Re: [patch] slab: add memory hotplug support

KAMEZAWA Hiroyuki
2010-03-03T02:54:45Z

On Tue, 2 Mar 2010 18:39:20 -0800 (PST)
David Rientjes <rientjes@google.com> wrote:

> On Wed, 3 Mar 2010, KAMEZAWA Hiroyuki wrote:
>
> > At node hot-add
> >
> > * pgdat is allocated from other node (because we have no memory for "nid")
> > * memmap for the first section (and possiby others) will be allocated from
> > other nodes.
> > * Once a section for the node is onlined, any memory can be allocated localy.
> >
>
> Correct, and the struct kmem_list3 is also alloacted from other nodes with
> my patch.
>
> > (Allocating memory from local node requires some new implementation as
> > bootmem allocater, we didn't that.)
> >
> > Before this patch, slab's control layer is allocated by cpuhotplug.
> > So, at least keeping this order,
> > memory online -> cpu online
> > slab's control layer is allocated from local node.
> >
> > When node-hotadd is done in this order
> > cpu online -> memory online
> > kmalloc_node() will allocate memory from other node via fallback.
> >
> > After this patch, slab's control layer is allocated by memory hotplug.
> > Then, in any order, slab's control will be allocated via fallback routine.
> >
>
> Again, this addresses memory hotplug that requires a new node to be
> onlined that do not have corresponding cpus that are being onlined. On
> x86, these represent ACPI_SRAT_MEM_HOT_PLUGGABLE regions that are onlined
> either by the acpi hotplug or done manually with CONFIG_ARCH_MEMORY_PROBE.
> On other architectures such as powerpc, this is done in different ways.
>
> All of this is spelled out in the changelog for the patch.
>
Ah, ok. for cpu-less node and kmallco_node() against that node.

Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

Thanks,
-Kame