On 04.06.20 17:06, Christoph Hellwig wrote: > On Thu, Jun 04, 2020 at 01:32:40PM +0200, David Hildenbrand wrote: >> Just a thought: If memory hotplug is applicable as well, you might >> either want to always assume data->enable_4GB, or handle memory hotplug >> events from the memory notifier, when new memory gets onlined (not sure >> how tricky that is). > > We probably want a highest_pfn_possible() or similar API instead of > having drivers poking into random VM internals.
Well, memory notifiers are a reasonable api used accross the kernel to get notified when new memory is onlined to the buddy that could be used for allocations. highest_pfn_possible() would have to default to something linked to MAX_PHYSMEM_BITS whenever memory hotplug is configured, I am not sure how helpful that is (IOW, you can just default to enable_4GB=true in that case instead in most cases). -- Thanks, David / dhildenb _______________________________________________ iommu mailing list firstname.lastname@example.org https://lists.linuxfoundation.org/mailman/listinfo/iommu