On 4/7/22 01:47, Wei Yang wrote: > On Tue, Apr 05, 2022 at 07:11:12PM +0200, Vlastimil Babka wrote: >>On 1/23/22 02:35, Wei Yang wrote: >>> To make node order in round-robin in the same distance group, we add a >>> penalty to the first node we got in each round. >>> >>> To get a round-robin order in the same distance group, we don't need to >>> decrease the penalty since: >>> >>> * find_next_best_node() always iterates node in the same order >>> * distance matters more then penalty in find_next_best_node() >>> * in nodes with the same distance, the first one would be picked up >>> >>> So it is fine to increase same penalty when we get the first node in the >>> same distance group. >> >>With that logic I'm not even sure if we need nr_online_nodes as penalty or >>it could be just 1. Would you know? > > Yes, it has the same effect. Good. > [ 0.031849] Fallback order for Node 0: 0 1 2 3 4 5 6 7 > [ 0.031854] Fallback order for Node 1: 1 2 3 0 5 6 7 4 > [ 0.031857] Fallback order for Node 2: 2 3 0 1 6 7 4 5 > [ 0.031860] Fallback order for Node 3: 3 0 1 2 7 4 5 6 > [ 0.031864] Fallback order for Node 4: 4 5 6 7 0 1 2 3 > [ 0.031867] Fallback order for Node 5: 5 6 7 4 1 2 3 0 > [ 0.031870] Fallback order for Node 6: 6 7 4 5 2 3 0 1 > [ 0.031873] Fallback order for Node 7: 7 4 5 6 3 0 1 2 > > Do you prefer to set it to 1? Yeah I think it's worth simplyfing as much as feasible, so the code is more obvious. I think we can also then remove the MAX_NODE_LOAD #define and usage. Also please Cc at least Oscar and David (added to Cc now) on v2 as they have been active in memory hotplug area recently. Thanks, Vlastimil
