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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-08-18 16:11:37 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-10-09 14:26:08 -0700
commit2b1516e55f8416acfb48d5f43d41222d180fb5a3 (patch)
tree68d5e48d865b53a5551f721dbac11d55913d6879 /kernel/rcu
parent8a5776a5f49812d29fe4b2d0a2d71675c3facf3f (diff)
downloadlwn-2b1516e55f8416acfb48d5f43d41222d180fb5a3.tar.gz
lwn-2b1516e55f8416acfb48d5f43d41222d180fb5a3.zip
rcutorture: Add interrupt-disable capability to stall-warning tests
When rcutorture sees the rcutorture.stall_cpu kernel boot parameter, it loops with preemption disabled, which does in fact normally generate an RCU CPU stall warning message. However, there are test scenarios that need the stalling CPU to have interrupts disabled. This commit therefore adds an rcutorture.stall_cpu_irqsoff kernel boot parameter that causes the stalling CPU to disable interrupts. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/rcutorture.c18
1 files changed, 13 insertions, 5 deletions
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 45f2ffbc1e78..0273bc0a8586 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -89,6 +89,7 @@ torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
torture_param(int, stall_cpu_holdoff, 10,
"Time to wait before starting stall (s).");
+torture_param(int, stall_cpu_irqsoff, 0, "Disable interrupts while stalling.");
torture_param(int, stat_interval, 60,
"Number of seconds between stats printk()s");
torture_param(int, stutter, 5, "Number of seconds to run/halt test");
@@ -1357,7 +1358,7 @@ rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
"fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
"test_boost=%d/%d test_boost_interval=%d "
"test_boost_duration=%d shutdown_secs=%d "
- "stall_cpu=%d stall_cpu_holdoff=%d "
+ "stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
"n_barrier_cbs=%d "
"onoff_interval=%d onoff_holdoff=%d\n",
torture_type, tag, nrealreaders, nfakewriters,
@@ -1365,7 +1366,7 @@ rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
test_boost, cur_ops->can_boost,
test_boost_interval, test_boost_duration, shutdown_secs,
- stall_cpu, stall_cpu_holdoff,
+ stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
n_barrier_cbs,
onoff_interval, onoff_holdoff);
}
@@ -1430,12 +1431,19 @@ static int rcu_torture_stall(void *args)
if (!kthread_should_stop()) {
stop_at = get_seconds() + stall_cpu;
/* RCU CPU stall is expected behavior in following code. */
- pr_alert("rcu_torture_stall start.\n");
rcu_read_lock();
- preempt_disable();
+ if (stall_cpu_irqsoff)
+ local_irq_disable();
+ else
+ preempt_disable();
+ pr_alert("rcu_torture_stall start on CPU %d.\n",
+ smp_processor_id());
while (ULONG_CMP_LT(get_seconds(), stop_at))
continue; /* Induce RCU CPU stall warning. */
- preempt_enable();
+ if (stall_cpu_irqsoff)
+ local_irq_enable();
+ else
+ preempt_enable();
rcu_read_unlock();
pr_alert("rcu_torture_stall end.\n");
}