On Thu, Apr 05, 2018 at 11:55:50AM +0200, Michal Hocko wrote: >On Wed 04-04-18 09:27:34, Wei Yang wrote: >> 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. > >or >C: do nothing and/or just document why do we call it this way >(convenience). Ok, maybe we can leave it alone now. >-- >Michal Hocko >SUSE Labs -- Wei Yang Help you, Help me
