On Thu, Jul 30, 2015 at 05:22:55PM +0200, Mike Galbraith wrote: > > I piddled about with the thought that it might be nice to be able to > sprinkle cond_resched() about to cut rt latencies without wrecking > normal load throughput, cobbled together a cond_resched_rt(). > > On my little box that was a waste of time, as the biggest hits are block > softirq and free_hot_cold_page_list(). Block softirq is one of our problems as well. It is a bit of a joke that __do_softirq() moves work to ksoftirqd after 2ms, but block softirq can take several 100ms in bad cases. We could give individual softirqs a time budget. If they exceed the budget they should complete, but reassert themselves. Not sure about the rest, but that would be pretty simple to implement for block softirq. Jörn -- Happiness isn't having what you want, it's wanting what you have. -- unknown -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>