On 03/14/2014 10:25 AM, Christoph Hellwig wrote: > On Thu, Mar 13, 2014 at 12:13:47PM -0400, Mike Snitzer wrote: >> Pretty ironic that in the same email that you ask someone to "Let's make >> this a little less personal." you start by asserting upstream >> dm-multipath sees very little testing -- and use your commit that >> recently broke dm-multipath as the basis. Anyway, please exapnd on what >> you feel is broken with upstream dm-multipath. > > Getting a little upset, eh? I didn't say it's broken, I said it gets > very little testing. The regression from me was found like so many > before only after it was backported o some enterprise kernel. > > I think the problem here is two-fold: > a) the hardware you use with dm-multipath isn't widely available. > b) it uses a very special code path in the block layer no one else uses > > a) might be fixable by having some RDAC or similar emulation in qemu if > someone wants to spend the effort. > b) is a bit harder, but we should think hard about it when rewriting the > multipath code to support blk-mq. Talking about which I think trying to > use dm-multipath on any blk-mq device will go horribly crash and boom at > the moment. > 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.
Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage h...@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg) -- 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/