On 20.01.21 09:33, Anshuman Khandual wrote: > > > On 1/19/21 5:51 PM, David Hildenbrand wrote: >> 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(). > > Just to be sure, will the following change achieve what you are > suggesting here. pagemap_range() after this change, will again > be the same like the V1 series. Yeah, as we used to have in v1. Maybe other reviewers (@Oscar?) have a different opinion. If you decide to leave as-is, please fixup the patch description. Thanks! -- Thanks, David / dhildenb
