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yaml
---
r: 277235
b: refs/heads/master
c: 84ad00c
h: refs/heads/master
i:
  277233: 1f3b2e7
  277231: 1adc768
v: v3
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Paul E. McKenney authored and Paul E. McKenney committed Dec 11, 2011
1 parent 2031e06 commit 428fce1
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Showing 2 changed files with 15 additions and 3 deletions.
2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 3084f2f80cc8a1fd66233722d88beac0fe85e26f
refs/heads/master: 84ad00cb61f1cb21f0b63bc6f7dc254399eb3830
16 changes: 14 additions & 2 deletions trunk/kernel/rcutree_plugin.h
Original file line number Diff line number Diff line change
Expand Up @@ -2027,6 +2027,9 @@ int rcu_needs_cpu(int cpu)
static void rcu_prepare_for_idle(int cpu)
{
int c = 0;
unsigned long flags;

local_irq_save(flags);

/*
* If there are no callbacks on this CPU or if RCU has no further
Expand All @@ -2036,14 +2039,17 @@ static void rcu_prepare_for_idle(int cpu)
if (!rcu_cpu_has_callbacks(cpu)) {
per_cpu(rcu_dyntick_holdoff, cpu) = jiffies - 1;
per_cpu(rcu_dyntick_drain, cpu) = 0;
per_cpu(rcu_awake_at_gp_end, cpu) = 0;
local_irq_restore(flags);
trace_rcu_prep_idle("No callbacks");
return;
}
if (!rcu_pending(cpu)) {
trace_rcu_prep_idle("Dyntick with callbacks");
per_cpu(rcu_dyntick_holdoff, cpu) = jiffies - 1;
per_cpu(rcu_dyntick_drain, cpu) = 0;
per_cpu(rcu_awake_at_gp_end, cpu) = 1;
local_irq_restore(flags);
trace_rcu_prep_idle("Dyntick with callbacks");
return; /* Nothing to do immediately. */
}

Expand All @@ -2052,6 +2058,7 @@ static void rcu_prepare_for_idle(int cpu)
* refrained from disabling the scheduling-clock tick.
*/
if (per_cpu(rcu_dyntick_holdoff, cpu) == jiffies) {
local_irq_restore(flags);
trace_rcu_prep_idle("In holdoff");
return;
}
Expand All @@ -2060,9 +2067,11 @@ static void rcu_prepare_for_idle(int cpu)
if (per_cpu(rcu_dyntick_drain, cpu) <= 0) {
/* First time through, initialize the counter. */
per_cpu(rcu_dyntick_drain, cpu) = RCU_NEEDS_CPU_FLUSHES;
per_cpu(rcu_awake_at_gp_end, cpu) = 0;
} else if (--per_cpu(rcu_dyntick_drain, cpu) <= 0) {
/* We have hit the limit, so time to give up. */
per_cpu(rcu_dyntick_holdoff, cpu) = jiffies;
local_irq_restore(flags);
trace_rcu_prep_idle("Begin holdoff");
invoke_rcu_core(); /* Force the CPU out of dyntick-idle. */
return;
Expand Down Expand Up @@ -2095,10 +2104,13 @@ static void rcu_prepare_for_idle(int cpu)
* So try forcing the callbacks through the grace period.
*/
if (c) {
local_irq_restore(flags);
trace_rcu_prep_idle("More callbacks");
invoke_rcu_core();
} else
} else {
local_irq_restore(flags);
trace_rcu_prep_idle("Callbacks drained");
}
}

/*
Expand Down

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