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rcutorture: Add test of RCU CPU stall notifiers

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This commit registers an RCU CPU stall notifier when testing RCU CPU
stalls.  The notifier logs a message similar to the following:

	rcu_torture_stall_nf: v=1, duration=21001.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
This commit is contained in:
Paul E. McKenney
2023-08-15 15:53:32 -07:00
committed by Frederic Weisbecker
parent 5b404fdaba
commit 7c1b3e0c98
1 changed files with 21 additions and 0 deletions
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kernel/rcu/rcutorture.c
+21
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@@ -21,6 +21,7 @@
#include <linux/spinlock.h>
#include <linux/smp.h>
#include <linux/rcupdate_wait.h>
#include <linux/rcu_notifier.h>
#include <linux/interrupt.h>
#include <linux/sched/signal.h>
#include <uapi/linux/sched/types.h>
@@ -2428,6 +2429,16 @@ static int rcutorture_booster_init(unsigned int cpu)
return 0;
}
static int rcu_torture_stall_nf(struct notifier_block *nb, unsigned long v, void *ptr)
{
pr_info("%s: v=%lu, duration=%lu.\n", __func__, v, (unsigned long)ptr);
return NOTIFY_OK;
}
static struct notifier_block rcu_torture_stall_block = {
.notifier_call = rcu_torture_stall_nf,
};
/*
* CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
* induces a CPU stall for the time specified by stall_cpu.
@@ -2435,9 +2446,14 @@ static int rcutorture_booster_init(unsigned int cpu)
static int rcu_torture_stall(void *args)
{
int idx;
int ret;
unsigned long stop_at;
VERBOSE_TOROUT_STRING("rcu_torture_stall task started");
ret = rcu_stall_chain_notifier_register(&rcu_torture_stall_block);
if (ret)
pr_info("%s: rcu_stall_chain_notifier_register() returned %d, %sexpected.\n",
__func__, ret, !IS_ENABLED(CONFIG_RCU_STALL_COMMON) ? "un" : "");
if (stall_cpu_holdoff > 0) {
VERBOSE_TOROUT_STRING("rcu_torture_stall begin holdoff");
schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
@@ -2481,6 +2497,11 @@ static int rcu_torture_stall(void *args)
cur_ops->readunlock(idx);
}
pr_alert("%s end.\n", __func__);
if (!ret) {
ret = rcu_stall_chain_notifier_unregister(&rcu_torture_stall_block);
if (ret)
pr_info("%s: rcu_stall_chain_notifier_unregister() returned %d.\n", __func__, ret);
}
torture_shutdown_absorb("rcu_torture_stall");
while (!kthread_should_stop())
schedule_timeout_interruptible(10 * HZ);