Yes right. The cacheline that also contains local_node is dirtied by the locking in the SMP case and will evict the cacheline used to lookup the per cpu vector and other important information. The per cpu patches aggravated that problem by making more use of the fields that are evicted with the cacheline. Acked-by: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>