measurement since it's a reasonable - * approximation of 1us and fast to compute. - */ - delta >>= 10; - if (!delta) - return 0; - - sa->last_update_time += delta << 10; - - /* - * running is a subset of runnable (weight) so running can't be set if - * runnable is clear. But there are some corner cases where the current - * se has been already dequeued but cfs_rq->curr still points to it. - * This means that weight will be 0 but not running for a sched_entity - * but also for a cfs_rq if the latter becomes idle. As an example, - * this happens during idle_balance() which calls - * update_blocked_averages() - */ - if (!load) - runnable = running = 0; - - /* - * Now we know we crossed measurement unit boundaries. The *_avg - * accrues by two steps: - * - * Step 1: accumulate *_sum since last_update_time. If we haven't - * crossed period boundaries, finish. - */ - if (!accumulate_sum(delta, cpu, sa, load, runnable, running)) - return 0; - - return 1; -} - -static __always_inline void -___update_load_avg(struct sched_avg *sa, unsigned long load, unsigned long runnable) -{ - u32 divider = LOAD_AVG_MAX - 1024 + sa->period_contrib; - - /* - * Step 2: update *_avg. - */ - sa->load_avg = div_u64(load * sa->load_sum, divider); - sa->runnable_load_avg = div_u64(runnable * sa->runnable_load_sum, divider); - sa->util_avg = sa->util_sum / divider; -} - -/* - * When a task is dequeued, its estimated utilization should not be update if - * its util_avg has not been updated at least once. - * This flag is used to synchronize util_avg updates with util_est updates. - * We map this information into the LSB bit of the utilization saved at - * dequeue time (i.e. util_est.dequeued). - */ -#define UTIL_AVG_UNCHANGED 0x1 - -static inline void cfs_se_util_change(struct sched_avg *avg) -{ - unsigned int enqueued; - - if (!sched_feat(UTIL_EST)) - return; - - /* Avoid store if the flag has been already set */ - enqueued = avg->util_est.enqueued; - if (!(enqueued & UTIL_AVG_UNCHANGED)) - return; - - /* Reset flag to report util_avg has been updated */ - enqueued &= ~UTIL_AVG_UNCHANGED; - WRITE_ONCE(avg->util_est.enqueued, enqueued); -} - -/* - * sched_entity: - * - * task: - * se_runnable() == se_weight() - * - * group: [ see update_cfs_group() ] - * se_weight() = tg->weight * grq->load_avg / tg->load_avg - * se_runnable() = se_weight(se) * grq->runnable_load_avg / grq->load_avg - * - * load_sum := runnable_sum - * load_avg = se_weight(se) * runnable_avg - * - * runnable_load_sum := runnable_sum - * runnable_load_avg = se_runnable(se) * runnable_avg - * - * XXX collapse load_sum and runnable_load_sum - * - * cfq_rs: - * - * load_sum = \Sum se_weight(se) * se->avg.load_sum - * load_avg = \Sum se->avg.load_avg - * - * runnable_load_sum = \Sum se_runnable(se) * se->avg.runnable_load_sum - * runnable_load_avg = \Sum se->avg.runable_load_avg - */ - -static int -__update_load_avg_blocked_se(u64 now, int cpu, struct sched_entity *se) -{ - if (entity_is_task(se)) - se->runnable_weight = se->load.weight; - - if (___update_load_sum(now, cpu, &se->avg, 0, 0, 0)) { - ___update_load_avg(&se->avg, se_weight(se), se_runnable(se)); - return 1; - } - - return 0; -} - -static int -__update_load_avg_se(u64 now, int cpu, struct cfs_rq *cfs_rq, struct sched_entity *se) -{ - if (entity_is_task(se)) - se->runnable_weight = se->load.weight; - - if (___update_load_sum(now, cpu, &se->avg, !!se->on_rq, !!se->on_rq, - cfs_rq->curr == se)) { - - ___update_load_avg(&se->avg, se_weight(se), se_runnable(se)); - cfs_se_util_change(&se->avg); - return 1; - } - - return 0; -} - -static int -__update_load_avg_cfs_rq(u64 now, int cpu, struct cfs_rq *cfs_rq) -{ - if (___update_load_sum(now, cpu, &cfs_rq->avg, - scale_load_down(cfs_rq->load.weight), - scale_load_down(cfs_rq->runnable_weight), - cfs_rq->curr != NULL)) { - - ___update_load_avg(&cfs_rq->avg, 1, 1); - return 1; - } - - return 0; -} - #ifdef CONFIG_FAIR_GROUP_SCHED /** * update_tg_load_avg - update the tg's load avg @@ -4037,12 +3648,6 @@ util_est_dequeue(struct cfs_rq *cfs_rq, struct task_struct *p, bool task_sleep) #else /* CONFIG_SMP */ -static inline int -update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) -{ - return 0; -} - #define UPDATE_TG 0x0 #define SKIP_AGE_LOAD 0x0 #define DO_ATTACH 0x0 @@ -4726,7 +4331,6 @@ static inline int throttled_lb_pair(struct task_group *tg, throttled_hierarchy(dest_cfs_rq); } -/* updated child weight may affect parent so we have to do this bottom up */ static int tg_unthrottle_up(struct task_group *tg, void *data) { struct rq *rq = data; @@ -5653,8 +5257,6 @@ static void cpu_load_update(struct rq *this_rq, unsigned long this_load, this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i; } - - sched_avg_update(this_rq); } /* Used instead of source_load when we know the type == 0 */ @@ -6237,6 +5839,7 @@ static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p } #ifdef CONFIG_SCHED_SMT +DEFINE_STATIC_KEY_FALSE(sched_smt_present); static inline void set_idle_cores(int cpu, int val) { @@ -7294,8 +6897,8 @@ static int task_hot(struct task_struct *p, struct lb_env *env) static int migrate_degrades_locality(struct task_struct *p, struct lb_env *env) { struct numa_group *numa_group = rcu_dereference(p->numa_group); - unsigned long src_faults, dst_faults; - int src_nid, dst_nid; + unsigned long src_weight, dst_weight; + int src_nid, dst_nid, dist; if (!static_branch_likely(&sched_numa_balancing)) return -1; @@ -7322,18 +6925,19 @@ static int migrate_degrades_locality(struct task_struct *p, struct lb_env *env) return 0; /* Leaving a core idle is often worse than degrading locality. */ - if (env->idle != CPU_NOT_IDLE) + if (env->idle == CPU_IDLE) return -1; + dist = node_distance(src_nid, dst_nid); if (numa_group) { - src_faults = group_faults(p, src_nid); - dst_faults = group_faults(p, dst_nid); + src_weight = group_weight(p, src_nid, dist); + dst_weight = group_weight(p, dst_nid, dist); } else { - src_faults = task_faults(p, src_nid); - dst_faults = task_faults(p, dst_nid); + src_weight = task_weight(p, src_nid, dist); + dst_weight = task_weight(p, dst_nid, dist); } - return dst_faults < src_faults; + return dst_weight < src_weight; } #else @@ -7620,6 +7224,22 @@ static inline bool cfs_rq_has_blocked(struct cfs_rq *cfs_rq) return false; } +static inline bool others_have_blocked(struct rq *rq) +{ + if (READ_ONCE(rq->avg_rt.util_avg)) + return true; + + if (READ_ONCE(rq->avg_dl.util_avg)) + return true; + +#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) + if (READ_ONCE(rq->avg_irq.util_avg)) + return true; +#endif + + return false; +} + #ifdef CONFIG_FAIR_GROUP_SCHED static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq) @@ -7679,6 +7299,12 @@ static void update_blocked_averages(int cpu) if (cfs_rq_has_blocked(cfs_rq)) done = false; } + update_rt_rq_load_avg(rq_clock_task(rq), rq, 0); + update_dl_rq_load_avg(rq_clock_task(rq), rq, 0); + update_irq_load_avg(rq, 0); + /* Don't need periodic decay once load/util_avg are null */ + if (others_have_blocked(rq)) + done = false; #ifdef CONFIG_NO_HZ_COMMON rq->last_blocked_load_update_tick = jiffies; @@ -7744,9 +7370,12 @@ static inline void update_blocked_averages(int cpu) rq_lock_irqsave(rq, &rf); update_rq_clock(rq); update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq); + update_rt_rq_load_avg(rq_clock_task(rq), rq, 0); + update_dl_rq_load_avg(rq_clock_task(rq), rq, 0); + update_irq_load_avg(rq, 0); #ifdef CONFIG_NO_HZ_COMMON rq->last_blocked_load_update_tick = jiffies; - if (!cfs_rq_has_blocked(cfs_rq)) + if (!cfs_rq_has_blocked(cfs_rq) && !others_have_blocked(rq)) rq->has_blocked_load = 0; #endif rq_unlock_irqrestore(rq, &rf); @@ -7856,39 +7485,32 @@ static inline int get_sd_load_idx(struct sched_domain *sd, static unsigned long scale_rt_capacity(int cpu) { struct rq *rq = cpu_rq(cpu); - u64 total, used, age_stamp, avg; - s64 delta; + unsigned long max = arch_scale_cpu_capacity(NULL, cpu); + unsigned long used, free; + unsigned long irq; - /* - * Since we're reading these variables without serialization make sure - * we read them once before doing sanity checks on them. - */ - age_stamp = READ_ONCE(rq->age_stamp); - avg = READ_ONCE(rq->rt_avg); - delta = __rq_clock_broken(rq) - age_stamp; + irq = cpu_util_irq(rq); - if (unlikely(delta < 0)) - delta = 0; + if (unlikely(irq >= max)) + return 1; - total = sched_avg_period() + delta; + used = READ_ONCE(rq->avg_rt.util_avg); + used += READ_ONCE(rq->avg_dl.util_avg); - used = div_u64(avg, total); + if (unlikely(used >= max)) + return 1; - if (likely(used < SCHED_CAPACITY_SCALE)) - return SCHED_CAPACITY_SCALE - used; + free = max - used; - return 1; + return scale_irq_capacity(free, irq, max); } static void update_cpu_capacity(struct sched_domain *sd, int cpu) { - unsigned long capacity = arch_scale_cpu_capacity(sd, cpu); + unsigned long capacity = scale_rt_capacity(cpu); struct sched_group *sdg = sd->groups; - cpu_rq(cpu)->cpu_capacity_orig = capacity; - - capacity *= scale_rt_capacity(cpu); - capacity >>= SCHED_CAPACITY_SHIFT; + cpu_rq(cpu)->cpu_capacity_orig = arch_scale_cpu_capacity(sd, cpu); if (!capacity) capacity = 1; diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c new file mode 100644 index 000000000000..35475c0c5419 --- /dev/null +++ b/kernel/sched/pelt.c @@ -0,0 +1,399 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Per Entity Load Tracking + * + * Copyright (C) 2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> + * + * Interactivity improvements by Mike Galbraith + * (C) 2007 Mike Galbraith <efault@gmx.de> + * + * Various enhancements by Dmitry Adamushko. + * (C) 2007 Dmitry Adamushko <dmitry.adamushko@gmail.com> + * + * Group scheduling enhancements by Srivatsa Vaddagiri + * Copyright IBM Corporation, 2007 + * Author: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> + * + * Scaled math optimizations by Thomas Gleixner + * Copyright (C) 2007, Thomas Gleixner <tglx@linutronix.de> + * + * Adaptive scheduling granularity, math enhancements by Peter Zijlstra + * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra + * + * Move PELT related code from fair.c into this pelt.c file + * Author: Vincent Guittot <vincent.guittot@linaro.org> + */ + +#include <linux/sched.h> +#include "sched.h" +#include "sched-pelt.h" +#include "pelt.h" + +/* + * Approximate: + * val * y^n, where y^32 ~= 0.5 (~1 scheduling period) + */ +static u64 decay_load(u64 val, u64 n) +{ + unsigned int local_n; + + if (unlikely(n > LOAD_AVG_PERIOD * 63)) + return 0; + + /* after bounds checking we can collapse to 32-bit */ + local_n = n; + + /* + * As y^PERIOD = 1/2, we can combine + * y^n = 1/2^(n/PERIOD) * y^(n%PERIOD) + * With a look-up table which covers y^n (n<PERIOD) + * + * To achieve constant time decay_load. + */ + if (unlikely(local_n >= LOAD_AVG_PERIOD)) { + val >>= local_n / LOAD_AVG_PERIOD; + local_n %= LOAD_AVG_PERIOD; + } + + val = mul_u64_u32_shr(val, runnable_avg_yN_inv[local_n], 32); + return val; +} + +static u32 __accumulate_pelt_segments(u64 periods, u32 d1, u32 d3) +{ + u32 c1, c2, c3 = d3; /* y^0 == 1 */ + + /* + * c1 = d1 y^p + */ + c1 = decay_load((u64)d1, periods); + + /* + * p-1 + * c2 = 1024 \Sum y^n + * n=1 + * + * inf inf + * = 1024 ( \Sum y^n - \Sum y^n - y^0 ) + * n=0 n=p + */ + c2 = LOAD_AVG_MAX - decay_load(LOAD_AVG_MAX, periods) - 1024; + + return c1 + c2 + c3; +} + +#define cap_scale(v, s) ((v)*(s) >> SCHED_CAPACITY_SHIFT) + +/* + * Accumulate the three separate parts of the sum; d1 the remainder + * of the last (incomplete) period, d2 the span of full periods and d3 + * the remainder of the (incomplete) current period. + * + * d1 d2 d3 + * ^ ^ ^ + * | | | + * |<->|<----------------->|<--->| + * ... |---x---|------| ... |------|-----x (now) + * + * p-1 + * u' = (u + d1) y^p + 1024 \Sum y^n + d3 y^0 + * n=1 + * + * = u y^p + (Step 1) + * + * p-1 + * d1 y^p + 1024 \Sum y^n + d3 y^0 (Step 2) + * n=1 + */ +static __always_inline u32 +accumulate_sum(u64 delta, int cpu, struct sched_avg *sa, + unsigned long load, unsigned long runnable, int running) +{ + unsigned long scale_freq, scale_cpu; + u32 contrib = (u32)delta; /* p == 0 -> delta < 1024 */ + u64 periods; + + scale_freq = arch_scale_freq_capacity(cpu); + scale_cpu = arch_scale_cpu_capacity(NULL, cpu); + + delta += sa->period_contrib; + periods = delta / 1024; /* A period is 1024us (~1ms) */ + + /* + * Step 1: decay old *_sum if we crossed period boundaries. + */ + if (periods) { + sa->load_sum = decay_load(sa->load_sum, periods); + sa->runnable_load_sum = + decay_load(sa->runnable_load_sum, periods); + sa->util_sum = decay_load((u64)(sa->util_sum), periods); + + /* + * Step 2 + */ + delta %= 1024; + contrib = __accumulate_pelt_segments(periods, + 1024 - sa->period_contrib, delta); + } + sa->period_contrib = delta; + + contrib = cap_scale(contrib, scale_freq); + if (load) + sa->load_sum += load * contrib; + if (runnable) + sa->runnable_load_sum += runnable * contrib; + if (running) + sa->util_sum += contrib * scale_cpu; + + return periods; +} + +/* + * We can represent the historical contribution to runnable average as the + * coefficients of a geometric series. To do this we sub-divide our runnable + * history into segments of approximately 1ms (1024us); label the segment that + * occurred N-ms ago p_N, with p_0 corresponding to the current period, e.g. + * + * [<- 1024us ->|<- 1024us ->|<- 1024us ->| ... + * p0 p1 p2 + * (now) (~1ms ago) (~2ms ago) + * + * Let u_i denote the fraction of p_i that the entity was runnable. + * + * We then designate the fractions u_i as our co-efficients, yielding the + * following representation of historical load: + * u_0 + u_1*y + u_2*y^2 + u_3*y^3 + ... + * + * We choose y based on the with of a reasonably scheduling period, fixing: + * y^32 = 0.5 + * + * This means that the contribution to load ~32ms ago (u_32) will be weighted + * approximately half as much as the contribution to load within the last ms + * (u_0). + * + * When a period "rolls over" and we have new u_0`, multiplying the previous + * sum again by y is sufficient to update: + * load_avg = u_0` + y*(u_0 + u_1*y + u_2*y^2 + ... ) + * = u_0 + u_1*y + u_2*y^2 + ... [re-labeling u_i --> u_{i+1}] + */ +static __always_inline int +___update_load_sum(u64 now, int cpu, struct sched_avg *sa, + unsigned long load, unsigned long runnable, int running) +{ + u64 delta; + + delta = now - sa->last_update_time; + /* + * This should only happen when time goes backwards, which it + * unfortunately does during sched clock init when we swap over to TSC. + */ + if ((s64)delta < 0) { + sa->last_update_time = now; + return 0; + } + + /* + * Use 1024ns as the unit of measurement since it's a reasonable + * approximation of 1us and fast to compute. + */ + delta >>= 10; + if (!delta) + return 0; + + sa->last_update_time += delta << 10; + + /* + * running is a subset of runnable (weight) so running can't be set if + * runnable is clear. But there are some corner cases where the current + * se has been already dequeued but cfs_rq->curr still points to it. + * This means that weight will be 0 but not running for a sched_entity + * but also for a cfs_rq if the latter becomes idle. As an example, + * this happens during idle_balance() which calls + * update_blocked_averages() + */ + if (!load) + runnable = running = 0; + + /* + * Now we know we crossed measurement unit boundaries. The *_avg + * accrues by two steps: + * + * Step 1: accumulate *_sum since last_update_time. If we haven't + * crossed period boundaries, finish. + */ + if (!accumulate_sum(delta, cpu, sa, load, runnable, running)) + return 0; + + return 1; +} + +static __always_inline void +___update_load_avg(struct sched_avg *sa, unsigned long load, unsigned long runnable) +{ + u32 divider = LOAD_AVG_MAX - 1024 + sa->period_contrib; + + /* + * Step 2: update *_avg. + */ + sa->load_avg = div_u64(load * sa->load_sum, divider); + sa->runnable_load_avg = div_u64(runnable * sa->runnable_load_sum, divider); + WRITE_ONCE(sa->util_avg, sa->util_sum / divider); +} + +/* + * sched_entity: + * + * task: + * se_runnable() == se_weight() + * + * group: [ see update_cfs_group() ] + * se_weight() = tg->weight * grq->load_avg / tg->load_avg + * se_runnable() = se_weight(se) * grq->runnable_load_avg / grq->load_avg + * + * load_sum := runnable_sum + * load_avg = se_weight(se) * runnable_avg + * + * runnable_load_sum := runnable_sum + * runnable_load_avg = se_runnable(se) * runnable_avg + * + * XXX collapse load_sum and runnable_load_sum + * + * cfq_rq: + * + * load_sum = \Sum se_weight(se) * se->avg.load_sum + * load_avg = \Sum se->avg.load_avg + * + * runnable_load_sum = \Sum se_runnable(se) * se->avg.runnable_load_sum + * runnable_load_avg = \Sum se->avg.runable_load_avg + */ + +int __update_load_avg_blocked_se(u64 now, int cpu, struct sched_entity *se) +{ + if (entity_is_task(se)) + se->runnable_weight = se->load.weight; + + if (___update_load_sum(now, cpu, &se->avg, 0, 0, 0)) { + ___update_load_avg(&se->avg, se_weight(se), se_runnable(se)); + return 1; + } + + return 0; +} + +int __update_load_avg_se(u64 now, int cpu, struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + if (entity_is_task(se)) + se->runnable_weight = se->load.weight; + + if (___update_load_sum(now, cpu, &se->avg, !!se->on_rq, !!se->on_rq, + cfs_rq->curr == se)) { + + ___update_load_avg(&se->avg, se_weight(se), se_runnable(se)); + cfs_se_util_change(&se->avg); + return 1; + } + + return 0; +} + +int __update_load_avg_cfs_rq(u64 now, int cpu, struct cfs_rq *cfs_rq) +{ + if (___update_load_sum(now, cpu, &cfs_rq->avg, + scale_load_down(cfs_rq->load.weight), + scale_load_down(cfs_rq->runnable_weight), + cfs_rq->curr != NULL)) { + + ___update_load_avg(&cfs_rq->avg, 1, 1); + return 1; + } + + return 0; +} + +/* + * rt_rq: + * + * util_sum = \Sum se->avg.util_sum but se->avg.util_sum is not tracked + * util_sum = cpu_scale * load_sum + * runnable_load_sum = load_sum + * + * load_avg and runnable_load_avg are not supported and meaningless. + * + */ + +int update_rt_rq_load_avg(u64 now, struct rq *rq, int running) +{ + if (___update_load_sum(now, rq->cpu, &rq->avg_rt, + running, + running, + running)) { + + ___update_load_avg(&rq->avg_rt, 1, 1); + return 1; + } + + return 0; +} + +/* + * dl_rq: + * + * util_sum = \Sum se->avg.util_sum but se->avg.util_sum is not tracked + * util_sum = cpu_scale * load_sum + * runnable_load_sum = load_sum + * + */ + +int update_dl_rq_load_avg(u64 now, struct rq *rq, int running) +{ + if (___update_load_sum(now, rq->cpu, &rq->avg_dl, + running, + running, + running)) { + + ___update_load_avg(&rq->avg_dl, 1, 1); + return 1; + } + + return 0; +} + +#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) +/* + * irq: + * + * util_sum = \Sum se->avg.util_sum but se->avg.util_sum is not tracked + * util_sum = cpu_scale * load_sum + * runnable_load_sum = load_sum + * + */ + +int update_irq_load_avg(struct rq *rq, u64 running) +{ + int ret = 0; + /* + * We know the time that has been used by interrupt since last update + * but we don't when. Let be pessimistic and assume that interrupt has + * happened just before the update. This is not so far from reality + * because interrupt will most probably wake up task and trig an update + * of rq clock during which the metric si updated. + * We start to decay with normal context time and then we add the + * interrupt context time. + * We can safely remove running from rq->clock because + * rq->clock += delta with delta >= running + */ + ret = ___update_load_sum(rq->clock - running, rq->cpu, &rq->avg_irq, + 0, + 0, + 0); + ret += ___update_load_sum(rq->clock, rq->cpu, &rq->avg_irq, + 1, + 1, + 1); + + if (ret) + ___update_load_avg(&rq->avg_irq, 1, 1); + + return ret; +} +#endif diff --git a/kernel/sched/pelt.h b/kernel/sched/pelt.h new file mode 100644 index 000000000000..d2894db28955 --- /dev/null +++ b/kernel/sched/pelt.h @@ -0,0 +1,72 @@ +#ifdef CONFIG_SMP + +int __update_load_avg_blocked_se(u64 now, int cpu, struct sched_entity *se); +int __update_load_avg_se(u64 now, int cpu, struct cfs_rq *cfs_rq, struct sched_entity *se); +int __update_load_avg_cfs_rq(u64 now, int cpu, struct cfs_rq *cfs_rq); +int update_rt_rq_load_avg(u64 now, struct rq *rq, int running); +int update_dl_rq_load_avg(u64 now, struct rq *rq, int running); + +#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) +int update_irq_load_avg(struct rq *rq, u64 running); +#else +static inline int +update_irq_load_avg(struct rq *rq, u64 running) +{ + return 0; +} +#endif + +/* + * When a task is dequeued, its estimated utilization should not be update if + * its util_avg has not been updated at least once. + * This flag is used to synchronize util_avg updates with util_est updates. + * We map this information into the LSB bit of the utilization saved at + * dequeue time (i.e. util_est.dequeued). + */ +#define UTIL_AVG_UNCHANGED 0x1 + +static inline void cfs_se_util_change(struct sched_avg *avg) +{ + unsigned int enqueued; + + if (!sched_feat(UTIL_EST)) + return; + + /* Avoid store if the flag has been already set */ + enqueued = avg->util_est.enqueued; + if (!(enqueued & UTIL_AVG_UNCHANGED)) + return; + + /* Reset flag to report util_avg has been updated */ + enqueued &= ~UTIL_AVG_UNCHANGED; + WRITE_ONCE(avg->util_est.enqueued, enqueued); +} + +#else + +static inline int +update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) +{ + return 0; +} + +static inline int +update_rt_rq_load_avg(u64 now, struct rq *rq, int running) +{ + return 0; +} + +static inline int +update_dl_rq_load_avg(u64 now, struct rq *rq, int running) +{ + return 0; +} + +static inline int +update_irq_load_avg(struct rq *rq, u64 running) +{ + return 0; +} +#endif + + diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index eaaec8364f96..2e2955a8cf8f 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -5,6 +5,8 @@ */ #include "sched.h" +#include "pelt.h" + int sched_rr_timeslice = RR_TIMESLICE; int sysctl_sched_rr_timeslice = (MSEC_PER_SEC / HZ) * RR_TIMESLICE; @@ -973,8 +975,6 @@ static void update_curr_rt(struct rq *rq) curr->se.exec_start = now; cgroup_account_cputime(curr, delta_exec); - sched_rt_avg_update(rq, delta_exec); - if (!rt_bandwidth_enabled()) return; @@ -1578,6 +1578,14 @@ pick_next_task_rt(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) rt_queue_push_tasks(rq); + /* + * If prev task was rt, put_prev_task() has already updated the + * utilization. We only care of the case where we start to schedule a + * rt task + */ + if (rq->curr->sched_class != &rt_sched_class) + update_rt_rq_load_avg(rq_clock_task(rq), rq, 0); + return p; } @@ -1585,6 +1593,8 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p) { update_curr_rt(rq); + update_rt_rq_load_avg(rq_clock_task(rq), rq, 1); + /* * The previous task needs to be made eligible for pushing * if it is still active @@ -2314,6 +2324,7 @@ static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued) struct sched_rt_entity *rt_se = &p->rt; update_curr_rt(rq); + update_rt_rq_load_avg(rq_clock_task(rq), rq, 1); watchdog(rq, p); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index c7742dcc136c..4a2e8cae63c4 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -594,6 +594,7 @@ struct rt_rq { unsigned long rt_nr_total; int overloaded; struct plist_head pushable_tasks; + #endif /* CONFIG_SMP */ int rt_queued; @@ -673,7 +674,26 @@ struct dl_rq { u64 bw_ratio; }; +#ifdef CONFIG_FAIR_GROUP_SCHED +/* An entity is a task if it doesn't "own" a runqueue */ +#define entity_is_task(se) (!se->my_q) +#else +#define entity_is_task(se) 1 +#endif + #ifdef CONFIG_SMP +/* + * XXX we want to get rid of these helpers and use the full load resolution. + */ +static inline long se_weight(struct sched_entity *se) +{ + return scale_load_down(se->load.weight); +} + +static inline long se_runnable(struct sched_entity *se) +{ + return scale_load_down(se->runnable_weight); +} static inline bool sched_asym_prefer(int a, int b) { @@ -833,8 +853,12 @@ struct rq { struct list_head cfs_tasks; - u64 rt_avg; - u64 age_stamp; + struct sched_avg avg_rt; + struct sched_avg avg_dl; +#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) +#define HAVE_SCHED_AVG_IRQ + struct sched_avg avg_irq; +#endif u64 idle_stamp; u64 avg_idle; @@ -1075,7 +1099,8 @@ enum numa_faults_stats { }; extern void sched_setnuma(struct task_struct *p, int node); extern int migrate_task_to(struct task_struct *p, int cpu); -extern int migrate_swap(struct task_struct *, struct task_struct *); +extern int migrate_swap(struct task_struct *p, struct task_struct *t, + int cpu, int scpu); extern void init_numa_balancing(unsigned long clone_flags, struct task_struct *p); #else static inline void @@ -1690,15 +1715,9 @@ extern void deactivate_task(struct rq *rq, struct task_struct *p, int flags); extern void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags); -extern const_debug unsigned int sysctl_sched_time_avg; extern const_debug unsigned int sysctl_sched_nr_migrate; extern const_debug unsigned int sysctl_sched_migration_cost; -static inline u64 sched_avg_period(void) -{ - return (u64)sysctl_sched_time_avg * NSEC_PER_MSEC / 2; -} - #ifdef CONFIG_SCHED_HRTICK /* @@ -1735,8 +1754,6 @@ unsigned long arch_scale_freq_capacity(int cpu) #endif #ifdef CONFIG_SMP -extern void sched_avg_update(struct rq *rq); - #ifndef arch_scale_cpu_capacity static __always_inline unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) @@ -1747,12 +1764,6 @@ unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) return SCHED_CAPACITY_SCALE; } #endif - -static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta) -{ - rq->rt_avg += rt_delta * arch_scale_freq_capacity(cpu_of(rq)); - sched_avg_update(rq); -} #else #ifndef arch_scale_cpu_capacity static __always_inline @@ -1761,8 +1772,6 @@ unsigned long arch_scale_cpu_capacity(void __always_unused *sd, int cpu) return SCHED_CAPACITY_SCALE; } #endif -static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta) { } -static inline void sched_avg_update(struct rq *rq) { } #endif struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf) @@ -2177,11 +2186,16 @@ static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {} #endif #ifdef CONFIG_CPU_FREQ_GOV_SCHEDUTIL -static inline unsigned long cpu_util_dl(struct rq *rq) +static inline unsigned long cpu_bw_dl(struct rq *rq) { return (rq->dl.running_bw * SCHED_CAPACITY_SCALE) >> BW_SHIFT; } +static inline unsigned long cpu_util_dl(struct rq *rq) +{ + return READ_ONCE(rq->avg_dl.util_avg); +} + static inline unsigned long cpu_util_cfs(struct rq *rq) { unsigned long util = READ_ONCE(rq->cfs.avg.util_avg); @@ -2193,4 +2207,37 @@ static inline unsigned long cpu_util_cfs(struct rq *rq) return util; } + +static inline unsigned long cpu_util_rt(struct rq *rq) +{ + return READ_ONCE(rq->avg_rt.util_avg); +} +#endif + +#ifdef HAVE_SCHED_AVG_IRQ +static inline unsigned long cpu_util_irq(struct rq *rq) +{ + return rq->avg_irq.util_avg; +} + +static inline +unsigned long scale_irq_capacity(unsigned long util, unsigned long irq, unsigned long max) +{ + util *= (max - irq); + util /= max; + + return util; + +} +#else +static inline unsigned long cpu_util_irq(struct rq *rq) +{ + return 0; +} + +static inline +unsigned long scale_irq_capacity(unsigned long util, unsigned long irq, unsigned long max) +{ + return util; +} #endif diff --git a/kernel/sched/swait.c b/kernel/sched/swait.c index b6fb2c3b3ff7..66b59ac77c22 100644 --- a/kernel/sched/swait.c +++ b/kernel/sched/swait.c @@ -32,7 +32,7 @@ void swake_up_locked(struct swait_queue_head *q) } EXPORT_SYMBOL(swake_up_locked); -void swake_up(struct swait_queue_head *q) +void swake_up_one(struct swait_queue_head *q) { unsigned long flags; @@ -40,7 +40,7 @@ void swake_up(struct swait_queue_head *q) swake_up_locked(q); raw_spin_unlock_irqrestore(&q->lock, flags); } -EXPORT_SYMBOL(swake_up); +EXPORT_SYMBOL(swake_up_one); /* * Does not allow usage from IRQ disabled, since we must be able to @@ -69,14 +69,14 @@ void swake_up_all(struct swait_queue_head *q) } EXPORT_SYMBOL(swake_up_all); -void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait) +static void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait) { wait->task = current; if (list_empty(&wait->task_list)) - list_add(&wait->task_list, &q->task_list); + list_add_tail(&wait->task_list, &q->task_list); } -void prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait, int state) +void prepare_to_swait_exclusive(struct swait_queue_head *q, struct swait_queue *wait, int state) { unsigned long flags; @@ -85,16 +85,28 @@ void prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait, int set_current_state(state); raw_spin_unlock_irqrestore(&q->lock, flags); } -EXPORT_SYMBOL(prepare_to_swait); +EXPORT_SYMBOL(prepare_to_swait_exclusive); long prepare_to_swait_event(struct swait_queue_head *q, struct swait_queue *wait, int state) { - if (signal_pending_state(state, current)) - return -ERESTARTSYS; + unsigned long flags; + long ret = 0; - prepare_to_swait(q, wait, state); + raw_spin_lock_irqsave(&q->lock, flags); + if (unlikely(signal_pending_state(state, current))) { + /* + * See prepare_to_wait_event(). TL;DR, subsequent swake_up_one() + * must not see us. + */ + list_del_init(&wait->task_list); + ret = -ERESTARTSYS; + } else { + __prepare_to_swait(q, wait); + set_current_state(state); + } + raw_spin_unlock_irqrestore(&q->lock, flags); - return 0; + return ret; } EXPORT_SYMBOL(prepare_to_swait_event); diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c index 928be527477e..870f97b313e3 100644 --- a/kernel/sched/wait.c +++ b/kernel/sched/wait.c @@ -134,8 +134,8 @@ static void __wake_up_common_lock(struct wait_queue_head *wq_head, unsigned int * @nr_exclusive: how many wake-one or wake-many threads to wake up * @key: is directly passed to the wakeup function * - * It may be assumed that this function implies a write memory barrier before - * changing the task state if and only if any tasks are woken up. + * If this function wakes up a task, it executes a full memory barrier before + * accessing the task state. */ void __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr_exclusive, void *key) @@ -180,8 +180,8 @@ EXPORT_SYMBOL_GPL(__wake_up_locked_key_bookmark); * * On UP it can prevent extra preemption. * - * It may be assumed that this function implies a write memory barrier before - * changing the task state if and only if any tasks are woken up. + * If this function wakes up a task, it executes a full memory barrier before + * accessing the task state. */ void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, int nr_exclusive, void *key) @@ -392,35 +392,36 @@ static inline bool is_kthread_should_stop(void) * if (condition) * break; * - * p->state = mode; condition = true; - * smp_mb(); // A smp_wmb(); // C - * if (!wq_entry->flags & WQ_FLAG_WOKEN) wq_entry->flags |= WQ_FLAG_WOKEN; - * schedule() try_to_wake_up(); - * p->state = TASK_RUNNING; ~~~~~~~~~~~~~~~~~~ - * wq_entry->flags &= ~WQ_FLAG_WOKEN; condition = true; - * smp_mb() // B smp_wmb(); // C - * wq_entry->flags |= WQ_FLAG_WOKEN; - * } - * remove_wait_queue(&wq_head, &wait); + * // in wait_woken() // in woken_wake_function() * + * p->state = mode; wq_entry->flags |= WQ_FLAG_WOKEN; + * smp_mb(); // A try_to_wake_up(): + * if (!(wq_entry->flags & WQ_FLAG_WOKEN)) <full barrier> + * schedule() if (p->state & mode) + * p->state = TASK_RUNNING; p->state = TASK_RUNNING; + * wq_entry->flags &= ~WQ_FLAG_WOKEN; ~~~~~~~~~~~~~~~~~~ + * smp_mb(); // B condition = true; + * } smp_mb(); // C + * remove_wait_queue(&wq_head, &wait); wq_entry->flags |= WQ_FLAG_WOKEN; */ long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout) { - set_current_state(mode); /* A */ /* - * The above implies an smp_mb(), which matches with the smp_wmb() from - * woken_wake_function() such that if we observe WQ_FLAG_WOKEN we must - * also observe all state before the wakeup. + * The below executes an smp_mb(), which matches with the full barrier + * executed by the try_to_wake_up() in woken_wake_function() such that + * either we see the store to wq_entry->flags in woken_wake_function() + * or woken_wake_function() sees our store to current->state. */ + set_current_state(mode); /* A */ if (!(wq_entry->flags & WQ_FLAG_WOKEN) && !is_kthread_should_stop()) timeout = schedule_timeout(timeout); __set_current_state(TASK_RUNNING); /* - * The below implies an smp_mb(), it too pairs with the smp_wmb() from - * woken_wake_function() such that we must either observe the wait - * condition being true _OR_ WQ_FLAG_WOKEN such that we will not miss - * an event. + * The below executes an smp_mb(), which matches with the smp_mb() (C) + * in woken_wake_function() such that either we see the wait condition + * being true or the store to wq_entry->flags in woken_wake_function() + * follows ours in the coherence order. */ smp_store_mb(wq_entry->flags, wq_entry->flags & ~WQ_FLAG_WOKEN); /* B */ @@ -430,14 +431,8 @@ EXPORT_SYMBOL(wait_woken); int woken_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key) { - /* - * Although this function is called under waitqueue lock, LOCK - * doesn't imply write barrier and the users expects write - * barrier semantics on wakeup functions. The following - * smp_wmb() is equivalent to smp_wmb() in try_to_wake_up() - * and is paired with smp_store_mb() in wait_woken(). - */ - smp_wmb(); /* C */ + /* Pairs with the smp_store_mb() in wait_woken(). */ + smp_mb(); /* C */ wq_entry->flags |= WQ_FLAG_WOKEN; return default_wake_function(wq_entry, mode, sync, key); |