> > I'm ok with it being 16M for now unless it causes a problem in > > practice, i.e. something like the minimum hardware mapping alignment > > for physical memory being less than 16M. > > On second thought, arbitrary differences across architectures is a bit > sad. The most common nvdimm namespace alignment granularity is > PMD_SIZE, so perhaps the default sub-section size should try to match > that default. I think that even if you keep it 16M for now, at very least you should make the map_active bitmap scalable so it will be possible to change as required later without revisiting all functions that use it. Making it a static array won't slowdown x86, as it will be still a single 64-bit word on x86. Pasha
