On 10/01/18 15:30, Christoph Hellwig wrote:
On Wed, Jan 10, 2018 at 12:06:22PM +0000, Robin Murphy wrote:On 10/01/18 08:00, Christoph Hellwig wrote:To preserve the x86 behavior.And combined with patch 10/22 of the SWIOTLB refactoring, this means SWIOTLB allocations will also end up NUMA-aware, right? Great, that's what we want on arm64 too :)Well, only for swiotlb allocations that can be satisfied by dma_direct_alloc. If we actually have to fall back to the swiotlb buffers there is not node affinity yet.
Yeah, when I looked into it I reached the conclusion that per-node bounce buffers probably weren't worth it - if you have to bounce you've already pretty much lost the performance game, and if the CPU doing the bouncing happens to be on a different node from the device you've certainly lost either way. Per-node CMA zones we definitely *would* like, but that's a future problem (it looks technically feasible without huge infrastructure changes, but fiddly).
Robin. -- 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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