On Fri, Mar 14, 2014 at 10:30:53AM +0100, Hannes Reinecke wrote: > That was actually one of my plans, move dm-multipath over to use > blk-mq. But then I'd need to discuss with Jens et al how to best > achieve this; the current static hctx allocation doesn't play well > with multipaths dynamic path management.
I'd say it the other way around: the clone + insert hacks in dm-multipath don't work well with blk-mq. Not allowing non-owned requests is fundamentally part of the blk-mq model to allow things like the integrated tag allocator and queue depth limiting or the preallocated driver specific data. Instead dm-multipath should alway resubmit the request like it already does for the slow path for the first step. Longer term we might be able to operate using a cheaper temporary structure, but I'm not sure that's going to be worth it. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
