Re: [PATCH 0/2] workqueue: fix a bug when numa mapping is changed

[Kamezawa Hiroyuki]

On 2015/04/01 0:28, Tejun Heo wrote:
> Hello, Kamezawa.
>
> On Tue, Mar 31, 2015 at 03:09:05PM +0900, Kamezawa Hiroyuki wrote:
> > But this may be considered as API change for most hot-add users.
>
> Hmm... Why would it be?  What can that possibly break?

Now, hot-added cpus will have the lowest free cpu id.

Because of this, in most of systems which has only cpu-hot-add, cpu-ids are always
contiguous even after cpu hot add.
In enterprise, this would be considered as imcompatibility.

determining cpuid <-> lapicid at boot will make cpuids sparse. That may corrupt
exisiting script or configuration/resource management software.

> > So, for now, I vote for detemining ids at online but record it is a good way.
>
> If we know the information during boot, let's please do it at boot
> time by all means.

I basically agree. Just thinking influence of this small imcompatibility of forcing
ideal way because of my standing point.

Thanks,
-Kame

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/