On 03.04.19 10:50, Oscar Salvador wrote: > 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. > I am talking about the memtrace and ACPI thing. Otherwise I agree, trust the user iff the user is the same person adding/removing memory. -- Thanks, David / dhildenb
