diff options
Diffstat (limited to 'kernel/sched/fair.c')
| -rw-r--r-- | kernel/sched/fair.c | 1049 |
1 files changed, 690 insertions, 359 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 5c09ddf8c832..0989676c50e9 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -33,6 +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> @@ -717,13 +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. @@ -731,13 +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 */ } @@ -785,7 +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)) { @@ -2026,7 +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; } @@ -2693,18 +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); @@ -2712,7 +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; @@ -2728,63 +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 */ @@ -2893,7 +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 */ @@ -2910,10 +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); /* @@ -2926,11 +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; @@ -2966,8 +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; @@ -3000,8 +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 @@ -3010,63 +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 /** @@ -3149,11 +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 */ @@ -3169,102 +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; + long runnable_sum = gcfs_rq->prop_runnable_sum; + long runnable_load_avg, load_avg; + s64 runnable_load_sum, load_sum; - /* - * 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; + if (!runnable_sum) + return; - /* Get tg's load and ensure tg_load > 0 */ - tg_load = atomic_long_read(&gcfs_rq->tg->load_avg) + 1; + gcfs_rq->prop_runnable_sum = 0; - /* Ensure tg_load >= load and updated with current load*/ - tg_load -= gcfs_rq->tg_load_avg_contrib; - tg_load += load; + load_sum = (s64)se_weight(se) * runnable_sum; + load_avg = div_s64(load_sum, LOAD_AVG_MAX); - /* - * 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; - } - } + add_positive(&se->avg.load_sum, runnable_sum); + add_positive(&se->avg.load_avg, load_avg); - delta = load - se->avg.load_avg; + add_positive(&cfs_rq->avg.load_avg, load_avg); + add_positive(&cfs_rq->avg.load_sum, load_sum); - /* Nothing to update */ - if (!delta) - return; - - /* 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; } @@ -3288,7 +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; /* @@ -3308,27 +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() @@ -3348,65 +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 (atomic_long_read(&cfs_rq->removed_load_avg)) { - s64 r = atomic_long_xchg(&cfs_rq->removed_load_avg, 0); + if (cfs_rq->removed.nr) { + unsigned long r; + u32 divider = LOAD_AVG_MAX - 1024 + sa->period_contrib; + + 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; } /** @@ -3419,12 +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); } @@ -3439,39 +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; + + /* + * 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); - cfs_rq->runnable_load_avg += sa->load_avg; - cfs_rq->runnable_load_sum += sa->load_sum; + 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 @@ -3515,6 +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() -> @@ -3527,13 +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) @@ -3553,16 +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 @@ -3707,9 +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) @@ -3791,8 +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); @@ -3815,7 +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, @@ -3879,7 +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); @@ -3981,7 +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; } @@ -3997,8 +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 /* @@ -4915,8 +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) @@ -4974,8 +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) @@ -5449,6 +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, @@ -5456,8 +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; @@ -5578,10 +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; @@ -5630,6 +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) @@ -5982,50 +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 @@ -6059,14 +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; @@ -6334,10 +6658,7 @@ again: set_next_entity(cfs_rq, se); } - if (hrtick_enabled(rq)) - hrtick_start_fair(rq, p); - - return p; + goto done; simple: #endif @@ -6351,6 +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); @@ -6786,11 +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; @@ -6836,7 +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 */ @@ -6886,7 +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); } /* @@ -6962,7 +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; @@ -6994,7 +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 @@ -7875,8 +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; @@ -8693,7 +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))) @@ -9158,7 +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 @@ -9170,7 +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); @@ -9189,7 +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); @@ -9271,11 +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 } @@ -9473,8 +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); } |