On Wed, Mar 17, 2021 at 03:35:41PM +0100, David Hildenbrand wrote: > Just assume you have two ranges > > [ ZONE_DEVICE 0 ][ ZONE_DEVICE 1] > > If the vmemmap of ZONE_DEVICE 1 could be taken from the altmap of > ZONE_DEVICE 0, we could be in trouble, as both parts can be > removed/repurposed independently ... I have to say my knowledge about ZONE_DEVICE and its intrinsencs tend to 0, that is why I thought it might not matter, but I agree that this is only asking for trouble. > If we check for > > IS_ALIGNED(nr_vmemmap_pages, PMD_SIZE), please add a proper TODO comment > that this is most probably the wrong place to take care of this. Sure, I will stuff the check in there and place a big TODO comment so we do not forget about addressing this issue the right way. I will prepare a v5 (hopefully the last one) and do some more testing before sending it out. Thanks David! -- Oscar Salvador SUSE L3
