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Commit fb58bac5 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: Remove unnecessary RCU exclusion 



As Nick pointed out, and realized by myself when doing:
   sched: Fix balance vs hotplug race
the patch:
   sched: for_each_domain() vs RCU

is wrong, sched_domains are freed after synchronize_sched(), which
means disabling preemption is enough.

Reported-by: default avatarNick Piggin <npiggin@suse.de>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 6cecd084

kernel/sched_fair.c

+2 −7
Original line number Diff line number Diff line
@@ -1403,7 +1403,6 @@ static int select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flag 
		new_cpu = prev_cpu;

	}



	rcu_read_lock();

	for_each_domain(cpu, tmp) {

		/*

		 * If power savings logic is enabled for a domain, see if we
@@ -1484,10 +1483,8 @@ static int select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flag 
			update_shares(tmp);

	}



	if (affine_sd && wake_affine(affine_sd, p, sync)) {

		new_cpu = cpu;

		goto out;

	}

	if (affine_sd && wake_affine(affine_sd, p, sync))

		return cpu;



	while (sd) {

		int load_idx = sd->forkexec_idx;
@@ -1528,8 +1525,6 @@ static int select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flag 
		/* while loop will break here if sd == NULL */

	}



out:

	rcu_read_unlock();

	return new_cpu;

}

#endif /* CONFIG_SMP */