(cc'ing Yinghai, hi!) Hello, On Thu, Jul 19, 2012 at 09:10:02AM +0900, Minchan Kim wrote: > On Wed, Jul 18, 2012 at 02:38:10PM -0700, Andrew Morton wrote: > > On Wed, 18 Jul 2012 10:22:00 +0900 > > Minchan Kim <minchan@xxxxxxxxxx> wrote: > > > > > > > > > > Is this really necessary? Does the zone start out all-zeroes? If not, can we > > > > make it do so? > > > > > > Good point. > > > It can remove zap_zone_vm_stats and zone->flags = 0, too. > > > More important thing is that we could remove adding code to initialize > > > zero whenever we add new field to zone. So I look at the code. > > > > > > In summary, IMHO, all is already initialie zero out but we need double > > > check in mips. > > > > > > > Well, this is hardly a performance-critical path. So rather than > > groveling around ensuring that each and every architectures does the > > right thing, would it not be better to put a single memset() into core > > MM if there is an appropriate place? > > I think most good place is free_area_init_node but at a glance, > bootmem_data is set up eariler than free_area_init_node so shouldn't we > keep that pointer still? I don't think zapping node_data that late is a good idea. It's used from very early in the boot and its usage during early boot is fairly platform dependent. Dunno whether there's a good solution for this. Maybe trigger warning if some fields which have to be zero aren't? Thanks. -- tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>