On Mon, Jan 27, 2025 at 10:34:03AM -0500, Gregory Price wrote: > Hotplug memory sources may have opinions on what the memblock size > should be - usually for alignment purposes. For example, CXL memory > extents can be 256MB with a matching alignment. If this size/alignment > is smaller than the block size, it can result in stranded capacity. > > Implement memory_block_advise_max_size for use prior to allocator init, > for software to advise the system on the max block size. > > Implement memory_block_probe_max_size for use by arch init code to > calculate the best block size. Use of advice is architecture defined. > > The probe value can never change after first probe. Calls to advise > after probe will return -EBUSY to aid debugging. > > On systems without hotplug, always return -ENODEV and 0 respectively. > > Suggested-by: Ira Weiny <ira.weiny@xxxxxxxxx> > Acked-by: David Hildenbrand <david@xxxxxxxxxx> > Acked-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx> > Acked-by: Dan Williams <dan.j.williams@xxxxxxxxx> > Tested-by: Fan Ni <fan.ni@xxxxxxxxxxx> > Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx> > Signed-off-by: Gregory Price <gourry@xxxxxxxxxx> Acked-by: Oscar Salvador <osalvador@xxxxxxx> -- Oscar Salvador SUSE Labs
