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rcu: Don't bother affinitying rcub kthreads away from offline CPUs

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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: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney
2014-11-10 08:07:08 -08:00
parent 1be0085b51
commit 5d0b024973
1 changed files with 1 additions and 5 deletions
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6
kernel/rcu/tree_plugin.h
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@@ -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) for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask >>= 1)
if ((mask & 0x1) && cpu != outgoingcpu) if ((mask & 0x1) && cpu != outgoingcpu)
cpumask_set_cpu(cpu, cm); cpumask_set_cpu(cpu, cm);
if (cpumask_weight(cm) == 0) { if (cpumask_weight(cm) == 0)
cpumask_setall(cm); 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); set_cpus_allowed_ptr(t, cm);
free_cpumask_var(cm); free_cpumask_var(cm);
} }