Messages in this thread | | | Subject | Re: [PATCH 19/32] nohz/cpuset: Restart tick when nohz flag is cleared on cpuset | From | Peter Zijlstra <> | Date | Mon, 29 Aug 2011 18:02:01 +0200 |
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On Mon, 2011-08-15 at 17:52 +0200, Frederic Weisbecker wrote: > +++ b/kernel/cpuset.c > @@ -1199,6 +1199,14 @@ static void cpuset_change_flag(struct task_struct *tsk, > > DEFINE_PER_CPU(int, cpu_adaptive_nohz_ref); > > +static void cpu_exit_nohz(int cpu) > +{ > + preempt_disable(); > + smp_call_function_single(cpu, cpuset_exit_nohz_interrupt, > + NULL, true); > + preempt_enable(); > +} > + > static void update_nohz_cpus(struct cpuset *old_cs, struct cpuset *cs) > { > int cpu; > @@ -1212,6 +1220,19 @@ static void update_nohz_cpus(struct cpuset *old_cs, struct cpuset *cs) > per_cpu(cpu_adaptive_nohz_ref, cpu) += 1; > else > per_cpu(cpu_adaptive_nohz_ref, cpu) -= 1; > + > + val = per_cpu(cpu_adaptive_nohz_ref, cpu); > + > + if (!val) { > + /* > + * The update to cpu_adaptive_nohz_ref must be > + * visible right away. So that once we restart the tick > + * from the IPI, it won't be stopped again due to cache > + * update lag. > + */ > + smp_mb(); > + cpu_exit_nohz(cpu); > + } > } > } > #else > diff --git a/kernel/sched.c b/kernel/sched.c > index 78ea0a5..75378be 100644 > --- a/kernel/sched.c > +++ b/kernel/sched.c > @@ -2513,6 +2513,14 @@ void cpuset_update_nohz(void) > cpuset_nohz_restart_tick(); > } > > +void cpuset_exit_nohz_interrupt(void *unused) > +{ > + if (!tick_nohz_adaptive_mode()) > + return; > + > + cpuset_nohz_restart_tick(); > +}
You do this just to annoy me, right? Why doesn't it live in cpuset.c where you use it?
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