On Mon, Aug 13, 2007 at 03:22:25PM -0700, Christoph Lameter wrote: > On Tue, 14 Aug 2007, Andi Kleen wrote: > > > > x86_64 is the only platforms that uses ZONE_DMA32. Ia64 and other 64 bit > > > platforms use ZONE_DMA for <4GB allocs. > > > > Yes, but ZONE_DMA32 == ZONE_DMA. > > I am not sure what you mean by that. Ia64 ZONE_DMA == x86_84 ZONE_DMA32?
Hmm, when I wrote GFP_DMA32 it was a #define GFP_DMA32 GFP_DMA on ia64 so that drivers not need to ifdef. Someone nasty seems to have removed that too. I guess it would be best to readd. > > > Also when the slab users of GFP_DMA are all gone ia64 won't need > > the slab support anymore. So either you change your ifdef in slub or > > switch to ZONE_DMA32 for IA64. > > If you have gotten rid of all slab users of GFP_DMA (and also all arch > uses of it) then we can drop the code in SLAB. No, e.g. s390 and some other architectures still use it. You'll need to bug their respective maintainers. > 1. Drop sl?b support for GFP_DMA. Not yet. > > 2. Drop GFP_DMA32 support. > > Then we only allow page allocator allocs using GFP_DMA? That may be the Kind of yes. > least invasive for arch code. I would prefer for GFP_DMA to go away on x86 (but GFP_DMA32 stay). This way we get clean compile errors instead of subtle breakage. Silently changing the semantics would be bad. But then it wouldn't make sense to have GFP_DMA on ia64 and GFP_DMA32 on x86. Since driver writers are more likely to test on x86 I would recommend ia64 having compatible semantics. It'll save everybody trouble long term. This means it wouldn't help on IA64 machines that don't have a DMA zone -- they would still need to validate drivers especially -- but at least the others. Also from my driver review driver authors often seem to have trouble understanding what GFP_DMA really does. With GFP_DMA32 it is clearer that it applies to a address range and is not some synonym for pci_map_* -Andi - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
