[PATCH tip/core/rcu 20/55] rcutorture: Abstract torture_shutdown_absorb()

From: Paul E. McKenney
Date: Mon Feb 17 2014 - 17:23:38 EST

Next message: Paul E. McKenney: "[PATCH tip/core/rcu 12/55] rcutorture: Add comments, especially on bin packing."
Previous message: Paul E. McKenney: "[PATCH tip/core/rcu 07/55] rcutorture: Enable concurrent rcutorture runs"
In reply to: Paul E. McKenney: "[PATCH tip/core/rcu 07/55] rcutorture: Enable concurrent rcutorture runs"
Next in thread: Paul E. McKenney: "[PATCH tip/core/rcu 12/55] rcutorture: Add comments, especially on bin packing."
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

From: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>

Because handling races between rmmod and normal shutdown is not specific
to rcutorture, this commit renames rcutorture_shutdown_absorb() to
torture_shutdown_absorb() and pulls it out into then kernel/torture.c
module. This implies pulling the fullstop mechanism into kernel/torture.c
as well.

The exporting of fullstop and fullstop_mutex is ugly and must die.
And it does in fact die in later commits that introduce higher-level
APIs that encapsulate both of these variables.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
include/linux/torture.h | 11 +++++++++++
kernel/rcu/rcutorture.c | 49 ++++++++++++-------------------------------------
kernel/torture.c | 20 ++++++++++++++++++++
3 files changed, 43 insertions(+), 37 deletions(-)

diff --git a/include/linux/torture.h b/include/linux/torture.h
index 8a4088f2f87b..c61b4ce18a13 100644
--- a/include/linux/torture.h
+++ b/include/linux/torture.h
@@ -41,6 +41,14 @@
module_param(name, type, 0444); \
MODULE_PARM_DESC(name, msg);

+/* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */
+#define FULLSTOP_DONTSTOP 0 /* Normal operation. */
+#define FULLSTOP_SHUTDOWN 1 /* System shutdown with rcutorture running. */
+#define FULLSTOP_RMMOD 2 /* Normal rmmod of rcutorture. */
+extern int fullstop;
+/* Protect fullstop transitions and spawning of kthreads. */
+extern struct mutex fullstop_mutex;
+
#define TORTURE_FLAG "-torture:"
#define TOROUT_STRING(s) \
pr_alert("%s" TORTURE_FLAG s "\n", torture_type)
@@ -57,4 +65,7 @@ struct torture_random_state {
#define DEFINE_TORTURE_RANDOM(name) struct torture_random_state name = { 0, 0 }
unsigned long torture_random(struct torture_random_state *trsp);

+/* Shutdown task absorption, for when the tasks cannot safely be killed. */
+void torture_shutdown_absorb(const char *title);
+
#endif /* __LINUX_TORTURE_H */
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 2bb3dcb67221..3687619b243a 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -199,17 +199,6 @@ static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);

-/* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */
-
-#define FULLSTOP_DONTSTOP 0 /* Normal operation. */
-#define FULLSTOP_SHUTDOWN 1 /* System shutdown with rcutorture running. */
-#define FULLSTOP_RMMOD 2 /* Normal rmmod of rcutorture. */
-static int fullstop = FULLSTOP_RMMOD;
-/*
- * Protect fullstop transitions and spawning of kthreads.
- */
-static DEFINE_MUTEX(fullstop_mutex);
-
/* Forward reference. */
static void rcu_torture_cleanup(void);

@@ -231,20 +220,6 @@ rcutorture_shutdown_notify(struct notifier_block *unused1,
}

/*
- * Absorb kthreads into a kernel function that won't return, so that
- * they won't ever access module text or data again.
- */
-static void rcutorture_shutdown_absorb(const char *title)
-{
- if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
- pr_notice(
- "rcutorture thread %s parking due to system shutdown\n",
- title);
- schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
- }
-}
-
-/*
* Allocate an element from the rcu_tortures pool.
*/
static struct rcu_torture *
@@ -285,7 +260,7 @@ rcu_stutter_wait(const char *title)
schedule_timeout_interruptible(1);
else
schedule_timeout_interruptible(round_jiffies_relative(HZ));
- rcutorture_shutdown_absorb(title);
+ torture_shutdown_absorb(title);
}
}

@@ -680,7 +655,7 @@ checkwait: rcu_stutter_wait("rcu_torture_boost");

/* Clean up and exit. */
VERBOSE_TOROUT_STRING("rcu_torture_boost task stopping");
- rcutorture_shutdown_absorb("rcu_torture_boost");
+ torture_shutdown_absorb("rcu_torture_boost");
while (!kthread_should_stop() || rbi.inflight)
schedule_timeout_uninterruptible(1);
smp_mb(); /* order accesses to ->inflight before stack-frame death. */
@@ -716,7 +691,7 @@ rcu_torture_fqs(void *arg)
rcu_stutter_wait("rcu_torture_fqs");
} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
VERBOSE_TOROUT_STRING("rcu_torture_fqs task stopping");
- rcutorture_shutdown_absorb("rcu_torture_fqs");
+ torture_shutdown_absorb("rcu_torture_fqs");
while (!kthread_should_stop())
schedule_timeout_uninterruptible(1);
return 0;
@@ -788,7 +763,7 @@ rcu_torture_writer(void *arg)
rcu_stutter_wait("rcu_torture_writer");
} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
VERBOSE_TOROUT_STRING("rcu_torture_writer task stopping");
- rcutorture_shutdown_absorb("rcu_torture_writer");
+ torture_shutdown_absorb("rcu_torture_writer");
while (!kthread_should_stop())
schedule_timeout_uninterruptible(1);
return 0;
@@ -826,7 +801,7 @@ rcu_torture_fakewriter(void *arg)
} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);

VERBOSE_TOROUT_STRING("rcu_torture_fakewriter task stopping");
- rcutorture_shutdown_absorb("rcu_torture_fakewriter");
+ torture_shutdown_absorb("rcu_torture_fakewriter");
while (!kthread_should_stop())
schedule_timeout_uninterruptible(1);
return 0;
@@ -970,7 +945,7 @@ rcu_torture_reader(void *arg)
rcu_stutter_wait("rcu_torture_reader");
} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
VERBOSE_TOROUT_STRING("rcu_torture_reader task stopping");
- rcutorture_shutdown_absorb("rcu_torture_reader");
+ torture_shutdown_absorb("rcu_torture_reader");
if (irqreader && cur_ops->irq_capable)
del_timer_sync(&t);
while (!kthread_should_stop())
@@ -1094,7 +1069,7 @@ rcu_torture_stats(void *arg)
do {
schedule_timeout_interruptible(stat_interval * HZ);
rcu_torture_stats_print();
- rcutorture_shutdown_absorb("rcu_torture_stats");
+ torture_shutdown_absorb("rcu_torture_stats");
} while (!kthread_should_stop());
VERBOSE_TOROUT_STRING("rcu_torture_stats task stopping");
return 0;
@@ -1178,7 +1153,7 @@ rcu_torture_shuffle(void *arg)
do {
schedule_timeout_interruptible(shuffle_interval * HZ);
rcu_torture_shuffle_tasks();
- rcutorture_shutdown_absorb("rcu_torture_shuffle");
+ torture_shutdown_absorb("rcu_torture_shuffle");
} while (!kthread_should_stop());
VERBOSE_TOROUT_STRING("rcu_torture_shuffle task stopping");
return 0;
@@ -1197,7 +1172,7 @@ rcu_torture_stutter(void *arg)
if (!kthread_should_stop())
schedule_timeout_interruptible(stutter * HZ);
stutter_pause_test = 0;
- rcutorture_shutdown_absorb("rcu_torture_stutter");
+ torture_shutdown_absorb("rcu_torture_stutter");
} while (!kthread_should_stop());
VERBOSE_TOROUT_STRING("rcu_torture_stutter task stopping");
return 0;
@@ -1469,7 +1444,7 @@ static int rcu_torture_stall(void *args)
rcu_read_unlock();
pr_alert("rcu_torture_stall end.\n");
}
- rcutorture_shutdown_absorb("rcu_torture_stall");
+ torture_shutdown_absorb("rcu_torture_stall");
while (!kthread_should_stop())
schedule_timeout_interruptible(10 * HZ);
return 0;
@@ -1533,7 +1508,7 @@ static int rcu_torture_barrier_cbs(void *arg)
wake_up(&barrier_wq);
} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
VERBOSE_TOROUT_STRING("rcu_torture_barrier_cbs task stopping");
- rcutorture_shutdown_absorb("rcu_torture_barrier_cbs");
+ torture_shutdown_absorb("rcu_torture_barrier_cbs");
while (!kthread_should_stop())
schedule_timeout_interruptible(1);
cur_ops->cb_barrier();
@@ -1570,7 +1545,7 @@ static int rcu_torture_barrier(void *arg)
schedule_timeout_interruptible(HZ / 10);
} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
VERBOSE_TOROUT_STRING("rcu_torture_barrier task stopping");
- rcutorture_shutdown_absorb("rcu_torture_barrier");
+ torture_shutdown_absorb("rcu_torture_barrier");
while (!kthread_should_stop())
schedule_timeout_interruptible(1);
return 0;
diff --git a/kernel/torture.c b/kernel/torture.c
index c82c70f7828e..f05042036ae8 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -49,6 +49,11 @@
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Paul E. McKenney <paulmck@xxxxxxxxxx>");

+int fullstop = FULLSTOP_RMMOD;
+EXPORT_SYMBOL_GPL(fullstop);
+DEFINE_MUTEX(fullstop_mutex);
+EXPORT_SYMBOL_GPL(fullstop_mutex);
+
#define TORTURE_RANDOM_MULT 39916801 /* prime */
#define TORTURE_RANDOM_ADD 479001701 /* prime */
#define TORTURE_RANDOM_REFRESH 10000
@@ -69,3 +74,18 @@ torture_random(struct torture_random_state *trsp)
return swahw32(trsp->trs_state);
}
EXPORT_SYMBOL_GPL(torture_random);
+
+/*
+ * Absorb kthreads into a kernel function that won't return, so that
+ * they won't ever access module text or data again.
+ */
+void torture_shutdown_absorb(const char *title)
+{
+ while (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
+ pr_notice(
+ "torture thread %s parking due to system shutdown\n",
+ title);
+ schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
+ }
+}
+EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
--
1.8.1.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

Next message: Paul E. McKenney: "[PATCH tip/core/rcu 12/55] rcutorture: Add comments, especially on bin packing."
Previous message: Paul E. McKenney: "[PATCH tip/core/rcu 07/55] rcutorture: Enable concurrent rcutorture runs"
In reply to: Paul E. McKenney: "[PATCH tip/core/rcu 07/55] rcutorture: Enable concurrent rcutorture runs"
Next in thread: Paul E. McKenney: "[PATCH tip/core/rcu 12/55] rcutorture: Add comments, especially on bin packing."
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]