Messages in this thread | | | Date | Tue, 30 Aug 2011 17:10:45 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 19/32] nohz/cpuset: Restart tick when nohz flag is cleared on cpuset |
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On Mon, Aug 29, 2011 at 06:02:01PM +0200, Peter Zijlstra wrote: > 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?
Right, I'll move all those things and fix the naming / namespace.
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