Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 29 Mar 2023 10:24:14 -0400 | Subject | Re: [PATCH 4/6] sched/deadline: Create DL BW alloc, free & check overflow interface | From | Waiman Long <> |
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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 >
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