diff mbox series

[4/6] sched/deadline: Create DL BW alloc, free & check overflow interface

Message ID 20230329125558.255239-5-juri.lelli@redhat.com
State New
Headers
Series sched/deadline: cpuset: Rework DEADLINE bandwidth restoration |

Commit Message

Juri Lelli March 29, 2023, 12:55 p.m. UTC 
  From: Dietmar Eggemann <dietmar.eggemann@arm.com>

Rework the existing dl_cpu_busy() interface which offers DL BW overflow
checking and per-task DL BW allocation.

Add dl_bw_free() as an interface to be able to free DL BW.
It will be used to allow freeing of the DL BW request done during
cpuset_can_attach() in case multiple controllers are attached to the
cgroup next to the cpuset controller and one of the non-cpuset
can_attach() fails.

dl_bw_alloc() (and dl_bw_free()) now take a `u64 dl_bw` parameter
instead of `struct task_struct *p` used in dl_cpu_busy().  This allows
to allocate DL BW for a set of tasks too rater than only for a single
task.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
---
 include/linux/sched.h   |  2 ++
 kernel/sched/core.c     |  4 ++--
 kernel/sched/deadline.c | 53 +++++++++++++++++++++++++++++++----------
 kernel/sched/sched.h    |  2 +-
 4 files changed, 45 insertions(+), 16 deletions(-)

Comments

Waiman Long March 29, 2023, 2:24 p.m. UTC | #1 
On 3/29/23 08:55, Juri Lelli wrote:
> From: Dietmar Eggemann <dietmar.eggemann@arm.com>
>
> Rework the existing dl_cpu_busy() interface which offers DL BW overflow
> checking and per-task DL BW allocation.
>
> Add dl_bw_free() as an interface to be able to free DL BW.
> It will be used to allow freeing of the DL BW request done during
> cpuset_can_attach() in case multiple controllers are attached to the
> cgroup next to the cpuset controller and one of the non-cpuset
> can_attach() fails.
>
> dl_bw_alloc() (and dl_bw_free()) now take a `u64 dl_bw` parameter
> instead of `struct task_struct *p` used in dl_cpu_busy().  This allows
> to allocate DL BW for a set of tasks too rater than only for a single
Typo: "rater" => "rather"
> task.
>
> Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
> Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
> ---
>   include/linux/sched.h   |  2 ++
>   kernel/sched/core.c     |  4 ++--
>   kernel/sched/deadline.c | 53 +++++++++++++++++++++++++++++++----------
>   kernel/sched/sched.h    |  2 +-
>   4 files changed, 45 insertions(+), 16 deletions(-)
>
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 6d654eb4cabd..6f3d84e0ed08 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -1848,6 +1848,8 @@ current_restore_flags(unsigned long orig_flags, unsigned long flags)
>   
>   extern int cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial);
>   extern int task_can_attach(struct task_struct *p, const struct cpumask *cs_effective_cpus);
> +extern int dl_bw_alloc(int cpu, u64 dl_bw);
> +extern void dl_bw_free(int cpu, u64 dl_bw);
>   #ifdef CONFIG_SMP
>   extern void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask);
>   extern int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask);
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 179266ff653f..c83dae6b8586 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -9294,7 +9294,7 @@ int task_can_attach(struct task_struct *p,
>   
>   		if (unlikely(cpu >= nr_cpu_ids))
>   			return -EINVAL;
> -		ret = dl_cpu_busy(cpu, p);
> +		ret = dl_bw_alloc(cpu, p->dl.dl_bw);
>   	}
>   
>   out:
> @@ -9579,7 +9579,7 @@ static void cpuset_cpu_active(void)
>   static int cpuset_cpu_inactive(unsigned int cpu)
>   {
>   	if (!cpuhp_tasks_frozen) {
> -		int ret = dl_cpu_busy(cpu, NULL);
> +		int ret = dl_bw_check_overflow(cpu);
>   
>   		if (ret)
>   			return ret;
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 8f92f0f87383..5b6965e0e537 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -3057,26 +3057,38 @@ int dl_cpuset_cpumask_can_shrink(const struct cpumask *cur,
>   	return ret;
>   }
>   
> -int dl_cpu_busy(int cpu, struct task_struct *p)
> +enum dl_bw_request {
> +	dl_bw_req_check_overflow = 0,
> +	dl_bw_req_alloc,
> +	dl_bw_req_free
> +};
> +
> +static int dl_bw_manage(enum dl_bw_request req, int cpu, u64 dl_bw)
>   {
> -	unsigned long flags, cap;
> +	unsigned long flags;
>   	struct dl_bw *dl_b;
> -	bool overflow;
> +	bool overflow = 0;
>   
>   	rcu_read_lock_sched();
>   	dl_b = dl_bw_of(cpu);
>   	raw_spin_lock_irqsave(&dl_b->lock, flags);
> -	cap = dl_bw_capacity(cpu);
> -	overflow = __dl_overflow(dl_b, cap, 0, p ? p->dl.dl_bw : 0);
>   
> -	if (!overflow && p) {
> -		/*
> -		 * We reserve space for this task in the destination
> -		 * root_domain, as we can't fail after this point.
> -		 * We will free resources in the source root_domain
> -		 * later on (see set_cpus_allowed_dl()).
> -		 */
> -		__dl_add(dl_b, p->dl.dl_bw, dl_bw_cpus(cpu));
> +	if (req == dl_bw_req_free) {
> +		__dl_sub(dl_b, dl_bw, dl_bw_cpus(cpu));
> +	} else {
> +		unsigned long cap = dl_bw_capacity(cpu);
> +
> +		overflow = __dl_overflow(dl_b, cap, 0, dl_bw);
> +
> +		if (req == dl_bw_req_alloc && !overflow) {
> +			/*
> +			 * We reserve space in the destination
> +			 * root_domain, as we can't fail after this point.
> +			 * We will free resources in the source root_domain
> +			 * later on (see set_cpus_allowed_dl()).
> +			 */
> +			__dl_add(dl_b, dl_bw, dl_bw_cpus(cpu));
> +		}
>   	}
>   
>   	raw_spin_unlock_irqrestore(&dl_b->lock, flags);
> @@ -3084,6 +3096,21 @@ int dl_cpu_busy(int cpu, struct task_struct *p)
>   
>   	return overflow ? -EBUSY : 0;
>   }
> +
> +int dl_bw_check_overflow(int cpu)
> +{
> +	return dl_bw_manage(dl_bw_req_check_overflow, cpu, 0);
> +}
> +
> +int dl_bw_alloc(int cpu, u64 dl_bw)
> +{
> +	return dl_bw_manage(dl_bw_req_alloc, cpu, dl_bw);
> +}
> +
> +void dl_bw_free(int cpu, u64 dl_bw)
> +{
> +	dl_bw_manage(dl_bw_req_free, cpu, dl_bw);
> +}
>   #endif
>   
>   #ifdef CONFIG_SCHED_DEBUG
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index 060616944d7a..81ecfd1a1a48 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -330,7 +330,7 @@ extern void __getparam_dl(struct task_struct *p, struct sched_attr *attr);
>   extern bool __checkparam_dl(const struct sched_attr *attr);
>   extern bool dl_param_changed(struct task_struct *p, const struct sched_attr *attr);
>   extern int  dl_cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial);
> -extern int  dl_cpu_busy(int cpu, struct task_struct *p);
> +extern int  dl_bw_check_overflow(int cpu);
>   
>   #ifdef CONFIG_CGROUP_SCHED
>
diff mbox series

Patch

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 6d654eb4cabd..6f3d84e0ed08 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1848,6 +1848,8 @@  current_restore_flags(unsigned long orig_flags, unsigned long flags)
 
 extern int cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial);
 extern int task_can_attach(struct task_struct *p, const struct cpumask *cs_effective_cpus);
+extern int dl_bw_alloc(int cpu, u64 dl_bw);
+extern void dl_bw_free(int cpu, u64 dl_bw);
 #ifdef CONFIG_SMP
 extern void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask);
 extern int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 179266ff653f..c83dae6b8586 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -9294,7 +9294,7 @@  int task_can_attach(struct task_struct *p,
 
 		if (unlikely(cpu >= nr_cpu_ids))
 			return -EINVAL;
-		ret = dl_cpu_busy(cpu, p);
+		ret = dl_bw_alloc(cpu, p->dl.dl_bw);
 	}
 
 out:
@@ -9579,7 +9579,7 @@  static void cpuset_cpu_active(void)
 static int cpuset_cpu_inactive(unsigned int cpu)
 {
 	if (!cpuhp_tasks_frozen) {
-		int ret = dl_cpu_busy(cpu, NULL);
+		int ret = dl_bw_check_overflow(cpu);
 
 		if (ret)
 			return ret;
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 8f92f0f87383..5b6965e0e537 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -3057,26 +3057,38 @@  int dl_cpuset_cpumask_can_shrink(const struct cpumask *cur,
 	return ret;
 }
 
-int dl_cpu_busy(int cpu, struct task_struct *p)
+enum dl_bw_request {
+	dl_bw_req_check_overflow = 0,
+	dl_bw_req_alloc,
+	dl_bw_req_free
+};
+
+static int dl_bw_manage(enum dl_bw_request req, int cpu, u64 dl_bw)
 {
-	unsigned long flags, cap;
+	unsigned long flags;
 	struct dl_bw *dl_b;
-	bool overflow;
+	bool overflow = 0;
 
 	rcu_read_lock_sched();
 	dl_b = dl_bw_of(cpu);
 	raw_spin_lock_irqsave(&dl_b->lock, flags);
-	cap = dl_bw_capacity(cpu);
-	overflow = __dl_overflow(dl_b, cap, 0, p ? p->dl.dl_bw : 0);
 
-	if (!overflow && p) {
-		/*
-		 * We reserve space for this task in the destination
-		 * root_domain, as we can't fail after this point.
-		 * We will free resources in the source root_domain
-		 * later on (see set_cpus_allowed_dl()).
-		 */
-		__dl_add(dl_b, p->dl.dl_bw, dl_bw_cpus(cpu));
+	if (req == dl_bw_req_free) {
+		__dl_sub(dl_b, dl_bw, dl_bw_cpus(cpu));
+	} else {
+		unsigned long cap = dl_bw_capacity(cpu);
+
+		overflow = __dl_overflow(dl_b, cap, 0, dl_bw);
+
+		if (req == dl_bw_req_alloc && !overflow) {
+			/*
+			 * We reserve space in the destination
+			 * root_domain, as we can't fail after this point.
+			 * We will free resources in the source root_domain
+			 * later on (see set_cpus_allowed_dl()).
+			 */
+			__dl_add(dl_b, dl_bw, dl_bw_cpus(cpu));
+		}
 	}
 
 	raw_spin_unlock_irqrestore(&dl_b->lock, flags);
@@ -3084,6 +3096,21 @@  int dl_cpu_busy(int cpu, struct task_struct *p)
 
 	return overflow ? -EBUSY : 0;
 }
+
+int dl_bw_check_overflow(int cpu)
+{
+	return dl_bw_manage(dl_bw_req_check_overflow, cpu, 0);
+}
+
+int dl_bw_alloc(int cpu, u64 dl_bw)
+{
+	return dl_bw_manage(dl_bw_req_alloc, cpu, dl_bw);
+}
+
+void dl_bw_free(int cpu, u64 dl_bw)
+{
+	dl_bw_manage(dl_bw_req_free, cpu, dl_bw);
+}
 #endif
 
 #ifdef CONFIG_SCHED_DEBUG
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 060616944d7a..81ecfd1a1a48 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -330,7 +330,7 @@  extern void __getparam_dl(struct task_struct *p, struct sched_attr *attr);
 extern bool __checkparam_dl(const struct sched_attr *attr);
 extern bool dl_param_changed(struct task_struct *p, const struct sched_attr *attr);
 extern int  dl_cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial);
-extern int  dl_cpu_busy(int cpu, struct task_struct *p);
+extern int  dl_bw_check_overflow(int cpu);
 
 #ifdef CONFIG_CGROUP_SCHED