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Commit 98834b83 authored by Paul E. McKenney's avatar Paul E. McKenney
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rcu: Exclude RCU-offline CPUs from expedited grace periods 



The expedited RCU grace periods currently rely on a failure indication
from smp_call_function_single() to determine that a given CPU is offline.
This works after a fashion, but is more contorted and less precise than
relying on RCU's internal state.  This commit therefore takes a first
step towards relying on internal state.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 24a6cff2

kernel/rcu/tree_exp.h

+2 −1
Original line number Diff line number Diff line
@@ -359,7 +359,8 @@ static void sync_rcu_exp_select_cpus(struct rcu_state *rsp, 
			struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);



			if (raw_smp_processor_id() == cpu ||

			    !(atomic_add_return(0, &rdtp->dynticks) & 0x1))

			    !(atomic_add_return(0, &rdtp->dynticks) & 0x1) ||

			    !(rnp->qsmaskinitnext & rdp->grpmask))

				mask_ofl_test |= rdp->grpmask;

		}

		mask_ofl_ipi = rnp->expmask & ~mask_ofl_test;