diff options
Diffstat (limited to 'kernel/sched/fair.c')
| -rw-r--r-- | kernel/sched/fair.c | 894 |
1 files changed, 631 insertions, 263 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index ee271bb661cc..ea74d43924b2 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -38,7 +38,7 @@ * (default: 6ms * (1 + ilog(ncpus)), units: nanoseconds) */ unsigned int sysctl_sched_latency = 6000000ULL; -unsigned int normalized_sysctl_sched_latency = 6000000ULL; +static unsigned int normalized_sysctl_sched_latency = 6000000ULL; /* * The initial- and re-scaling of tunables is configurable @@ -58,8 +58,8 @@ enum sched_tunable_scaling sysctl_sched_tunable_scaling = SCHED_TUNABLESCALING_L * * (default: 0.75 msec * (1 + ilog(ncpus)), units: nanoseconds) */ -unsigned int sysctl_sched_min_granularity = 750000ULL; -unsigned int normalized_sysctl_sched_min_granularity = 750000ULL; +unsigned int sysctl_sched_min_granularity = 750000ULL; +static unsigned int normalized_sysctl_sched_min_granularity = 750000ULL; /* * This value is kept at sysctl_sched_latency/sysctl_sched_min_granularity @@ -81,8 +81,8 @@ unsigned int sysctl_sched_child_runs_first __read_mostly; * * (default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds) */ -unsigned int sysctl_sched_wakeup_granularity = 1000000UL; -unsigned int normalized_sysctl_sched_wakeup_granularity = 1000000UL; +unsigned int sysctl_sched_wakeup_granularity = 1000000UL; +static unsigned int normalized_sysctl_sched_wakeup_granularity = 1000000UL; const_debug unsigned int sysctl_sched_migration_cost = 500000UL; @@ -94,6 +94,14 @@ int __weak arch_asym_cpu_priority(int cpu) { return -cpu; } + +/* + * The margin used when comparing utilization with CPU capacity: + * util * margin < capacity * 1024 + * + * (default: ~20%) + */ +static unsigned int capacity_margin = 1280; #endif #ifdef CONFIG_CFS_BANDWIDTH @@ -110,14 +118,6 @@ int __weak arch_asym_cpu_priority(int cpu) unsigned int sysctl_sched_cfs_bandwidth_slice = 5000UL; #endif -/* - * The margin used when comparing utilization with CPU capacity: - * util * margin < capacity * 1024 - * - * (default: ~20%) - */ -unsigned int capacity_margin = 1280; - static inline void update_load_add(struct load_weight *lw, unsigned long inc) { lw->weight += inc; @@ -248,13 +248,6 @@ const struct sched_class fair_sched_class; */ #ifdef CONFIG_FAIR_GROUP_SCHED - -/* cpu runqueue to which this cfs_rq is attached */ -static inline struct rq *rq_of(struct cfs_rq *cfs_rq) -{ - return cfs_rq->rq; -} - static inline struct task_struct *task_of(struct sched_entity *se) { SCHED_WARN_ON(!entity_is_task(se)); @@ -282,76 +275,99 @@ static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) return grp->my_q; } -static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq) +static inline bool list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq) { - if (!cfs_rq->on_list) { - struct rq *rq = rq_of(cfs_rq); - int cpu = cpu_of(rq); + struct rq *rq = rq_of(cfs_rq); + int cpu = cpu_of(rq); + + if (cfs_rq->on_list) + return rq->tmp_alone_branch == &rq->leaf_cfs_rq_list; + + cfs_rq->on_list = 1; + + /* + * Ensure we either appear before our parent (if already + * enqueued) or force our parent to appear after us when it is + * enqueued. The fact that we always enqueue bottom-up + * reduces this to two cases and a special case for the root + * cfs_rq. Furthermore, it also means that we will always reset + * tmp_alone_branch either when the branch is connected + * to a tree or when we reach the top of the tree + */ + if (cfs_rq->tg->parent && + cfs_rq->tg->parent->cfs_rq[cpu]->on_list) { /* - * Ensure we either appear before our parent (if already - * enqueued) or force our parent to appear after us when it is - * enqueued. The fact that we always enqueue bottom-up - * reduces this to two cases and a special case for the root - * cfs_rq. Furthermore, it also means that we will always reset - * tmp_alone_branch either when the branch is connected - * to a tree or when we reach the beg of the tree + * If parent is already on the list, we add the child + * just before. Thanks to circular linked property of + * the list, this means to put the child at the tail + * of the list that starts by parent. */ - if (cfs_rq->tg->parent && - cfs_rq->tg->parent->cfs_rq[cpu]->on_list) { - /* - * If parent is already on the list, we add the child - * just before. Thanks to circular linked property of - * the list, this means to put the child at the tail - * of the list that starts by parent. - */ - list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list, - &(cfs_rq->tg->parent->cfs_rq[cpu]->leaf_cfs_rq_list)); - /* - * The branch is now connected to its tree so we can - * reset tmp_alone_branch to the beginning of the - * list. - */ - rq->tmp_alone_branch = &rq->leaf_cfs_rq_list; - } else if (!cfs_rq->tg->parent) { - /* - * cfs rq without parent should be put - * at the tail of the list. - */ - list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list, - &rq->leaf_cfs_rq_list); - /* - * We have reach the beg of a tree so we can reset - * tmp_alone_branch to the beginning of the list. - */ - rq->tmp_alone_branch = &rq->leaf_cfs_rq_list; - } else { - /* - * The parent has not already been added so we want to - * make sure that it will be put after us. - * tmp_alone_branch points to the beg of the branch - * where we will add parent. - */ - list_add_rcu(&cfs_rq->leaf_cfs_rq_list, - rq->tmp_alone_branch); - /* - * update tmp_alone_branch to points to the new beg - * of the branch - */ - rq->tmp_alone_branch = &cfs_rq->leaf_cfs_rq_list; - } + list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list, + &(cfs_rq->tg->parent->cfs_rq[cpu]->leaf_cfs_rq_list)); + /* + * The branch is now connected to its tree so we can + * reset tmp_alone_branch to the beginning of the + * list. + */ + rq->tmp_alone_branch = &rq->leaf_cfs_rq_list; + return true; + } - cfs_rq->on_list = 1; + if (!cfs_rq->tg->parent) { + /* + * cfs rq without parent should be put + * at the tail of the list. + */ + list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list, + &rq->leaf_cfs_rq_list); + /* + * We have reach the top of a tree so we can reset + * tmp_alone_branch to the beginning of the list. + */ + rq->tmp_alone_branch = &rq->leaf_cfs_rq_list; + return true; } + + /* + * The parent has not already been added so we want to + * make sure that it will be put after us. + * tmp_alone_branch points to the begin of the branch + * where we will add parent. + */ + list_add_rcu(&cfs_rq->leaf_cfs_rq_list, rq->tmp_alone_branch); + /* + * update tmp_alone_branch to points to the new begin + * of the branch + */ + rq->tmp_alone_branch = &cfs_rq->leaf_cfs_rq_list; + return false; } static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq) { if (cfs_rq->on_list) { + struct rq *rq = rq_of(cfs_rq); + + /* + * With cfs_rq being unthrottled/throttled during an enqueue, + * it can happen the tmp_alone_branch points the a leaf that + * we finally want to del. In this case, tmp_alone_branch moves + * to the prev element but it will point to rq->leaf_cfs_rq_list + * at the end of the enqueue. + */ + if (rq->tmp_alone_branch == &cfs_rq->leaf_cfs_rq_list) + rq->tmp_alone_branch = cfs_rq->leaf_cfs_rq_list.prev; + list_del_rcu(&cfs_rq->leaf_cfs_rq_list); cfs_rq->on_list = 0; } } +static inline void assert_list_leaf_cfs_rq(struct rq *rq) +{ + SCHED_WARN_ON(rq->tmp_alone_branch != &rq->leaf_cfs_rq_list); +} + /* Iterate thr' all leaf cfs_rq's on a runqueue */ #define for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos) \ list_for_each_entry_safe(cfs_rq, pos, &rq->leaf_cfs_rq_list, \ @@ -411,12 +427,6 @@ static inline struct task_struct *task_of(struct sched_entity *se) return container_of(se, struct task_struct, se); } -static inline struct rq *rq_of(struct cfs_rq *cfs_rq) -{ - return container_of(cfs_rq, struct rq, cfs); -} - - #define for_each_sched_entity(se) \ for (; se; se = NULL) @@ -439,14 +449,19 @@ static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) return NULL; } -static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq) +static inline bool list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq) { + return true; } static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq) { } +static inline void assert_list_leaf_cfs_rq(struct rq *rq) +{ +} + #define for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos) \ for (cfs_rq = &rq->cfs, pos = NULL; cfs_rq; cfs_rq = pos) @@ -687,9 +702,8 @@ static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se) return calc_delta_fair(sched_slice(cfs_rq, se), se); } -#ifdef CONFIG_SMP #include "pelt.h" -#include "sched-pelt.h" +#ifdef CONFIG_SMP static int select_idle_sibling(struct task_struct *p, int prev_cpu, int cpu); static unsigned long task_h_load(struct task_struct *p); @@ -703,9 +717,9 @@ void init_entity_runnable_average(struct sched_entity *se) memset(sa, 0, sizeof(*sa)); /* - * Tasks are intialized with full load to be seen as heavy tasks until + * Tasks are initialized with full load to be seen as heavy tasks until * they get a chance to stabilize to their real load level. - * Group entities are intialized with zero load to reflect the fact that + * Group entities are initialized with zero load to reflect the fact that * nothing has been attached to the task group yet. */ if (entity_is_task(se)) @@ -745,8 +759,9 @@ static void attach_entity_cfs_rq(struct sched_entity *se); * Finally, that extrapolated util_avg is clamped to the cap (util_avg_cap) * if util_avg > util_avg_cap. */ -void post_init_entity_util_avg(struct sched_entity *se) +void post_init_entity_util_avg(struct task_struct *p) { + struct sched_entity *se = &p->se; struct cfs_rq *cfs_rq = cfs_rq_of(se); struct sched_avg *sa = &se->avg; long cpu_scale = arch_scale_cpu_capacity(NULL, cpu_of(rq_of(cfs_rq))); @@ -764,22 +779,19 @@ void post_init_entity_util_avg(struct sched_entity *se) } } - if (entity_is_task(se)) { - struct task_struct *p = task_of(se); - if (p->sched_class != &fair_sched_class) { - /* - * For !fair tasks do: - * - update_cfs_rq_load_avg(now, cfs_rq); - attach_entity_load_avg(cfs_rq, se, 0); - switched_from_fair(rq, p); - * - * such that the next switched_to_fair() has the - * expected state. - */ - se->avg.last_update_time = cfs_rq_clock_task(cfs_rq); - return; - } + if (p->sched_class != &fair_sched_class) { + /* + * For !fair tasks do: + * + update_cfs_rq_load_avg(now, cfs_rq); + attach_entity_load_avg(cfs_rq, se, 0); + switched_from_fair(rq, p); + * + * such that the next switched_to_fair() has the + * expected state. + */ + se->avg.last_update_time = cfs_rq_clock_pelt(cfs_rq); + return; } attach_entity_cfs_rq(se); @@ -789,7 +801,7 @@ void post_init_entity_util_avg(struct sched_entity *se) void init_entity_runnable_average(struct sched_entity *se) { } -void post_init_entity_util_avg(struct sched_entity *se) +void post_init_entity_util_avg(struct task_struct *p) { } static void update_tg_load_avg(struct cfs_rq *cfs_rq, int force) @@ -1036,7 +1048,7 @@ unsigned int sysctl_numa_balancing_scan_size = 256; unsigned int sysctl_numa_balancing_scan_delay = 1000; struct numa_group { - atomic_t refcount; + refcount_t refcount; spinlock_t lock; /* nr_tasks, tasks */ int nr_tasks; @@ -1105,7 +1117,7 @@ static unsigned int task_scan_start(struct task_struct *p) unsigned long shared = group_faults_shared(ng); unsigned long private = group_faults_priv(ng); - period *= atomic_read(&ng->refcount); + period *= refcount_read(&ng->refcount); period *= shared + 1; period /= private + shared + 1; } @@ -1128,7 +1140,7 @@ static unsigned int task_scan_max(struct task_struct *p) unsigned long private = group_faults_priv(ng); unsigned long period = smax; - period *= atomic_read(&ng->refcount); + period *= refcount_read(&ng->refcount); period *= shared + 1; period /= private + shared + 1; @@ -1161,7 +1173,7 @@ void init_numa_balancing(unsigned long clone_flags, struct task_struct *p) /* New address space, reset the preferred nid */ if (!(clone_flags & CLONE_VM)) { - p->numa_preferred_nid = -1; + p->numa_preferred_nid = NUMA_NO_NODE; return; } @@ -1181,13 +1193,13 @@ void init_numa_balancing(unsigned long clone_flags, struct task_struct *p) static void account_numa_enqueue(struct rq *rq, struct task_struct *p) { - rq->nr_numa_running += (p->numa_preferred_nid != -1); + rq->nr_numa_running += (p->numa_preferred_nid != NUMA_NO_NODE); rq->nr_preferred_running += (p->numa_preferred_nid == task_node(p)); } static void account_numa_dequeue(struct rq *rq, struct task_struct *p) { - rq->nr_numa_running -= (p->numa_preferred_nid != -1); + rq->nr_numa_running -= (p->numa_preferred_nid != NUMA_NO_NODE); rq->nr_preferred_running -= (p->numa_preferred_nid == task_node(p)); } @@ -1401,7 +1413,7 @@ bool should_numa_migrate_memory(struct task_struct *p, struct page * page, * two full passes of the "multi-stage node selection" test that is * executed below. */ - if ((p->numa_preferred_nid == -1 || p->numa_scan_seq <= 4) && + if ((p->numa_preferred_nid == NUMA_NO_NODE || p->numa_scan_seq <= 4) && (cpupid_pid_unset(last_cpupid) || cpupid_match_pid(p, last_cpupid))) return true; @@ -1849,7 +1861,7 @@ static void numa_migrate_preferred(struct task_struct *p) unsigned long interval = HZ; /* This task has no NUMA fault statistics yet */ - if (unlikely(p->numa_preferred_nid == -1 || !p->numa_faults)) + if (unlikely(p->numa_preferred_nid == NUMA_NO_NODE || !p->numa_faults)) return; /* Periodically retry migrating the task to the preferred node */ @@ -2096,7 +2108,7 @@ static int preferred_group_nid(struct task_struct *p, int nid) static void task_numa_placement(struct task_struct *p) { - int seq, nid, max_nid = -1; + int seq, nid, max_nid = NUMA_NO_NODE; unsigned long max_faults = 0; unsigned long fault_types[2] = { 0, 0 }; unsigned long total_faults; @@ -2204,12 +2216,12 @@ static void task_numa_placement(struct task_struct *p) static inline int get_numa_group(struct numa_group *grp) { - return atomic_inc_not_zero(&grp->refcount); + return refcount_inc_not_zero(&grp->refcount); } static inline void put_numa_group(struct numa_group *grp) { - if (atomic_dec_and_test(&grp->refcount)) + if (refcount_dec_and_test(&grp->refcount)) kfree_rcu(grp, rcu); } @@ -2230,7 +2242,7 @@ static void task_numa_group(struct task_struct *p, int cpupid, int flags, if (!grp) return; - atomic_set(&grp->refcount, 1); + refcount_set(&grp->refcount, 1); grp->active_nodes = 1; grp->max_faults_cpu = 0; spin_lock_init(&grp->lock); @@ -2400,8 +2412,8 @@ void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags) local = 1; /* - * Retry task to preferred node migration periodically, in case it - * case it previously failed, or the scheduler moved us. + * Retry to migrate task to preferred node periodically, in case it + * previously failed, or the scheduler moved us. */ if (time_after(jiffies, p->numa_migrate_retry)) { task_numa_placement(p); @@ -2639,7 +2651,8 @@ static void update_scan_period(struct task_struct *p, int new_cpu) * the preferred node. */ if (dst_nid == p->numa_preferred_nid || - (p->numa_preferred_nid != -1 && src_nid != p->numa_preferred_nid)) + (p->numa_preferred_nid != NUMA_NO_NODE && + src_nid != p->numa_preferred_nid)) return; } @@ -2734,6 +2747,17 @@ account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) WRITE_ONCE(*ptr, res); \ } while (0) +/* + * Remove and clamp on negative, from a local variable. + * + * A variant of sub_positive(), which does not use explicit load-store + * and is thus optimized for local variable updates. + */ +#define lsub_positive(_ptr, _val) do { \ + typeof(_ptr) ptr = (_ptr); \ + *ptr -= min_t(typeof(*ptr), *ptr, _val); \ +} while (0) + #ifdef CONFIG_SMP static inline void enqueue_runnable_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) @@ -3112,7 +3136,7 @@ void set_task_rq_fair(struct sched_entity *se, p_last_update_time = prev->avg.last_update_time; n_last_update_time = next->avg.last_update_time; #endif - __update_load_avg_blocked_se(p_last_update_time, cpu_of(rq_of(prev)), se); + __update_load_avg_blocked_se(p_last_update_time, se); se->avg.last_update_time = n_last_update_time; } @@ -3247,11 +3271,11 @@ update_tg_cfs_runnable(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cf /* * runnable_sum can't be lower than running_sum - * As running sum is scale with CPU capacity wehreas the runnable sum - * is not we rescale running_sum 1st + * Rescale running sum to be in the same range as runnable sum + * running_sum is in [0 : LOAD_AVG_MAX << SCHED_CAPACITY_SHIFT] + * runnable_sum is in [0 : LOAD_AVG_MAX] */ - running_sum = se->avg.util_sum / - arch_scale_cpu_capacity(NULL, cpu_of(rq_of(cfs_rq))); + running_sum = se->avg.util_sum >> SCHED_CAPACITY_SHIFT; runnable_sum = max(runnable_sum, running_sum); load_sum = (s64)se_weight(se) * runnable_sum; @@ -3354,7 +3378,7 @@ static inline void add_tg_cfs_propagate(struct cfs_rq *cfs_rq, long runnable_sum /** * update_cfs_rq_load_avg - update the cfs_rq's load/util averages - * @now: current time, as per cfs_rq_clock_task() + * @now: current time, as per cfs_rq_clock_pelt() * @cfs_rq: cfs_rq to update * * The cfs_rq avg is the direct sum of all its entities (blocked and runnable) @@ -3399,7 +3423,7 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) decayed = 1; } - decayed |= __update_load_avg_cfs_rq(now, cpu_of(rq_of(cfs_rq)), cfs_rq); + decayed |= __update_load_avg_cfs_rq(now, cfs_rq); #ifndef CONFIG_64BIT smp_wmb(); @@ -3489,9 +3513,7 @@ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s /* 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) { - u64 now = cfs_rq_clock_task(cfs_rq); - struct rq *rq = rq_of(cfs_rq); - int cpu = cpu_of(rq); + u64 now = cfs_rq_clock_pelt(cfs_rq); int decayed; /* @@ -3499,7 +3521,7 @@ static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s * 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); + __update_load_avg_se(now, cfs_rq, se); decayed = update_cfs_rq_load_avg(now, cfs_rq); decayed |= propagate_entity_load_avg(se); @@ -3551,7 +3573,7 @@ void sync_entity_load_avg(struct sched_entity *se) u64 last_update_time; last_update_time = cfs_rq_last_update_time(cfs_rq); - __update_load_avg_blocked_se(last_update_time, cpu_of(rq_of(cfs_rq)), se); + __update_load_avg_blocked_se(last_update_time, se); } /* @@ -3567,10 +3589,6 @@ void remove_entity_load_avg(struct sched_entity *se) * tasks cannot exit without having gone through wake_up_new_task() -> * post_init_entity_util_avg() which will have added things to the * cfs_rq, so we can remove unconditionally. - * - * Similarly for groups, they will have passed through - * post_init_entity_util_avg() before unregister_sched_fair_group() - * calls this. */ sync_entity_load_avg(se); @@ -3604,7 +3622,7 @@ static inline unsigned long _task_util_est(struct task_struct *p) { struct util_est ue = READ_ONCE(p->se.avg.util_est); - return max(ue.ewma, ue.enqueued); + return (max(ue.ewma, ue.enqueued) | UTIL_AVG_UNCHANGED); } static inline unsigned long task_util_est(struct task_struct *p) @@ -3622,7 +3640,7 @@ static inline void util_est_enqueue(struct cfs_rq *cfs_rq, /* Update root cfs_rq's estimated utilization */ enqueued = cfs_rq->avg.util_est.enqueued; - enqueued += (_task_util_est(p) | UTIL_AVG_UNCHANGED); + enqueued += _task_util_est(p); WRITE_ONCE(cfs_rq->avg.util_est.enqueued, enqueued); } @@ -3644,14 +3662,14 @@ util_est_dequeue(struct cfs_rq *cfs_rq, struct task_struct *p, bool task_sleep) { long last_ewma_diff; struct util_est ue; + int cpu; if (!sched_feat(UTIL_EST)) return; /* Update root cfs_rq's estimated utilization */ ue.enqueued = cfs_rq->avg.util_est.enqueued; - ue.enqueued -= min_t(unsigned int, ue.enqueued, - (_task_util_est(p) | UTIL_AVG_UNCHANGED)); + ue.enqueued -= min_t(unsigned int, ue.enqueued, _task_util_est(p)); WRITE_ONCE(cfs_rq->avg.util_est.enqueued, ue.enqueued); /* @@ -3679,6 +3697,14 @@ util_est_dequeue(struct cfs_rq *cfs_rq, struct task_struct *p, bool task_sleep) return; /* + * To avoid overestimation of actual task utilization, skip updates if + * we cannot grant there is idle time in this CPU. + */ + cpu = cpu_of(rq_of(cfs_rq)); + if (task_util(p) > capacity_orig_of(cpu)) + return; + + /* * Update Task's estimated utilization * * When *p completes an activation we can consolidate another sample @@ -3966,8 +3992,8 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) /* * When dequeuing a sched_entity, we must: * - Update loads to have both entity and cfs_rq synced with now. - * - Substract its load from the cfs_rq->runnable_avg. - * - Substract its previous weight from cfs_rq->load.weight. + * - Subtract its load from the cfs_rq->runnable_avg. + * - Subtract its previous weight from cfs_rq->load.weight. * - For group entity, update its weight to reflect the new share * of its group cfs_rq. */ @@ -4208,7 +4234,7 @@ entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued) #ifdef CONFIG_CFS_BANDWIDTH -#ifdef HAVE_JUMP_LABEL +#ifdef CONFIG_JUMP_LABEL static struct static_key __cfs_bandwidth_used; static inline bool cfs_bandwidth_used(void) @@ -4225,7 +4251,7 @@ void cfs_bandwidth_usage_dec(void) { static_key_slow_dec_cpuslocked(&__cfs_bandwidth_used); } -#else /* HAVE_JUMP_LABEL */ +#else /* CONFIG_JUMP_LABEL */ static bool cfs_bandwidth_used(void) { return true; @@ -4233,7 +4259,7 @@ static bool cfs_bandwidth_used(void) void cfs_bandwidth_usage_inc(void) {} void cfs_bandwidth_usage_dec(void) {} -#endif /* HAVE_JUMP_LABEL */ +#endif /* CONFIG_JUMP_LABEL */ /* * default period for cfs group bandwidth. @@ -4420,6 +4446,10 @@ static int tg_unthrottle_up(struct task_group *tg, void *data) /* adjust cfs_rq_clock_task() */ cfs_rq->throttled_clock_task_time += rq_clock_task(rq) - cfs_rq->throttled_clock_task; + + /* Add cfs_rq with already running entity in the list */ + if (cfs_rq->nr_running >= 1) + list_add_leaf_cfs_rq(cfs_rq); } return 0; @@ -4431,8 +4461,10 @@ static int tg_throttle_down(struct task_group *tg, void *data) struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)]; /* group is entering throttled state, stop time */ - if (!cfs_rq->throttle_count) + if (!cfs_rq->throttle_count) { cfs_rq->throttled_clock_task = rq_clock_task(rq); + list_del_leaf_cfs_rq(cfs_rq); + } cfs_rq->throttle_count++; return 0; @@ -4535,6 +4567,8 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq) break; } + assert_list_leaf_cfs_rq(rq); + if (!se) add_nr_running(rq, task_delta); @@ -4556,7 +4590,7 @@ static u64 distribute_cfs_runtime(struct cfs_bandwidth *cfs_b, struct rq *rq = rq_of(cfs_rq); struct rq_flags rf; - rq_lock(rq, &rf); + rq_lock_irqsave(rq, &rf); if (!cfs_rq_throttled(cfs_rq)) goto next; @@ -4573,7 +4607,7 @@ static u64 distribute_cfs_runtime(struct cfs_bandwidth *cfs_b, unthrottle_cfs_rq(cfs_rq); next: - rq_unlock(rq, &rf); + rq_unlock_irqrestore(rq, &rf); if (!remaining) break; @@ -4589,7 +4623,7 @@ next: * period the timer is deactivated until scheduling resumes; cfs_b->idle is * used to track this state. */ -static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun) +static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun, unsigned long flags) { u64 runtime, runtime_expires; int throttled; @@ -4631,16 +4665,16 @@ static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun) while (throttled && cfs_b->runtime > 0 && !cfs_b->distribute_running) { runtime = cfs_b->runtime; cfs_b->distribute_running = 1; - raw_spin_unlock(&cfs_b->lock); + raw_spin_unlock_irqrestore(&cfs_b->lock, flags); /* we can't nest cfs_b->lock while distributing bandwidth */ runtime = distribute_cfs_runtime(cfs_b, runtime, runtime_expires); - raw_spin_lock(&cfs_b->lock); + raw_spin_lock_irqsave(&cfs_b->lock, flags); cfs_b->distribute_running = 0; throttled = !list_empty(&cfs_b->throttled_cfs_rq); - cfs_b->runtime -= min(runtime, cfs_b->runtime); + lsub_positive(&cfs_b->runtime, runtime); } /* @@ -4744,17 +4778,18 @@ static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq) static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b) { u64 runtime = 0, slice = sched_cfs_bandwidth_slice(); + unsigned long flags; u64 expires; /* confirm we're still not at a refresh boundary */ - raw_spin_lock(&cfs_b->lock); + raw_spin_lock_irqsave(&cfs_b->lock, flags); if (cfs_b->distribute_running) { - raw_spin_unlock(&cfs_b->lock); + raw_spin_unlock_irqrestore(&cfs_b->lock, flags); return; } if (runtime_refresh_within(cfs_b, min_bandwidth_expiration)) { - raw_spin_unlock(&cfs_b->lock); + raw_spin_unlock_irqrestore(&cfs_b->lock, flags); return; } @@ -4765,18 +4800,18 @@ static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b) if (runtime) cfs_b->distribute_running = 1; - raw_spin_unlock(&cfs_b->lock); + raw_spin_unlock_irqrestore(&cfs_b->lock, flags); if (!runtime) return; runtime = distribute_cfs_runtime(cfs_b, runtime, expires); - raw_spin_lock(&cfs_b->lock); + raw_spin_lock_irqsave(&cfs_b->lock, flags); if (expires == cfs_b->runtime_expires) - cfs_b->runtime -= min(runtime, cfs_b->runtime); + lsub_positive(&cfs_b->runtime, runtime); cfs_b->distribute_running = 0; - raw_spin_unlock(&cfs_b->lock); + raw_spin_unlock_irqrestore(&cfs_b->lock, flags); } /* @@ -4854,20 +4889,21 @@ static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer) { struct cfs_bandwidth *cfs_b = container_of(timer, struct cfs_bandwidth, period_timer); + unsigned long flags; int overrun; int idle = 0; - raw_spin_lock(&cfs_b->lock); + raw_spin_lock_irqsave(&cfs_b->lock, flags); for (;;) { overrun = hrtimer_forward_now(timer, cfs_b->period); if (!overrun) break; - idle = do_sched_cfs_period_timer(cfs_b, overrun); + idle = do_sched_cfs_period_timer(cfs_b, overrun, flags); } if (idle) cfs_b->period_active = 0; - raw_spin_unlock(&cfs_b->lock); + raw_spin_unlock_irqrestore(&cfs_b->lock, flags); return idle ? HRTIMER_NORESTART : HRTIMER_RESTART; } @@ -4977,6 +5013,12 @@ static void __maybe_unused unthrottle_offline_cfs_rqs(struct rq *rq) } #else /* CONFIG_CFS_BANDWIDTH */ + +static inline bool cfs_bandwidth_used(void) +{ + return false; +} + static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq) { return rq_clock_task(rq_of(cfs_rq)); @@ -5072,6 +5114,24 @@ static inline void hrtick_update(struct rq *rq) } #endif +#ifdef CONFIG_SMP +static inline unsigned long cpu_util(int cpu); +static unsigned long capacity_of(int cpu); + +static inline bool cpu_overutilized(int cpu) +{ + return (capacity_of(cpu) * 1024) < (cpu_util(cpu) * capacity_margin); +} + +static inline void update_overutilized_status(struct rq *rq) +{ + if (!READ_ONCE(rq->rd->overutilized) && cpu_overutilized(rq->cpu)) + WRITE_ONCE(rq->rd->overutilized, SG_OVERUTILIZED); +} +#else +static inline void update_overutilized_status(struct rq *rq) { } +#endif + /* * The enqueue_task method is called before nr_running is * increased. Here we update the fair scheduling stats and @@ -5129,8 +5189,43 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) update_cfs_group(se); } - if (!se) + if (!se) { add_nr_running(rq, 1); + /* + * Since new tasks are assigned an initial util_avg equal to + * half of the spare capacity of their CPU, tiny tasks have the + * ability to cross the overutilized threshold, which will + * result in the load balancer ruining all the task placement + * done by EAS. As a way to mitigate that effect, do not account + * for the first enqueue operation of new tasks during the + * overutilized flag detection. + * + * A better way of solving this problem would be to wait for + * the PELT signals of tasks to converge before taking them + * into account, but that is not straightforward to implement, + * and the following generally works well enough in practice. + */ + if (flags & ENQUEUE_WAKEUP) + update_overutilized_status(rq); + + } + + if (cfs_bandwidth_used()) { + /* + * When bandwidth control is enabled; the cfs_rq_throttled() + * breaks in the above iteration can result in incomplete + * leaf list maintenance, resulting in triggering the assertion + * below. + */ + for_each_sched_entity(se) { + cfs_rq = cfs_rq_of(se); + + if (list_add_leaf_cfs_rq(cfs_rq)) + break; + } + } + + assert_list_leaf_cfs_rq(rq); hrtick_update(rq); } @@ -5511,11 +5606,6 @@ static unsigned long capacity_of(int cpu) return cpu_rq(cpu)->cpu_capacity; } -static unsigned long capacity_orig_of(int cpu) -{ - return cpu_rq(cpu)->cpu_capacity_orig; -} - static unsigned long cpu_avg_load_per_task(int cpu) { struct rq *rq = cpu_rq(cpu); @@ -5674,11 +5764,11 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, return target; } -static unsigned long cpu_util_wake(int cpu, struct task_struct *p); +static unsigned long cpu_util_without(int cpu, struct task_struct *p); -static unsigned long capacity_spare_wake(int cpu, struct task_struct *p) +static unsigned long capacity_spare_without(int cpu, struct task_struct *p) { - return max_t(long, capacity_of(cpu) - cpu_util_wake(cpu, p), 0); + return max_t(long, capacity_of(cpu) - cpu_util_without(cpu, p), 0); } /* @@ -5738,7 +5828,7 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, avg_load += cfs_rq_load_avg(&cpu_rq(i)->cfs); - spare_cap = capacity_spare_wake(i, p); + spare_cap = capacity_spare_without(i, p); if (spare_cap > max_spare_cap) max_spare_cap = spare_cap; @@ -5889,8 +5979,8 @@ static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p return prev_cpu; /* - * We need task's util for capacity_spare_wake, sync it up to prev_cpu's - * last_update_time. + * We need task's util for capacity_spare_without, sync it up to + * prev_cpu's last_update_time. */ if (!(sd_flag & SD_BALANCE_FORK)) sync_entity_load_avg(&p->se); @@ -5935,6 +6025,7 @@ static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p #ifdef CONFIG_SCHED_SMT DEFINE_STATIC_KEY_FALSE(sched_smt_present); +EXPORT_SYMBOL_GPL(sched_smt_present); static inline void set_idle_cores(int cpu, int val) { @@ -6007,7 +6098,7 @@ static int select_idle_core(struct task_struct *p, struct sched_domain *sd, int bool idle = true; for_each_cpu(cpu, cpu_smt_mask(core)) { - cpumask_clear_cpu(cpu, cpus); + __cpumask_clear_cpu(cpu, cpus); if (!available_idle_cpu(cpu)) idle = false; } @@ -6027,7 +6118,7 @@ static int select_idle_core(struct task_struct *p, struct sched_domain *sd, int /* * Scan the local SMT mask for idle CPUs. */ -static int select_idle_smt(struct task_struct *p, struct sched_domain *sd, int target) +static int select_idle_smt(struct task_struct *p, int target) { int cpu; @@ -6051,7 +6142,7 @@ static inline int select_idle_core(struct task_struct *p, struct sched_domain *s return -1; } -static inline int select_idle_smt(struct task_struct *p, struct sched_domain *sd, int target) +static inline int select_idle_smt(struct task_struct *p, int target) { return -1; } @@ -6156,7 +6247,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target) if ((unsigned)i < nr_cpumask_bits) return i; - i = select_idle_smt(p, sd, target); + i = select_idle_smt(p, target); if ((unsigned)i < nr_cpumask_bits) return i; @@ -6216,10 +6307,19 @@ static inline unsigned long cpu_util(int cpu) } /* - * cpu_util_wake: Compute CPU utilization with any contributions from - * the waking task p removed. + * cpu_util_without: compute cpu utilization without any contributions from *p + * @cpu: the CPU which utilization is requested + * @p: the task which utilization should be discounted + * + * The utilization of a CPU is defined by the utilization of tasks currently + * enqueued on that CPU as well as tasks which are currently sleeping after an + * execution on that CPU. + * + * This method returns the utilization of the specified CPU by discounting the + * utilization of the specified task, whenever the task is currently + * contributing to the CPU utilization. */ -static unsigned long cpu_util_wake(int cpu, struct task_struct *p) +static unsigned long cpu_util_without(int cpu, struct task_struct *p) { struct cfs_rq *cfs_rq; unsigned int util; @@ -6231,8 +6331,8 @@ static unsigned long cpu_util_wake(int cpu, struct task_struct *p) cfs_rq = &cpu_rq(cpu)->cfs; util = READ_ONCE(cfs_rq->avg.util_avg); - /* Discount task's blocked util from CPU's util */ - util -= min_t(unsigned int, util, task_util(p)); + /* Discount task's util from CPU's util */ + lsub_positive(&util, task_util(p)); /* * Covered cases: @@ -6240,14 +6340,14 @@ static unsigned long cpu_util_wake(int cpu, struct task_struct *p) * a) if *p is the only task sleeping on this CPU, then: * cpu_util (== task_util) > util_est (== 0) * and thus we return: - * cpu_util_wake = (cpu_util - task_util) = 0 + * cpu_util_without = (cpu_util - task_util) = 0 * * b) if other tasks are SLEEPING on this CPU, which is now exiting * IDLE, then: * cpu_util >= task_util * cpu_util > util_est (== 0) * and thus we discount *p's blocked utilization to return: - * cpu_util_wake = (cpu_util - task_util) >= 0 + * cpu_util_without = (cpu_util - task_util) >= 0 * * c) if other tasks are RUNNABLE on that CPU and * util_est > cpu_util @@ -6260,8 +6360,32 @@ static unsigned long cpu_util_wake(int cpu, struct task_struct *p) * covered by the following code when estimated utilization is * enabled. */ - if (sched_feat(UTIL_EST)) - util = max(util, READ_ONCE(cfs_rq->avg.util_est.enqueued)); + if (sched_feat(UTIL_EST)) { + unsigned int estimated = + READ_ONCE(cfs_rq->avg.util_est.enqueued); + + /* + * Despite the following checks we still have a small window + * for a possible race, when an execl's select_task_rq_fair() + * races with LB's detach_task(): + * + * detach_task() + * p->on_rq = TASK_ON_RQ_MIGRATING; + * ---------------------------------- A + * deactivate_task() \ + * dequeue_task() + RaceTime + * util_est_dequeue() / + * ---------------------------------- B + * + * The additional check on "current == p" it's required to + * properly fix the execl regression and it helps in further + * reducing the chances for the above race. + */ + if (unlikely(task_on_rq_queued(p) || current == p)) + lsub_positive(&estimated, _task_util_est(p)); + + util = max(util, estimated); + } /* * Utilization (estimated) can exceed the CPU capacity, thus let's @@ -6299,6 +6423,213 @@ static int wake_cap(struct task_struct *p, int cpu, int prev_cpu) } /* + * Predicts what cpu_util(@cpu) would return if @p was migrated (and enqueued) + * to @dst_cpu. + */ +static unsigned long cpu_util_next(int cpu, struct task_struct *p, int dst_cpu) +{ + struct cfs_rq *cfs_rq = &cpu_rq(cpu)->cfs; + unsigned long util_est, util = READ_ONCE(cfs_rq->avg.util_avg); + + /* + * If @p migrates from @cpu to another, remove its contribution. Or, + * if @p migrates from another CPU to @cpu, add its contribution. In + * the other cases, @cpu is not impacted by the migration, so the + * util_avg should already be correct. + */ + if (task_cpu(p) == cpu && dst_cpu != cpu) + sub_positive(&util, task_util(p)); + else if (task_cpu(p) != cpu && dst_cpu == cpu) + util += task_util(p); + + if (sched_feat(UTIL_EST)) { + util_est = READ_ONCE(cfs_rq->avg.util_est.enqueued); + + /* + * During wake-up, the task isn't enqueued yet and doesn't + * appear in the cfs_rq->avg.util_est.enqueued of any rq, + * so just add it (if needed) to "simulate" what will be + * cpu_util() after the task has been enqueued. + */ + if (dst_cpu == cpu) + util_est += _task_util_est(p); + + util = max(util, util_est); + } + + return min(util, capacity_orig_of(cpu)); +} + +/* + * compute_energy(): Estimates the energy that would be consumed if @p was + * migrated to @dst_cpu. compute_energy() predicts what will be the utilization + * landscape of the * CPUs after the task migration, and uses the Energy Model + * to compute what would be the energy if we decided to actually migrate that + * task. + */ +static long +compute_energy(struct task_struct *p, int dst_cpu, struct perf_domain *pd) +{ + long util, max_util, sum_util, energy = 0; + int cpu; + + for (; pd; pd = pd->next) { + max_util = sum_util = 0; + /* + * The capacity state of CPUs of the current rd can be driven by + * CPUs of another rd if they belong to the same performance + * domain. So, account for the utilization of these CPUs too + * by masking pd with cpu_online_mask instead of the rd span. + * + * If an entire performance domain is outside of the current rd, + * it will not appear in its pd list and will not be accounted + * by compute_energy(). + */ + for_each_cpu_and(cpu, perf_domain_span(pd), cpu_online_mask) { + util = cpu_util_next(cpu, p, dst_cpu); + util = schedutil_energy_util(cpu, util); + max_util = max(util, max_util); + sum_util += util; + } + + energy += em_pd_energy(pd->em_pd, max_util, sum_util); + } + + return energy; +} + +/* + * find_energy_efficient_cpu(): Find most energy-efficient target CPU for the + * waking task. find_energy_efficient_cpu() looks for the CPU with maximum + * spare capacity in each performance domain and uses it as a potential + * candidate to execute the task. Then, it uses the Energy Model to figure + * out which of the CPU candidates is the most energy-efficient. + * + * The rationale for this heuristic is as follows. In a performance domain, + * all the most energy efficient CPU candidates (according to the Energy + * Model) are those for which we'll request a low frequency. When there are + * several CPUs for which the frequency request will be the same, we don't + * have enough data to break the tie between them, because the Energy Model + * only includes active power costs. With this model, if we assume that + * frequency requests follow utilization (e.g. using schedutil), the CPU with + * the maximum spare capacity in a performance domain is guaranteed to be among + * the best candidates of the performance domain. + * + * In practice, it could be preferable from an energy standpoint to pack + * small tasks on a CPU in order to let other CPUs go in deeper idle states, + * but that could also hurt our chances to go cluster idle, and we have no + * ways to tell with the current Energy Model if this is actually a good + * idea or not. So, find_energy_efficient_cpu() basically favors + * cluster-packing, and spreading inside a cluster. That should at least be + * a good thing for latency, and this is consistent with the idea that most + * of the energy savings of EAS come from the asymmetry of the system, and + * not so much from breaking the tie between identical CPUs. That's also the + * reason why EAS is enabled in the topology code only for systems where + * SD_ASYM_CPUCAPACITY is set. + * + * NOTE: Forkees are not accepted in the energy-aware wake-up path because + * they don't have any useful utilization data yet and it's not possible to + * forecast their impact on energy consumption. Consequently, they will be + * placed by find_idlest_cpu() on the least loaded CPU, which might turn out + * to be energy-inefficient in some use-cases. The alternative would be to + * bias new tasks towards specific types of CPUs first, or to try to infer + * their util_avg from the parent task, but those heuristics could hurt + * other use-cases too. So, until someone finds a better way to solve this, + * let's keep things simple by re-using the existing slow path. + */ + +static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu) +{ + unsigned long prev_energy = ULONG_MAX, best_energy = ULONG_MAX; + struct root_domain *rd = cpu_rq(smp_processor_id())->rd; + int cpu, best_energy_cpu = prev_cpu; + struct perf_domain *head, *pd; + unsigned long cpu_cap, util; + struct sched_domain *sd; + + rcu_read_lock(); + pd = rcu_dereference(rd->pd); + if (!pd || READ_ONCE(rd->overutilized)) + goto fail; + head = pd; + + /* + * Energy-aware wake-up happens on the lowest sched_domain starting + * from sd_asym_cpucapacity spanning over this_cpu and prev_cpu. + */ + sd = rcu_dereference(*this_cpu_ptr(&sd_asym_cpucapacity)); + while (sd && !cpumask_test_cpu(prev_cpu, sched_domain_span(sd))) + sd = sd->parent; + if (!sd) + goto fail; + + sync_entity_load_avg(&p->se); + if (!task_util_est(p)) + goto unlock; + + for (; pd; pd = pd->next) { + unsigned long cur_energy, spare_cap, max_spare_cap = 0; + int max_spare_cap_cpu = -1; + + for_each_cpu_and(cpu, perf_domain_span(pd), sched_domain_span(sd)) { + if (!cpumask_test_cpu(cpu, &p->cpus_allowed)) + continue; + + /* Skip CPUs that will be overutilized. */ + util = cpu_util_next(cpu, p, cpu); + cpu_cap = capacity_of(cpu); + if (cpu_cap * 1024 < util * capacity_margin) + continue; + + /* Always use prev_cpu as a candidate. */ + if (cpu == prev_cpu) { + prev_energy = compute_energy(p, prev_cpu, head); + best_energy = min(best_energy, prev_energy); + continue; + } + + /* + * Find the CPU with the maximum spare capacity in + * the performance domain + */ + spare_cap = cpu_cap - util; + if (spare_cap > max_spare_cap) { + max_spare_cap = spare_cap; + max_spare_cap_cpu = cpu; + } + } + + /* Evaluate the energy impact of using this CPU. */ + if (max_spare_cap_cpu >= 0) { + cur_energy = compute_energy(p, max_spare_cap_cpu, head); + if (cur_energy < best_energy) { + best_energy = cur_energy; + best_energy_cpu = max_spare_cap_cpu; + } + } + } +unlock: + rcu_read_unlock(); + + /* + * Pick the best CPU if prev_cpu cannot be used, or if it saves at + * least 6% of the energy used by prev_cpu. + */ + if (prev_energy == ULONG_MAX) + return best_energy_cpu; + + if ((prev_energy - best_energy) > (prev_energy >> 4)) + return best_energy_cpu; + + return prev_cpu; + +fail: + rcu_read_unlock(); + + return -1; +} + +/* * select_task_rq_fair: Select target runqueue for the waking task in domains * that have the 'sd_flag' flag set. In practice, this is SD_BALANCE_WAKE, * SD_BALANCE_FORK, or SD_BALANCE_EXEC. @@ -6321,8 +6652,16 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f if (sd_flag & SD_BALANCE_WAKE) { record_wakee(p); - want_affine = !wake_wide(p) && !wake_cap(p, cpu, prev_cpu) - && cpumask_test_cpu(cpu, &p->cpus_allowed); + + if (sched_energy_enabled()) { + new_cpu = find_energy_efficient_cpu(p, prev_cpu); + if (new_cpu >= 0) + return new_cpu; + new_cpu = prev_cpu; + } + + want_affine = !wake_wide(p) && !wake_cap(p, cpu, prev_cpu) && + cpumask_test_cpu(cpu, &p->cpus_allowed); } rcu_read_lock(); @@ -6486,7 +6825,7 @@ wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se) static void set_last_buddy(struct sched_entity *se) { - if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE)) + if (entity_is_task(se) && unlikely(task_has_idle_policy(task_of(se)))) return; for_each_sched_entity(se) { @@ -6498,7 +6837,7 @@ static void set_last_buddy(struct sched_entity *se) static void set_next_buddy(struct sched_entity *se) { - if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE)) + if (entity_is_task(se) && unlikely(task_has_idle_policy(task_of(se)))) return; for_each_sched_entity(se) { @@ -6556,8 +6895,8 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_ return; /* Idle tasks are by definition preempted by non-idle tasks. */ - if (unlikely(curr->policy == SCHED_IDLE) && - likely(p->policy != SCHED_IDLE)) + if (unlikely(task_has_idle_policy(curr)) && + likely(!task_has_idle_policy(p))) goto preempt; /* @@ -6733,6 +7072,12 @@ idle: if (new_tasks > 0) goto again; + /* + * rq is about to be idle, check if we need to update the + * lost_idle_time of clock_pelt + */ + update_idle_rq_clock_pelt(rq); + return NULL; } @@ -6978,7 +7323,7 @@ static int task_hot(struct task_struct *p, struct lb_env *env) if (p->sched_class != &fair_sched_class) return 0; - if (unlikely(p->policy == SCHED_IDLE)) + if (unlikely(task_has_idle_policy(p))) return 0; /* @@ -7388,11 +7733,7 @@ static void update_blocked_averages(int cpu) for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos) { struct sched_entity *se; - /* throttled entities do not contribute to load */ - if (throttled_hierarchy(cfs_rq)) - continue; - - if (update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq)) + if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq)) update_tg_load_avg(cfs_rq, 0); /* Propagate pending load changes to the parent, if any: */ @@ -7413,8 +7754,8 @@ static void update_blocked_averages(int cpu) } curr_class = rq->curr->sched_class; - update_rt_rq_load_avg(rq_clock_task(rq), rq, curr_class == &rt_sched_class); - update_dl_rq_load_avg(rq_clock_task(rq), rq, curr_class == &dl_sched_class); + update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class); + update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class); update_irq_load_avg(rq, 0); /* Don't need periodic decay once load/util_avg are null */ if (others_have_blocked(rq)) @@ -7484,11 +7825,11 @@ static inline void update_blocked_averages(int cpu) rq_lock_irqsave(rq, &rf); update_rq_clock(rq); - update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq); + update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq); curr_class = rq->curr->sched_class; - update_rt_rq_load_avg(rq_clock_task(rq), rq, curr_class == &rt_sched_class); - update_dl_rq_load_avg(rq_clock_task(rq), rq, curr_class == &dl_sched_class); + update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class); + update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class); update_irq_load_avg(rq, 0); #ifdef CONFIG_NO_HZ_COMMON rq->last_blocked_load_update_tick = jiffies; @@ -7862,16 +8203,16 @@ static bool update_nohz_stats(struct rq *rq, bool force) * update_sg_lb_stats - Update sched_group's statistics for load balancing. * @env: The load balancing environment. * @group: sched_group whose statistics are to be updated. - * @load_idx: Load index of sched_domain of this_cpu for load calc. - * @local_group: Does group contain this_cpu. * @sgs: variable to hold the statistics for this group. - * @overload: Indicate pullable load (e.g. >1 runnable task). + * @sg_status: Holds flag indicating the status of the sched_group */ static inline void update_sg_lb_stats(struct lb_env *env, - struct sched_group *group, int load_idx, - int local_group, struct sg_lb_stats *sgs, - bool *overload) + struct sched_group *group, + struct sg_lb_stats *sgs, + int *sg_status) { + int local_group = cpumask_test_cpu(env->dst_cpu, sched_group_span(group)); + int load_idx = get_sd_load_idx(env->sd, env->idle); unsigned long load; int i, nr_running; @@ -7895,7 +8236,10 @@ static inline void update_sg_lb_stats(struct lb_env *env, nr_running = rq->nr_running; if (nr_running > 1) - *overload = true; + *sg_status |= SG_OVERLOAD; + + if (cpu_overutilized(i)) + *sg_status |= SG_OVERUTILIZED; #ifdef CONFIG_NUMA_BALANCING sgs->nr_numa_running += rq->nr_numa_running; @@ -7911,7 +8255,7 @@ static inline void update_sg_lb_stats(struct lb_env *env, if (env->sd->flags & SD_ASYM_CPUCAPACITY && sgs->group_misfit_task_load < rq->misfit_task_load) { sgs->group_misfit_task_load = rq->misfit_task_load; - *overload = 1; + *sg_status |= SG_OVERLOAD; } } @@ -8056,17 +8400,14 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd struct sched_group *sg = env->sd->groups; struct sg_lb_stats *local = &sds->local_stat; struct sg_lb_stats tmp_sgs; - int load_idx; - bool overload = false; bool prefer_sibling = child && child->flags & SD_PREFER_SIBLING; + int sg_status = 0; #ifdef CONFIG_NO_HZ_COMMON if (env->idle == CPU_NEWLY_IDLE && READ_ONCE(nohz.has_blocked)) env->flags |= LBF_NOHZ_STATS; #endif - load_idx = get_sd_load_idx(env->sd, env->idle); - do { struct sg_lb_stats *sgs = &tmp_sgs; int local_group; @@ -8081,8 +8422,7 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd update_group_capacity(env->sd, env->dst_cpu); } - update_sg_lb_stats(env, sg, load_idx, local_group, sgs, - &overload); + update_sg_lb_stats(env, sg, sgs, &sg_status); if (local_group) goto next_group; @@ -8131,9 +8471,15 @@ next_group: env->fbq_type = fbq_classify_group(&sds->busiest_stat); if (!env->sd->parent) { + struct root_domain *rd = env->dst_rq->rd; + /* update overload indicator if we are at root domain */ - if (READ_ONCE(env->dst_rq->rd->overload) != overload) - WRITE_ONCE(env->dst_rq->rd->overload, overload); + WRITE_ONCE(rd->overload, sg_status & SG_OVERLOAD); + + /* Update over-utilization (tipping point, U >= 0) indicator */ + WRITE_ONCE(rd->overutilized, sg_status & SG_OVERUTILIZED); + } else if (sg_status & SG_OVERUTILIZED) { + WRITE_ONCE(env->dst_rq->rd->overutilized, SG_OVERUTILIZED); } } @@ -8177,9 +8523,7 @@ static int check_asym_packing(struct lb_env *env, struct sd_lb_stats *sds) if (sched_asym_prefer(busiest_cpu, env->dst_cpu)) return 0; - env->imbalance = DIV_ROUND_CLOSEST( - sds->busiest_stat.avg_load * sds->busiest_stat.group_capacity, - SCHED_CAPACITY_SCALE); + env->imbalance = sds->busiest_stat.group_load; return 1; } @@ -8360,6 +8704,14 @@ static struct sched_group *find_busiest_group(struct lb_env *env) * this level. */ update_sd_lb_stats(env, &sds); + + if (sched_energy_enabled()) { + struct root_domain *rd = env->dst_rq->rd; + + if (rcu_dereference(rd->pd) && !READ_ONCE(rd->overutilized)) + goto out_balanced; + } + local = &sds.local_stat; busiest = &sds.busiest_stat; @@ -8544,21 +8896,25 @@ static struct rq *find_busiest_queue(struct lb_env *env, */ #define MAX_PINNED_INTERVAL 512 -static int need_active_balance(struct lb_env *env) +static inline bool +asym_active_balance(struct lb_env *env) { - struct sched_domain *sd = env->sd; + /* + * ASYM_PACKING needs to force migrate tasks from busy but + * lower priority CPUs in order to pack all tasks in the + * highest priority CPUs. + */ + return env->idle != CPU_NOT_IDLE && (env->sd->flags & SD_ASYM_PACKING) && + sched_asym_prefer(env->dst_cpu, env->src_cpu); +} - if (env->idle == CPU_NEWLY_IDLE) { +static inline bool +voluntary_active_balance(struct lb_env *env) +{ + struct sched_domain *sd = env->sd; - /* - * ASYM_PACKING needs to force migrate tasks from busy but - * lower priority CPUs in order to pack all tasks in the - * highest priority CPUs. - */ - if ((sd->flags & SD_ASYM_PACKING) && - sched_asym_prefer(env->dst_cpu, env->src_cpu)) - return 1; - } + if (asym_active_balance(env)) + return 1; /* * The dst_cpu is idle and the src_cpu CPU has only 1 CFS task. @@ -8576,6 +8932,16 @@ static int need_active_balance(struct lb_env *env) if (env->src_grp_type == group_misfit_task) return 1; + return 0; +} + +static int need_active_balance(struct lb_env *env) +{ + struct sched_domain *sd = env->sd; + + if (voluntary_active_balance(env)) + return 1; + return unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2); } @@ -8740,7 +9106,7 @@ more_balance: if ((env.flags & LBF_DST_PINNED) && env.imbalance > 0) { /* Prevent to re-select dst_cpu via env's CPUs */ - cpumask_clear_cpu(env.dst_cpu, env.cpus); + __cpumask_clear_cpu(env.dst_cpu, env.cpus); env.dst_rq = cpu_rq(env.new_dst_cpu); env.dst_cpu = env.new_dst_cpu; @@ -8767,7 +9133,7 @@ more_balance: /* All tasks on this runqueue were pinned by CPU affinity */ if (unlikely(env.flags & LBF_ALL_PINNED)) { - cpumask_clear_cpu(cpu_of(busiest), cpus); + __cpumask_clear_cpu(cpu_of(busiest), cpus); /* * Attempting to continue load balancing at the current * sched_domain level only makes sense if there are @@ -8837,7 +9203,7 @@ more_balance: } else sd->nr_balance_failed = 0; - if (likely(!active_balance)) { + if (likely(!active_balance) || voluntary_active_balance(&env)) { /* We were unbalanced, so reset the balancing interval */ sd->balance_interval = sd->min_interval; } else { @@ -8876,13 +9242,22 @@ out_all_pinned: sd->nr_balance_failed = 0; out_one_pinned: + ld_moved = 0; + + /* + * idle_balance() disregards balance intervals, so we could repeatedly + * reach this code, which would lead to balance_interval skyrocketting + * in a short amount of time. Skip the balance_interval increase logic + * to avoid that. + */ + if (env.idle == CPU_NEWLY_IDLE) + goto out; + /* tune up the balancing interval */ - if (((env.flags & LBF_ALL_PINNED) && - sd->balance_interval < MAX_PINNED_INTERVAL) || - (sd->balance_interval < sd->max_interval)) + if ((env.flags & LBF_ALL_PINNED && + sd->balance_interval < MAX_PINNED_INTERVAL) || + sd->balance_interval < sd->max_interval) sd->balance_interval *= 2; - - ld_moved = 0; out: return ld_moved; } @@ -9177,15 +9552,8 @@ static void kick_ilb(unsigned int flags) } /* - * Current heuristic for kicking the idle load balancer in the presence - * of an idle cpu in the system. - * - This rq has more than one task. - * - This rq has at least one CFS task and the capacity of the CPU is - * significantly reduced because of RT tasks or IRQs. - * - At parent of LLC scheduler domain level, this cpu's scheduler group has - * multiple busy cpu. - * - For SD_ASYM_PACKING, if the lower numbered cpu's in the scheduler - * domain span are idle. + * Current decision point for kicking the idle load balancer in the presence + * of idle CPUs in the system. */ static void nohz_balancer_kick(struct rq *rq) { @@ -9227,8 +9595,13 @@ static void nohz_balancer_kick(struct rq *rq) sds = rcu_dereference(per_cpu(sd_llc_shared, cpu)); if (sds) { /* - * XXX: write a coherent comment on why we do this. - * See also: http://lkml.kernel.org/r/20111202010832.602203411@sbsiddha-desk.sc.intel.com + * If there is an imbalance between LLC domains (IOW we could + * increase the overall cache use), we need some less-loaded LLC + * domain to pull some load. Likewise, we may need to spread + * load within the current LLC domain (e.g. packed SMT cores but + * other CPUs are idle). We can't really know from here how busy + * the others are - so just get a nohz balance going if it looks + * like this LLC domain has tasks we could move. */ nr_busy = atomic_read(&sds->nr_busy_cpus); if (nr_busy > 1) { @@ -9241,19 +9614,15 @@ static void nohz_balancer_kick(struct rq *rq) sd = rcu_dereference(rq->sd); if (sd) { if ((rq->cfs.h_nr_running >= 1) && - check_cpu_capacity(rq, sd)) { + check_cpu_capacity(rq, sd)) { flags = NOHZ_KICK_MASK; goto unlock; } } - sd = rcu_dereference(per_cpu(sd_asym, cpu)); + sd = rcu_dereference(per_cpu(sd_asym_packing, cpu)); if (sd) { - for_each_cpu(i, sched_domain_span(sd)) { - if (i == cpu || - !cpumask_test_cpu(i, nohz.idle_cpus_mask)) - continue; - + for_each_cpu_and(i, sched_domain_span(sd), nohz.idle_cpus_mask) { if (sched_asym_prefer(i, cpu)) { flags = NOHZ_KICK_MASK; goto unlock; @@ -9499,9 +9868,7 @@ static bool nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) return false; } - /* - * barrier, pairs with nohz_balance_enter_idle(), ensures ... - */ + /* could be _relaxed() */ flags = atomic_fetch_andnot(NOHZ_KICK_MASK, nohz_flags(this_cpu)); if (!(flags & NOHZ_KICK_MASK)) return false; @@ -9751,6 +10118,7 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued) task_tick_numa(rq, curr); update_misfit_status(curr, rq); + update_overutilized_status(task_rq(curr)); } /* |