Messages in this thread | | | Date | Sun, 15 Jun 2003 01:18:12 -0700 (PDT) | Subject | Re: problem with blk_queue_bounce_limit() | From | "David S. Miller" <> |
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From: Anton Blanchard <anton@samba.org> Date: Sun, 15 Jun 2003 18:04:42 +1000
To make the best use of the IOMMU we would want to have it filled with addresses (to have the best chance that we will find an existing mapping). And for zero copy stuff it could be all over RAM. In effect we are looking at a mapping from 512GB -> 3GB. (assuming the top 1GB of PCI addresses are for PCI IO and memory)
We have this same problem with huge files in the page cache. Maybe you should use a trie.
Because that data structure will expand wrt. actual use.
I bet the management (especially the shared memory refcount bump) will outweight the costs saved unless your hardware is really stupid. But judging by the e1000/ppc64 issue, your hardware is stupid and thus maybe it's worthwhile for you to continue to pursue this idea :) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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