On Fri, Oct 31, 2014 at 09:27:16PM +0100, Vlastimil Babka wrote: > What could help would be to cache one or few free huge pages per > zone with cache > re-fill done asynchronously, e.g. via work queues. The cache could > benefit fault-THP > allocations as well. And adding some logic that if nobody uses the > cached pages and > memory is low, then free them. And importantly, if it's not possible > to allocate huge > pages for the cache, then prevent scanning for collapse candidates > as there's no point. > (well this is probably more complex if some nodes can allocate huge > pages and others > not). I think this would be a pretty cool addition, even separately from this effort. If we keep a page cached on each NUMA node, then we could, theoretically, really speed up the khugepaged scans (even if we don't move those scans to task_work), and regular THP faults. I'll add it to my ever-growing wish list :) - Alex -- 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>