Messages in this thread | | | Date | Thu, 28 Oct 2021 01:20:38 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 1/2] sched: isolation: cpu isolation handles for cpuset |
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On Wed, Oct 27, 2021 at 04:43:18PM -0400, Paul Gortmaker wrote: > Assuming we want to drive isolation from cpuset and not something > like /sys/devices/system/cpu/cpu*/hotplug/isolation then we'll > need some kind of handle for cpuset to drive it from. > > These would also serve as a collection point for all the isolation > related operations - current and future. While only RCU nocb toggle > is currently deployed, I've left some guesses at what is probably to > come in the future. > > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Josh Triplett <josh@joshtriplett.org> > Cc: Paul E. McKenney <paulmck@kernel.org> > Cc: Frederic Weisbecker <frederic@kernel.org> > Cc: Valentin Schneider <valentin.schneider@arm.com> > [PG: RFC code - not for merge] > Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> > --- > include/linux/sched/isolation.h | 4 ++++ > kernel/sched/isolation.c | 22 ++++++++++++++++++++++ > 2 files changed, 26 insertions(+) > > diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h > index cc9f393e2a70..3ab9c667c441 100644 > --- a/include/linux/sched/isolation.h > +++ b/include/linux/sched/isolation.h > @@ -25,6 +25,8 @@ extern bool housekeeping_enabled(enum hk_flags flags); > extern void housekeeping_affine(struct task_struct *t, enum hk_flags flags); > extern bool housekeeping_test_cpu(int cpu, enum hk_flags flags); > extern void __init housekeeping_init(void); > +extern void isolate_cpu(int cpu); > +extern void deisolate_cpu(int cpu);
I first read "desolate_cpu()". That gives me ideas to rename nohz_full.
> > #else > > @@ -46,6 +48,8 @@ static inline bool housekeeping_enabled(enum hk_flags flags) > static inline void housekeeping_affine(struct task_struct *t, > enum hk_flags flags) { } > static inline void housekeeping_init(void) { } > +static void isolate_cpu(int cpu) { } > +static void deisolate_cpu(int cpu) { } > #endif /* CONFIG_CPU_ISOLATION */ > > static inline bool housekeeping_cpu(int cpu, enum hk_flags flags) > diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c > index 7f06eaf12818..57b105d42632 100644 > --- a/kernel/sched/isolation.c > +++ b/kernel/sched/isolation.c > @@ -63,6 +63,28 @@ bool housekeeping_test_cpu(int cpu, enum hk_flags flags) > } > EXPORT_SYMBOL_GPL(housekeeping_test_cpu); > > +void isolate_cpu(int cpu) > +{ > + pr_info("Isolating core %d\n", cpu); > + if (rcu_nocb_cpu_offload(cpu)) > + pr_warn("RCU; unable to nocb offload CPU %d\n", cpu); > +#if 0 /* TODO */ > + housekeeping_clear_cpu(cpu); > + tick_nohz_full_add_cpus_to(cpumask_of(cpu)); > +#endif > +} > + > +void deisolate_cpu(int cpu) > +{ > + pr_info("Deisolating core %d\n", cpu); > +#if 0 /* TODO */ > + tick_nohz_full_clear_cpus_from(cpumask_of(cpu)); > + housekeeping_add_cpu(cpu); > +#endif > + if (rcu_nocb_cpu_deoffload(cpu)) > + pr_warn("RCU: unable to nocb reload CPU %d\n", cpu); > +}
In my series I'm eventually splitting housekeeping cpumasks so that we can modify HK_FLAG_RCU without modifying the others.
Thanks.
> + > void __init housekeeping_init(void) > { > if (!housekeeping_flags) > -- > 2.15.0 >
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