On Tue, 8 May 2012, Gilad Ben-Yossef wrote: > My line of thought was that if we explicitly choose a scapegoat cpu we > and the user need to manage this - such as worry about what happens if > the scapegoats is offlines and let the user explicitly designate the > scapegoat cpu thus creating another knob, and worrying about what > happens if the user designate such a cpu but then it goes offlines... The scapegoat can be chosen on boot. One can f.e. create a file in /sys/device/syste/cpu called "scapegoat" which contains the number of the processor chosen. Then one can even write a userspace daemon to automatize the moving of the processing elsewhere. Could be integrated into something horrible like irqbalance f.e. > I figured the user needs to worry about other unbounded work items > anyway if he cares about where such things are run in the general case, > but using isolcpus for example. True. So the scapegoat heuristic could be to pick the first unisolated cpu. > The same should be doable with cpusets, except that right now we mark > unbounded workqueue worker threads as pinned even though they aren't. If > I understood the discussion, the idea is exactly to stop users from > putting these threads in non root cpusets. I am not 100% sure why.. Not sure that cpusets is a good thing to bring in here because that is an optional feature of the kernel and tying basic functionality like this to cpuset support does not sound right to me. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>