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Subject[PATCH tip/core/rcu 1/5] torture: Convert torture_shutdown() to hrtimer
Date
Upcoming changes to the timer wheel introduce significant inaccuracy
and possibly also an ultimate limit on timeout duration. This is
a problem for the current implementation of torture_shutdown() because
(1) shutdown times are user-specified, and can therefore be quite
long, and (2) the torture scripting will kill a test instance that
runs for more than a few minutes longer than scheduled. This commit
therefore converts the torture_shutdown() timed waits to an hrtimer.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
kernel/torture.c | 27 +++++++++++++--------------
1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/kernel/torture.c b/kernel/torture.c
index 75961b3decfe..0d887eb62856 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -43,6 +43,7 @@
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/trace_clock.h>
+#include <linux/ktime.h>
#include <asm/byteorder.h>
#include <linux/torture.h>

@@ -446,9 +447,8 @@ EXPORT_SYMBOL_GPL(torture_shuffle_cleanup);
* Variables for auto-shutdown. This allows "lights out" torture runs
* to be fully scripted.
*/
-static int shutdown_secs; /* desired test duration in seconds. */
static struct task_struct *shutdown_task;
-static unsigned long shutdown_time; /* jiffies to system shutdown. */
+static ktime_t shutdown_time; /* time to system shutdown. */
static void (*torture_shutdown_hook)(void);

/*
@@ -471,20 +471,20 @@ EXPORT_SYMBOL_GPL(torture_shutdown_absorb);
*/
static int torture_shutdown(void *arg)
{
- long delta;
- unsigned long jiffies_snap;
+ ktime_t ktime_snap;

VERBOSE_TOROUT_STRING("torture_shutdown task started");
- jiffies_snap = jiffies;
- while (ULONG_CMP_LT(jiffies_snap, shutdown_time) &&
+ ktime_snap = ktime_get();
+ while (ktime_before(ktime_snap, shutdown_time) &&
!torture_must_stop()) {
- delta = shutdown_time - jiffies_snap;
if (verbose)
pr_alert("%s" TORTURE_FLAG
- "torture_shutdown task: %lu jiffies remaining\n",
- torture_type, delta);
- schedule_timeout_interruptible(delta);
- jiffies_snap = jiffies;
+ "torture_shutdown task: %llu ms remaining\n",
+ torture_type,
+ ktime_ms_delta(shutdown_time, ktime_snap));
+ set_current_state(TASK_INTERRUPTIBLE);
+ schedule_hrtimeout(&shutdown_time, HRTIMER_MODE_ABS);
+ ktime_snap = ktime_get();
}
if (torture_must_stop()) {
torture_kthread_stopping("torture_shutdown");
@@ -511,10 +511,9 @@ int torture_shutdown_init(int ssecs, void (*cleanup)(void))
{
int ret = 0;

- shutdown_secs = ssecs;
torture_shutdown_hook = cleanup;
- if (shutdown_secs > 0) {
- shutdown_time = jiffies + shutdown_secs * HZ;
+ if (ssecs > 0) {
+ shutdown_time = ktime_add(ktime_get(), ktime_set(ssecs, 0));
ret = torture_create_kthread(torture_shutdown, NULL,
shutdown_task);
}
--
2.5.2
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