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Commit 5d0b0249 authored by Paul E. McKenney's avatar Paul E. McKenney
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rcu: Don't bother affinitying rcub kthreads away from offline CPUs 



When rcu_boost_kthread_setaffinity() sees that all CPUs for a given
rcu_node structure are now offline, it affinities the corresponding
RCU-boost ("rcub") kthread away from those CPUs.  This is pointless
because the kthread cannot run on those offline CPUs in any case.
This commit therefore removes this unneeded code.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 1be0085b

kernel/rcu/tree_plugin.h

+1 −5
Original line number Diff line number Diff line
@@ -1322,12 +1322,8 @@ static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu) 
	for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask >>= 1)

		if ((mask & 0x1) && cpu != outgoingcpu)

			cpumask_set_cpu(cpu, cm);

	if (cpumask_weight(cm) == 0) {

	if (cpumask_weight(cm) == 0)

		cpumask_setall(cm);

		for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++)

			cpumask_clear_cpu(cpu, cm);

		WARN_ON_ONCE(cpumask_weight(cm) == 0);

	}

	set_cpus_allowed_ptr(t, cm);

	free_cpumask_var(cm);

}