On 17.12.20 16:28, Anshuman Khandual wrote: > This series adds a mechanism allowing platforms to weigh in and prevalidate > incoming address range before proceeding further with the memory hotplug. > This helps prevent potential platform errors for the given address range, > down the hotplug call chain, which inevitably fails the hotplug itself. > > This mechanism was suggested by David Hildenbrand during another discussion > with respect to a memory hotplug fix on arm64 platform. > > https://lore.kernel.org/linux-arm-kernel/1600332402-30123-1-git-send-email-anshuman.khandual@xxxxxxx/ > > This mechanism focuses on the addressibility aspect and not [sub] section > alignment aspect. Hence check_hotplug_memory_range() and check_pfn_span() > have been left unchanged. Wondering if all these can still be unified in > an expanded memhp_range_allowed() check, that can be called from multiple > memory hot add and remove paths. > > This series applies on v5.10 and has been tested on arm64. But only > build tested on s390. > > Changes in V2: > > - Changed s390 version per Heiko and updated the commit message > - Called memhp_range_allowed() only for arch_add_memory() in pagemap_range() > - Exported the symbol memhp_get_pluggable_range() > > Changes in V1: > > https://lore.kernel.org/linux-mm/1607400978-31595-1-git-send-email-anshuman.khandual@xxxxxxx/ > > - Fixed build problems with (MEMORY_HOTPLUG & !MEMORY_HOTREMOVE) > - Added missing prototype for arch_get_mappable_range() > - Added VM_BUG_ON() check for memhp_range_allowed() in arch_add_memory() per David > > Changes in RFC V2: > > https://lore.kernel.org/linux-mm/1606706992-26656-1-git-send-email-anshuman.khandual@xxxxxxx/ > > Incorporated all review feedbacks from David. > > - Added additional range check in __segment_load() on s390 which was lost > - Changed is_private init in pagemap_range() > - Moved the framework into mm/memory_hotplug.c > - Made arch_get_addressable_range() a __weak function > - Renamed arch_get_addressable_range() as arch_get_mappable_range() > - Callback arch_get_mappable_range() only handles range requiring linear mapping > - Merged multiple memhp_range_allowed() checks in register_memory_resource() > - Replaced WARN() with pr_warn() in memhp_range_allowed() > - Replaced error return code ERANGE with E2BIG > > Changes in RFC V1: > > https://lore.kernel.org/linux-mm/1606098529-7907-1-git-send-email-anshuman.khandual@xxxxxxx/ > > Cc: Heiko Carstens <hca@xxxxxxxxxxxxx> > Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx> > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > Cc: Will Deacon <will@xxxxxxxxxx> > Cc: Ard Biesheuvel <ardb@xxxxxxxxxx> > Cc: Mark Rutland <mark.rutland@xxxxxxx> > Cc: David Hildenbrand <david@xxxxxxxxxx> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > Cc: linux-s390@xxxxxxxxxxxxxxx > Cc: linux-mm@xxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx > > Anshuman Khandual (3): > mm/hotplug: Prevalidate the address range being added with platform > arm64/mm: Define arch_get_mappable_range() > s390/mm: Define arch_get_mappable_range() Thanks, I'm planning on reviewing + sending a virtio-mem patch to use memhp_get_mappable_range() in the new year. I assume we also have restrictions when it comes to x86-64, will have a look. -- Thanks, David / dhildenb
