Messages in this thread | | | Date | Wed, 18 Sep 2002 19:36:00 +0200 (CEST) | From | Ingo Molnar <> | Subject | Re: [patch] lockless, scalable get_pid(), for_each_process() elimination, 2.5.35-BK |
| |
On Wed, 18 Sep 2002, William Lee Irwin III wrote:
> > i agree that this is okay, as an added mechanism. Nevertheless this does > > not eliminate the 'box locks up for seconds' (or even minutes) situation. > > The lockups I see range from hours to "it spun over the weekend, time to > pull the plug".
this can happen if there's a genuine PID space squeeze wrt. nr_threads - that is solved by adding Linus' suggestion to the PID allocator. I believe you saw that problem, not any inherent get_pid() algorithmic inefficiency.
nevertheless we do lock up for 32 seconds if there are 32K PIDs allocated in a row and last_pid hits that range - regardless of pid_max. (Depending on the cache architecture it could take significantly more.)
Ingo
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |