Re: [RFC][PATCH] avoid cpu hot removal if busy take3

[Pavel Machek <pavel@suse.cz>]

On Fri 2006-06-23 23:35:25, KAMEZAWA Hiroyuki wrote:
> On Fri, 23 Jun 2006 09:27:46 -0500
> Nathan Lynch <ntl@pobox.com> wrote:
> 
> > KAMEZAWA Hiroyuki wrote:
> > > This patch adds sysctl cpu_removal_migration.
> > > If cpu_removal_migration == 1, all tasks are migrated by force.
> > > If cpu_removal_migration == 0, cpu_hotremoval can fail because of not-migratable
> > > tasks.
> > > 
> > > Note: cpu scheduler's notifier chain has the highest priority. then, this
> > >       failure detection will be done at first.
> > 
> > I'm still not convinced that this is a good thing to do.  I reiterate:
> > this can be implemented in userspace (probably with fewer lines of
> > code, even).  Why should this policy be in the kernel?
> > 
> I don't think so.
> If we can expect all things can be maintained by user-space in proper way,
> why we need forced migration ? This patch is just one of possible workarounds. 
> and implemtns, "success always" and "fail if busy" policy to cpu-hot-remove.

So... we have piece of policy in kernel, that maybe should not be
there (forced migration). Now, you want to make that policy optional,
and add second piece of policy?

No no, I'm afraid.							Pavel

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