diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2012-10-03 17:21:53 +0100 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2013-08-13 16:08:58 -0400 |
| commit | 5879bc1412b646ca81ccb1f827b6a7a44b11db3a (patch) | |
| tree | 79ecd6c35ce00a53f556af8c25f2f3f9b8408f3a | |
| parent | 8c874b19cbc3f4706bd2e5e9fd587d84dc3f38ea (diff) | |
stomp_machine: Use mutex_trylock when called from inactive cpu
If the stop machinery is called from inactive CPU we cannot use
mutex_lock, because some other stomp machine invokation might be in
progress and the mutex can be contended. We cannot schedule from this
context, so trylock and loop.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable-rt@vger.kernel.org
| -rw-r--r-- | kernel/stop_machine.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index 561ba3a7b8cf..e98c70b7f073 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -158,7 +158,7 @@ static DEFINE_PER_CPU(struct cpu_stop_work, stop_cpus_work); static void queue_stop_cpus_work(const struct cpumask *cpumask, cpu_stop_fn_t fn, void *arg, - struct cpu_stop_done *done) + struct cpu_stop_done *done, bool inactive) { struct cpu_stop_work *work; unsigned int cpu; @@ -175,7 +175,12 @@ static void queue_stop_cpus_work(const struct cpumask *cpumask, * Make sure that all work is queued on all cpus before we * any of the cpus can execute it. */ - mutex_lock(&stopper_lock); + if (!inactive) { + mutex_lock(&stopper_lock); + } else { + while (!mutex_trylock(&stopper_lock)) + cpu_relax(); + } for_each_cpu(cpu, cpumask) cpu_stop_queue_work(&per_cpu(cpu_stopper, cpu), &per_cpu(stop_cpus_work, cpu)); @@ -188,7 +193,7 @@ static int __stop_cpus(const struct cpumask *cpumask, struct cpu_stop_done done; cpu_stop_init_done(&done, cpumask_weight(cpumask)); - queue_stop_cpus_work(cpumask, fn, arg, &done); + queue_stop_cpus_work(cpumask, fn, arg, &done, false); wait_for_stop_done(&done); return done.executed ? done.ret : -ENOENT; } @@ -601,7 +606,7 @@ int stop_machine_from_inactive_cpu(int (*fn)(void *), void *data, set_state(&smdata, STOPMACHINE_PREPARE); cpu_stop_init_done(&done, num_active_cpus()); queue_stop_cpus_work(cpu_active_mask, stop_machine_cpu_stop, &smdata, - &done); + &done, true); ret = stop_machine_cpu_stop(&smdata); /* Busy wait for completion. */ |