diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/fair.c | 63 | ||||
| -rw-r--r-- | kernel/sched/sched.h | 47 |
2 files changed, 50 insertions, 60 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index df0ff905a4aa..09e3be2e0464 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7202,11 +7202,41 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target) return target; } -/* - * Predicts what cpu_util(@cpu) would return if @p was removed from @cpu - * (@dst_cpu = -1) or migrated to @dst_cpu. - */ -static unsigned long cpu_util_next(int cpu, struct task_struct *p, int dst_cpu) +/** + * cpu_util() - Estimates the amount of CPU capacity used by CFS tasks. + * @cpu: the CPU to get the utilization for + * @p: task for which the CPU utilization should be predicted or NULL + * @dst_cpu: CPU @p migrates to, -1 if @p moves from @cpu or @p == NULL + * + * The unit of the return value must be the same as the one of CPU capacity + * so that CPU utilization can be compared with CPU capacity. + * + * CPU utilization is the sum of running time of runnable tasks plus the + * recent utilization of currently non-runnable tasks on that CPU. + * It represents the amount of CPU capacity currently used by CFS tasks in + * the range [0..max CPU capacity] with max CPU capacity being the CPU + * capacity at f_max. + * + * The estimated CPU utilization is defined as the maximum between CPU + * utilization and sum of the estimated utilization of the currently + * runnable tasks on that CPU. It preserves a utilization "snapshot" of + * previously-executed tasks, which helps better deduce how busy a CPU will + * be when a long-sleeping task wakes up. The contribution to CPU utilization + * of such a task would be significantly decayed at this point of time. + * + * CPU utilization can be higher than the current CPU capacity + * (f_curr/f_max * max CPU capacity) or even the max CPU capacity because + * of rounding errors as well as task migrations or wakeups of new tasks. + * CPU utilization has to be capped to fit into the [0..max CPU capacity] + * range. Otherwise a group of CPUs (CPU0 util = 121% + CPU1 util = 80%) + * could be seen as over-utilized even though CPU1 has 20% of spare CPU + * capacity. CPU utilization is allowed to overshoot current CPU capacity + * though since this is useful for predicting the CPU capacity required + * after task migrations (scheduler-driven DVFS). + * + * Return: (Estimated) utilization for the specified CPU. + */ +static unsigned long cpu_util(int cpu, struct task_struct *p, int dst_cpu) { struct cfs_rq *cfs_rq = &cpu_rq(cpu)->cfs; unsigned long util = READ_ONCE(cfs_rq->avg.util_avg); @@ -7217,9 +7247,9 @@ static unsigned long cpu_util_next(int cpu, struct task_struct *p, int dst_cpu) * contribution. In all the other cases @cpu is not impacted by the * migration so its util_avg is already correct. */ - if (task_cpu(p) == cpu && dst_cpu != cpu) + if (p && task_cpu(p) == cpu && dst_cpu != cpu) lsub_positive(&util, task_util(p)); - else if (task_cpu(p) != cpu && dst_cpu == cpu) + else if (p && task_cpu(p) != cpu && dst_cpu == cpu) util += task_util(p); if (sched_feat(UTIL_EST)) { @@ -7255,7 +7285,7 @@ static unsigned long cpu_util_next(int cpu, struct task_struct *p, int dst_cpu) */ if (dst_cpu == cpu) util_est += _task_util_est(p); - else if (unlikely(task_on_rq_queued(p) || current == p)) + else if (p && unlikely(task_on_rq_queued(p) || current == p)) lsub_positive(&util_est, _task_util_est(p)); util = max(util, util_est); @@ -7264,6 +7294,11 @@ static unsigned long cpu_util_next(int cpu, struct task_struct *p, int dst_cpu) return min(util, capacity_orig_of(cpu)); } +unsigned long cpu_util_cfs(int cpu) +{ + return cpu_util(cpu, NULL, -1); +} + /* * cpu_util_without: compute cpu utilization without any contributions from *p * @cpu: the CPU which utilization is requested @@ -7281,9 +7316,9 @@ static unsigned long cpu_util_without(int cpu, struct task_struct *p) { /* Task has no contribution or is new */ if (cpu != task_cpu(p) || !READ_ONCE(p->se.avg.last_update_time)) - return cpu_util_cfs(cpu); + p = NULL; - return cpu_util_next(cpu, p, -1); + return cpu_util(cpu, p, -1); } /* @@ -7330,7 +7365,7 @@ static inline void eenv_task_busy_time(struct energy_env *eenv, * cpu_capacity. * * The contribution of the task @p for which we want to estimate the - * energy cost is removed (by cpu_util_next()) and must be calculated + * energy cost is removed (by cpu_util()) and must be calculated * separately (see eenv_task_busy_time). This ensures: * * - A stable PD utilization, no matter which CPU of that PD we want to place @@ -7351,7 +7386,7 @@ static inline void eenv_pd_busy_time(struct energy_env *eenv, int cpu; for_each_cpu(cpu, pd_cpus) { - unsigned long util = cpu_util_next(cpu, p, -1); + unsigned long util = cpu_util(cpu, p, -1); busy_time += effective_cpu_util(cpu, util, ENERGY_UTIL, NULL); } @@ -7375,7 +7410,7 @@ eenv_pd_max_util(struct energy_env *eenv, struct cpumask *pd_cpus, for_each_cpu(cpu, pd_cpus) { struct task_struct *tsk = (cpu == dst_cpu) ? p : NULL; - unsigned long util = cpu_util_next(cpu, p, dst_cpu); + unsigned long util = cpu_util(cpu, p, dst_cpu); unsigned long cpu_util; /* @@ -7521,7 +7556,7 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu) if (!cpumask_test_cpu(cpu, p->cpus_ptr)) continue; - util = cpu_util_next(cpu, p, cpu); + util = cpu_util(cpu, p, cpu); cpu_cap = capacity_of(cpu); /* diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index d8ba81c66579..aaf6fc2df6ff 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2955,53 +2955,8 @@ static inline unsigned long cpu_util_dl(struct rq *rq) return READ_ONCE(rq->avg_dl.util_avg); } -/** - * cpu_util_cfs() - Estimates the amount of CPU capacity used by CFS tasks. - * @cpu: the CPU to get the utilization for. - * - * The unit of the return value must be the same as the one of CPU capacity - * so that CPU utilization can be compared with CPU capacity. - * - * CPU utilization is the sum of running time of runnable tasks plus the - * recent utilization of currently non-runnable tasks on that CPU. - * It represents the amount of CPU capacity currently used by CFS tasks in - * the range [0..max CPU capacity] with max CPU capacity being the CPU - * capacity at f_max. - * - * The estimated CPU utilization is defined as the maximum between CPU - * utilization and sum of the estimated utilization of the currently - * runnable tasks on that CPU. It preserves a utilization "snapshot" of - * previously-executed tasks, which helps better deduce how busy a CPU will - * be when a long-sleeping task wakes up. The contribution to CPU utilization - * of such a task would be significantly decayed at this point of time. - * - * CPU utilization can be higher than the current CPU capacity - * (f_curr/f_max * max CPU capacity) or even the max CPU capacity because - * of rounding errors as well as task migrations or wakeups of new tasks. - * CPU utilization has to be capped to fit into the [0..max CPU capacity] - * range. Otherwise a group of CPUs (CPU0 util = 121% + CPU1 util = 80%) - * could be seen as over-utilized even though CPU1 has 20% of spare CPU - * capacity. CPU utilization is allowed to overshoot current CPU capacity - * though since this is useful for predicting the CPU capacity required - * after task migrations (scheduler-driven DVFS). - * - * Return: (Estimated) utilization for the specified CPU. - */ -static inline unsigned long cpu_util_cfs(int cpu) -{ - struct cfs_rq *cfs_rq; - unsigned long util; - - cfs_rq = &cpu_rq(cpu)->cfs; - util = READ_ONCE(cfs_rq->avg.util_avg); - if (sched_feat(UTIL_EST)) { - util = max_t(unsigned long, util, - READ_ONCE(cfs_rq->avg.util_est.enqueued)); - } - - return min(util, capacity_orig_of(cpu)); -} +extern unsigned long cpu_util_cfs(int cpu); static inline unsigned long cpu_util_rt(struct rq *rq) { |