But, I myself found that what I really need in my case is not the RB tree but a simple list sorting (list_sort()). Will do sorting anyway. Enabling/disabling sorting in my case is really simple if I use list_sort() and will do. The default should be ON because I also don't see any reason to turn it off except benchmarking reason. -- Akira -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel