On Wed, Apr 03, 2019 at 10:41:35AM +0200, David Hildenbrand wrote: > > That being said it should be the caller of the hotplug code to tell > > the vmemmap allocation strategy. For starter, I would only pack vmemmaps > > for "regular" kernel zone memory. Movable zones should be more careful. > > We can always re-evaluate later when there is a strong demand for huge > > pages on movable zones but this is not the case now because those pages > > are not really movable in practice. > > Remains the issue with potential different user trying to remove memory > it didn't add in some other granularity. We then really have to identify > and isolate that case.
If we let the caller specify whether it wants vmemmaps per memblock or range, I would trust that caller to do the correct thing and specify one thing or another depending on what it wants to do in the future. So, say a driver adds 512MB memory and it specifies that it wants vmemmaps per memblock because later on it will like to hot-remove in chunks of 128MB. -- Oscar Salvador SUSE L3
