On Fri, Feb 16, 2024 at 08:52:30AM +0100, Oscar Salvador wrote: > On Fri, Feb 16, 2024 at 04:07:54PM +0900, Byungchul Park wrote: > > For normal numa nodes, node_data[] is initialized at alloc_node_data(), > > but it's not for memoryless node. However, the node *gets onlined* at > > init_cpu_to_node(). > > > > Let's look at back free_area_init(). free_area_init_node() will be called > > with node_data[] not set yet, because it's already *onlined*. So > > ->zone_pgdat cannot be initialized properly in the path you mentioned. > > I am might be missing something., so bear with me. > > free_area_init() gets called before init_cpu_to_node() does. > free_area_init_node() gets called on every possible node. > > free_area_init_node then() does > > pg_data_t *pgdat = NODE_DATA(nid);, > > and then we call free_area_init_core(). > > free_area_init_core() does > > free_area_init_core() does > zone_init_internals() > > which ends up doing zone->zone_pgdat = NODE_DATA(nid); > > If node_data[] was not set at all, we would already blow up when doing > the first > > for_each_node() > pgdat = NODE_DATA(nid); > free_area_init_node(nid); > > back in free_area_init(). It seems that I got it wrong about the reason. Let me check it again and share the reason. Just in case, this patch is still definitely necessary tho. Byungchul
