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| author | Paul E. McKenney <paul.mckenney@linaro.org> | 2011-11-22 21:08:13 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2011-12-11 10:32:03 -0800 |
| commit | 3ad0decf98d97b9039d8ed47cee287366b929cdf (patch) | |
| tree | 3d6c02ceb148b55b9632422346978bf369e790e9 | |
| parent | f535a607c13c7b674e0788ca5765779aa74a01c3 (diff) | |
| download | linux-3ad0decf98d97b9039d8ed47cee287366b929cdf.tar.gz linux-3ad0decf98d97b9039d8ed47cee287366b929cdf.tar.bz2 linux-3ad0decf98d97b9039d8ed47cee287366b929cdf.zip | |
rcu: Reduce latency of rcu_prepare_for_idle()
Re-enable interrupts across calls to quiescent-state functions and
also across force_quiescent_state() to reduce latency.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| -rw-r--r-- | kernel/rcutree_plugin.h | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 3d84dbc113d6..42ca5a400ae3 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -2009,7 +2009,6 @@ int rcu_needs_cpu(int cpu) */ static void rcu_prepare_for_idle(int cpu) { - int c = 0; unsigned long flags; local_irq_save(flags); @@ -2055,27 +2054,30 @@ static void rcu_prepare_for_idle(int cpu) */ #ifdef CONFIG_TREE_PREEMPT_RCU if (per_cpu(rcu_preempt_data, cpu).nxtlist) { + local_irq_restore(flags); rcu_preempt_qs(cpu); force_quiescent_state(&rcu_preempt_state, 0); - c = c || per_cpu(rcu_preempt_data, cpu).nxtlist; + local_irq_save(flags); } #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */ if (per_cpu(rcu_sched_data, cpu).nxtlist) { + local_irq_restore(flags); rcu_sched_qs(cpu); force_quiescent_state(&rcu_sched_state, 0); - c = c || per_cpu(rcu_sched_data, cpu).nxtlist; + local_irq_save(flags); } if (per_cpu(rcu_bh_data, cpu).nxtlist) { + local_irq_restore(flags); rcu_bh_qs(cpu); force_quiescent_state(&rcu_bh_state, 0); - c = c || per_cpu(rcu_bh_data, cpu).nxtlist; + local_irq_save(flags); } /* * If RCU callbacks are still pending, RCU still needs this CPU. * So try forcing the callbacks through the grace period. */ - if (c) { + if (rcu_cpu_has_callbacks(cpu)) { local_irq_restore(flags); trace_rcu_prep_idle("More callbacks"); invoke_rcu_core(); |