Greetings network wizards,
Quoting kernel/sched/core.c:
/**
* yield - yield the current processor to other threads.
*
* Do not ever use this function, there's a 99% chance you're doing it wrong.
*
* The scheduler is at all times free to pick the calling task as the most
* eligible task to run, if removing the yield() call from your code breaks
* it, its already broken.
*
* Typical broken usage is:
*
* while (!event)
* yield();
*
* where one assumes that yield() will let 'the other' process run that will
* make event true. If the current task is a SCHED_FIFO task that will never
* happen. Never use yield() as a progress guarantee!!
*
* If you want to use yield() to wait for something, use wait_event().
* If you want to use yield() to be 'nice' for others, use cond_resched().
* If you still want to use yield(), do not!
*/
Livelock can be triggered by setting kworkers to SCHED_FIFO, then
suspend/resume.. you come back from sleepy-land with a spinning
kworker. For whatever reason, I can only do that with an enterprise
like config, my standard config refuses to play, but no matter, it's
"Typical broken usage".
(yield() should be rendered dead)
-Mike
