On Sat, May 12, 2018 at 11:35:00AM +0000, Huaisheng HS1 Ye wrote: > > The point of this exercise is to actually encode the zone number in > > the bottom bits of the GFP flags instead of something which has to be > > interpreted into a zone number. When somebody sets __GFP_MOVABLE, they > > should also be setting ZONE_MOVABLE: > > > > -#define __GFP_MOVABLE ((__force gfp_t)___GFP_MOVABLE) /* ZONE_MOVABLE allowed */ > > +#define __GFP_MOVABLE ((__force gfp_t)(___GFP_MOVABLE | (ZONE_MOVABLE ^ ZONE_NORMAL))) > > > I am afraid we couldn't do that, because __GFP_MOVABLE would be used potentially with other __GFPs like __GFP_DMA and __GFP_DMA32. That's not a combination that makes much sense. I know it's permitted today (and it has the effect of being a no-op), but when you think about it, it doesn't actually make any sense.
