From: Roland Dreier <[EMAIL PROTECTED]> Date: Tue, 24 Apr 2007 14:32:42 -0700
> > My suggestion would be to allocate top-down in the 32-bit IOMMU space. > > I think that's good for normal things, but it's not unreasonable to > want to map > 4 GB of memory at once for an Infiniband device. That's what the DAC interfaces were for, but people wanted to remoe that since no in-tree users existed. Devices like that want to essentially map the entire address space, via pass-thru, not IOMMU mappings. Clustering cards, such as those made by Dolphin, are another example. I realize that this doesn't work when we absolutely must use an IOMMU such as for virtualization which is the whole impetus of the Intel IOMMU. :-) > So maybe we would want some heuristics about the size of the mapping > being requested or the amount of 32-bit space left to decide whether a > mapping should be below 4 GB. Perhaps, but as I said heuristics might not be enough here. - 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/