On Tue, Apr 2, 2019 at 9:30 PM Anshuman Khandual <anshuman.khandual@xxxxxxx> wrote: > > This series enables memory hot remove on arm64, fixes a memblock removal > ordering problem in generic __remove_memory(), enables sysfs memory probe > interface on arm64. It also enables ZONE_DEVICE with struct vmem_altmap > support. > > Testing: > > Tested hot remove on arm64 for all 4K, 16K, 64K page config options with > all possible VA_BITS and PGTABLE_LEVELS combinations. Tested ZONE_DEVICE > with ARM64_4K_PAGES through a dummy driver. > > Build tested on non arm64 platforms. I will appreciate if folks can test > arch_remove_memory() re-ordering in __remove_memory() on other platforms. > > Dependency: > > V5 series in the thread (https://lkml.org/lkml/2019/2/14/1096) will make > kernel linear mapping loose pgtable_page_ctor() init. When this happens > the proposed functions free_pte|pmd|pud_table() in [PATCH 2/6] will have > to stop calling pgtable_page_dtor(). Hi Anshuman, I'd be interested to integrate this with the sub-section hotplug support [1]. Otherwise the padding implementation in libnvdimm can't be removed unless all ZONE_DEVICE capable archs also agree on the minimum arch_add_memory() granularity. I'd prefer not to special case which archs support which granularity, but it unfortunately complicates what you're trying to achieve. I think at a minimum we, mm hotplug co-travellers, need to come to a consensus on whether sub-section support is viable for v5.2 and / or a pre-requisite for new arch-ZONE_DEVICE implementations.
