Re: [ANNOUNCE] Kernel Janitor's TODO list

[Roman Zippel]

Hi,

On Mon, 29 Jan 2001, Andi Kleen wrote:

> You can miss wakeups. The standard pattern is:
> 
> 	get locks
> 
> 	add_wait_queue(&waitqueue, &wait);
> 	for (;;) { 
> 		if (condition you're waiting for is true) 
> 			break; 
> 		unlock any non sleeping locks you need for condition
> 		__set_task_state(current, TASK_UNINTERRUPTIBLE); 
> 		schedule(); 
> 		__set_task_state(current, TASK_RUNNING); 
> 		reaquire locks
> 	}
> 	remove_wait_queue(&waitqueue, &wait); 

You still miss wakeups. :)
Always set the task state first, then check the condition. See the
wait_event*() macros you mentioned for the right order.

bye, Roman