Commit 8cf40440 authored Dec 07, 2016 by Olav Haugan

sched/core: Fix race condition in clearing hmp request



There is a race condition between clearing an HMP request for active
migration and the actual active migration. Active migration can he
half-way through doing the migration when the HMP request can be cleared
by another core. Move clearing of HMP request to the stopper thread to
avoid this.

Change-Id: I6d73b8f246ae3754ab60984af198333fd284ae16
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>

parent 584d38f1

kernel/sched/core.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -5609,6 +5609,7 @@ int do_isolation_work_cpu_stop(void *data)
		*/
		nohz_balance_clear_nohz_mask(cpu);

		clear_hmp_request(cpu);
		local_irq_enable();
		return 0;
		}
		@@ -5733,7 +5734,6 @@ int sched_isolate_cpu(int cpu)

		migrate_sync_cpu(cpu, cpumask_first(&avail_cpus));
		stop_cpus(cpumask_of(cpu), do_isolation_work_cpu_stop, 0);
		clear_hmp_request(cpu);

		calc_load_migrate(rq);
		update_max_interval();