On Tue 07-12-21 17:17:27, Alexey Makhalov wrote:
On Dec 7, 2021, at 9:13 AM, David Hildenbrand david@redhat.com wrote:
On 07.12.21 18:02, Alexey Makhalov wrote:
On Dec 7, 2021, at 8:36 AM, Michal Hocko mhocko@suse.com wrote:
On Tue 07-12-21 17:27:29, Michal Hocko wrote: [...]
So your proposal is to drop set_node_online from the patch and add it as a separate one which handles
- sysfs part (i.e. do not register a node which doesn't span a physical address space)
- hotplug side of (drop the pgd allocation, register node lazily when a first memblocks are registered)
In other words, the first stage diff --git a/mm/page_alloc.c b/mm/page_alloc.c index c5952749ad40..f9024ba09c53 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6382,7 +6382,11 @@ static void __build_all_zonelists(void *data) if (self && !node_online(self->node_id)) { build_zonelists(self); } else {
for_each_online_node(nid) {
/** All possible nodes have pgdat preallocated* free_area_init*/for_each_node(nid) { pg_data_t *pgdat = NODE_DATA(nid); build_zonelists(pgdat);Will it blow up memory usage for the nodes which might never be onlined? I prefer the idea of init on demand.
Even now there is an existing problem. In my experiments, I observed _huge_ memory consumption increase by increasing number of possible numa nodes. I’m going to report it in separate mail thread.
I already raised that PPC might be problematic in that regard. Which architecture / setup do you have in mind that can have a lot of possible nodes?
It is x86_64 VMware VM, not the regular one, but specially configured (1 vCPU per node, with hot-plug support, 128 possible nodes)
This is slightly tangent but could you elaborate more on this setup and reasoning behind it. I was already curious when you mentioned this previously. Why would you want to have so many nodes and having 1:1 with CPUs. What is the resulting NUMA topology?