Messages in this thread | | | Date | Wed, 20 Mar 2013 15:52:18 +0900 | From | Joonsoo Kim <> | Subject | Re: [PATCH 3/8] sched: don't consider other cpus in our group in case of NEWLY_IDLE |
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On Tue, Mar 19, 2013 at 03:20:57PM +0100, Peter Zijlstra wrote: > On Thu, 2013-02-14 at 14:48 +0900, Joonsoo Kim wrote: > > Commit 88b8dac0 makes load_balance() consider other cpus in its group, > > regardless of idle type. When we do NEWLY_IDLE balancing, we should not > > consider it, because a motivation of NEWLY_IDLE balancing is to turn > > this cpu to non idle state if needed. This is not the case of other cpus. > > So, change code not to consider other cpus for NEWLY_IDLE balancing. > > > > With this patch, assign 'if (pulled_task) this_rq->idle_stamp = 0' > > in idle_balance() is corrected, because NEWLY_IDLE balancing doesn't > > consider other cpus. Assigning to 'this_rq->idle_stamp' is now valid. > > > > Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> > > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> > > Fair enough, good catch. > > Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index 0c6aaf6..97498f4 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -5016,8 +5016,15 @@ static int load_balance(int this_cpu, struct rq *this_rq, > > .cpus = cpus, > > }; > > > > + /* For NEWLY_IDLE load_balancing, we don't need to consider > > + * other cpus in our group */ > > + if (idle == CPU_NEWLY_IDLE) { > > + env.dst_grpmask = NULL; > > + max_lb_iterations = 0; > > Just a small nit; I don't think we'll ever get to evaluate > max_lb_iterations when !dst_grpmask. So strictly speaking its > superfluous to touch it.
Okay. In next spin, I will remove it and add a comment here.
Thanks.
> > > + } else { > > + max_lb_iterations = cpumask_weight(env.dst_grpmask); > > + } > > cpumask_copy(cpus, cpu_active_mask); > > - max_lb_iterations = cpumask_weight(env.dst_grpmask); > > > > schedstat_inc(sd, lb_count[idle]); > > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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