Re: [PATCH v3] mm: fix panic in __alloc_pages

On Thu 09-12-21 19:01:03, Alexey Makhalov wrote:

quoted

On Dec 9, 2021, at 5:29 AM, Michal Hocko [off-list ref] wrote:

On Thu 09-12-21 10:23:52, Alexey Makhalov wrote:

quoted

quoted

On Dec 9, 2021, at 1:56 AM, Michal Hocko [off-list ref] wrote:

On Thu 09-12-21 09:28:55, Alexey Makhalov wrote:

quoted

[    0.081777] Node 4 uninitialized by the platform. Please report with boot dmesg.
[    0.081790] Initmem setup node 4 [mem 0x0000000000000000-0x0000000000000000]
...
[    0.086441] Node 127 uninitialized by the platform. Please report with boot dmesg.
[    0.086454] Initmem setup node 127 [mem 0x0000000000000000-0x0000000000000000]

Interesting that only those two didn't get a proper arch specific
initialization. Could you check why? I assume init_cpu_to_node
doesn't see any CPU pointing at this node. Wondering why that would be
the case but that can be a bug in the affinity tables.

My bad shrinking. Not just these 2, but all possible and not present nodes from 4 to 127
are having this message.

Does that mean that your possible (but offline) cpus do not set their
affinity?

Hi Michal,

I didn’t quite gut a question here. Do you mean scheduler affinity for offlined/not present CPUs?
From the patch, this message should be printed for every possible offlined node:
	for_each_node(nid) {
...
		if (!node_online(nid)) {
			pr_warn("Node %d uninitialized by the platform. Please report with boot dmesg.\n", nid);

Sure, let me expand on this a bit. X86 initialization code
(init_cpu_to_node) does
        for_each_possible_cpu(cpu) {
                int node = numa_cpu_node(cpu);

                if (node == NUMA_NO_NODE)
                        continue;

                if (!node_online(node))
                        init_memory_less_node(node);

                numa_set_node(cpu, node);
        }

which means that a memory less node is not initialized either when
	- your offline CPUs are not listed in possible cpus for some
	  reason
	- or they do not have any node affinity (numa_cpu_node is
	  NUMA_NO_NODE).

Could you check what is the reason in your particular case please?

-- 
Michal Hocko
SUSE Labs