Re: [PATCH v9 1/2] Documentation: kdump: remind user of nr_cpus

["Zhou, Wenjian/åæå"]

On 08/19/2016 11:57 PM, Jonathan Corbet wrote:
> On Fri, 19 Aug 2016 08:33:21 +0800
> "Zhou, Wenjian/åæå" <zhouwj-fnst@xxxxxxxxxxxxxx> wrote:
>
> > I was also confused by maxcpus and nr_cpus before writing this patch.
> > I think it is a good choice to describe it in kernel-parameters.txt.
> >
> > Then, only two things need to be done I think.
> > One is move the above description to maxcpus= in kernel-parameters.txt.
> > And the other is replace maxcpus with maxcpus/nr_cpus in kdump.txt.
> >
> > How do you think?
>
> That is not quite what I had in mind, sorry.  What I would really like to
> see in kernel-parameters.txt is an explanation of how those two parameters
> differ - what do they do differently and how should a user choose one over
> the other?  What we have now offers no guidance in that matter.

I thought about it. I think user may not need this.
What user really want to know is how to choose.
And it is also not a hard work. If nr_cpus is not supported by the ARCH, use maxcpus.
Otherwise, nr_cpus. The reason why maxcpus still exists is nr_cpus can't be supported
by some ARCHes.

I think it may be why the author didn't write too much description of it.

> I suspect that may be a bit more than you had signed up to do.  As an
> intermediate step, how about this: rather than tacking on those lines in
> kdump.txt, rewrite that paragraph to simply say what the reader should
> use.  If nr_cpus is good for everybody, just say that, but your previous
> patch suggests that the situation isn't quite that simple?

Actually, if nr_cpus always usable, there won't be these discussions.


--
Thanks
Zhou