Re: [CFT][RFC] HT scheduler

Rusty Russell
2003-12-21T00:30:24Z

In message <3FE28529.1010003@cyberone.com.au> you write:
> + * See comment for set_cpus_allowed. calling rules are different:
> + * the task's runqueue lock must be held, and __set_cpus_allowed
> + * will return with the runqueue unlocked.

Please, never *ever* do this.

Locking is probably the hardest thing to get right, and code like this
makes it harder.

Fortunately, there is a simple solution coming with the hotplug CPU
code: we need to hold the cpucontrol semaphore here anyway, against
cpus vanishing.

Perhaps we should just use that in both places.
Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.