On Tue, 11 Nov 2014, Andrew Morton wrote: > There's no point in doing > > #define GFP_SLAB_BUG_MASK (__GFP_DMA32|__GFP_HIGHMEM|~__GFP_BITS_MASK) > > because __GFP_DMA32|__GFP_HIGHMEM are already part of ~__GFP_BITS_MASK. ?? ~__GFP_BITS_MASK means bits 25 to 31 are set. __GFP_DMA32 is bit 2 and __GFP_HIGHMEM is bit 1.