On 04/10/2017 01:03 PM, Michal Hocko wrote:
> From: Michal Hocko <mhocko@xxxxxxxx>
>
> Memory hotplug (add_memory_resource) has to reinitialize node
> infrastructure if the node is offline (one which went through the
> complete add_memory(); remove_memory() cycle). That involves node
> registration to the kobj infrastructure (register_node), the proper
> association with cpus (register_cpu_under_node) and finally creation of
> node<->memblock symlinks (link_mem_sections).
>
> The last part requires to know node_start_pfn and node_spanned_pages
> which we currently have but a leter patch will postpone this
> initialization to the onlining phase which happens later. In fact we do
> not need to rely on the early pgdat initialization even now because the
> currently hot added pfn range is currently known.
>
> Split register_one_node into core which does all the common work for
> the boot time NUMA initialization and the hotplug (__register_one_node).
> register_one_node keeps the full initialization while hotplug calls
> __register_one_node and manually calls link_mem_sections for the proper
> range.
>
> This shouldn't introduce any functional change.
>
> Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
nit:
> @@ -1387,7 +1387,22 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online)
> node_set_online(nid);
>
> if (new_node) {
> - ret = register_one_node(nid);
> + unsigned long start_pfn = start >> PAGE_SHIFT;
> + unsigned long nr_pages = size >> PAGE_SHIFT;
> +
> + ret = __register_one_node(nid);
> + if (ret)
> + goto register_fail;
> +
> + /*
> + * link memory sections under this node. This is already
> + * done when creatig memory section in register_new_memory
> + * but that depends to have the node registered so offline
> + * nodes have to go through register_node.
> + * TODO clean up this mess.
Is this a work-in-progress or final TODO? :)
> + */
> + ret = link_mem_sections(nid, start_pfn, nr_pages);
> +register_fail:
> /*
> * If sysfs file of new node can't create, cpu on the node
> * can't be hot-added. There is no rollback way now.
>
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