Commit bbf18b19 authored Jun 19, 2012 by Prashanth Nageshappa Committed by Ingo Molnar Jul 24, 2012

sched: Reset loop counters if all tasks are pinned and we need to redo load balance

While load balancing, if all tasks on the source runqueue are pinned,
we retry after excluding the corresponding source cpu. However, loop counters
env.loop and env.loop_break are not reset before retrying, which can lead
to failure in moving the tasks. In this patch we reset env.loop and
env.loop_break to their inital values before we retry.

Signed-off-by: Prashanth Nageshappa <prashanth@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/4FE06EEF.2090709@linux.vnet.ibm.com

Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 85c1e7da

kernel/sched/fair.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -4288,8 +4288,11 @@ more_balance:
		/* All tasks on this runqueue were pinned by CPU affinity */
		if (unlikely(env.flags & LBF_ALL_PINNED)) {
		cpumask_clear_cpu(cpu_of(busiest), cpus);
		if (!cpumask_empty(cpus))
		if (!cpumask_empty(cpus)) {
		env.loop = 0;
		env.loop_break = sched_nr_migrate_break;
		goto redo;
		}
		goto out_balanced;
		}
		}