On Fri, Apr 24, 2015 at 03:04:27PM -0400, Waiman Long wrote: > >>Within a NUMA node, however, we can split the > >>memory initialization to 2 or more local CPUs if the memory size is > >>big enough. > >> > >I considered it but discarded the idea. It'd be more complex to setup and > >the two CPUs could simply end up contending on the same memory bus as > >well as contending on zone->lock. > > > > I don't think we need that now. However, we may have to consider > this when one day even a single node can have TBs of memory unless > we move to a page size larger than 4k. >
We'll cross that bridge when we come to it. I suspect there is more room for improvement in the initialisation that would be worth trying before resorting to more threads. With more threads there is a risk that we hit memory bus contention and a high risk that it actually is worse due to contending on zone->lock when freeing the pages. In the meantime, do you mind updating the before/after figures for your test machine with this series please? -- Mel Gorman SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/