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

Andrew Morton
2007-09-14T20:51:54Z

On Fri, 14 Sep 2007 10:09:27 -0400
Lee Schermerhorn <Lee.Schermerhorn@hp.com> wrote:

> 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?

not really ;)

See, when I get some rinky-dink little fix for a patch in -mm I will
position that patch immediately after the patch which it is fixing, with a
filename which is derived from the fixed patch's name. So when
send-to-Linus time comes, I can fold the fixes into the base patch. This
practice also keeps the patches in a sensible presentation order, with
minimum interdependencies and good git-bisect friendliness.

However it sometimes (rarely) takes considerable effort to work out which
patch in -mm a particular fix is fixing. That was the case with
update-n_high_memory-node-state-for-memory-hotadd.patch.

It helps me quite a bit if people tell me which patch they're fixing.
Usually they don't and I get to work it out. Usually it's fairly obvious.