Shorten rcu_check_quiescent_state.

davej@codemonkey.org.uk
Thu, 15 May 2003 04:31:13 +0100


Single spin_unlock path cuts this down a little..

diff -urpN --exclude-from=/home/davej/.exclude bk-linus/kernel/rcupdate.c linux-2.5/kernel/rcupdate.c
--- bk-linus/kernel/rcupdate.c 2003-04-10 06:01:42.000000000 +0100
+++ linux-2.5/kernel/rcupdate.c 2003-04-03 06:02:38.000000000 +0100
@@ -121,9 +121,8 @@ static void rcu_check_quiescent_state(vo
{
int cpu = smp_processor_id();

- if (!test_bit(cpu, &rcu_ctrlblk.rcu_cpu_mask)) {
+ if (!test_bit(cpu, &rcu_ctrlblk.rcu_cpu_mask))
return;
- }

/*
* Races with local timer interrupt - in the worst case
@@ -134,23 +133,22 @@ static void rcu_check_quiescent_state(vo
RCU_last_qsctr(cpu) = RCU_qsctr(cpu);
return;
}
- if (RCU_qsctr(cpu) == RCU_last_qsctr(cpu)) {
+ if (RCU_qsctr(cpu) == RCU_last_qsctr(cpu))
return;
- }

spin_lock(&rcu_ctrlblk.mutex);
- if (!test_bit(cpu, &rcu_ctrlblk.rcu_cpu_mask)) {
- spin_unlock(&rcu_ctrlblk.mutex);
- return;
- }
+ if (!test_bit(cpu, &rcu_ctrlblk.rcu_cpu_mask))
+ goto out_unlock;
+
clear_bit(cpu, &rcu_ctrlblk.rcu_cpu_mask);
RCU_last_qsctr(cpu) = RCU_QSCTR_INVALID;
- if (rcu_ctrlblk.rcu_cpu_mask != 0) {
- spin_unlock(&rcu_ctrlblk.mutex);
- return;
- }
+ if (rcu_ctrlblk.rcu_cpu_mask != 0)
+ goto out_unlock;
+
rcu_ctrlblk.curbatch++;
rcu_start_batch(rcu_ctrlblk.maxbatch);
+
+out_unlock:
spin_unlock(&rcu_ctrlblk.mutex);
}

-
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