Re: [PATCH -mm] mm: Fix memory hotplug + sparsemem build.

Lee Schermerhorn
2007-09-14T14:09:27Z

On Thu, 2007-09-13 at 19:41 -0700, Andrew Morton wrote:
> On Fri, 14 Sep 2007 11:02:43 +0900 Yasunori Goto <y-goto@jp.fujitsu.com> wrote:
>
> > > > /* call arch's memory hotadd */
> > > >
> > >
> > > OK, we're getting into a mess here. This patch fixes
> > > update-n_high_memory-node-state-for-memory-hotadd.patch, but which patch
> > > does update-n_high_memory-node-state-for-memory-hotadd.patch fix?
> > >
> > > At present I just whacked
> > > update-n_high_memory-node-state-for-memory-hotadd.patch at the end of
> > > everything, but that was lazy of me and it ends up making a mess.
> >
> > It is enough. No more patch is necessary for these issues.
> > I already fixed about Andy-san's comment. :-)
>
> Now I'm more confused. I have two separeate questions:
>
> a) Is the justr-added update-n_high_memory-node-state-for-memory-hotadd-fix.patch
> still needed?
>
> b) Which patch in 2.6.22-rc4-mm1 does
> update-n_high_memory-node-state-for-memory-hotadd.patch fix? In other
> words, into which patch should I fold
> update-n_high_memory-node-state-for-memory-hotadd.patch prior to sending
> to Linus?

Andrew:

I originally sent in the "update-n_high_memory..." patch against
23-rc3-mm1 on 27aug to fix a problem that I introduced when I moved the
populating of N_HIGH_MEMORY state to free_area_init_nodes(). This would
miss setting the "has memory" node state for hot added memory. I never
saw any response, but then it ended up in 23-rc4-mm1.

This Tuesday, Paul Mundt sent in a patch to fix a build problem with
MEMORY_HOTPLUG_SPARSE introduced by my patch. He replaced zone->node
with zone_to_nid(zone) in the node_set_state() arguments.

The latest patch, from Yasunori-san, I believe, starts kswapd for nodes
to which memory has been hot-added. As I understand it, his is needed
because the memoryless nodes patch results in no kswapd for memoryless
nodes.

Does that help?

Lee

>
> (I (usually) get to work this out for myself. Sometimes it is painful).
>
> Generally, if people tell me which patch-in-mm their patch is fixing,
> it really helps. Adrian does this all the time.
>
> Thanks.
>
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