On Thu, Jul 04, 2013 at 05:56:44PM +0530, Srikar Dronamraju wrote: > * Mel Gorman <[email protected]> [2013-07-03 15:21:33]: > > > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index 2a0bbc2..b9139be 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -800,6 +800,37 @@ unsigned int sysctl_numa_balancing_scan_delay = 1000; > > */ > > unsigned int sysctl_numa_balancing_settle_count __read_mostly = 3; > > > > +static unsigned long weighted_cpuload(const int cpu); > > + > > +static int > > +find_idlest_cpu_node(int this_cpu, int nid) > > +{ > > + unsigned long load, min_load = ULONG_MAX; > > + int i, idlest_cpu = this_cpu; > > + > > + BUG_ON(cpu_to_node(this_cpu) == nid); > > + > > + for_each_cpu(i, cpumask_of_node(nid)) { > > + load = weighted_cpuload(i); > > + > > + if (load < min_load) { > > + struct task_struct *p; > > + > > + /* Do not preempt a task running on its preferred node > > */ > > + struct rq *rq = cpu_rq(i); > > + raw_spin_lock_irq(&rq->lock); > > Not sure why we need this spin_lock? Cant this be done in a rcu block > instead? >
Judging by how find_idlest_cpu works it would appear you are correct. Thanks very much, I'm still pretty much a scheduler wuss. I know what I want but not always how to get it :) -- Mel Gorman SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
