diff options
Diffstat (limited to 'kernel/sched')
30 files changed, 1456 insertions, 800 deletions
diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile index 78f54932ea1d..e2f9d4feff40 100644 --- a/kernel/sched/Makefile +++ b/kernel/sched/Makefile @@ -1,3 +1,4 @@ +# SPDX-License-Identifier: GPL-2.0 ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_clock.o = $(CC_FLAGS_FTRACE) endif @@ -26,3 +27,4 @@ obj-$(CONFIG_CGROUP_CPUACCT) += cpuacct.o obj-$(CONFIG_CPU_FREQ) += cpufreq.o obj-$(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) += cpufreq_schedutil.o obj-$(CONFIG_MEMBARRIER) += membarrier.o +obj-$(CONFIG_CPU_ISOLATION) += isolation.o diff --git a/kernel/sched/autogroup.c b/kernel/sched/autogroup.c index de6d7f4dfcb5..a43df5193538 100644 --- a/kernel/sched/autogroup.c +++ b/kernel/sched/autogroup.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 #include "sched.h" #include <linux/proc_fs.h> diff --git a/kernel/sched/autogroup.h b/kernel/sched/autogroup.h index ce40c810cd5c..27cd22b89824 100644 --- a/kernel/sched/autogroup.h +++ b/kernel/sched/autogroup.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifdef CONFIG_SCHED_AUTOGROUP #include <linux/kref.h> diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c index ca0f8fc945c6..e086babe6c61 100644 --- a/kernel/sched/clock.c +++ b/kernel/sched/clock.c @@ -388,7 +388,7 @@ void sched_clock_tick(void) if (unlikely(!sched_clock_running)) return; - WARN_ON_ONCE(!irqs_disabled()); + lockdep_assert_irqs_disabled(); scd = this_scd(); __scd_stamp(scd); diff --git a/kernel/sched/completion.c b/kernel/sched/completion.c index cc873075c3bd..2ddaec40956f 100644 --- a/kernel/sched/completion.c +++ b/kernel/sched/completion.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 /* * Generic wait-for-completion handler; * diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 18a6966567da..75554f366fd3 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -16,6 +16,7 @@ #include <linux/init_task.h> #include <linux/context_tracking.h> #include <linux/rcupdate_wait.h> +#include <linux/compat.h> #include <linux/blkdev.h> #include <linux/kprobes.h> @@ -26,6 +27,7 @@ #include <linux/profile.h> #include <linux/security.h> #include <linux/syscalls.h> +#include <linux/sched/isolation.h> #include <asm/switch_to.h> #include <asm/tlb.h> @@ -42,18 +44,21 @@ DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); +#if defined(CONFIG_SCHED_DEBUG) && defined(HAVE_JUMP_LABEL) /* * Debugging: various feature bits + * + * If SCHED_DEBUG is disabled, each compilation unit has its own copy of + * sysctl_sched_features, defined in sched.h, to allow constants propagation + * at compile time and compiler optimization based on features default. */ - #define SCHED_FEAT(name, enabled) \ (1UL << __SCHED_FEAT_##name) * enabled | - const_debug unsigned int sysctl_sched_features = #include "features.h" 0; - #undef SCHED_FEAT +#endif /* * Number of tasks to iterate in a single balance run. @@ -83,9 +88,6 @@ __read_mostly int scheduler_running; */ int sysctl_sched_rt_runtime = 950000; -/* CPUs with isolated domains */ -cpumask_var_t cpu_isolated_map; - /* * __task_rq_lock - lock the rq @p resides on. */ @@ -505,8 +507,7 @@ void resched_cpu(int cpu) struct rq *rq = cpu_rq(cpu); unsigned long flags; - if (!raw_spin_trylock_irqsave(&rq->lock, flags)) - return; + raw_spin_lock_irqsave(&rq->lock, flags); resched_curr(rq); raw_spin_unlock_irqrestore(&rq->lock, flags); } @@ -526,7 +527,7 @@ int get_nohz_timer_target(void) int i, cpu = smp_processor_id(); struct sched_domain *sd; - if (!idle_cpu(cpu) && is_housekeeping_cpu(cpu)) + if (!idle_cpu(cpu) && housekeeping_cpu(cpu, HK_FLAG_TIMER)) return cpu; rcu_read_lock(); @@ -535,15 +536,15 @@ int get_nohz_timer_target(void) if (cpu == i) continue; - if (!idle_cpu(i) && is_housekeeping_cpu(i)) { + if (!idle_cpu(i) && housekeeping_cpu(i, HK_FLAG_TIMER)) { cpu = i; goto unlock; } } } - if (!is_housekeeping_cpu(cpu)) - cpu = housekeeping_any_cpu(); + if (!housekeeping_cpu(cpu, HK_FLAG_TIMER)) + cpu = housekeeping_any_cpu(HK_FLAG_TIMER); unlock: rcu_read_unlock(); return cpu; @@ -733,7 +734,7 @@ int tg_nop(struct task_group *tg, void *data) } #endif -static void set_load_weight(struct task_struct *p) +static void set_load_weight(struct task_struct *p, bool update_load) { int prio = p->static_prio - MAX_RT_PRIO; struct load_weight *load = &p->se.load; @@ -747,8 +748,16 @@ static void set_load_weight(struct task_struct *p) return; } - load->weight = scale_load(sched_prio_to_weight[prio]); - load->inv_weight = sched_prio_to_wmult[prio]; + /* + * SCHED_OTHER tasks have to update their load when changing their + * weight + */ + if (update_load && p->sched_class == &fair_sched_class) { + reweight_task(p, prio); + } else { + load->weight = scale_load(sched_prio_to_weight[prio]); + load->inv_weight = sched_prio_to_wmult[prio]; + } } static inline void enqueue_task(struct rq *rq, struct task_struct *p, int flags) @@ -2358,7 +2367,7 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p) p->static_prio = NICE_TO_PRIO(0); p->prio = p->normal_prio = __normal_prio(p); - set_load_weight(p); + set_load_weight(p, false); /* * We don't need the reset flag anymore after the fork. It has @@ -3805,7 +3814,7 @@ void set_user_nice(struct task_struct *p, long nice) put_prev_task(rq, p); p->static_prio = NICE_TO_PRIO(nice); - set_load_weight(p); + set_load_weight(p, true); old_prio = p->prio; p->prio = effective_prio(p); delta = p->prio - old_prio; @@ -3962,7 +3971,7 @@ static void __setscheduler_params(struct task_struct *p, */ p->rt_priority = attr->sched_priority; p->normal_prio = normal_prio(p); - set_load_weight(p); + set_load_weight(p, true); } /* Actually do priority change: must hold pi & rq lock. */ @@ -4842,6 +4851,7 @@ int __sched _cond_resched(void) preempt_schedule_common(); return 1; } + rcu_all_qs(); return 0; } EXPORT_SYMBOL(_cond_resched); @@ -5098,13 +5108,11 @@ SYSCALL_DEFINE1(sched_get_priority_min, int, policy) * Return: On success, 0 and the timeslice is in @interval. Otherwise, * an error code. */ -SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, - struct timespec __user *, interval) +static int sched_rr_get_interval(pid_t pid, struct timespec64 *t) { struct task_struct *p; unsigned int time_slice; struct rq_flags rf; - struct timespec t; struct rq *rq; int retval; @@ -5128,15 +5136,40 @@ SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, task_rq_unlock(rq, p, &rf); rcu_read_unlock(); - jiffies_to_timespec(time_slice, &t); - retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; - return retval; + jiffies_to_timespec64(time_slice, t); + return 0; out_unlock: rcu_read_unlock(); return retval; } +SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, + struct timespec __user *, interval) +{ + struct timespec64 t; + int retval = sched_rr_get_interval(pid, &t); + + if (retval == 0) + retval = put_timespec64(&t, interval); + + return retval; +} + +#ifdef CONFIG_COMPAT +COMPAT_SYSCALL_DEFINE2(sched_rr_get_interval, + compat_pid_t, pid, + struct compat_timespec __user *, interval) +{ + struct timespec64 t; + int retval = sched_rr_get_interval(pid, &t); + + if (retval == 0) + retval = compat_put_timespec64(&t, interval); + return retval; +} +#endif + void sched_show_task(struct task_struct *p) { unsigned long free = 0; @@ -5165,6 +5198,29 @@ void sched_show_task(struct task_struct *p) show_stack(p, NULL); put_task_stack(p); } +EXPORT_SYMBOL_GPL(sched_show_task); + +static inline bool +state_filter_match(unsigned long state_filter, struct task_struct *p) +{ + /* no filter, everything matches */ + if (!state_filter) + return true; + + /* filter, but doesn't match */ + if (!(p->state & state_filter)) + return false; + + /* + * When looking for TASK_UNINTERRUPTIBLE skip TASK_IDLE (allows + * TASK_KILLABLE). + */ + if (state_filter == TASK_UNINTERRUPTIBLE && p->state == TASK_IDLE) + return false; + + return true; +} + void show_state_filter(unsigned long state_filter) { @@ -5188,7 +5244,7 @@ void show_state_filter(unsigned long state_filter) */ touch_nmi_watchdog(); touch_all_softlockup_watchdogs(); - if (!state_filter || (p->state & state_filter)) + if (state_filter_match(state_filter, p)) sched_show_task(p); } @@ -5704,10 +5760,6 @@ static inline void sched_init_smt(void) { } void __init sched_init_smp(void) { - cpumask_var_t non_isolated_cpus; - - alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); - sched_init_numa(); /* @@ -5717,16 +5769,12 @@ void __init sched_init_smp(void) */ mutex_lock(&sched_domains_mutex); sched_init_domains(cpu_active_mask); - cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); - if (cpumask_empty(non_isolated_cpus)) - cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); mutex_unlock(&sched_domains_mutex); /* Move init over to a non-isolated CPU */ - if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) + if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_FLAG_DOMAIN)) < 0) BUG(); sched_init_granularity(); - free_cpumask_var(non_isolated_cpus); init_sched_rt_class(); init_sched_dl_class(); @@ -5911,7 +5959,7 @@ void __init sched_init(void) atomic_set(&rq->nr_iowait, 0); } - set_load_weight(&init_task); + set_load_weight(&init_task, false); /* * The boot idle thread does lazy MMU switching as well: @@ -5930,9 +5978,6 @@ void __init sched_init(void) calc_load_update = jiffies + LOAD_FREQ; #ifdef CONFIG_SMP - /* May be allocated at isolcpus cmdline parse time */ - if (cpu_isolated_map == NULL) - zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); idle_thread_set_boot_cpu(); set_cpu_rq_start_time(smp_processor_id()); #endif @@ -6599,7 +6644,7 @@ static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) return ret; } -static int cpu_stats_show(struct seq_file *sf, void *v) +static int cpu_cfs_stat_show(struct seq_file *sf, void *v) { struct task_group *tg = css_tg(seq_css(sf)); struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; @@ -6639,7 +6684,7 @@ static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css, } #endif /* CONFIG_RT_GROUP_SCHED */ -static struct cftype cpu_files[] = { +static struct cftype cpu_legacy_files[] = { #ifdef CONFIG_FAIR_GROUP_SCHED { .name = "shares", @@ -6660,7 +6705,7 @@ static struct cftype cpu_files[] = { }, { .name = "stat", - .seq_show = cpu_stats_show, + .seq_show = cpu_cfs_stat_show, }, #endif #ifdef CONFIG_RT_GROUP_SCHED @@ -6678,16 +6723,182 @@ static struct cftype cpu_files[] = { { } /* Terminate */ }; +static int cpu_extra_stat_show(struct seq_file *sf, + struct cgroup_subsys_state *css) +{ +#ifdef CONFIG_CFS_BANDWIDTH + { + struct task_group *tg = css_tg(css); + struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; + u64 throttled_usec; + + throttled_usec = cfs_b->throttled_time; + do_div(throttled_usec, NSEC_PER_USEC); + + seq_printf(sf, "nr_periods %d\n" + "nr_throttled %d\n" + "throttled_usec %llu\n", + cfs_b->nr_periods, cfs_b->nr_throttled, + throttled_usec); + } +#endif + return 0; +} + +#ifdef CONFIG_FAIR_GROUP_SCHED +static u64 cpu_weight_read_u64(struct cgroup_subsys_state *css, + struct cftype *cft) +{ + struct task_group *tg = css_tg(css); + u64 weight = scale_load_down(tg->shares); + + return DIV_ROUND_CLOSEST_ULL(weight * CGROUP_WEIGHT_DFL, 1024); +} + +static int cpu_weight_write_u64(struct cgroup_subsys_state *css, + struct cftype *cft, u64 weight) +{ + /* + * cgroup weight knobs should use the common MIN, DFL and MAX + * values which are 1, 100 and 10000 respectively. While it loses + * a bit of range on both ends, it maps pretty well onto the shares + * value used by scheduler and the round-trip conversions preserve + * the original value over the entire range. + */ + if (weight < CGROUP_WEIGHT_MIN || weight > CGROUP_WEIGHT_MAX) + return -ERANGE; + + weight = DIV_ROUND_CLOSEST_ULL(weight * 1024, CGROUP_WEIGHT_DFL); + + return sched_group_set_shares(css_tg(css), scale_load(weight)); +} + +static s64 cpu_weight_nice_read_s64(struct cgroup_subsys_state *css, + struct cftype *cft) +{ + unsigned long weight = scale_load_down(css_tg(css)->shares); + int last_delta = INT_MAX; + int prio, delta; + + /* find the closest nice value to the current weight */ + for (prio = 0; prio < ARRAY_SIZE(sched_prio_to_weight); prio++) { + delta = abs(sched_prio_to_weight[prio] - weight); + if (delta >= last_delta) + break; + last_delta = delta; + } + + return PRIO_TO_NICE(prio - 1 + MAX_RT_PRIO); +} + +static int cpu_weight_nice_write_s64(struct cgroup_subsys_state *css, + struct cftype *cft, s64 nice) +{ + unsigned long weight; + + if (nice < MIN_NICE || nice > MAX_NICE) + return -ERANGE; + + weight = sched_prio_to_weight[NICE_TO_PRIO(nice) - MAX_RT_PRIO]; + return sched_group_set_shares(css_tg(css), scale_load(weight)); +} +#endif + +static void __maybe_unused cpu_period_quota_print(struct seq_file *sf, + long period, long quota) +{ + if (quota < 0) + seq_puts(sf, "max"); + else + seq_printf(sf, "%ld", quota); + + seq_printf(sf, " %ld\n", period); +} + +/* caller should put the current value in *@periodp before calling */ +static int __maybe_unused cpu_period_quota_parse(char *buf, + u64 *periodp, u64 *quotap) +{ + char tok[21]; /* U64_MAX */ + + if (!sscanf(buf, "%s %llu", tok, periodp)) + return -EINVAL; + + *periodp *= NSEC_PER_USEC; + + if (sscanf(tok, "%llu", quotap)) + *quotap *= NSEC_PER_USEC; + else if (!strcmp(tok, "max")) + *quotap = RUNTIME_INF; + else + return -EINVAL; + + return 0; +} + +#ifdef CONFIG_CFS_BANDWIDTH +static int cpu_max_show(struct seq_file *sf, void *v) +{ + struct task_group *tg = css_tg(seq_css(sf)); + + cpu_period_quota_print(sf, tg_get_cfs_period(tg), tg_get_cfs_quota(tg)); + return 0; +} + +static ssize_t cpu_max_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct task_group *tg = css_tg(of_css(of)); + u64 period = tg_get_cfs_period(tg); + u64 quota; + int ret; + + ret = cpu_period_quota_parse(buf, &period, "a); + if (!ret) + ret = tg_set_cfs_bandwidth(tg, period, quota); + return ret ?: nbytes; +} +#endif + +static struct cftype cpu_files[] = { +#ifdef CONFIG_FAIR_GROUP_SCHED + { + .name = "weight", + .flags = CFTYPE_NOT_ON_ROOT, + .read_u64 = cpu_weight_read_u64, + .write_u64 = cpu_weight_write_u64, + }, + { + .name = "weight.nice", + .flags = CFTYPE_NOT_ON_ROOT, + .read_s64 = cpu_weight_nice_read_s64, + .write_s64 = cpu_weight_nice_write_s64, + }, +#endif +#ifdef CONFIG_CFS_BANDWIDTH + { + .name = "max", + .flags = CFTYPE_NOT_ON_ROOT, + .seq_show = cpu_max_show, + .write = cpu_max_write, + }, +#endif + { } /* terminate */ +}; + struct cgroup_subsys cpu_cgrp_subsys = { .css_alloc = cpu_cgroup_css_alloc, .css_online = cpu_cgroup_css_online, .css_released = cpu_cgroup_css_released, .css_free = cpu_cgroup_css_free, + .css_extra_stat_show = cpu_extra_stat_show, .fork = cpu_cgroup_fork, .can_attach = cpu_cgroup_can_attach, .attach = cpu_cgroup_attach, - .legacy_cftypes = cpu_files, + .legacy_cftypes = cpu_legacy_files, + .dfl_cftypes = cpu_files, .early_init = true, + .threaded = true, }; #endif /* CONFIG_CGROUP_SCHED */ diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c index f95ab29a45d0..44ab32a4fab6 100644 --- a/kernel/sched/cpuacct.c +++ b/kernel/sched/cpuacct.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 #include <linux/cgroup.h> #include <linux/slab.h> #include <linux/percpu.h> diff --git a/kernel/sched/cpuacct.h b/kernel/sched/cpuacct.h deleted file mode 100644 index ba72807c73d4..000000000000 --- a/kernel/sched/cpuacct.h +++ /dev/null @@ -1,17 +0,0 @@ -#ifdef CONFIG_CGROUP_CPUACCT - -extern void cpuacct_charge(struct task_struct *tsk, u64 cputime); -extern void cpuacct_account_field(struct task_struct *tsk, int index, u64 val); - -#else - -static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) -{ -} - -static inline void -cpuacct_account_field(struct task_struct *tsk, int index, u64 val) -{ -} - -#endif diff --git a/kernel/sched/cpudeadline.h b/kernel/sched/cpudeadline.h index f7da8c55bba0..b010d26e108e 100644 --- a/kernel/sched/cpudeadline.h +++ b/kernel/sched/cpudeadline.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_CPUDL_H #define _LINUX_CPUDL_H diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 9209d83ecdcf..2f52ec0f1539 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -282,8 +282,12 @@ static void sugov_update_single(struct update_util_data *hook, u64 time, * Do not reduce the frequency if the CPU has not been idle * recently, as the reduction is likely to be premature then. */ - if (busy && next_f < sg_policy->next_freq) + if (busy && next_f < sg_policy->next_freq) { next_f = sg_policy->next_freq; + + /* Reset cached freq as next_freq has changed */ + sg_policy->cached_raw_freq = 0; + } } sugov_update_commit(sg_policy, time, next_f); } @@ -649,6 +653,7 @@ static int sugov_start(struct cpufreq_policy *policy) struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu); memset(sg_cpu, 0, sizeof(*sg_cpu)); + sg_cpu->cpu = cpu; sg_cpu->sg_policy = sg_policy; sg_cpu->flags = SCHED_CPUFREQ_RT; sg_cpu->iowait_boost_max = policy->cpuinfo.max_freq; @@ -714,11 +719,6 @@ struct cpufreq_governor *cpufreq_default_governor(void) static int __init sugov_register(void) { - int cpu; - - for_each_possible_cpu(cpu) - per_cpu(sugov_cpu, cpu).cpu = cpu; - return cpufreq_register_governor(&schedutil_gov); } fs_initcall(sugov_register); diff --git a/kernel/sched/cpupri.h b/kernel/sched/cpupri.h index 63cbb9ca0496..bab050019071 100644 --- a/kernel/sched/cpupri.h +++ b/kernel/sched/cpupri.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_CPUPRI_H #define _LINUX_CPUPRI_H diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c index 14d2dbf97c53..bac6ac9a4ec7 100644 --- a/kernel/sched/cputime.c +++ b/kernel/sched/cputime.c @@ -109,7 +109,7 @@ static inline void task_group_account_field(struct task_struct *p, int index, */ __this_cpu_add(kernel_cpustat.cpustat[index], tmp); - cpuacct_account_field(p, index, tmp); + cgroup_account_cputime_field(p, index, tmp); } /* @@ -259,8 +259,7 @@ static inline u64 account_other_time(u64 max) { u64 accounted; - /* Shall be converted to a lockdep-enabled lightweight check */ - WARN_ON_ONCE(!irqs_disabled()); + lockdep_assert_irqs_disabled(); accounted = steal_account_process_time(max); @@ -447,6 +446,13 @@ void vtime_account_irq_enter(struct task_struct *tsk) EXPORT_SYMBOL_GPL(vtime_account_irq_enter); #endif /* __ARCH_HAS_VTIME_ACCOUNT */ +void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev, + u64 *ut, u64 *st) +{ + *ut = curr->utime; + *st = curr->stime; +} + void task_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st) { *ut = p->utime; @@ -585,9 +591,8 @@ drop_precision: * * Assuming that rtime_i+1 >= rtime_i. */ -static void cputime_adjust(struct task_cputime *curr, - struct prev_cputime *prev, - u64 *ut, u64 *st) +void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev, + u64 *ut, u64 *st) { u64 rtime, stime, utime; unsigned long flags; diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 0191ec7667c3..2473736c7616 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 /* * Deadline Scheduling Class (SCHED_DEADLINE) * @@ -242,7 +243,7 @@ static void task_non_contending(struct task_struct *p) if (p->state == TASK_DEAD) sub_rq_bw(p->dl.dl_bw, &rq->dl); raw_spin_lock(&dl_b->lock); - __dl_clear(dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p))); + __dl_sub(dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p))); __dl_clear_params(p); raw_spin_unlock(&dl_b->lock); } @@ -1143,7 +1144,7 @@ static void update_curr_dl(struct rq *rq) account_group_exec_runtime(curr, delta_exec); curr->se.exec_start = rq_clock_task(rq); - cpuacct_charge(curr, delta_exec); + cgroup_account_cputime(curr, delta_exec); sched_rt_avg_update(rq, delta_exec); @@ -1209,7 +1210,7 @@ static enum hrtimer_restart inactive_task_timer(struct hrtimer *timer) } raw_spin_lock(&dl_b->lock); - __dl_clear(dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p))); + __dl_sub(dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p))); raw_spin_unlock(&dl_b->lock); __dl_clear_params(p); @@ -1364,6 +1365,10 @@ enqueue_dl_entity(struct sched_dl_entity *dl_se, update_dl_entity(dl_se, pi_se); } else if (flags & ENQUEUE_REPLENISH) { replenish_dl_entity(dl_se, pi_se); + } else if ((flags & ENQUEUE_RESTORE) && + dl_time_before(dl_se->deadline, + rq_clock(rq_of_dl_rq(dl_rq_of_se(dl_se))))) { + setup_new_dl_entity(dl_se); } __enqueue_dl_entity(dl_se); @@ -2166,7 +2171,7 @@ static void set_cpus_allowed_dl(struct task_struct *p, * until we complete the update. */ raw_spin_lock(&src_dl_b->lock); - __dl_clear(src_dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p))); + __dl_sub(src_dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p))); raw_spin_unlock(&src_dl_b->lock); } @@ -2255,13 +2260,6 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p) return; } - /* - * If p is boosted we already updated its params in - * rt_mutex_setprio()->enqueue_task(..., ENQUEUE_REPLENISH), - * p's deadline being now already after rq_clock(rq). - */ - if (dl_time_before(p->dl.deadline, rq_clock(rq))) - setup_new_dl_entity(&p->dl); if (rq->curr != p) { #ifdef CONFIG_SMP @@ -2451,7 +2449,7 @@ int sched_dl_overflow(struct task_struct *p, int policy, if (dl_policy(policy) && !task_has_dl_policy(p) && !__dl_overflow(dl_b, cpus, 0, new_bw)) { if (hrtimer_active(&p->dl.inactive_timer)) - __dl_clear(dl_b, p->dl.dl_bw, cpus); + __dl_sub(dl_b, p->dl.dl_bw, cpus); __dl_add(dl_b, new_bw, cpus); err = 0; } else if (dl_policy(policy) && task_has_dl_policy(p) && @@ -2463,7 +2461,7 @@ int sched_dl_overflow(struct task_struct *p, int policy, * But this would require to set the task's "inactive * timer" when the task is not inactive. */ - __dl_clear(dl_b, p->dl.dl_bw, cpus); + __dl_sub(dl_b, p->dl.dl_bw, cpus); __dl_add(dl_b, new_bw, cpus); dl_change_utilization(p, new_bw); err = 0; diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index 01217fb5a5de..1ca0130ed4f9 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -441,9 +441,11 @@ static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group P_SCHEDSTAT(se->statistics.wait_count); } P(se->load.weight); + P(se->runnable_weight); #ifdef CONFIG_SMP P(se->avg.load_avg); P(se->avg.util_avg); + P(se->avg.runnable_load_avg); #endif #undef PN_SCHEDSTAT @@ -466,8 +468,6 @@ static char *task_group_path(struct task_group *tg) } #endif -static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; - static void print_task(struct seq_file *m, struct rq *rq, struct task_struct *p) { @@ -560,16 +560,19 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq) SEQ_printf(m, " .%-30s: %d\n", "nr_running", cfs_rq->nr_running); SEQ_printf(m, " .%-30s: %ld\n", "load", cfs_rq->load.weight); #ifdef CONFIG_SMP + SEQ_printf(m, " .%-30s: %ld\n", "runnable_weight", cfs_rq->runnable_weight); SEQ_printf(m, " .%-30s: %lu\n", "load_avg", cfs_rq->avg.load_avg); SEQ_printf(m, " .%-30s: %lu\n", "runnable_load_avg", - cfs_rq->runnable_load_avg); + cfs_rq->avg.runnable_load_avg); SEQ_printf(m, " .%-30s: %lu\n", "util_avg", cfs_rq->avg.util_avg); - SEQ_printf(m, " .%-30s: %ld\n", "removed_load_avg", - atomic_long_read(&cfs_rq->removed_load_avg)); - SEQ_printf(m, " .%-30s: %ld\n", "removed_util_avg", - atomic_long_read(&cfs_rq->removed_util_avg)); + SEQ_printf(m, " .%-30s: %ld\n", "removed.load_avg", + cfs_rq->removed.load_avg); + SEQ_printf(m, " .%-30s: %ld\n", "removed.util_avg", + cfs_rq->removed.util_avg); + SEQ_printf(m, " .%-30s: %ld\n", "removed.runnable_sum", + cfs_rq->removed.runnable_sum); #ifdef CONFIG_FAIR_GROUP_SCHED SEQ_printf(m, " .%-30s: %lu\n", "tg_load_avg_contrib", cfs_rq->tg_load_avg_contrib); @@ -1006,10 +1009,13 @@ void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns, "nr_involuntary_switches", (long long)p->nivcsw); P(se.load.weight); + P(se.runnable_weight); #ifdef CONFIG_SMP P(se.avg.load_sum); + P(se.avg.runnable_load_sum); P(se.avg.util_sum); P(se.avg.load_avg); + P(se.avg.runnable_load_avg); P(se.avg.util_avg); P(se.avg.last_update_time); #endif diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 70ba32e08a23..4037e19bbca2 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 /* * Completely Fair Scheduling (CFS) Class (SCHED_NORMAL/SCHED_BATCH) * @@ -32,6 +33,7 @@ #include <linux/mempolicy.h> #include <linux/migrate.h> #include <linux/task_work.h> +#include <linux/sched/isolation.h> #include <trace/events/sched.h> @@ -716,13 +718,8 @@ void init_entity_runnable_average(struct sched_entity *se) { struct sched_avg *sa = &se->avg; - sa->last_update_time = 0; - /* - * sched_avg's period_contrib should be strictly less then 1024, so - * we give it 1023 to make sure it is almost a period (1024us), and - * will definitely be update (after enqueue). - */ - sa->period_contrib = 1023; + memset(sa, 0, sizeof(*sa)); + /* * Tasks are intialized with full load to be seen as heavy tasks until * they get a chance to stabilize to their real load level. @@ -730,13 +727,10 @@ void init_entity_runnable_average(struct sched_entity *se) * nothing has been attached to the task group yet. */ if (entity_is_task(se)) - sa->load_avg = scale_load_down(se->load.weight); - sa->load_sum = sa->load_avg * LOAD_AVG_MAX; - /* - * At this point, util_avg won't be used in select_task_rq_fair anyway - */ - sa->util_avg = 0; - sa->util_sum = 0; + sa->runnable_load_avg = sa->load_avg = scale_load_down(se->load.weight); + + se->runnable_weight = se->load.weight; + /* when this task enqueue'ed, it will contribute to its cfs_rq's load_avg */ } @@ -784,7 +778,6 @@ void post_init_entity_util_avg(struct sched_entity *se) } else { sa->util_avg = cap; } - sa->util_sum = sa->util_avg * LOAD_AVG_MAX; } if (entity_is_task(se)) { @@ -851,7 +844,7 @@ static void update_curr(struct cfs_rq *cfs_rq) struct task_struct *curtask = task_of(curr); trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime); - cpuacct_charge(curtask, delta_exec); + cgroup_account_cputime(curtask, delta_exec); account_group_exec_runtime(curtask, delta_exec); } @@ -2025,7 +2018,7 @@ static u64 numa_get_avg_runtime(struct task_struct *p, u64 *period) delta = runtime - p->last_sum_exec_runtime; *period = now - p->last_task_numa_placement; } else { - delta = p->se.avg.load_sum / p->se.load.weight; + delta = p->se.avg.load_sum; *period = LOAD_AVG_MAX; } @@ -2692,18 +2685,226 @@ account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) cfs_rq->nr_running--; } +/* + * Signed add and clamp on underflow. + * + * Explicitly do a load-store to ensure the intermediate value never hits + * memory. This allows lockless observations without ever seeing the negative + * values. + */ +#define add_positive(_ptr, _val) do { \ + typeof(_ptr) ptr = (_ptr); \ + typeof(_val) val = (_val); \ + typeof(*ptr) res, var = READ_ONCE(*ptr); \ + \ + res = var + val; \ + \ + if (val < 0 && res > var) \ + res = 0; \ + \ + WRITE_ONCE(*ptr, res); \ +} while (0) + +/* + * Unsigned subtract and clamp on underflow. + * + * Explicitly do a load-store to ensure the intermediate value never hits + * memory. This allows lockless observations without ever seeing the negative + * values. + */ +#define sub_positive(_ptr, _val) do { \ + typeof(_ptr) ptr = (_ptr); \ + typeof(*ptr) val = (_val); \ + typeof(*ptr) res, var = READ_ONCE(*ptr); \ + res = var - val; \ + if (res > var) \ + res = 0; \ + WRITE_ONCE(*ptr, res); \ +} 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) +{ + cfs_rq->runnable_weight += se->runnable_weight; + + cfs_rq->avg.runnable_load_avg += se->avg.runnable_load_avg; + cfs_rq->avg.runnable_load_sum += se_runnable(se) * se->avg.runnable_load_sum; +} + +static inline void +dequeue_runnable_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + cfs_rq->runnable_weight -= se->runnable_weight; + + sub_positive(&cfs_rq->avg.runnable_load_avg, se->avg.runnable_load_avg); + sub_positive(&cfs_rq->avg.runnable_load_sum, + se_runnable(se) * se->avg.runnable_load_sum); +} + +static inline void +enqueue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + cfs_rq->avg.load_avg += se->avg.load_avg; + cfs_rq->avg.load_sum += se_weight(se) * se->avg.load_sum; +} + +static inline void +dequeue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + sub_positive(&cfs_rq->avg.load_avg, se->avg.load_avg); + sub_positive(&cfs_rq->avg.load_sum, se_weight(se) * se->avg.load_sum); +} +#else +static inline void +enqueue_runnable_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { } +static inline void +dequeue_runnable_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { } +static inline void +enqueue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { } +static inline void +dequeue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { } +#endif + +static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, + unsigned long weight, unsigned long runnable) +{ + if (se->on_rq) { + /* commit outstanding execution time */ + if (cfs_rq->curr == se) + update_curr(cfs_rq); + account_entity_dequeue(cfs_rq, se); + dequeue_runnable_load_avg(cfs_rq, se); + } + dequeue_load_avg(cfs_rq, se); + + se->runnable_weight = runnable; + update_load_set(&se->load, weight); + +#ifdef CONFIG_SMP + do { + u32 divider = LOAD_AVG_MAX - 1024 + se->avg.period_contrib; + + se->avg.load_avg = div_u64(se_weight(se) * se->avg.load_sum, divider); + se->avg.runnable_load_avg = + div_u64(se_runnable(se) * se->avg.runnable_load_sum, divider); + } while (0); +#endif + + enqueue_load_avg(cfs_rq, se); + if (se->on_rq) { + account_entity_enqueue(cfs_rq, se); + enqueue_runnable_load_avg(cfs_rq, se); + } +} + +void reweight_task(struct task_struct *p, int prio) +{ + struct sched_entity *se = &p->se; + struct cfs_rq *cfs_rq = cfs_rq_of(se); + struct load_weight *load = &se->load; + unsigned long weight = scale_load(sched_prio_to_weight[prio]); + + reweight_entity(cfs_rq, se, weight, weight); + load->inv_weight = sched_prio_to_wmult[prio]; +} + #ifdef CONFIG_FAIR_GROUP_SCHED # ifdef CONFIG_SMP -static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg) +/* + * All this does is approximate the hierarchical proportion which includes that + * global sum we all love to hate. + * + * That is, the weight of a group entity, is the proportional share of the + * group weight based on the group runqueue weights. That is: + * + * tg->weight * grq->load.weight + * ge->load.weight = ----------------------------- (1) + * \Sum grq->load.weight + * + * Now, because computing that sum is prohibitively expensive to compute (been + * there, done that) we approximate it with this average stuff. The average + * moves slower and therefore the approximation is cheaper and more stable. + * + * So instead of the above, we substitute: + * + * grq->load.weight -> grq->avg.load_avg (2) + * + * which yields the following: + * + * tg->weight * grq->avg.load_avg + * ge->load.weight = ------------------------------ (3) + * tg->load_avg + * + * Where: tg->load_avg ~= \Sum grq->avg.load_avg + * + * That is shares_avg, and it is right (given the approximation (2)). + * + * The problem with it is that because the average is slow -- it was designed + * to be exactly that of course -- this leads to transients in boundary + * conditions. In specific, the case where the group was idle and we start the + * one task. It takes time for our CPU's grq->avg.load_avg to build up, + * yielding bad latency etc.. + * + * Now, in that special case (1) reduces to: + * + * tg->weight * grq->load.weight + * ge->load.weight = ----------------------------- = tg->weight (4) + * grp->load.weight + * + * That is, the sum collapses because all other CPUs are idle; the UP scenario. + * + * So what we do is modify our approximation (3) to approach (4) in the (near) + * UP case, like: + * + * ge->load.weight = + * + * tg->weight * grq->load.weight + * --------------------------------------------------- (5) + * tg->load_avg - grq->avg.load_avg + grq->load.weight + * + * But because grq->load.weight can drop to 0, resulting in a divide by zero, + * we need to use grq->avg.load_avg as its lower bound, which then gives: + * + * + * tg->weight * grq->load.weight + * ge->load.weight = ----------------------------- (6) + * tg_load_avg' + * + * Where: + * + * tg_load_avg' = tg->load_avg - grq->avg.load_avg + + * max(grq->load.weight, grq->avg.load_avg) + * + * And that is shares_weight and is icky. In the (near) UP case it approaches + * (4) while in the normal case it approaches (3). It consistently + * overestimates the ge->load.weight and therefore: + * + * \Sum ge->load.weight >= tg->weight + * + * hence icky! + */ +static long calc_group_shares(struct cfs_rq *cfs_rq) { - long tg_weight, load, shares; + long tg_weight, tg_shares, load, shares; + struct task_group *tg = cfs_rq->tg; - /* - * This really should be: cfs_rq->avg.load_avg, but instead we use - * cfs_rq->load.weight, which is its upper bound. This helps ramp up - * the shares for small weight interactive tasks. - */ - load = scale_load_down(cfs_rq->load.weight); + tg_shares = READ_ONCE(tg->shares); + + load = max(scale_load_down(cfs_rq->load.weight), cfs_rq->avg.load_avg); tg_weight = atomic_long_read(&tg->load_avg); @@ -2711,7 +2912,7 @@ static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg) tg_weight -= cfs_rq->tg_load_avg_contrib; tg_weight += load; - shares = (tg->shares * load); + shares = (tg_shares * load); if (tg_weight) shares /= tg_weight; @@ -2727,63 +2928,86 @@ static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg) * case no task is runnable on a CPU MIN_SHARES=2 should be returned * instead of 0. */ - if (shares < MIN_SHARES) - shares = MIN_SHARES; - if (shares > tg->shares) - shares = tg->shares; - - return shares; -} -# else /* CONFIG_SMP */ -static inline long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg) -{ - return tg->shares; + return clamp_t(long, shares, MIN_SHARES, tg_shares); } -# endif /* CONFIG_SMP */ -static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, - unsigned long weight) +/* + * This calculates the effective runnable weight for a group entity based on + * the group entity weight calculated above. + * + * Because of the above approximation (2), our group entity weight is + * an load_avg based ratio (3). This means that it includes blocked load and + * does not represent the runnable weight. + * + * Approximate the group entity's runnable weight per ratio from the group + * runqueue: + * + * grq->avg.runnable_load_avg + * ge->runnable_weight = ge->load.weight * -------------------------- (7) + * grq->avg.load_avg + * + * However, analogous to above, since the avg numbers are slow, this leads to + * transients in the from-idle case. Instead we use: + * + * ge->runnable_weight = ge->load.weight * + * + * max(grq->avg.runnable_load_avg, grq->runnable_weight) + * ----------------------------------------------------- (8) + * max(grq->avg.load_avg, grq->load.weight) + * + * Where these max() serve both to use the 'instant' values to fix the slow + * from-idle and avoid the /0 on to-idle, similar to (6). + */ +static long calc_group_runnable(struct cfs_rq *cfs_rq, long shares) { - if (se->on_rq) { - /* commit outstanding execution time */ - if (cfs_rq->curr == se) - update_curr(cfs_rq); - account_entity_dequeue(cfs_rq, se); - } + long runnable, load_avg; - update_load_set(&se->load, weight); + load_avg = max(cfs_rq->avg.load_avg, + scale_load_down(cfs_rq->load.weight)); - if (se->on_rq) - account_entity_enqueue(cfs_rq, se); + runnable = max(cfs_rq->avg.runnable_load_avg, + scale_load_down(cfs_rq->runnable_weight)); + + runnable *= shares; + if (load_avg) + runnable /= load_avg; + + return clamp_t(long, runnable, MIN_SHARES, shares); } +# endif /* CONFIG_SMP */ static inline int throttled_hierarchy(struct cfs_rq *cfs_rq); -static void update_cfs_shares(struct sched_entity *se) +/* + * Recomputes the group entity based on the current state of its group + * runqueue. + */ +static void update_cfs_group(struct sched_entity *se) { - struct cfs_rq *cfs_rq = group_cfs_rq(se); - struct task_group *tg; - long shares; + struct cfs_rq *gcfs_rq = group_cfs_rq(se); + long shares, runnable; - if (!cfs_rq) + if (!gcfs_rq) return; - if (throttled_hierarchy(cfs_rq)) + if (throttled_hierarchy(gcfs_rq)) return; - tg = cfs_rq->tg; - #ifndef CONFIG_SMP - if (likely(se->load.weight == tg->shares)) + runnable = shares = READ_ONCE(gcfs_rq->tg->shares); + + if (likely(se->load.weight == shares)) return; +#else + shares = calc_group_shares(gcfs_rq); + runnable = calc_group_runnable(gcfs_rq, shares); #endif - shares = calc_cfs_shares(cfs_rq, tg); - reweight_entity(cfs_rq_of(se), se, shares); + reweight_entity(cfs_rq_of(se), se, shares, runnable); } #else /* CONFIG_FAIR_GROUP_SCHED */ -static inline void update_cfs_shares(struct sched_entity *se) +static inline void update_cfs_group(struct sched_entity *se) { } #endif /* CONFIG_FAIR_GROUP_SCHED */ @@ -2892,7 +3116,7 @@ static u32 __accumulate_pelt_segments(u64 periods, u32 d1, u32 d3) */ static __always_inline u32 accumulate_sum(u64 delta, int cpu, struct sched_avg *sa, - unsigned long weight, int running, struct cfs_rq *cfs_rq) + unsigned long load, unsigned long runnable, int running) { unsigned long scale_freq, scale_cpu; u32 contrib = (u32)delta; /* p == 0 -> delta < 1024 */ @@ -2909,10 +3133,8 @@ accumulate_sum(u64 delta, int cpu, struct sched_avg *sa, */ if (periods) { sa->load_sum = decay_load(sa->load_sum, periods); - if (cfs_rq) { - cfs_rq->runnable_load_sum = - decay_load(cfs_rq->runnable_load_sum, periods); - } + sa->runnable_load_sum = + decay_load(sa->runnable_load_sum, periods); sa->util_sum = decay_load((u64)(sa->util_sum), periods); /* @@ -2925,11 +3147,10 @@ accumulate_sum(u64 delta, int cpu, struct sched_avg *sa, sa->period_contrib = delta; contrib = cap_scale(contrib, scale_freq); - if (weight) { - sa->load_sum += weight * contrib; - if (cfs_rq) - cfs_rq->runnable_load_sum += weight * contrib; - } + if (load) + sa->load_sum += load * contrib; + if (runnable) + sa->runnable_load_sum += runnable * contrib; if (running) sa->util_sum += contrib * scale_cpu; @@ -2965,8 +3186,8 @@ accumulate_sum(u64 delta, int cpu, struct sched_avg *sa, * = u_0 + u_1*y + u_2*y^2 + ... [re-labeling u_i --> u_{i+1}] */ static __always_inline int -___update_load_avg(u64 now, int cpu, struct sched_avg *sa, - unsigned long weight, int running, struct cfs_rq *cfs_rq) +___update_load_sum(u64 now, int cpu, struct sched_avg *sa, + unsigned long load, unsigned long runnable, int running) { u64 delta; @@ -2999,8 +3220,8 @@ ___update_load_avg(u64 now, int cpu, struct sched_avg *sa, * this happens during idle_balance() which calls * update_blocked_averages() */ - if (!weight) - running = 0; + if (!load) + runnable = running = 0; /* * Now we know we crossed measurement unit boundaries. The *_avg @@ -3009,63 +3230,96 @@ ___update_load_avg(u64 now, int cpu, struct sched_avg *sa, * Step 1: accumulate *_sum since last_update_time. If we haven't * crossed period boundaries, finish. */ - if (!accumulate_sum(delta, cpu, sa, weight, running, cfs_rq)) + 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(sa->load_sum, LOAD_AVG_MAX - 1024 + sa->period_contrib); - if (cfs_rq) { - cfs_rq->runnable_load_avg = - div_u64(cfs_rq->runnable_load_sum, LOAD_AVG_MAX - 1024 + sa->period_contrib); - } - sa->util_avg = sa->util_sum / (LOAD_AVG_MAX - 1024 + sa->period_contrib); - - return 1; + 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; } +/* + * 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) { - return ___update_load_avg(now, cpu, &se->avg, 0, 0, NULL); + 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) { - return ___update_load_avg(now, cpu, &se->avg, - se->on_rq * scale_load_down(se->load.weight), - cfs_rq->curr == se, NULL); + 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)); + return 1; + } + + return 0; } static int __update_load_avg_cfs_rq(u64 now, int cpu, struct cfs_rq *cfs_rq) { - return ___update_load_avg(now, cpu, &cfs_rq->avg, - scale_load_down(cfs_rq->load.weight), - cfs_rq->curr != NULL, 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)) { -/* - * Signed add and clamp on underflow. - * - * Explicitly do a load-store to ensure the intermediate value never hits - * memory. This allows lockless observations without ever seeing the negative - * values. - */ -#define add_positive(_ptr, _val) do { \ - typeof(_ptr) ptr = (_ptr); \ - typeof(_val) val = (_val); \ - typeof(*ptr) res, var = READ_ONCE(*ptr); \ - \ - res = var + val; \ - \ - if (val < 0 && res > var) \ - res = 0; \ - \ - WRITE_ONCE(*ptr, res); \ -} while (0) + ___update_load_avg(&cfs_rq->avg, 1, 1); + return 1; + } + + return 0; +} #ifdef CONFIG_FAIR_GROUP_SCHED /** @@ -3148,11 +3402,77 @@ void set_task_rq_fair(struct sched_entity *se, se->avg.last_update_time = n_last_update_time; } -/* Take into account change of utilization of a child task group */ + +/* + * When on migration a sched_entity joins/leaves the PELT hierarchy, we need to + * propagate its contribution. The key to this propagation is the invariant + * that for each group: + * + * ge->avg == grq->avg (1) + * + * _IFF_ we look at the pure running and runnable sums. Because they + * represent the very same entity, just at different points in the hierarchy. + * + * + * Per the above update_tg_cfs_util() is trivial (and still 'wrong') and + * simply copies the running sum over. + * + * However, update_tg_cfs_runnable() is more complex. So we have: + * + * ge->avg.load_avg = ge->load.weight * ge->avg.runnable_avg (2) + * + * And since, like util, the runnable part should be directly transferable, + * the following would _appear_ to be the straight forward approach: + * + * grq->avg.load_avg = grq->load.weight * grq->avg.running_avg (3) + * + * And per (1) we have: + * + * ge->avg.running_avg == grq->avg.running_avg + * + * Which gives: + * + * ge->load.weight * grq->avg.load_avg + * ge->avg.load_avg = ----------------------------------- (4) + * grq->load.weight + * + * Except that is wrong! + * + * Because while for entities historical weight is not important and we + * really only care about our future and therefore can consider a pure + * runnable sum, runqueues can NOT do this. + * + * We specifically want runqueues to have a load_avg that includes + * historical weights. Those represent the blocked load, the load we expect + * to (shortly) return to us. This only works by keeping the weights as + * integral part of the sum. We therefore cannot decompose as per (3). + * + * OK, so what then? + * + * + * Another way to look at things is: + * + * grq->avg.load_avg = \Sum se->avg.load_avg + * + * Therefore, per (2): + * + * grq->avg.load_avg = \Sum se->load.weight * se->avg.runnable_avg + * + * And the very thing we're propagating is a change in that sum (someone + * joined/left). So we can easily know the runnable change, which would be, per + * (2) the already tracked se->load_avg divided by the corresponding + * se->weight. + * + * Basically (4) but in differential form: + * + * d(runnable_avg) += se->avg.load_avg / se->load.weight + * (5) + * ge->avg.load_avg += ge->load.weight * d(runnable_avg) + */ + static inline void -update_tg_cfs_util(struct cfs_rq *cfs_rq, struct sched_entity *se) +update_tg_cfs_util(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq *gcfs_rq) { - struct cfs_rq *gcfs_rq = group_cfs_rq(se); long delta = gcfs_rq->avg.util_avg - se->avg.util_avg; /* Nothing to update */ @@ -3168,102 +3488,65 @@ update_tg_cfs_util(struct cfs_rq *cfs_rq, struct sched_entity *se) cfs_rq->avg.util_sum = cfs_rq->avg.util_avg * LOAD_AVG_MAX; } -/* Take into account change of load of a child task group */ static inline void -update_tg_cfs_load(struct cfs_rq *cfs_rq, struct sched_entity *se) +update_tg_cfs_runnable(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cfs_rq *gcfs_rq) { - struct cfs_rq *gcfs_rq = group_cfs_rq(se); - long delta, load = gcfs_rq->avg.load_avg; - - /* - * If the load of group cfs_rq is null, the load of the - * sched_entity will also be null so we can skip the formula - */ - if (load) { - long tg_load; + long runnable_sum = gcfs_rq->prop_runnable_sum; + long runnable_load_avg, load_avg; + s64 runnable_load_sum, load_sum; - /* Get tg's load and ensure tg_load > 0 */ - tg_load = atomic_long_read(&gcfs_rq->tg->load_avg) + 1; + if (!runnable_sum) + return; - /* Ensure tg_load >= load and updated with current load*/ - tg_load -= gcfs_rq->tg_load_avg_contrib; - tg_load += load; + gcfs_rq->prop_runnable_sum = 0; - /* - * We need to compute a correction term in the case that the - * task group is consuming more CPU than a task of equal - * weight. A task with a weight equals to tg->shares will have - * a load less or equal to scale_load_down(tg->shares). - * Similarly, the sched_entities that represent the task group - * at parent level, can't have a load higher than - * scale_load_down(tg->shares). And the Sum of sched_entities' - * load must be <= scale_load_down(tg->shares). - */ - if (tg_load > scale_load_down(gcfs_rq->tg->shares)) { - /* scale gcfs_rq's load into tg's shares*/ - load *= scale_load_down(gcfs_rq->tg->shares); - load /= tg_load; - } - } + load_sum = (s64)se_weight(se) * runnable_sum; + load_avg = div_s64(load_sum, LOAD_AVG_MAX); - delta = load - se->avg.load_avg; + add_positive(&se->avg.load_sum, runnable_sum); + add_positive(&se->avg.load_avg, load_avg); - /* Nothing to update */ - if (!delta) - return; + add_positive(&cfs_rq->avg.load_avg, load_avg); + add_positive(&cfs_rq->avg.load_sum, load_sum); - /* Set new sched_entity's load */ - se->avg.load_avg = load; - se->avg.load_sum = se->avg.load_avg * LOAD_AVG_MAX; + runnable_load_sum = (s64)se_runnable(se) * runnable_sum; + runnable_load_avg = div_s64(runnable_load_sum, LOAD_AVG_MAX); - /* Update parent cfs_rq load */ - add_positive(&cfs_rq->avg.load_avg, delta); - cfs_rq->avg.load_sum = cfs_rq->avg.load_avg * LOAD_AVG_MAX; + add_positive(&se->avg.runnable_load_sum, runnable_sum); + add_positive(&se->avg.runnable_load_avg, runnable_load_avg); - /* - * If the sched_entity is already enqueued, we also have to update the - * runnable load avg. - */ if (se->on_rq) { - /* Update parent cfs_rq runnable_load_avg */ - add_positive(&cfs_rq->runnable_load_avg, delta); - cfs_rq->runnable_load_sum = cfs_rq->runnable_load_avg * LOAD_AVG_MAX; + add_positive(&cfs_rq->avg.runnable_load_avg, runnable_load_avg); + add_positive(&cfs_rq->avg.runnable_load_sum, runnable_load_sum); } } -static inline void set_tg_cfs_propagate(struct cfs_rq *cfs_rq) -{ - cfs_rq->propagate_avg = 1; -} - -static inline int test_and_clear_tg_cfs_propagate(struct sched_entity *se) +static inline void add_tg_cfs_propagate(struct cfs_rq *cfs_rq, long runnable_sum) { - struct cfs_rq *cfs_rq = group_cfs_rq(se); - - if (!cfs_rq->propagate_avg) - return 0; - - cfs_rq->propagate_avg = 0; - return 1; + cfs_rq->propagate = 1; + cfs_rq->prop_runnable_sum += runnable_sum; } /* Update task and its cfs_rq load average */ static inline int propagate_entity_load_avg(struct sched_entity *se) { - struct cfs_rq *cfs_rq; + struct cfs_rq *cfs_rq, *gcfs_rq; if (entity_is_task(se)) return 0; - if (!test_and_clear_tg_cfs_propagate(se)) + gcfs_rq = group_cfs_rq(se); + if (!gcfs_rq->propagate) return 0; + gcfs_rq->propagate = 0; + cfs_rq = cfs_rq_of(se); - set_tg_cfs_propagate(cfs_rq); + add_tg_cfs_propagate(cfs_rq, gcfs_rq->prop_runnable_sum); - update_tg_cfs_util(cfs_rq, se); - update_tg_cfs_load(cfs_rq, se); + update_tg_cfs_util(cfs_rq, se, gcfs_rq); + update_tg_cfs_runnable(cfs_rq, se, gcfs_rq); return 1; } @@ -3287,7 +3570,7 @@ static inline bool skip_blocked_update(struct sched_entity *se) * If there is a pending propagation, we have to update the load and * the utilization of the sched_entity: */ - if (gcfs_rq->propagate_avg) + if (gcfs_rq->propagate) return false; /* @@ -3307,27 +3590,10 @@ static inline int propagate_entity_load_avg(struct sched_entity *se) return 0; } -static inline void set_tg_cfs_propagate(struct cfs_rq *cfs_rq) {} +static inline void add_tg_cfs_propagate(struct cfs_rq *cfs_rq, long runnable_sum) {} #endif /* CONFIG_FAIR_GROUP_SCHED */ -/* - * Unsigned subtract and clamp on underflow. - * - * Explicitly do a load-store to ensure the intermediate value never hits - * memory. This allows lockless observations without ever seeing the negative - * values. - */ -#define sub_positive(_ptr, _val) do { \ - typeof(_ptr) ptr = (_ptr); \ - typeof(*ptr) val = (_val); \ - typeof(*ptr) res, var = READ_ONCE(*ptr); \ - res = var - val; \ - if (res > var) \ - res = 0; \ - WRITE_ONCE(*ptr, res); \ -} while (0) - /** * update_cfs_rq_load_avg - update the cfs_rq's load/util averages * @now: current time, as per cfs_rq_clock_task() @@ -3347,65 +3613,45 @@ static inline void set_tg_cfs_propagate(struct cfs_rq *cfs_rq) {} static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) { + unsigned long removed_load = 0, removed_util = 0, removed_runnable_sum = 0; struct sched_avg *sa = &cfs_rq->avg; - int decayed, removed_load = 0, removed_util = 0; + int decayed = 0; + + if (cfs_rq->removed.nr) { + unsigned long r; + u32 divider = LOAD_AVG_MAX - 1024 + sa->period_contrib; - if (atomic_long_read(&cfs_rq->removed_load_avg)) { - s64 r = atomic_long_xchg(&cfs_rq->removed_load_avg, 0); + raw_spin_lock(&cfs_rq->removed.lock); + swap(cfs_rq->removed.util_avg, removed_util); + swap(cfs_rq->removed.load_avg, removed_load); + swap(cfs_rq->removed.runnable_sum, removed_runnable_sum); + cfs_rq->removed.nr = 0; + raw_spin_unlock(&cfs_rq->removed.lock); + + r = removed_load; sub_positive(&sa->load_avg, r); - sub_positive(&sa->load_sum, r * LOAD_AVG_MAX); - removed_load = 1; - set_tg_cfs_propagate(cfs_rq); - } + sub_positive(&sa->load_sum, r * divider); - if (atomic_long_read(&cfs_rq->removed_util_avg)) { - long r = atomic_long_xchg(&cfs_rq->removed_util_avg, 0); + r = removed_util; sub_positive(&sa->util_avg, r); - sub_positive(&sa->util_sum, r * LOAD_AVG_MAX); - removed_util = 1; - set_tg_cfs_propagate(cfs_rq); + sub_positive(&sa->util_sum, r * divider); + + add_tg_cfs_propagate(cfs_rq, -(long)removed_runnable_sum); + + decayed = 1; } - decayed = __update_load_avg_cfs_rq(now, cpu_of(rq_of(cfs_rq)), cfs_rq); + decayed |= __update_load_avg_cfs_rq(now, cpu_of(rq_of(cfs_rq)), cfs_rq); #ifndef CONFIG_64BIT smp_wmb(); cfs_rq->load_last_update_time_copy = sa->last_update_time; #endif - if (decayed || removed_util) + if (decayed) cfs_rq_util_change(cfs_rq); - return decayed || removed_load; -} - -/* - * Optional action to be done while updating the load average - */ -#define UPDATE_TG 0x1 -#define SKIP_AGE_LOAD 0x2 - -/* Update task and its cfs_rq load average */ -static inline void update_load_avg(struct sched_entity *se, int flags) -{ - struct cfs_rq *cfs_rq = cfs_rq_of(se); - u64 now = cfs_rq_clock_task(cfs_rq); - struct rq *rq = rq_of(cfs_rq); - int cpu = cpu_of(rq); - int decayed; - - /* - * Track task load average for carrying it to new CPU after migrated, and - * track group sched_entity load average for task_h_load calc in migration - */ - if (se->avg.last_update_time && !(flags & SKIP_AGE_LOAD)) - __update_load_avg_se(now, cpu, cfs_rq, se); - - decayed = update_cfs_rq_load_avg(now, cfs_rq); - decayed |= propagate_entity_load_avg(se); - - if (decayed && (flags & UPDATE_TG)) - update_tg_load_avg(cfs_rq, 0); + return decayed; } /** @@ -3418,12 +3664,39 @@ static inline void update_load_avg(struct sched_entity *se, int flags) */ static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { + u32 divider = LOAD_AVG_MAX - 1024 + cfs_rq->avg.period_contrib; + + /* + * When we attach the @se to the @cfs_rq, we must align the decay + * window because without that, really weird and wonderful things can + * happen. + * + * XXX illustrate + */ se->avg.last_update_time = cfs_rq->avg.last_update_time; - cfs_rq->avg.load_avg += se->avg.load_avg; - cfs_rq->avg.load_sum += se->avg.load_sum; + se->avg.period_contrib = cfs_rq->avg.period_contrib; + + /* + * Hell(o) Nasty stuff.. we need to recompute _sum based on the new + * period_contrib. This isn't strictly correct, but since we're + * entirely outside of the PELT hierarchy, nobody cares if we truncate + * _sum a little. + */ + se->avg.util_sum = se->avg.util_avg * divider; + + se->avg.load_sum = divider; + if (se_weight(se)) { + se->avg.load_sum = + div_u64(se->avg.load_avg * se->avg.load_sum, se_weight(se)); + } + + se->avg.runnable_load_sum = se->avg.load_sum; + + enqueue_load_avg(cfs_rq, se); cfs_rq->avg.util_avg += se->avg.util_avg; cfs_rq->avg.util_sum += se->avg.util_sum; - set_tg_cfs_propagate(cfs_rq); + + add_tg_cfs_propagate(cfs_rq, se->avg.load_sum); cfs_rq_util_change(cfs_rq); } @@ -3438,39 +3711,47 @@ static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s */ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { - - sub_positive(&cfs_rq->avg.load_avg, se->avg.load_avg); - sub_positive(&cfs_rq->avg.load_sum, se->avg.load_sum); + dequeue_load_avg(cfs_rq, se); sub_positive(&cfs_rq->avg.util_avg, se->avg.util_avg); sub_positive(&cfs_rq->avg.util_sum, se->avg.util_sum); - set_tg_cfs_propagate(cfs_rq); + + add_tg_cfs_propagate(cfs_rq, -se->avg.load_sum); cfs_rq_util_change(cfs_rq); } -/* Add the load generated by se into cfs_rq's load average */ -static inline void -enqueue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) +/* + * Optional action to be done while updating the load average + */ +#define UPDATE_TG 0x1 +#define SKIP_AGE_LOAD 0x2 +#define DO_ATTACH 0x4 + +/* Update task and its cfs_rq load average */ +static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) { - struct sched_avg *sa = &se->avg; + u64 now = cfs_rq_clock_task(cfs_rq); + struct rq *rq = rq_of(cfs_rq); + int cpu = cpu_of(rq); + int decayed; - cfs_rq->runnable_load_avg += sa->load_avg; - cfs_rq->runnable_load_sum += sa->load_sum; + /* + * Track task load average for carrying it to new CPU after migrated, and + * track group sched_entity load average for task_h_load calc in migration + */ + if (se->avg.last_update_time && !(flags & SKIP_AGE_LOAD)) + __update_load_avg_se(now, cpu, cfs_rq, se); + + decayed = update_cfs_rq_load_avg(now, cfs_rq); + decayed |= propagate_entity_load_avg(se); + + if (!se->avg.last_update_time && (flags & DO_ATTACH)) { - if (!sa->last_update_time) { attach_entity_load_avg(cfs_rq, se); update_tg_load_avg(cfs_rq, 0); - } -} -/* Remove the runnable load generated by se from cfs_rq's runnable load average */ -static inline void -dequeue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) -{ - cfs_rq->runnable_load_avg = - max_t(long, cfs_rq->runnable_load_avg - se->avg.load_avg, 0); - cfs_rq->runnable_load_sum = - max_t(s64, cfs_rq->runnable_load_sum - se->avg.load_sum, 0); + } else if (decayed && (flags & UPDATE_TG)) + update_tg_load_avg(cfs_rq, 0); } #ifndef CONFIG_64BIT @@ -3514,6 +3795,7 @@ void sync_entity_load_avg(struct sched_entity *se) void remove_entity_load_avg(struct sched_entity *se) { struct cfs_rq *cfs_rq = cfs_rq_of(se); + unsigned long flags; /* * tasks cannot exit without having gone through wake_up_new_task() -> @@ -3526,13 +3808,18 @@ void remove_entity_load_avg(struct sched_entity *se) */ sync_entity_load_avg(se); - atomic_long_add(se->avg.load_avg, &cfs_rq->removed_load_avg); - atomic_long_add(se->avg.util_avg, &cfs_rq->removed_util_avg); + + raw_spin_lock_irqsave(&cfs_rq->removed.lock, flags); + ++cfs_rq->removed.nr; + cfs_rq->removed.util_avg += se->avg.util_avg; + cfs_rq->removed.load_avg += se->avg.load_avg; + cfs_rq->removed.runnable_sum += se->avg.load_sum; /* == runnable_sum */ + raw_spin_unlock_irqrestore(&cfs_rq->removed.lock, flags); } static inline unsigned long cfs_rq_runnable_load_avg(struct cfs_rq *cfs_rq) { - return cfs_rq->runnable_load_avg; + return cfs_rq->avg.runnable_load_avg; } static inline unsigned long cfs_rq_load_avg(struct cfs_rq *cfs_rq) @@ -3552,16 +3839,13 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) #define UPDATE_TG 0x0 #define SKIP_AGE_LOAD 0x0 +#define DO_ATTACH 0x0 -static inline void update_load_avg(struct sched_entity *se, int not_used1) +static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int not_used1) { - cfs_rq_util_change(cfs_rq_of(se)); + cfs_rq_util_change(cfs_rq); } -static inline void -enqueue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {} -static inline void -dequeue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {} static inline void remove_entity_load_avg(struct sched_entity *se) {} static inline void @@ -3706,9 +3990,9 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) * its group cfs_rq * - Add its new weight to cfs_rq->load.weight */ - update_load_avg(se, UPDATE_TG); - enqueue_entity_load_avg(cfs_rq, se); - update_cfs_shares(se); + update_load_avg(cfs_rq, se, UPDATE_TG | DO_ATTACH); + update_cfs_group(se); + enqueue_runnable_load_avg(cfs_rq, se); account_entity_enqueue(cfs_rq, se); if (flags & ENQUEUE_WAKEUP) @@ -3790,8 +4074,8 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) * - For group entity, update its weight to reflect the new share * of its group cfs_rq. */ - update_load_avg(se, UPDATE_TG); - dequeue_entity_load_avg(cfs_rq, se); + update_load_avg(cfs_rq, se, UPDATE_TG); + dequeue_runnable_load_avg(cfs_rq, se); update_stats_dequeue(cfs_rq, se, flags); @@ -3814,7 +4098,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) /* return excess runtime on last dequeue */ return_cfs_rq_runtime(cfs_rq); - update_cfs_shares(se); + update_cfs_group(se); /* * Now advance min_vruntime if @se was the entity holding it back, @@ -3878,7 +4162,7 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) */ update_stats_wait_end(cfs_rq, se); __dequeue_entity(cfs_rq, se); - update_load_avg(se, UPDATE_TG); + update_load_avg(cfs_rq, se, UPDATE_TG); } update_stats_curr_start(cfs_rq, se); @@ -3980,7 +4264,7 @@ static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev) /* Put 'current' back into the tree. */ __enqueue_entity(cfs_rq, prev); /* in !on_rq case, update occurred at dequeue */ - update_load_avg(prev, 0); + update_load_avg(cfs_rq, prev, 0); } cfs_rq->curr = NULL; } @@ -3996,8 +4280,8 @@ entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued) /* * Ensure that runnable average is periodically updated. */ - update_load_avg(curr, UPDATE_TG); - update_cfs_shares(curr); + update_load_avg(cfs_rq, curr, UPDATE_TG); + update_cfs_group(curr); #ifdef CONFIG_SCHED_HRTICK /* @@ -4914,8 +5198,8 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) if (cfs_rq_throttled(cfs_rq)) break; - update_load_avg(se, UPDATE_TG); - update_cfs_shares(se); + update_load_avg(cfs_rq, se, UPDATE_TG); + update_cfs_group(se); } if (!se) @@ -4973,8 +5257,8 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) if (cfs_rq_throttled(cfs_rq)) break; - update_load_avg(se, UPDATE_TG); - update_cfs_shares(se); + update_load_avg(cfs_rq, se, UPDATE_TG); + update_cfs_group(se); } if (!se) @@ -5356,91 +5640,62 @@ static int wake_wide(struct task_struct *p) return 1; } -struct llc_stats { - unsigned long nr_running; - unsigned long load; - unsigned long capacity; - int has_capacity; -}; +/* + * The purpose of wake_affine() is to quickly determine on which CPU we can run + * soonest. For the purpose of speed we only consider the waking and previous + * CPU. + * + * wake_affine_idle() - only considers 'now', it check if the waking CPU is (or + * will be) idle. + * + * wake_affine_weight() - considers the weight to reflect the average + * scheduling latency of the CPUs. This seems to work + * for the overloaded case. + */ -static bool get_llc_stats(struct llc_stats *stats, int cpu) +static bool +wake_affine_idle(struct sched_domain *sd, struct task_struct *p, + int this_cpu, int prev_cpu, int sync) { - struct sched_domain_shared *sds = rcu_dereference(per_cpu(sd_llc_shared, cpu)); - - if (!sds) - return false; + if (idle_cpu(this_cpu)) + return true; - stats->nr_running = READ_ONCE(sds->nr_running); - stats->load = READ_ONCE(sds->load); - stats->capacity = READ_ONCE(sds->capacity); - stats->has_capacity = stats->nr_running < per_cpu(sd_llc_size, cpu); + if (sync && cpu_rq(this_cpu)->nr_running == 1) + return true; - return true; + return false; } -/* - * Can a task be moved from prev_cpu to this_cpu without causing a load - * imbalance that would trigger the load balancer? - * - * Since we're running on 'stale' values, we might in fact create an imbalance - * but recomputing these values is expensive, as that'd mean iteration 2 cache - * domains worth of CPUs. - */ static bool -wake_affine_llc(struct sched_domain *sd, struct task_struct *p, - int this_cpu, int prev_cpu, int sync) +wake_affine_weight(struct sched_domain *sd, struct task_struct *p, + int this_cpu, int prev_cpu, int sync) { - struct llc_stats prev_stats, this_stats; s64 this_eff_load, prev_eff_load; unsigned long task_load; - if (!get_llc_stats(&prev_stats, prev_cpu) || - !get_llc_stats(&this_stats, this_cpu)) - return false; + this_eff_load = target_load(this_cpu, sd->wake_idx); + prev_eff_load = source_load(prev_cpu, sd->wake_idx); - /* - * If sync wakeup then subtract the (maximum possible) - * effect of the currently running task from the load - * of the current LLC. - */ if (sync) { unsigned long current_load = task_h_load(current); - /* in this case load hits 0 and this LLC is considered 'idle' */ - if (current_load > this_stats.load) + if (current_load > this_eff_load) return true; - this_stats.load -= current_load; + this_eff_load -= current_load; } - /* - * The has_capacity stuff is not SMT aware, but by trying to balance - * the nr_running on both ends we try and fill the domain at equal - * rates, thereby first consuming cores before siblings. - */ - - /* if the old cache has capacity, stay there */ - if (prev_stats.has_capacity && prev_stats.nr_running < this_stats.nr_running+1) - return false; - - /* if this cache has capacity, come here */ - if (this_stats.has_capacity && this_stats.nr_running+1 < prev_stats.nr_running) - return true; - - /* - * Check to see if we can move the load without causing too much - * imbalance. - */ task_load = task_h_load(p); - this_eff_load = 100; - this_eff_load *= prev_stats.capacity; - - prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2; - prev_eff_load *= this_stats.capacity; + this_eff_load += task_load; + if (sched_feat(WA_BIAS)) + this_eff_load *= 100; + this_eff_load *= capacity_of(prev_cpu); - this_eff_load *= this_stats.load + task_load; - prev_eff_load *= prev_stats.load - task_load; + prev_eff_load -= task_load; + if (sched_feat(WA_BIAS)) + prev_eff_load *= 100 + (sd->imbalance_pct - 100) / 2; + prev_eff_load *= capacity_of(this_cpu); return this_eff_load <= prev_eff_load; } @@ -5449,22 +5704,13 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int prev_cpu, int sync) { int this_cpu = smp_processor_id(); - bool affine; + bool affine = false; - /* - * Default to no affine wakeups; wake_affine() should not effect a task - * placement the load-balancer feels inclined to undo. The conservative - * option is therefore to not move tasks when they wake up. - */ - affine = false; + if (sched_feat(WA_IDLE) && !affine) + affine = wake_affine_idle(sd, p, this_cpu, prev_cpu, sync); - /* - * If the wakeup is across cache domains, try to evaluate if movement - * makes sense, otherwise rely on select_idle_siblings() to do - * placement inside the cache domain. - */ - if (!cpus_share_cache(prev_cpu, this_cpu)) - affine = wake_affine_llc(sd, p, this_cpu, prev_cpu, sync); + if (sched_feat(WA_WEIGHT) && !affine) + affine = wake_affine_weight(sd, p, this_cpu, prev_cpu, sync); schedstat_inc(p->se.statistics.nr_wakeups_affine_attempts); if (affine) { @@ -5486,6 +5732,8 @@ static unsigned long capacity_spare_wake(int cpu, struct task_struct *p) /* * find_idlest_group finds and returns the least busy CPU group within the * domain. + * + * Assumes p is allowed on at least one CPU in sd. */ static struct sched_group * find_idlest_group(struct sched_domain *sd, struct task_struct *p, @@ -5493,8 +5741,9 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, { struct sched_group *idlest = NULL, *group = sd->groups; struct sched_group *most_spare_sg = NULL; - unsigned long min_runnable_load = ULONG_MAX, this_runnable_load = 0; - unsigned long min_avg_load = ULONG_MAX, this_avg_load = 0; + unsigned long min_runnable_load = ULONG_MAX; + unsigned long this_runnable_load = ULONG_MAX; + unsigned long min_avg_load = ULONG_MAX, this_avg_load = ULONG_MAX; unsigned long most_spare = 0, this_spare = 0; int load_idx = sd->forkexec_idx; int imbalance_scale = 100 + (sd->imbalance_pct-100)/2; @@ -5615,10 +5864,10 @@ skip_spare: } /* - * find_idlest_cpu - find the idlest cpu among the cpus in group. + * find_idlest_group_cpu - find the idlest cpu among the cpus in group. */ static int -find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) +find_idlest_group_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) { unsigned long load, min_load = ULONG_MAX; unsigned int min_exit_latency = UINT_MAX; @@ -5667,6 +5916,53 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) return shallowest_idle_cpu != -1 ? shallowest_idle_cpu : least_loaded_cpu; } +static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p, + int cpu, int prev_cpu, int sd_flag) +{ + int new_cpu = cpu; + + if (!cpumask_intersects(sched_domain_span(sd), &p->cpus_allowed)) + return prev_cpu; + + while (sd) { + struct sched_group *group; + struct sched_domain *tmp; + int weight; + + if (!(sd->flags & sd_flag)) { + sd = sd->child; + continue; + } + + group = find_idlest_group(sd, p, cpu, sd_flag); + if (!group) { + sd = sd->child; + continue; + } + + new_cpu = find_idlest_group_cpu(group, p, cpu); + if (new_cpu == cpu) { + /* Now try balancing at a lower domain level of cpu */ + sd = sd->child; + continue; + } + + /* Now try balancing at a lower domain level of new_cpu */ + cpu = new_cpu; + weight = sd->span_weight; + sd = NULL; + for_each_domain(cpu, tmp) { + if (weight <= tmp->span_weight) + break; + if (tmp->flags & sd_flag) + sd = tmp; + } + /* while loop will break here if sd == NULL */ + } + + return new_cpu; +} + #ifdef CONFIG_SCHED_SMT static inline void set_idle_cores(int cpu, int val) @@ -6019,50 +6315,30 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f new_cpu = cpu; } + if (sd && !(sd_flag & SD_BALANCE_FORK)) { + /* + * We're going to need the task's util for capacity_spare_wake + * in find_idlest_group. Sync it up to prev_cpu's + * last_update_time. + */ + sync_entity_load_avg(&p->se); + } + if (!sd) { - pick_cpu: +pick_cpu: if (sd_flag & SD_BALANCE_WAKE) /* XXX always ? */ new_cpu = select_idle_sibling(p, prev_cpu, new_cpu); - } else while (sd) { - struct sched_group *group; - int weight; - - if (!(sd->flags & sd_flag)) { - sd = sd->child; - continue; - } - - group = find_idlest_group(sd, p, cpu, sd_flag); - if (!group) { - sd = sd->child; - continue; - } - - new_cpu = find_idlest_cpu(group, p, cpu); - if (new_cpu == -1 || new_cpu == cpu) { - /* Now try balancing at a lower domain level of cpu */ - sd = sd->child; - continue; - } - - /* Now try balancing at a lower domain level of new_cpu */ - cpu = new_cpu; - weight = sd->span_weight; - sd = NULL; - for_each_domain(cpu, tmp) { - if (weight <= tmp->span_weight) - break; - if (tmp->flags & sd_flag) - sd = tmp; - } - /* while loop will break here if sd == NULL */ + } else { + new_cpu = find_idlest_cpu(sd, p, cpu, prev_cpu, sd_flag); } rcu_read_unlock(); return new_cpu; } +static void detach_entity_cfs_rq(struct sched_entity *se); + /* * Called immediately before a task is migrated to a new cpu; task_cpu(p) and * cfs_rq_of(p) references at time of call are still valid and identify the @@ -6096,14 +6372,25 @@ static void migrate_task_rq_fair(struct task_struct *p) se->vruntime -= min_vruntime; } - /* - * We are supposed to update the task to "current" time, then its up to date - * and ready to go to new CPU/cfs_rq. But we have difficulty in getting - * what current time is, so simply throw away the out-of-date time. This - * will result in the wakee task is less decayed, but giving the wakee more - * load sounds not bad. - */ - remove_entity_load_avg(&p->se); + if (p->on_rq == TASK_ON_RQ_MIGRATING) { + /* + * In case of TASK_ON_RQ_MIGRATING we in fact hold the 'old' + * rq->lock and can modify state directly. + */ + lockdep_assert_held(&task_rq(p)->lock); + detach_entity_cfs_rq(&p->se); + + } else { + /* + * We are supposed to update the task to "current" time, then + * its up to date and ready to go to new CPU/cfs_rq. But we + * have difficulty in getting what current time is, so simply + * throw away the out-of-date time. This will result in the + * wakee task is less decayed, but giving the wakee more load + * sounds not bad. + */ + remove_entity_load_avg(&p->se); + } /* Tell new CPU we are migrated */ p->se.avg.last_update_time = 0; @@ -6371,10 +6658,7 @@ again: set_next_entity(cfs_rq, se); } - if (hrtick_enabled(rq)) - hrtick_start_fair(rq, p); - - return p; + goto done; simple: #endif @@ -6388,6 +6672,16 @@ simple: p = task_of(se); +done: __maybe_unused +#ifdef CONFIG_SMP + /* + * Move the next running task to the front of + * the list, so our cfs_tasks list becomes MRU + * one. + */ + list_move(&p->se.group_node, &rq->cfs_tasks); +#endif + if (hrtick_enabled(rq)) hrtick_start_fair(rq, p); @@ -6823,11 +7117,12 @@ static void detach_task(struct task_struct *p, struct lb_env *env) */ static struct task_struct *detach_one_task(struct lb_env *env) { - struct task_struct *p, *n; + struct task_struct *p; lockdep_assert_held(&env->src_rq->lock); - list_for_each_entry_safe(p, n, &env->src_rq->cfs_tasks, se.group_node) { + list_for_each_entry_reverse(p, + &env->src_rq->cfs_tasks, se.group_node) { if (!can_migrate_task(p, env)) continue; @@ -6873,7 +7168,7 @@ static int detach_tasks(struct lb_env *env) if (env->idle != CPU_NOT_IDLE && env->src_rq->nr_running <= 1) break; - p = list_first_entry(tasks, struct task_struct, se.group_node); + p = list_last_entry(tasks, struct task_struct, se.group_node); env->loop++; /* We've more or less seen every task there is, call it quits */ @@ -6923,7 +7218,7 @@ static int detach_tasks(struct lb_env *env) continue; next: - list_move_tail(&p->se.group_node, tasks); + list_move(&p->se.group_node, tasks); } /* @@ -6999,7 +7294,7 @@ static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq) if (cfs_rq->avg.util_sum) return false; - if (cfs_rq->runnable_load_sum) + if (cfs_rq->avg.runnable_load_sum) return false; return true; @@ -7031,7 +7326,7 @@ static void update_blocked_averages(int cpu) /* Propagate pending load changes to the parent, if any: */ se = cfs_rq->tg->se[cpu]; if (se && !skip_blocked_update(se)) - update_load_avg(se, 0); + update_load_avg(cfs_rq_of(se), se, 0); /* * There can be a lot of idle CPU cgroups. Don't let fully @@ -7600,7 +7895,6 @@ static inline enum fbq_type fbq_classify_rq(struct rq *rq) */ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sds) { - struct sched_domain_shared *shared = env->sd->shared; struct sched_domain *child = env->sd->child; struct sched_group *sg = env->sd->groups; struct sg_lb_stats *local = &sds->local_stat; @@ -7672,22 +7966,6 @@ next_group: if (env->dst_rq->rd->overload != overload) env->dst_rq->rd->overload = overload; } - - if (!shared) - return; - - /* - * Since these are sums over groups they can contain some CPUs - * multiple times for the NUMA domains. - * - * Currently only wake_affine_llc() and find_busiest_group() - * uses these numbers, only the last is affected by this problem. - * - * XXX fix that. - */ - WRITE_ONCE(shared->nr_running, sds->total_running); - WRITE_ONCE(shared->load, sds->total_load); - WRITE_ONCE(shared->capacity, sds->total_capacity); } /** @@ -7929,8 +8207,11 @@ static struct sched_group *find_busiest_group(struct lb_env *env) if (busiest->group_type == group_imbalanced) goto force_balance; - /* SD_BALANCE_NEWIDLE trumps SMP nice when underutilized */ - if (env->idle == CPU_NEWLY_IDLE && group_has_capacity(env, local) && + /* + * When dst_cpu is idle, prevent SMP nice and/or asymmetric group + * capacities from resulting in underutilization due to avg_load. + */ + if (env->idle != CPU_NOT_IDLE && group_has_capacity(env, local) && busiest->group_no_capacity) goto force_balance; @@ -8098,6 +8379,13 @@ static int should_we_balance(struct lb_env *env) int cpu, balance_cpu = -1; /* + * Ensure the balancing environment is consistent; can happen + * when the softirq triggers 'during' hotplug. + */ + if (!cpumask_test_cpu(env->dst_cpu, env->cpus)) + return 0; + + /* * In the newly idle case, we will allow all the cpu's * to do the newly idle load balance. */ @@ -8740,7 +9028,7 @@ void nohz_balance_enter_idle(int cpu) return; /* Spare idle load balancing on CPUs that don't want to be disturbed: */ - if (!is_housekeeping_cpu(cpu)) + if (!housekeeping_cpu(cpu, HK_FLAG_SCHED)) return; if (test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu))) @@ -9205,7 +9493,7 @@ static void propagate_entity_cfs_rq(struct sched_entity *se) if (cfs_rq_throttled(cfs_rq)) break; - update_load_avg(se, UPDATE_TG); + update_load_avg(cfs_rq, se, UPDATE_TG); } } #else @@ -9217,7 +9505,7 @@ static void detach_entity_cfs_rq(struct sched_entity *se) struct cfs_rq *cfs_rq = cfs_rq_of(se); /* Catch up with the cfs_rq and remove our load when we leave */ - update_load_avg(se, 0); + update_load_avg(cfs_rq, se, 0); detach_entity_load_avg(cfs_rq, se); update_tg_load_avg(cfs_rq, false); propagate_entity_cfs_rq(se); @@ -9236,7 +9524,7 @@ static void attach_entity_cfs_rq(struct sched_entity *se) #endif /* Synchronize entity with its cfs_rq */ - update_load_avg(se, sched_feat(ATTACH_AGE_LOAD) ? 0 : SKIP_AGE_LOAD); + update_load_avg(cfs_rq, se, sched_feat(ATTACH_AGE_LOAD) ? 0 : SKIP_AGE_LOAD); attach_entity_load_avg(cfs_rq, se); update_tg_load_avg(cfs_rq, false); propagate_entity_cfs_rq(se); @@ -9318,11 +9606,7 @@ void init_cfs_rq(struct cfs_rq *cfs_rq) cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime; #endif #ifdef CONFIG_SMP -#ifdef CONFIG_FAIR_GROUP_SCHED - cfs_rq->propagate_avg = 0; -#endif - atomic_long_set(&cfs_rq->removed_load_avg, 0); - atomic_long_set(&cfs_rq->removed_util_avg, 0); + raw_spin_lock_init(&cfs_rq->removed.lock); #endif } @@ -9520,8 +9804,8 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares) rq_lock_irqsave(rq, &rf); update_rq_clock(rq); for_each_sched_entity(se) { - update_load_avg(se, UPDATE_TG); - update_cfs_shares(se); + update_load_avg(cfs_rq_of(se), se, UPDATE_TG); + update_cfs_group(se); } rq_unlock_irqrestore(rq, &rf); } diff --git a/kernel/sched/features.h b/kernel/sched/features.h index d3fb15555291..9552fd5854bf 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ /* * Only give sleepers 50% of their service deficit. This allows * them to run sooner, but does not allow tons of sleepers to @@ -81,3 +82,6 @@ SCHED_FEAT(RT_RUNTIME_SHARE, true) SCHED_FEAT(LB_MIN, false) SCHED_FEAT(ATTACH_AGE_LOAD, true) +SCHED_FEAT(WA_IDLE, true) +SCHED_FEAT(WA_WEIGHT, true) +SCHED_FEAT(WA_BIAS, true) diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index 257f4f0b4532..7dae9eb8c042 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -209,6 +209,7 @@ exit_idle: */ static void do_idle(void) { + int cpu = smp_processor_id(); /* * If the arch has a polling bit, we maintain an invariant: * @@ -219,14 +220,13 @@ static void do_idle(void) */ __current_set_polling(); - quiet_vmstat(); tick_nohz_idle_enter(); while (!need_resched()) { check_pgt_cache(); rmb(); - if (cpu_is_offline(smp_processor_id())) { + if (cpu_is_offline(cpu)) { cpuhp_report_idle_dead(); arch_cpu_idle_dead(); } diff --git a/kernel/sched/idle_task.c b/kernel/sched/idle_task.c index 0c00172db63e..d518664cce4f 100644 --- a/kernel/sched/idle_task.c +++ b/kernel/sched/idle_task.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 #include "sched.h" /* diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c new file mode 100644 index 000000000000..b71b436f59f2 --- /dev/null +++ b/kernel/sched/isolation.c @@ -0,0 +1,155 @@ +/* + * Housekeeping management. Manage the targets for routine code that can run on + * any CPU: unbound workqueues, timers, kthreads and any offloadable work. + * + * Copyright (C) 2017 Red Hat, Inc., Frederic Weisbecker + * + */ + +#include <linux/sched/isolation.h> +#include <linux/tick.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/static_key.h> +#include <linux/ctype.h> + +DEFINE_STATIC_KEY_FALSE(housekeeping_overriden); +EXPORT_SYMBOL_GPL(housekeeping_overriden); +static cpumask_var_t housekeeping_mask; +static unsigned int housekeeping_flags; + +int housekeeping_any_cpu(enum hk_flags flags) +{ + if (static_branch_unlikely(&housekeeping_overriden)) + if (housekeeping_flags & flags) + return cpumask_any_and(housekeeping_mask, cpu_online_mask); + return smp_processor_id(); +} +EXPORT_SYMBOL_GPL(housekeeping_any_cpu); + +const struct cpumask *housekeeping_cpumask(enum hk_flags flags) +{ + if (static_branch_unlikely(&housekeeping_overriden)) + if (housekeeping_flags & flags) + return housekeeping_mask; + return cpu_possible_mask; +} +EXPORT_SYMBOL_GPL(housekeeping_cpumask); + +void housekeeping_affine(struct task_struct *t, enum hk_flags flags) +{ + if (static_branch_unlikely(&housekeeping_overriden)) + if (housekeeping_flags & flags) + set_cpus_allowed_ptr(t, housekeeping_mask); +} +EXPORT_SYMBOL_GPL(housekeeping_affine); + +bool housekeeping_test_cpu(int cpu, enum hk_flags flags) +{ + if (static_branch_unlikely(&housekeeping_overriden)) + if (housekeeping_flags & flags) + return cpumask_test_cpu(cpu, housekeeping_mask); + return true; +} +EXPORT_SYMBOL_GPL(housekeeping_test_cpu); + +void __init housekeeping_init(void) +{ + if (!housekeeping_flags) + return; + + static_branch_enable(&housekeeping_overriden); + + /* We need at least one CPU to handle housekeeping work */ + WARN_ON_ONCE(cpumask_empty(housekeeping_mask)); +} + +static int __init housekeeping_setup(char *str, enum hk_flags flags) +{ + cpumask_var_t non_housekeeping_mask; + int err; + + alloc_bootmem_cpumask_var(&non_housekeeping_mask); + err = cpulist_parse(str, non_housekeeping_mask); + if (err < 0 || cpumask_last(non_housekeeping_mask) >= nr_cpu_ids) { + pr_warn("Housekeeping: nohz_full= or isolcpus= incorrect CPU range\n"); + free_bootmem_cpumask_var(non_housekeeping_mask); + return 0; + } + + if (!housekeeping_flags) { + alloc_bootmem_cpumask_var(&housekeeping_mask); + cpumask_andnot(housekeeping_mask, + cpu_possible_mask, non_housekeeping_mask); + if (cpumask_empty(housekeeping_mask)) + cpumask_set_cpu(smp_processor_id(), housekeeping_mask); + } else { + cpumask_var_t tmp; + + alloc_bootmem_cpumask_var(&tmp); + cpumask_andnot(tmp, cpu_possible_mask, non_housekeeping_mask); + if (!cpumask_equal(tmp, housekeeping_mask)) { + pr_warn("Housekeeping: nohz_full= must match isolcpus=\n"); + free_bootmem_cpumask_var(tmp); + free_bootmem_cpumask_var(non_housekeeping_mask); + return 0; + } + free_bootmem_cpumask_var(tmp); + } + + if ((flags & HK_FLAG_TICK) && !(housekeeping_flags & HK_FLAG_TICK)) { + if (IS_ENABLED(CONFIG_NO_HZ_FULL)) { + tick_nohz_full_setup(non_housekeeping_mask); + } else { + pr_warn("Housekeeping: nohz unsupported." + " Build with CONFIG_NO_HZ_FULL\n"); + free_bootmem_cpumask_var(non_housekeeping_mask); + return 0; + } + } + + housekeeping_flags |= flags; + + free_bootmem_cpumask_var(non_housekeeping_mask); + + return 1; +} + +static int __init housekeeping_nohz_full_setup(char *str) +{ + unsigned int flags; + + flags = HK_FLAG_TICK | HK_FLAG_TIMER | HK_FLAG_RCU | HK_FLAG_MISC; + + return housekeeping_setup(str, flags); +} +__setup("nohz_full=", housekeeping_nohz_full_setup); + +static int __init housekeeping_isolcpus_setup(char *str) +{ + unsigned int flags = 0; + + while (isalpha(*str)) { + if (!strncmp(str, "nohz,", 5)) { + str += 5; + flags |= HK_FLAG_TICK; + continue; + } + + if (!strncmp(str, "domain,", 7)) { + str += 7; + flags |= HK_FLAG_DOMAIN; + continue; + } + + pr_warn("isolcpus: Error, unknown flag\n"); + return 0; + } + + /* Default behaviour for isolcpus without flags */ + if (!flags) + flags |= HK_FLAG_DOMAIN; + + return housekeeping_setup(str, flags); +} +__setup("isolcpus=", housekeeping_isolcpus_setup); diff --git a/kernel/sched/loadavg.c b/kernel/sched/loadavg.c index f14716a3522f..89a989e4d758 100644 --- a/kernel/sched/loadavg.c +++ b/kernel/sched/loadavg.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 /* * kernel/sched/loadavg.c * diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c index a92fddc22747..dd7908743dab 100644 --- a/kernel/sched/membarrier.c +++ b/kernel/sched/membarrier.c @@ -18,6 +18,7 @@ #include <linux/membarrier.h> #include <linux/tick.h> #include <linux/cpumask.h> +#include <linux/atomic.h> #include "sched.h" /* for cpu_rq(). */ @@ -26,21 +27,26 @@ * except MEMBARRIER_CMD_QUERY. */ #define MEMBARRIER_CMD_BITMASK \ - (MEMBARRIER_CMD_SHARED | MEMBARRIER_CMD_PRIVATE_EXPEDITED) + (MEMBARRIER_CMD_SHARED | MEMBARRIER_CMD_PRIVATE_EXPEDITED \ + | MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED) static void ipi_mb(void *info) { smp_mb(); /* IPIs should be serializing but paranoid. */ } -static void membarrier_private_expedited(void) +static int membarrier_private_expedited(void) { int cpu; bool fallback = false; cpumask_var_t tmpmask; + if (!(atomic_read(¤t->mm->membarrier_state) + & MEMBARRIER_STATE_PRIVATE_EXPEDITED_READY)) + return -EPERM; + if (num_online_cpus() == 1) - return; + return 0; /* * Matches memory barriers around rq->curr modification in @@ -94,6 +100,24 @@ static void membarrier_private_expedited(void) * rq->curr modification in scheduler. */ smp_mb(); /* exit from system call is not a mb */ + return 0; +} + +static void membarrier_register_private_expedited(void) +{ + struct task_struct *p = current; + struct mm_struct *mm = p->mm; + + /* + * We need to consider threads belonging to different thread + * groups, which use the same mm. (CLONE_VM but not + * CLONE_THREAD). + */ + if (atomic_read(&mm->membarrier_state) + & MEMBARRIER_STATE_PRIVATE_EXPEDITED_READY) + return; + atomic_or(MEMBARRIER_STATE_PRIVATE_EXPEDITED_READY, + &mm->membarrier_state); } /** @@ -144,7 +168,9 @@ SYSCALL_DEFINE2(membarrier, int, cmd, int, flags) synchronize_sched(); return 0; case MEMBARRIER_CMD_PRIVATE_EXPEDITED: - membarrier_private_expedited(); + return membarrier_private_expedited(); + case MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED: + membarrier_register_private_expedited(); return 0; default: return -EINVAL; diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 0af5ca9e3e3f..4056c19ca3f0 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 /* * Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR * policies) @@ -73,10 +74,6 @@ static void start_rt_bandwidth(struct rt_bandwidth *rt_b) raw_spin_unlock(&rt_b->rt_runtime_lock); } -#if defined(CONFIG_SMP) && defined(HAVE_RT_PUSH_IPI) -static void push_irq_work_func(struct irq_work *work); -#endif - void init_rt_rq(struct rt_rq *rt_rq) { struct rt_prio_array *array; @@ -96,13 +93,6 @@ void init_rt_rq(struct rt_rq *rt_rq) rt_rq->rt_nr_migratory = 0; rt_rq->overloaded = 0; plist_head_init(&rt_rq->pushable_tasks); - -#ifdef HAVE_RT_PUSH_IPI - rt_rq->push_flags = 0; - rt_rq->push_cpu = nr_cpu_ids; - raw_spin_lock_init(&rt_rq->push_lock); - init_irq_work(&rt_rq->push_work, push_irq_work_func); -#endif #endif /* CONFIG_SMP */ /* We start is dequeued state, because no RT tasks are queued */ rt_rq->rt_queued = 0; @@ -979,7 +969,7 @@ static void update_curr_rt(struct rq *rq) account_group_exec_runtime(curr, delta_exec); curr->se.exec_start = rq_clock_task(rq); - cpuacct_charge(curr, delta_exec); + cgroup_account_cputime(curr, delta_exec); sched_rt_avg_update(rq, delta_exec); @@ -1875,241 +1865,166 @@ static void push_rt_tasks(struct rq *rq) } #ifdef HAVE_RT_PUSH_IPI + /* - * The search for the next cpu always starts at rq->cpu and ends - * when we reach rq->cpu again. It will never return rq->cpu. - * This returns the next cpu to check, or nr_cpu_ids if the loop - * is complete. + * When a high priority task schedules out from a CPU and a lower priority + * task is scheduled in, a check is made to see if there's any RT tasks + * on other CPUs that are waiting to run because a higher priority RT task + * is currently running on its CPU. In this case, the CPU with multiple RT + * tasks queued on it (overloaded) needs to be notified that a CPU has opened + * up that may be able to run one of its non-running queued RT tasks. + * + * All CPUs with overloaded RT tasks need to be notified as there is currently + * no way to know which of these CPUs have the highest priority task waiting + * to run. Instead of trying to take a spinlock on each of these CPUs, + * which has shown to cause large latency when done on machines with many + * CPUs, sending an IPI to the CPUs to have them push off the overloaded + * RT tasks waiting to run. + * + * Just sending an IPI to each of the CPUs is also an issue, as on large + * count CPU machines, this can cause an IPI storm on a CPU, especially + * if its the only CPU with multiple RT tasks queued, and a large number + * of CPUs scheduling a lower priority task at the same time. + * + * Each root domain has its own irq work function that can iterate over + * all CPUs with RT overloaded tasks. Since all CPUs with overloaded RT + * tassk must be checked if there's one or many CPUs that are lowering + * their priority, there's a single irq work iterator that will try to + * push off RT tasks that are waiting to run. + * + * When a CPU schedules a lower priority task, it will kick off the + * irq work iterator that will jump to each CPU with overloaded RT tasks. + * As it only takes the first CPU that schedules a lower priority task + * to start the process, the rto_start variable is incremented and if + * the atomic result is one, then that CPU will try to take the rto_lock. + * This prevents high contention on the lock as the process handles all + * CPUs scheduling lower priority tasks. + * + * All CPUs that are scheduling a lower priority task will increment the + * rt_loop_next variable. This will make sure that the irq work iterator + * checks all RT overloaded CPUs whenever a CPU schedules a new lower + * priority task, even if the iterator is in the middle of a scan. Incrementing + * the rt_loop_next will cause the iterator to perform another scan. * - * rq->rt.push_cpu holds the last cpu returned by this function, - * or if this is the first instance, it must hold rq->cpu. */ static int rto_next_cpu(struct rq *rq) { - int prev_cpu = rq->rt.push_cpu; + struct root_domain *rd = rq->rd; + int next; int cpu; - cpu = cpumask_next(prev_cpu, rq->rd->rto_mask); - /* - * If the previous cpu is less than the rq's CPU, then it already - * passed the end of the mask, and has started from the beginning. - * We end if the next CPU is greater or equal to rq's CPU. + * When starting the IPI RT pushing, the rto_cpu is set to -1, + * rt_next_cpu() will simply return the first CPU found in + * the rto_mask. + * + * If rto_next_cpu() is called with rto_cpu is a valid cpu, it + * will return the next CPU found in the rto_mask. + * + * If there are no more CPUs left in the rto_mask, then a check is made + * against rto_loop and rto_loop_next. rto_loop is only updated with + * the rto_lock held, but any CPU may increment the rto_loop_next + * without any locking. */ - if (prev_cpu < rq->cpu) { - if (cpu >= rq->cpu) - return nr_cpu_ids; + for (;;) { - } else if (cpu >= nr_cpu_ids) { - /* - * We passed the end of the mask, start at the beginning. - * If the result is greater or equal to the rq's CPU, then - * the loop is finished. - */ - cpu = cpumask_first(rq->rd->rto_mask); - if (cpu >= rq->cpu) - return nr_cpu_ids; - } - rq->rt.push_cpu = cpu; + /* When rto_cpu is -1 this acts like cpumask_first() */ + cpu = cpumask_next(rd->rto_cpu, rd->rto_mask); - /* Return cpu to let the caller know if the loop is finished or not */ - return cpu; -} + rd->rto_cpu = cpu; -static int find_next_push_cpu(struct rq *rq) -{ - struct rq *next_rq; - int cpu; + if (cpu < nr_cpu_ids) + return cpu; - while (1) { - cpu = rto_next_cpu(rq); - if (cpu >= nr_cpu_ids) - break; - next_rq = cpu_rq(cpu); + rd->rto_cpu = -1; + + /* + * ACQUIRE ensures we see the @rto_mask changes + * made prior to the @next value observed. + * + * Matches WMB in rt_set_overload(). + */ + next = atomic_read_acquire(&rd->rto_loop_next); - /* Make sure the next rq can push to this rq */ - if (next_rq->rt.highest_prio.next < rq->rt.highest_prio.curr) + if (rd->rto_loop == next) break; + + rd->rto_loop = next; } - return cpu; + return -1; } -#define RT_PUSH_IPI_EXECUTING 1 -#define RT_PUSH_IPI_RESTART 2 +static inline bool rto_start_trylock(atomic_t *v) +{ + return !atomic_cmpxchg_acquire(v, 0, 1); +} -/* - * When a high priority task schedules out from a CPU and a lower priority - * task is scheduled in, a check is made to see if there's any RT tasks - * on other CPUs that are waiting to run because a higher priority RT task - * is currently running on its CPU. In this case, the CPU with multiple RT - * tasks queued on it (overloaded) needs to be notified that a CPU has opened - * up that may be able to run one of its non-running queued RT tasks. - * - * On large CPU boxes, there's the case that several CPUs could schedule - * a lower priority task at the same time, in which case it will look for - * any overloaded CPUs that it could pull a task from. To do this, the runqueue - * lock must be taken from that overloaded CPU. Having 10s of CPUs all fighting - * for a single overloaded CPU's runqueue lock can produce a large latency. - * (This has actually been observed on large boxes running cyclictest). - * Instead of taking the runqueue lock of the overloaded CPU, each of the - * CPUs that scheduled a lower priority task simply sends an IPI to the - * overloaded CPU. An IPI is much cheaper than taking an runqueue lock with - * lots of contention. The overloaded CPU will look to push its non-running - * RT task off, and if it does, it can then ignore the other IPIs coming - * in, and just pass those IPIs off to any other overloaded CPU. - * - * When a CPU schedules a lower priority task, it only sends an IPI to - * the "next" CPU that has overloaded RT tasks. This prevents IPI storms, - * as having 10 CPUs scheduling lower priority tasks and 10 CPUs with - * RT overloaded tasks, would cause 100 IPIs to go out at once. - * - * The overloaded RT CPU, when receiving an IPI, will try to push off its - * overloaded RT tasks and then send an IPI to the next CPU that has - * overloaded RT tasks. This stops when all CPUs with overloaded RT tasks - * have completed. Just because a CPU may have pushed off its own overloaded - * RT task does not mean it should stop sending the IPI around to other - * overloaded CPUs. There may be another RT task waiting to run on one of - * those CPUs that are of higher priority than the one that was just - * pushed. - * - * An optimization that could possibly be made is to make a CPU array similar - * to the cpupri array mask of all running RT tasks, but for the overloaded - * case, then the IPI could be sent to only the CPU with the highest priority - * RT task waiting, and that CPU could send off further IPIs to the CPU with - * the next highest waiting task. Since the overloaded case is much less likely - * to happen, the complexity of this implementation may not be worth it. - * Instead, just send an IPI around to all overloaded CPUs. - * - * The rq->rt.push_flags holds the status of the IPI that is going around. - * A run queue can only send out a single IPI at a time. The possible flags - * for rq->rt.push_flags are: - * - * (None or zero): No IPI is going around for the current rq - * RT_PUSH_IPI_EXECUTING: An IPI for the rq is being passed around - * RT_PUSH_IPI_RESTART: The priority of the running task for the rq - * has changed, and the IPI should restart - * circulating the overloaded CPUs again. - * - * rq->rt.push_cpu contains the CPU that is being sent the IPI. It is updated - * before sending to the next CPU. - * - * Instead of having all CPUs that schedule a lower priority task send - * an IPI to the same "first" CPU in the RT overload mask, they send it - * to the next overloaded CPU after their own CPU. This helps distribute - * the work when there's more than one overloaded CPU and multiple CPUs - * scheduling in lower priority tasks. - * - * When a rq schedules a lower priority task than what was currently - * running, the next CPU with overloaded RT tasks is examined first. - * That is, if CPU 1 and 5 are overloaded, and CPU 3 schedules a lower - * priority task, it will send an IPI first to CPU 5, then CPU 5 will - * send to CPU 1 if it is still overloaded. CPU 1 will clear the - * rq->rt.push_flags if RT_PUSH_IPI_RESTART is not set. - * - * The first CPU to notice IPI_RESTART is set, will clear that flag and then - * send an IPI to the next overloaded CPU after the rq->cpu and not the next - * CPU after push_cpu. That is, if CPU 1, 4 and 5 are overloaded when CPU 3 - * schedules a lower priority task, and the IPI_RESTART gets set while the - * handling is being done on CPU 5, it will clear the flag and send it back to - * CPU 4 instead of CPU 1. - * - * Note, the above logic can be disabled by turning off the sched_feature - * RT_PUSH_IPI. Then the rq lock of the overloaded CPU will simply be - * taken by the CPU requesting a pull and the waiting RT task will be pulled - * by that CPU. This may be fine for machines with few CPUs. - */ -static void tell_cpu_to_push(struct rq *rq) +static inline void rto_start_unlock(atomic_t *v) { - int cpu; + atomic_set_release(v, 0); +} - if (rq->rt.push_flags & RT_PUSH_IPI_EXECUTING) { - raw_spin_lock(&rq->rt.push_lock); - /* Make sure it's still executing */ - if (rq->rt.push_flags & RT_PUSH_IPI_EXECUTING) { - /* - * Tell the IPI to restart the loop as things have - * changed since it started. - */ - rq->rt.push_flags |= RT_PUSH_IPI_RESTART; - raw_spin_unlock(&rq->rt.push_lock); - return; - } - raw_spin_unlock(&rq->rt.push_lock); - } +static void tell_cpu_to_push(struct rq *rq) +{ + int cpu = -1; - /* When here, there's no IPI going around */ + /* Keep the loop going if the IPI is currently active */ + atomic_inc(&rq->rd->rto_loop_next); - rq->rt.push_cpu = rq->cpu; - cpu = find_next_push_cpu(rq); - if (cpu >= nr_cpu_ids) + /* Only one CPU can initiate a loop at a time */ + if (!rto_start_trylock(&rq->rd->rto_loop_start)) return; - rq->rt.push_flags = RT_PUSH_IPI_EXECUTING; + raw_spin_lock(&rq->rd->rto_lock); + + /* + * The rto_cpu is updated under the lock, if it has a valid cpu + * then the IPI is still running and will continue due to the + * update to loop_next, and nothing needs to be done here. + * Otherwise it is finishing up and an ipi needs to be sent. + */ + if (rq->rd->rto_cpu < 0) + cpu = rto_next_cpu(rq); - irq_work_queue_on(&rq->rt.push_work, cpu); + raw_spin_unlock(&rq->rd->rto_lock); + + rto_start_unlock(&rq->rd->rto_loop_start); + + if (cpu >= 0) + irq_work_queue_on(&rq->rd->rto_push_work, cpu); } /* Called from hardirq context */ -static void try_to_push_tasks(void *arg) +void rto_push_irq_work_func(struct irq_work *work) { - struct rt_rq *rt_rq = arg; - struct rq *rq, *src_rq; - int this_cpu; + struct rq *rq; int cpu; - this_cpu = rt_rq->push_cpu; + rq = this_rq(); - /* Paranoid check */ - BUG_ON(this_cpu != smp_processor_id()); - - rq = cpu_rq(this_cpu); - src_rq = rq_of_rt_rq(rt_rq); - -again: + /* + * We do not need to grab the lock to check for has_pushable_tasks. + * When it gets updated, a check is made if a push is possible. + */ if (has_pushable_tasks(rq)) { raw_spin_lock(&rq->lock); - push_rt_task(rq); + push_rt_tasks(rq); raw_spin_unlock(&rq->lock); } - /* Pass the IPI to the next rt overloaded queue */ - raw_spin_lock(&rt_rq->push_lock); - /* - * If the source queue changed since the IPI went out, - * we need to restart the search from that CPU again. - */ - if (rt_rq->push_flags & RT_PUSH_IPI_RESTART) { - rt_rq->push_flags &= ~RT_PUSH_IPI_RESTART; - rt_rq->push_cpu = src_rq->cpu; - } + raw_spin_lock(&rq->rd->rto_lock); - cpu = find_next_push_cpu(src_rq); + /* Pass the IPI to the next rt overloaded queue */ + cpu = rto_next_cpu(rq); - if (cpu >= nr_cpu_ids) - rt_rq->push_flags &= ~RT_PUSH_IPI_EXECUTING; - raw_spin_unlock(&rt_rq->push_lock); + raw_spin_unlock(&rq->rd->rto_lock); - if (cpu >= nr_cpu_ids) + if (cpu < 0) return; - /* - * It is possible that a restart caused this CPU to be - * chosen again. Don't bother with an IPI, just see if we - * have more to push. - */ - if (unlikely(cpu == rq->cpu)) - goto again; - /* Try the next RT overloaded CPU */ - irq_work_queue_on(&rt_rq->push_work, cpu); -} - -static void push_irq_work_func(struct irq_work *work) -{ - struct rt_rq *rt_rq = container_of(work, struct rt_rq, push_work); - - try_to_push_tasks(rt_rq); + irq_work_queue_on(&rq->rd->rto_push_work, cpu); } #endif /* HAVE_RT_PUSH_IPI */ diff --git a/kernel/sched/sched-pelt.h b/kernel/sched/sched-pelt.h index cd200d16529e..a26473674fb7 100644 --- a/kernel/sched/sched-pelt.h +++ b/kernel/sched/sched-pelt.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ /* Generated by Documentation/scheduler/sched-pelt; do not modify. */ static const u32 runnable_avg_yN_inv[] = { diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 14db76cd496f..b19552a212de 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #include <linux/sched.h> #include <linux/sched/autogroup.h> @@ -29,6 +30,7 @@ #include <linux/irq_work.h> #include <linux/tick.h> #include <linux/slab.h> +#include <linux/cgroup.h> #ifdef CONFIG_PARAVIRT #include <asm/paravirt.h> @@ -36,7 +38,6 @@ #include "cpupri.h" #include "cpudeadline.h" -#include "cpuacct.h" #ifdef CONFIG_SCHED_DEBUG # define SCHED_WARN_ON(x) WARN_ONCE(x, #x) @@ -226,7 +227,7 @@ struct dl_bw { static inline void __dl_update(struct dl_bw *dl_b, s64 bw); static inline -void __dl_clear(struct dl_bw *dl_b, u64 tsk_bw, int cpus) +void __dl_sub(struct dl_bw *dl_b, u64 tsk_bw, int cpus) { dl_b->total_bw -= tsk_bw; __dl_update(dl_b, (s32)tsk_bw / cpus); @@ -255,7 +256,6 @@ extern int sched_dl_overflow(struct task_struct *p, int policy, extern void __setparam_dl(struct task_struct *p, const struct sched_attr *attr); extern void __getparam_dl(struct task_struct *p, struct sched_attr *attr); extern bool __checkparam_dl(const struct sched_attr *attr); -extern void __dl_clear_params(struct task_struct *p); extern bool dl_param_changed(struct task_struct *p, const struct sched_attr *attr); extern int dl_task_can_attach(struct task_struct *p, const struct cpumask *cs_cpus_allowed); @@ -418,6 +418,7 @@ struct cfs_bandwidth { }; /* CFS-related fields in a runqueue */ struct cfs_rq { struct load_weight load; + unsigned long runnable_weight; unsigned int nr_running, h_nr_running; u64 exec_clock; @@ -443,18 +444,22 @@ struct cfs_rq { * CFS load tracking */ struct sched_avg avg; - u64 runnable_load_sum; - unsigned long runnable_load_avg; -#ifdef CONFIG_FAIR_GROUP_SCHED - unsigned long tg_load_avg_contrib; - unsigned long propagate_avg; -#endif - atomic_long_t removed_load_avg, removed_util_avg; #ifndef CONFIG_64BIT u64 load_last_update_time_copy; #endif + struct { + raw_spinlock_t lock ____cacheline_aligned; + int nr; + unsigned long load_avg; + unsigned long util_avg; + unsigned long runnable_sum; + } removed; #ifdef CONFIG_FAIR_GROUP_SCHED + unsigned long tg_load_avg_contrib; + long propagate; + long prop_runnable_sum; + /* * h_load = weight * f(tg) * @@ -501,7 +506,7 @@ static inline int rt_bandwidth_enabled(void) } /* RT IPI pull logic requires IRQ_WORK */ -#ifdef CONFIG_IRQ_WORK +#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_SMP) # define HAVE_RT_PUSH_IPI #endif @@ -523,12 +528,6 @@ struct rt_rq { unsigned long rt_nr_total; int overloaded; struct plist_head pushable_tasks; -#ifdef HAVE_RT_PUSH_IPI - int push_flags; - int push_cpu; - struct irq_work push_work; - raw_spinlock_t push_lock; -#endif #endif /* CONFIG_SMP */ int rt_queued; @@ -637,6 +636,19 @@ struct root_domain { struct dl_bw dl_bw; struct cpudl cpudl; +#ifdef HAVE_RT_PUSH_IPI + /* + * For IPI pull requests, loop across the rto_mask. + */ + struct irq_work rto_push_work; + raw_spinlock_t rto_lock; + /* These are only updated and read within rto_lock */ + int rto_loop; + int rto_cpu; + /* These atomics are updated outside of a lock */ + atomic_t rto_loop_next; + atomic_t rto_loop_start; +#endif /* * The "RT overload" flag: it gets set if a CPU has more than * one runnable RT task. @@ -654,6 +666,9 @@ extern void init_defrootdomain(void); extern int sched_init_domains(const struct cpumask *cpu_map); extern void rq_attach_root(struct rq *rq, struct root_domain *rd); +#ifdef HAVE_RT_PUSH_IPI +extern void rto_push_irq_work_func(struct irq_work *work); +#endif #endif /* CONFIG_SMP */ /* @@ -1218,8 +1233,6 @@ static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) # define const_debug const #endif -extern const_debug unsigned int sysctl_sched_features; - #define SCHED_FEAT(name, enabled) \ __SCHED_FEAT_##name , @@ -1231,6 +1244,13 @@ enum { #undef SCHED_FEAT #if defined(CONFIG_SCHED_DEBUG) && defined(HAVE_JUMP_LABEL) + +/* + * To support run-time toggling of sched features, all the translation units + * (but core.c) reference the sysctl_sched_features defined in core.c. + */ +extern const_debug unsigned int sysctl_sched_features; + #define SCHED_FEAT(name, enabled) \ static __always_inline bool static_branch_##name(struct static_key *key) \ { \ @@ -1238,13 +1258,27 @@ static __always_inline bool static_branch_##name(struct static_key *key) \ } #include "features.h" - #undef SCHED_FEAT extern struct static_key sched_feat_keys[__SCHED_FEAT_NR]; #define sched_feat(x) (static_branch_##x(&sched_feat_keys[__SCHED_FEAT_##x])) + #else /* !(SCHED_DEBUG && HAVE_JUMP_LABEL) */ + +/* + * Each translation unit has its own copy of sysctl_sched_features to allow + * constants propagation at compile time and compiler optimization based on + * features default. + */ +#define SCHED_FEAT(name, enabled) \ + (1UL << __SCHED_FEAT_##name) * enabled | +static const_debug __maybe_unused unsigned int sysctl_sched_features = +#include "features.h" + 0; +#undef SCHED_FEAT + #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x)) + #endif /* SCHED_DEBUG && HAVE_JUMP_LABEL */ extern struct static_key_false sched_numa_balancing; @@ -1529,6 +1563,8 @@ extern void init_sched_dl_class(void); extern void init_sched_rt_class(void); extern void init_sched_fair_class(void); +extern void reweight_task(struct task_struct *p, int prio); + extern void resched_curr(struct rq *rq); extern void resched_cpu(int cpu); diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c index 87e2c9f0c33e..940b1fa1d2ce 100644 --- a/kernel/sched/stats.c +++ b/kernel/sched/stats.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 #include <linux/slab.h> #include <linux/fs.h> diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h index d5710651043b..baf500d12b7c 100644 --- a/kernel/sched/stats.h +++ b/kernel/sched/stats.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifdef CONFIG_SCHEDSTATS diff --git a/kernel/sched/stop_task.c b/kernel/sched/stop_task.c index 9f69fb630853..210b1f2146ff 100644 --- a/kernel/sched/stop_task.c +++ b/kernel/sched/stop_task.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 #include "sched.h" /* @@ -71,7 +72,7 @@ static void put_prev_task_stop(struct rq *rq, struct task_struct *prev) account_group_exec_runtime(curr, delta_exec); curr->se.exec_start = rq_clock_task(rq); - cpuacct_charge(curr, delta_exec); + cgroup_account_cputime(curr, delta_exec); } static void task_tick_stop(struct rq *rq, struct task_struct *curr, int queued) diff --git a/kernel/sched/swait.c b/kernel/sched/swait.c index 2227e183e202..9ff1555341ed 100644 --- a/kernel/sched/swait.c +++ b/kernel/sched/swait.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 #include <linux/sched/signal.h> #include <linux/swait.h> diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index f1cf4f306a82..034cbed7f88b 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -1,8 +1,10 @@ +// SPDX-License-Identifier: GPL-2.0 /* * Scheduler topology setup/handling methods */ #include <linux/sched.h> #include <linux/mutex.h> +#include <linux/sched/isolation.h> #include "sched.h" @@ -268,6 +270,12 @@ static int init_rootdomain(struct root_domain *rd) if (!zalloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) goto free_dlo_mask; +#ifdef HAVE_RT_PUSH_IPI + rd->rto_cpu = -1; + raw_spin_lock_init(&rd->rto_lock); + init_irq_work(&rd->rto_push_work, rto_push_irq_work_func); +#endif + init_dl_bw(&rd->dl_bw); if (cpudl_init(&rd->cpudl) != 0) goto free_rto_mask; @@ -463,21 +471,6 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) update_top_cache_domain(cpu); } -/* Setup the mask of CPUs configured for isolated domains */ -static int __init isolated_cpu_setup(char *str) -{ - int ret; - - alloc_bootmem_cpumask_var(&cpu_isolated_map); - ret = cpulist_parse(str, cpu_isolated_map); - if (ret) { - pr_err("sched: Error, all isolcpus= values must be between 0 and %u\n", nr_cpu_ids); - return 0; - } - return 1; -} -__setup("isolcpus=", isolated_cpu_setup); - struct s_data { struct sched_domain ** __percpu sd; struct root_domain *rd; @@ -1157,6 +1150,7 @@ sd_init(struct sched_domain_topology_level *tl, sd->smt_gain = 1178; /* ~15% */ } else if (sd->flags & SD_SHARE_PKG_RESOURCES) { + sd->flags |= SD_PREFER_SIBLING; sd->imbalance_pct = 117; sd->cache_nice_tries = 1; sd->busy_idx = 2; @@ -1331,6 +1325,10 @@ void sched_init_numa(void) if (!sched_domains_numa_distance) return; + /* Includes NUMA identity node at level 0. */ + sched_domains_numa_distance[level++] = curr_distance; + sched_domains_numa_levels = level; + /* * O(nr_nodes^2) deduplicating selection sort -- in order to find the * unique distances in the node_distance() table. @@ -1378,8 +1376,7 @@ void sched_init_numa(void) return; /* - * 'level' contains the number of unique distances, excluding the - * identity distance node_distance(i,i). + * 'level' contains the number of unique distances * * The sched_domains_numa_distance[] array includes the actual distance * numbers. @@ -1441,9 +1438,18 @@ void sched_init_numa(void) tl[i] = sched_domain_topology[i]; /* + * Add the NUMA identity distance, aka single NODE. + */ + tl[i++] = (struct sched_domain_topology_level){ + .mask = sd_numa_mask, + .numa_level = 0, + SD_INIT_NAME(NODE) + }; + + /* * .. and append 'j' levels of NUMA goodness. */ - for (j = 0; j < level; i++, j++) { + for (j = 1; j < level; i++, j++) { tl[i] = (struct sched_domain_topology_level){ .mask = sd_numa_mask, .sd_flags = cpu_numa_flags, @@ -1773,7 +1779,7 @@ int sched_init_domains(const struct cpumask *cpu_map) doms_cur = alloc_sched_domains(ndoms_cur); if (!doms_cur) doms_cur = &fallback_doms; - cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); + cpumask_and(doms_cur[0], cpu_map, housekeeping_cpumask(HK_FLAG_DOMAIN)); err = build_sched_domains(doms_cur[0], NULL); register_sched_domain_sysctl(); @@ -1856,7 +1862,8 @@ void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], doms_new = alloc_sched_domains(1); if (doms_new) { n = 1; - cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); + cpumask_and(doms_new[0], cpu_active_mask, + housekeeping_cpumask(HK_FLAG_DOMAIN)); } } else { n = ndoms_new; @@ -1879,7 +1886,8 @@ match1: if (!doms_new) { n = 0; doms_new = &fallback_doms; - cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); + cpumask_and(doms_new[0], cpu_active_mask, + housekeeping_cpumask(HK_FLAG_DOMAIN)); } /* Build new domains: */ diff --git a/kernel/sched/wait_bit.c b/kernel/sched/wait_bit.c index f8159698aa4d..84cb3acd9260 100644 --- a/kernel/sched/wait_bit.c +++ b/kernel/sched/wait_bit.c @@ -183,7 +183,7 @@ static int wake_atomic_t_function(struct wait_queue_entry *wq_entry, unsigned mo */ static __sched int __wait_on_atomic_t(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_entry, - int (*action)(atomic_t *), unsigned mode) + wait_atomic_t_action_f action, unsigned int mode) { atomic_t *val; int ret = 0; @@ -193,7 +193,7 @@ int __wait_on_atomic_t(struct wait_queue_head *wq_head, struct wait_bit_queue_en val = wbq_entry->key.flags; if (atomic_read(val) == 0) break; - ret = (*action)(val); + ret = (*action)(val, mode); } while (!ret && atomic_read(val) != 0); finish_wait(wq_head, &wbq_entry->wq_entry); return ret; @@ -210,8 +210,9 @@ int __wait_on_atomic_t(struct wait_queue_head *wq_head, struct wait_bit_queue_en }, \ } -__sched int out_of_line_wait_on_atomic_t(atomic_t *p, int (*action)(atomic_t *), - unsigned mode) +__sched int out_of_line_wait_on_atomic_t(atomic_t *p, + wait_atomic_t_action_f action, + unsigned int mode) { struct wait_queue_head *wq_head = atomic_t_waitqueue(p); DEFINE_WAIT_ATOMIC_T(wq_entry, p); @@ -220,6 +221,15 @@ __sched int out_of_line_wait_on_atomic_t(atomic_t *p, int (*action)(atomic_t *), } EXPORT_SYMBOL(out_of_line_wait_on_atomic_t); +__sched int atomic_t_wait(atomic_t *counter, unsigned int mode) +{ + schedule(); + if (signal_pending_state(mode, current)) + return -EINTR; + return 0; +} +EXPORT_SYMBOL(atomic_t_wait); + /** * wake_up_atomic_t - Wake up a waiter on a atomic_t * @p: The atomic_t being waited on, a kernel virtual address |