On 12/01/2021 16:53, Daniel Bristot de Oliveira wrote:
[...]
> ----- %< -----
> #!/bin/bash
> # Enter on the cgroup directory
> cd /sys/fs/cgroup/
>
> # Check it if is cgroup v2 and enable cpuset
> if [ -e cgroup.subtree_control ]; then
> # Enable cpuset controller on cgroup v2
> echo +cpuset > cgroup.subtree_control
> fi
>
> echo LOG: create an exclusive cpuset and assigned the CPU 0 to it
> # Create cpuset groups
> rmdir dl-group &> /dev/null
> mkdir dl-group
>
> # Restrict the task to the CPU 0
> echo 0 > dl-group/cpuset.mems
> echo 0 > dl-group/cpuset.cpus
> echo root > dl-group/cpuset.cpus.partition
>
> echo LOG: dispatching a regular task
> sleep 100 &
> CPUSET_PID="$!"
>
> # let it settle down
> sleep 1
>
> # Assign the second task to the cgroup
There is only one task 'CPUSET_PID' involved here?
> echo LOG: moving the second DL task to the cpuset
> echo "$CPUSET_PID" > dl-group/cgroup.procs 2> /dev/null
>
> CPUSET_ALLOWED=`cat /proc/$CPUSET_PID/status | grep Cpus_allowed_list | awk
> '{print $2}'`
>
> chrt -p -d --sched-period 1000000000 --sched-runtime 100000000 0 $CPUSET_PID
> ACCEPTED=$?
>
> if [ $ACCEPTED == 0 ]; then
> echo PASS: the task became DL
> else
> echo FAIL: the task was rejected as DL
> fi
[...]
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 5961a97541c2..3c2775e6869f 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -5905,15 +5905,15 @@ static int __sched_setscheduler(struct task_struct *p,
> #ifdef CONFIG_SMP
> if (dl_bandwidth_enabled() && dl_policy(policy) &&
> !(attr->sched_flags & SCHED_FLAG_SUGOV)) {
> - cpumask_t *span = rq->rd->span;
> + struct root_domain *rd = dl_task_rd(p);
>
> /*
> * Don't allow tasks with an affinity mask smaller than
> * the entire root_domain to become SCHED_DEADLINE. We
> * will also fail if there's no bandwidth available.
> */
> - if (!cpumask_subset(span, p->cpus_ptr) ||
> - rq->rd->dl_bw.bw == 0) {
> + if (!cpumask_subset(rd->span, p->cpus_ptr) ||
> + rd->dl_bw.bw == 0) {
> retval = -EPERM;
> goto unlock;
> }
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index c221e14d5b86..1f6264cb8867 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -2678,8 +2678,8 @@ int sched_dl_overflow(struct task_struct *p, int policy,
> u64 period = attr->sched_period ?: attr->sched_deadline;
> u64 runtime = attr->sched_runtime;
> u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0;
> - int cpus, err = -1, cpu = task_cpu(p);
> - struct dl_bw *dl_b = dl_bw_of(cpu);
> + int cpus, err = -1, cpu = dl_task_cpu(p);
> + struct dl_bw *dl_b = dl_task_root_bw(p);
> unsigned long cap;
>
> if (attr->sched_flags & SCHED_FLAG_SUGOV)
>
Wouldn't it be sufficient to just introduce dl_task_cpu() and use the
correct cpu to get rd->span or struct dl_bw in __sched_setscheduler()
-> sched_dl_overflow()?
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5961a97541c2..0573f676696a 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5905,7 +5905,8 @@ static int __sched_setscheduler(struct task_struct *p,
#ifdef CONFIG_SMP
if (dl_bandwidth_enabled() && dl_policy(policy) &&
!(attr->sched_flags & SCHED_FLAG_SUGOV)) {
- cpumask_t *span = rq->rd->span;
+ int cpu = dl_task_cpu(p);
+ cpumask_t *span = cpu_rq(cpu)->rd->span;
/*
* Don't allow tasks with an affinity mask smaller than
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index c221e14d5b86..308ecaaf3d28 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2678,7 +2678,7 @@ int sched_dl_overflow(struct task_struct *p, int policy,
u64 period = attr->sched_period ?: attr->sched_deadline;
u64 runtime = attr->sched_runtime;
u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0;
- int cpus, err = -1, cpu = task_cpu(p);
+ int cpus, err = -1, cpu = dl_task_cpu(p);
struct dl_bw *dl_b = dl_bw_of(cpu);
unsigned long cap;
