DMA32 zone unusable

[Mika Penttilä <mika.penttila@kolumbus.fi>]

The new DMA32 zone (which at least x86-64 has) is quite "interesting" :

#define __GFP_DMA32    ((__force gfp_t)0x04) <-----!!!!!  

#define GFP_ZONEMASK    0x03   <------!!!!!

#define gfp_zone(mask) ((__force int)((mask) & (__force gfp_t)GFP_ZONEMASK))

static inline struct page *alloc_pages_node(int nid, gfp_t gfp_mask,
                       unsigned int order)
{
   if (unlikely(order >= MAX_ORDER))
       return NULL;

   return __alloc_pages(gfp_mask, order,
       NODE_DATA(nid)->node_zonelists + gfp_zone(gfp_mask));
}


So with GFP_DMA32 you never get those pages (but DMA instead).

--Mika

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