Dan Williams dan.j.williams@intel.com 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.
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.
Cheers, Jeff