From ff3bf92d90d396e51eb78c5ecde11a994ab7a179 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 9 Apr 2019 14:44:49 -0700 Subject: [PATCH] torture: Allow inter-stutter interval to be specified Currently, the inter-stutter interval is the same as the stutter duration, that is, whatever number of jiffies is passed into torture_stutter_init(). This has worked well for quite some time, but the addition of forward-progress testing to rcutorture can delay processes for several seconds, which can triple the time that they are stuttered. This commit therefore adds a second argument to torture_stutter_init() that specifies the inter-stutter interval. While locktorture preserves the current behavior, rcutorture uses the RCU CPU stall warning interval to provide a wider inter-stutter interval. Signed-off-by: Paul E. McKenney --- include/linux/torture.h | 2 +- kernel/locking/locktorture.c | 2 +- kernel/rcu/rcutorture.c | 5 ++++- kernel/torture.c | 6 ++++-- 4 files changed, 10 insertions(+), 5 deletions(-) diff --git a/include/linux/torture.h b/include/linux/torture.h index 23d80db426d7..a620118385bb 100644 --- a/include/linux/torture.h +++ b/include/linux/torture.h @@ -66,7 +66,7 @@ int torture_shutdown_init(int ssecs, void (*cleanup)(void)); /* Task stuttering, which forces load/no-load transitions. */ bool stutter_wait(const char *title); -int torture_stutter_init(int s); +int torture_stutter_init(int s, int sgap); /* Initialization and cleanup. */ bool torture_init_begin(char *ttype, int v); diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c index 80a463d31a8d..c513031cd7e3 100644 --- a/kernel/locking/locktorture.c +++ b/kernel/locking/locktorture.c @@ -975,7 +975,7 @@ static int __init lock_torture_init(void) goto unwind; } if (stutter > 0) { - firsterr = torture_stutter_init(stutter); + firsterr = torture_stutter_init(stutter, stutter); if (firsterr) goto unwind; } diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 954ac2b98619..a16d6abe1715 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -2373,7 +2373,10 @@ rcu_torture_init(void) if (stutter < 0) stutter = 0; if (stutter) { - firsterr = torture_stutter_init(stutter * HZ); + int t; + + t = cur_ops->stall_dur ? cur_ops->stall_dur() : stutter * HZ; + firsterr = torture_stutter_init(stutter * HZ, t); if (firsterr) goto unwind; } diff --git a/kernel/torture.c b/kernel/torture.c index de0e0ecf88e1..a8d9bdfba7c3 100644 --- a/kernel/torture.c +++ b/kernel/torture.c @@ -570,6 +570,7 @@ static void torture_shutdown_cleanup(void) static struct task_struct *stutter_task; static int stutter_pause_test; static int stutter; +static int stutter_gap; /* * Block until the stutter interval ends. This must be called periodically @@ -621,7 +622,7 @@ static int torture_stutter(void *arg) } WRITE_ONCE(stutter_pause_test, 0); if (!torture_must_stop()) - schedule_timeout_interruptible(stutter); + schedule_timeout_interruptible(stutter_gap); torture_shutdown_absorb("torture_stutter"); } while (!torture_must_stop()); torture_kthread_stopping("torture_stutter"); @@ -631,9 +632,10 @@ static int torture_stutter(void *arg) /* * Initialize and kick off the torture_stutter kthread. */ -int torture_stutter_init(const int s) +int torture_stutter_init(const int s, const int sgap) { stutter = s; + stutter_gap = sgap; return torture_create_kthread(torture_stutter, NULL, stutter_task); } EXPORT_SYMBOL_GPL(torture_stutter_init);