On 07.12.21 14:23, Michal Hocko wrote:
On Tue 07-12-21 13:28:31, David Hildenbrand wrote: [...]
But maybe I am missing something important regarding online vs. offline nodes that your patch changes?
I am relying on alloc_node_data setting the node online. But if we are to change the call to arch_alloc_node_data then the patch needs to be more involved. Here is what I have right now. If this happens to be the right way then there is some additional work to sync up with the hotplug code.
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index c5952749ad40..a296e934ad2f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -8032,8 +8032,23 @@ void __init free_area_init(unsigned long *max_zone_pfn) /* Initialise every node */ mminit_verify_pageflags_layout(); setup_nr_node_ids();
- for_each_online_node(nid) {
pg_data_t *pgdat = NODE_DATA(nid);
- for_each_node(nid) {
pg_data_t *pgdat;if (!node_online(nid)) {pr_warn("Node %d uninitialized by the platform. Please report with memory map.\n", nid);pgdat = arch_alloc_nodedata(nid);pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat);arch_refresh_nodedata(nid, pgdat);node_set_online(nid);
Setting all possible nodes online might result in quite some QE noice, because all these nodes will then be visible in the sysfs and try_offline_nodes() is essentially for the trash.
I agree to prealloc the pgdat, I don't think we should actually set the nodes online. Node onlining/offlining should be done when we do have actual CPUs/memory populated.