On 18.01.21 14:12, Anshuman Khandual wrote: > This introduces memhp_range_allowed() which can be called in various memory > hotplug paths to prevalidate the address range which is being added, with > the platform. Then memhp_range_allowed() calls memhp_get_pluggable_range() > which provides applicable address range depending on whether linear mapping > is required or not. For ranges that require linear mapping, it calls a new > arch callback arch_get_mappable_range() which the platform can override. So > the new callback, in turn provides the platform an opportunity to configure > acceptable memory hotplug address ranges in case there are constraints. > > This mechanism will help prevent platform specific errors deep down during > hotplug calls. This drops now redundant check_hotplug_memory_addressable() > check in __add_pages() but instead adds a VM_BUG_ON() check which would In this patch, you keep the __add_pages() checks. But as discussed, we could perform it in mm/memremap.c:pagemap_range() insted and convert it to a VM_BUG_ON(). Apart from that looks good to me. -- Thanks, David / dhildenb
