Arve Hjønnevåg <arve@xxxxxxxxxxx> wrote: > On Fri, Mar 8, 2013 at 12:49 PM, Eric Wong <normalperson@xxxxxxxx> wrote: > > What happens if ep_modify calls ep_destroy_wakeup_source > > while __pm_stay_awake is running on the same epi->ws? > > Yes, that looks like a problem. I think calling > ep_destroy_wakeup_source with ep->lock held should fix that. It is not > clear how useful changing EPOLLWAKEUP in ep_modify is, so > alternatively we could remove that feature and instead only allow it > to be set in ep_insert. ep->lock would work, but ep->lock is already a source of heavy contention in my multithreaded+epoll webservers. Perhaps RCU can be used? I've no experience with RCU, but I've been meaning to get acquainted with RCU. Another possible solution is to only use ep->ws and add an atomic counter to ep; so __pm_relax(ep->ws) is only called when the atomic counter reaches zero. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
