On Tue, May 26, 2020 at 01:52:21PM -0700, Dan Williams wrote: > On Tue, May 26, 2020 at 1:49 PM Jeff Moyer <jmoyer@xxxxxxxxxx> wrote: > > > > Dan Williams <dan.j.williams@xxxxxxxxx> writes: > > > > >> What problems with 5.4.y and 5.6.y is this series fixing > > >> that used to work before? > > > > > > The "used to work" bug fixed by this set is the fact that the kernel > > > used to force a 128MB (memory hotplug section size) alignment padding > > > on all persistent memory namespaces to enable DAX operation. The > > > support for sub-sections (2MB) dropped forced alignment padding, but > > > unfortunately introduced a regression for the case of trying to create > > > multiple unaligned namespaces. When that bug triggers namespace > > > creation for the region is disabled, iirc, previously that lockout > > > scenario was prevented. > > > > > > Jeff, can you corroborate this? > > > > So, I don't pretend to remember the exact state of brokenness for each > > iteration. :) As far as I can recall, though, the issue you describe > > with a misaligned namespace preventing further namespace creation was > > present in all kernels up until it was finally fixed. > > Well, if it was always there, then there is nothing to fix, and I > misremembered that we went backwards. > > > > I otherwise agree, if the above never worked then this can all wait > > > for v5.7 upgrades. > > > > I can test specific kernel versions if that would help out. > > Thanks for that offer, but outside of a clear regression I don't think > this meets -stable criteria. I agree, I'll drop this series from my pending-queue. thanks, greg k-h
