On 09/07/23 at 10:17am, Baoquan He wrote: > 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. Except of the empty vmap_area_list, this patch looks good to me. We may need think of another way to export the vmalloc_start value or deduce it in makedumpfile/Crash utility. And then remove the useless vmap_area_list. I am not sure if we should remove vmap_area_list in this patch because the empty value will cause breakage anyway. Otherwise, Reviewed-by: Baoquan He <bhe@xxxxxxxxxx> > > > > > 3. The vmallocinfo and vread() have to be reworked to be able to > > handle multiple nodes. >
