On Mon 25-03-19 10:28:00, Jeff Moyer wrote: > Michal Hocko <mhocko@xxxxxxxxxx> writes: > > >> > and I would like to know that you are > >> > not just shifting the problem to a smaller unit and a new/creative HW > >> > will force us to go even more complicated. > >> > >> HW will not do this to us. It's software that has the problem. > >> Namespace creation is unnecessarily constrained to 128MB alignment. > > > > And why is that a problem? A lack of documentation that this is a > > requirement? Something will not work with a larger alignment? Someting > > else? > > See this email for one user-visible problem: > https://lore.kernel.org/lkml/x49imxbx22d.fsf@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ : # ndctl create-namespace -m fsdax -s 128m : Error: '--size=' must align to interleave-width: 6 and alignment: 2097152 : did you intend --size=132M? : : failed to create namespace: Invalid argument So the size is in section size units. So what prevents the userspace to use a proper alignment? I am sorry if this is a stupid question but I am not really familiar with ndctl nor the pmem side of it. -- Michal Hocko SUSE Labs
