On Tue, Apr 03, 2018 at 09:57:37AM +0200, Michal Hocko wrote: >On Fri 30-03-18 09:02:43, Wei Yang wrote: >> On Thu, Mar 29, 2018 at 01:11:09PM +0100, Mel Gorman wrote: >> >On Thu, Mar 29, 2018 at 11:36:07AM +0800, Wei Yang wrote: >> >> set_pageblock_order() is a standalone function which sets pageblock_order, >> >> while current implementation calls this function on each ZONE of each node >> >> in free_area_init_core(). >> >> >> >> Since free_area_init_node() is the only user of free_area_init_core(), >> >> this patch moves set_pageblock_order() up one level to invoke >> >> set_pageblock_order() only once on each node. >> >> >> >> Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx> >> > >> >The patch looks ok but given that set_pageblock_order returns immediately >> >if it has already been called, I expect the benefit is marginal. Was any >> >improvement in boot time measured? >> >> No, I don't expect measurable improvement from this since the number of nodes >> and zones are limited. >> >> This is just a code refine from logic point of view. > >Then, please make sure it is a real refinement. Calling this function >per node is only half way to get there as the function is by no means >per node. > Hi, Michal I guess you are willing to see this function is only called once for the whole system. Yes, that is the ideal way, well I don't come up with an elegant way. The best way is to move this to free_area_init_nodes(), while you can see not all arch use this function. Then I have two options: A: Move this to free_area_init_nodes() for those arch using it. Call it specifically for those arch not using free_area_init_nodes(). B: call it before setup_arch() in start_kernel() Hmm... which one you would prefer? If you have a better idea, that would be great. >-- >Michal Hocko >SUSE Labs -- Wei Yang Help you, Help me
