Add Kazu and Lianbo to CC, and kexec mailing list On 08/29/23 at 10:11am, Uladzislau Rezki (Sony) wrote: > Store allocated objects in a separate nodes. A va->va_start > address is converted into a correct node where it should > be placed and resided. An addr_to_node() function is used > to do a proper address conversion to determine a node that > contains a VA. > > Such approach balances VAs across nodes as a result an access > becomes scalable. Number of nodes in a system depends on number > of CPUs divided by two. The density factor in this case is 1/2. > > Please note: > > 1. As of now allocated VAs are bound to a node-0. It means the > patch does not give any difference comparing with a current > behavior; > > 2. The global vmap_area_lock, vmap_area_root are removed as there > is no need in it anymore. The vmap_area_list is still kept and > is _empty_. It is exported for a kexec only; I haven't taken a test, while accessing all nodes' busy tree to get va of the lowest address could severely impact kcore reading efficiency on system with many vmap nodes. People doing live debugging via /proc/kcore will get a little surprise. Empty vmap_area_list will break makedumpfile utility, Crash utility could be impactd too. I checked makedumpfile code, it relys on vmap_area_list to deduce the vmalloc_start value. > > 3. The vmallocinfo and vread() have to be reworked to be able to > handle multiple nodes.
