On Tue, Mar 05 2019 at 1:02pm -0500, Alexander Duyck <alexander.duyck@xxxxxxxxx> wrote: > On Mon, Mar 4, 2019 at 8:03 PM Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > > > > Hi, > > > > Alexander reported this same boot hang in another thread. I was able to > > reproduce using an x86_64 .config that Alexander provided. > > > > I've pushed this fix out to linux-next: > > https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-5.1&id=be2c5301817833f692aadb2e5fa209582db01d3b > > > > If you could verify this fix works for you I'd appreciate it. > > > > Thanks, > > Mike > > I've verified I am no longer seeing the issue with this patch applied. Thanks for testing. But so you and others are aware: based on further internal discussion with Mikulas, I decided to drop all the bio-based DM "noclone" changes that were developed for 5.1. Mikulas had a really good point that the 10-13% performance benefit seen with 512b IO workloads all but disappears to only a 1% improvement as soon as the bio's payload is increased to >= 4K. Meaning the risk associated with the noclone changes really is _not_ worth the reward. I've rebased the dm-5.1 branch accordingly and linux-next will pick it up tonight. Mike ps. in case anyone cares, the noclone changes have been preserved in this dm-noclone-support branch: https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/log/?h=dm-noclone-support
