Messages in this thread Patch in this message | | | From | Dietmar Eggemann <> | Subject | [PATCH 2/3] sched/deadline: Make dl_cpuset_cpumask_can_shrink() capacity-aware | Date | Wed, 29 Jun 2022 14:20:52 +0200 |
| |
dl_cpuset_cpumask_can_shrink() is used to validate whether there is still enough CPU capacity for DL tasks in the reduced cpuset.
Currently it still operates on `# remaining CPUs in the cpuset` (1). Change this to use the already capacity-aware DL admission control __dl_overflow() for the `cpumask can shrink` test.
dl_b->bw = sched_rt_period << BW_SHIFT / sched_rt_period
dl_b->bw * (1) >= currently allocated bandwidth in root_domain (rd)
Replace (1) w/ `\Sum CPU capacity in rd >> SCHED_CAPACITY_SHIFT`
Adapt __dl_bw_capacity() to take a cpumask instead of a CPU number argument so that `rd->span` and `cpumask of the reduced cpuset` can be used here.
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> --- kernel/sched/deadline.c | 24 +++++++++++------------- 1 file changed, 11 insertions(+), 13 deletions(-)
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 3f9d90b8a8b6..34de6060dea6 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -124,15 +124,12 @@ static inline int dl_bw_cpus(int i) return cpus; } -static inline unsigned long __dl_bw_capacity(int i) +static inline unsigned long __dl_bw_capacity(const struct cpumask *mask) { - struct root_domain *rd = cpu_rq(i)->rd; unsigned long cap = 0; + int i; - RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(), - "sched RCU must be held"); - - for_each_cpu_and(i, rd->span, cpu_active_mask) + for_each_cpu_and(i, mask, cpu_active_mask) cap += capacity_orig_of(i); return cap; @@ -148,7 +145,10 @@ static inline unsigned long dl_bw_capacity(int i) capacity_orig_of(i) == SCHED_CAPACITY_SCALE) { return dl_bw_cpus(i) << SCHED_CAPACITY_SHIFT; } else { - return __dl_bw_capacity(i); + RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(), + "sched RCU must be held"); + + return __dl_bw_capacity(cpu_rq(i)->rd->span); } } @@ -3004,17 +3004,15 @@ bool dl_param_changed(struct task_struct *p, const struct sched_attr *attr) int dl_cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial) { - int ret = 1, trial_cpus; + unsigned long flags, cap; struct dl_bw *cur_dl_b; - unsigned long flags; + int ret = 1; rcu_read_lock_sched(); cur_dl_b = dl_bw_of(cpumask_any(cur)); - trial_cpus = cpumask_weight(trial); - + cap = __dl_bw_capacity(trial); raw_spin_lock_irqsave(&cur_dl_b->lock, flags); - if (cur_dl_b->bw != -1 && - cur_dl_b->bw * trial_cpus < cur_dl_b->total_bw) + if (__dl_overflow(cur_dl_b, cap, 0, 0)) ret = 0; raw_spin_unlock_irqrestore(&cur_dl_b->lock, flags); rcu_read_unlock_sched(); -- 2.25.1
| |