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). -- Michal Hocko SUSE Labs
