DMA32 zone unusable

From: Mika Penttilä
Date: Wed Nov 16 2005 - 10:22:43 EST

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).


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