Messages in this thread | | | Date | Tue, 3 Aug 2004 00:20:00 +0200 | From | Andi Kleen <> | Subject | Re: [PATCH] [ppc64] watch IOMMU virtual merging |
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On Tue, Aug 03, 2004 at 07:45:51AM +1000, Benjamin Herrenschmidt wrote:
[adding linux-scsi with full quote] > > Actually, we could tune the ratio between large allocs and small allocs, > the real problem is the failure case. We can't really afford to break > down a physical segment at the iommu level because that would increase > the size of the SG list which can't be dealt at the upper level (we don't > know how much space has been allocated and the HW may have limitations on > the number of entries). > > What we really need is a way for drivers to return the BIO upstream and > ask for a split in case of iommu allocation error, but I've been told that > would be horribly complex...
Not very, according to James B. It just needs driver changes. I would like to have it too.
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