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Date: Mon, 15 Aug 2022 20:04:59 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org,
Dietmar Eggemann <dietmar.eggemann@....com>,
"Peter Zijlstra (Intel)" <peterz@...radead.org>,
Juri Lelli <juri.lelli@...hat.com>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.15 655/779] sched/deadline: Merge dl_task_can_attach() and dl_cpu_busy()
From: Dietmar Eggemann <dietmar.eggemann@....com>
[ Upstream commit 772b6539fdda31462cc08368e78df60b31a58bab ]
Both functions are doing almost the same, that is checking if admission
control is still respected.
With exclusive cpusets, dl_task_can_attach() checks if the destination
cpuset (i.e. its root domain) has enough CPU capacity to accommodate the
task.
dl_cpu_busy() checks if there is enough CPU capacity in the cpuset in
case the CPU is hot-plugged out.
dl_task_can_attach() is used to check if a task can be admitted while
dl_cpu_busy() is used to check if a CPU can be hotplugged out.
Make dl_cpu_busy() able to deal with a task and use it instead of
dl_task_can_attach() in task_can_attach().
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@....com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Acked-by: Juri Lelli <juri.lelli@...hat.com>
Link: https://lore.kernel.org/r/20220302183433.333029-4-dietmar.eggemann@arm.com
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
kernel/sched/core.c | 13 +++++++----
kernel/sched/deadline.c | 52 +++++++++++------------------------------
kernel/sched/sched.h | 3 +--
3 files changed, 24 insertions(+), 44 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 012c037da58a..154506e4d1f5 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -8760,8 +8760,11 @@ int task_can_attach(struct task_struct *p,
}
if (dl_task(p) && !cpumask_intersects(task_rq(p)->rd->span,
- cs_cpus_allowed))
- ret = dl_task_can_attach(p, cs_cpus_allowed);
+ cs_cpus_allowed)) {
+ int cpu = cpumask_any_and(cpu_active_mask, cs_cpus_allowed);
+
+ ret = dl_cpu_busy(cpu, p);
+ }
out:
return ret;
@@ -9045,8 +9048,10 @@ static void cpuset_cpu_active(void)
static int cpuset_cpu_inactive(unsigned int cpu)
{
if (!cpuhp_tasks_frozen) {
- if (dl_cpu_busy(cpu))
- return -EBUSY;
+ int ret = dl_cpu_busy(cpu, NULL);
+
+ if (ret)
+ return ret;
cpuset_update_active_cpus();
} else {
num_cpus_frozen++;
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index ee673a205e22..147b757d162b 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2864,41 +2864,6 @@ bool dl_param_changed(struct task_struct *p, const struct sched_attr *attr)
}
#ifdef CONFIG_SMP
-int dl_task_can_attach(struct task_struct *p, const struct cpumask *cs_cpus_allowed)
-{
- unsigned long flags, cap;
- unsigned int dest_cpu;
- struct dl_bw *dl_b;
- bool overflow;
- int ret;
-
- dest_cpu = cpumask_any_and(cpu_active_mask, cs_cpus_allowed);
-
- rcu_read_lock_sched();
- dl_b = dl_bw_of(dest_cpu);
- raw_spin_lock_irqsave(&dl_b->lock, flags);
- cap = dl_bw_capacity(dest_cpu);
- overflow = __dl_overflow(dl_b, cap, 0, p->dl.dl_bw);
- if (overflow) {
- ret = -EBUSY;
- } else {
- /*
- * 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()).
- */
- int cpus = dl_bw_cpus(dest_cpu);
-
- __dl_add(dl_b, p->dl.dl_bw, cpus);
- ret = 0;
- }
- raw_spin_unlock_irqrestore(&dl_b->lock, flags);
- rcu_read_unlock_sched();
-
- return ret;
-}
-
int dl_cpuset_cpumask_can_shrink(const struct cpumask *cur,
const struct cpumask *trial)
{
@@ -2920,7 +2885,7 @@ int dl_cpuset_cpumask_can_shrink(const struct cpumask *cur,
return ret;
}
-bool dl_cpu_busy(unsigned int cpu)
+int dl_cpu_busy(int cpu, struct task_struct *p)
{
unsigned long flags, cap;
struct dl_bw *dl_b;
@@ -2930,11 +2895,22 @@ bool dl_cpu_busy(unsigned int cpu)
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, 0);
+ 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));
+ }
+
raw_spin_unlock_irqrestore(&dl_b->lock, flags);
rcu_read_unlock_sched();
- return overflow;
+ return overflow ? -EBUSY : 0;
}
#endif
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index fe8be2f8a47d..2bbf1f006d63 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -348,9 +348,8 @@ extern void __setparam_dl(struct task_struct *p, const struct sched_attr *attr);
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_task_can_attach(struct task_struct *p, const struct cpumask *cs_cpus_allowed);
extern int dl_cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial);
-extern bool dl_cpu_busy(unsigned int cpu);
+extern int dl_cpu_busy(int cpu, struct task_struct *p);
#ifdef CONFIG_CGROUP_SCHED
--
2.35.1
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