On Tue, 12 Sep 2006, Nick Piggin wrote: > Christoph Lameter wrote: > > On Tue, 12 Sep 2006, Nick Piggin wrote: > > > I can't see from your patches, but what happens if someone asks > > > for a GFP_DMA page or dma slab allocation when there is no ZONE_DMA? > > The page/slab allocator will simply ignore the flag and return ZONE_NORMAL > > memory. See gfp_zone(). > That's wrong, I think? It should return NULL surely? (and possibly do > a printk telling the user they should enable ZONE_DMA config, although > some users have valid fallback strategies). Ignoring GFP_DMA is consistent with how GFP_DMA32 and GFP_HIGHMEM ar treated. There are subsystems that sporadically set GFP_DMA and the earlier patchset was so full of #ifdefs because it attempted to cover all cases. ZONE_DMA must be enabled if a device drivers relies on ISA DMA or GENERIC DMA. Otherwise we do not allow the selection of the driver. We could add a BUG in gfp_zone which will give us all locations. - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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