This patch series introduces two xarrays of LMBs in an effort to speed up the drmem code and simplify the hotplug code on pseries machines.
The first patch introduces an xarray of LMBs indexed by physical address. xa_load() is then used to accelerate LMB lookup during memory_add_physaddr_to_nid(). The interface is used during boot, in drmem_init(), and memory hot-add, in dlpar_add_lmb(), on pseries machines. Its linear LMB search is a serious bottleneck on larger machines that xa_load() flattens nicely as shown in the before/after example. The second patch introduces a second xarray of LMBs, this one indexed by DRC index. The xarray API is leveraged to replace the custom LMB search/iteration/marking code currently used in the pseries memory hotplug module. The result is cleaner and, again thanks to xa_load(), faster. v1: One big patch. v2 changes: - Split up the big patch from v1 into a series. - Provide a more dramatic example in patch 1/2 to emphasize the linear search bottleneck in memory_add_physaddr_to_nid(). - Expand the use of the xarray API in patch 2/2 to replace more custom code.
