Re: [Linaro-mm-sig] [PATCH] [RFC] mutex: w/w mutex slowpath debugging

On Tue, 2013-04-30 at 20:45 +0200, Daniel Vetter wrote:

/** diff --git a/kernel/mutex.c b/kernel/mutex.c index 66807c7..1cc3487 100644 --- a/kernel/mutex.c +++ b/kernel/mutex.c @@ -827,6 +827,35 @@ int __sched mutex_trylock(struct mutex *lock) EXPORT_SYMBOL(mutex_trylock); #ifndef CONFIG_DEBUG_LOCK_ALLOC

+#ifdef CONFIG_DEBUG_WW_MUTEX_SLOWPATH +static int __sched +ww_mutex_deadlock_injection(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) +{

• if (ctx->deadlock_inject_countdown-- == 0) {

• tmp = ctx->deadlock_inject_interval;
  

• if (tmp > UINT_MAX/4)
  

• 	tmp = UINT_MAX;
  

• else
  

• 	tmp = tmp*2 + tmp + tmp/2;
  

• ctx->deadlock_inject_interval = tmp;
  

• ctx->deadlock_inject_countdown = tmp;
  

• ww_mutex_unlock(lock);
  

• return -EDEADLK;
  

• }
• return 0;

+} +#else +static int __sched +ww_mutex_deadlock_injection(struct ww_mutex *lock, struct ww_acquire_ctx *ctx) +{

• return 0;

+}

This should be a static inline, and remove the __sched. There's no reason to make this anything but a nop when disabled.

-- Steve