Messages in this thread | | | Subject | Re: [PATCH 8/8] sched: reset lb_env when redo in load_balance() | From | Peter Zijlstra <> | Date | Tue, 19 Mar 2013 16:21:23 +0100 |
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On Thu, 2013-02-14 at 14:48 +0900, Joonsoo Kim wrote: > Commit 88b8dac0 makes load_balance() consider other cpus in its group. > So, now, When we redo in load_balance(), we should reset some fields of > lb_env to ensure that load_balance() works for initial cpu, not for other > cpus in its group. So correct it. > > Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 70631e8..25c798c 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -5014,14 +5014,20 @@ static int load_balance(int this_cpu, struct rq *this_rq, > > struct lb_env env = { > .sd = sd, > - .dst_cpu = this_cpu, > - .dst_rq = this_rq, > .dst_grpmask = dst_grp, > .idle = idle, > - .loop_break = sched_nr_migrate_break, > .cpus = cpus, > }; > > + schedstat_inc(sd, lb_count[idle]); > + cpumask_copy(cpus, cpu_active_mask); > + > +redo: > + env.dst_cpu = this_cpu; > + env.dst_rq = this_rq; > + env.loop = 0; > + env.loop_break = sched_nr_migrate_break; > + > /* For NEWLY_IDLE load_balancing, we don't need to consider > * other cpus in our group */ > if (idle == CPU_NEWLY_IDLE) {
OK, so this is the case where we tried to balance !this_cpu and found ALL_PINNED, right?
You can only get here in very weird cases where people love their sched_setaffinity() waaaaay too much, do we care? Why not give up?
Also, looking at this, shouldn't we consider env->cpus in can_migrate_task() where we compute new_dst_cpu?
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