On 06/23/2015 11:01 PM, Bharata B Rao wrote: > So will it be correct to say that memory hotplug to memory-less node > isn't supported by PowerPC kernel ? Should I enforce the same in QEMU > for PowerKVM ? >
I'm not sure if that is correct. It appears that we initialize all online nodes, even those without spanned_pages, at boot time. This occurs in setup_node_data() called from initmem_init(). Looking at this I would think that we could add memory to any online node even if it does not have any spanned_pages. I think an interesting test we be to check for the node being online instead of checking to see if it has any memory. -Nathan > On Mon, Jun 22, 2015 at 10:18 AM, Bharata B Rao <bharata....@gmail.com> wrote: >> Hi, >> >> While developing memory hotplug support in QEMU for PoweKVM, I >> realized that guest kernel has specific checks to prevent hot addition >> of memory to a memory-less node. >> >> I am referring to arch/powerpc/mm/numa.c:hot_add_scn_to_nid() which >> has explicit checks to ensure that it returns a nid that has some some >> memory (NODE_DATA(nid)->node_spanned_pages) even when user wants to >> hotplug to a node that currently has zero memory. >> >> Is this limitation by design ? >> >> Regards, >> Bharata. >> -- >> http://raobharata.wordpress.com/ > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
