Re: [PATCH] jump_label: jump_label for boot options.

From: KAMEZAWA Hiroyuki
Date: Fri Dec 02 2011 - 00:49:06 EST


On Fri, 02 Dec 2011 06:34:05 +0100
Mike Galbraith <efault@xxxxxx> wrote:

> On Fri, 2011-12-02 at 09:28 +0900, KAMEZAWA Hiroyuki wrote:
> > On Thu, 1 Dec 2011 10:40:36 -0500
> > Jason Baron <jbaron@xxxxxxxxxx> wrote:
> >
> > > On Thu, Dec 01, 2011 at 11:53:53AM +0900, KAMEZAWA Hiroyuki wrote:
> > > > I tried to use jump_label for handling memcg's boot options which sets
> > > > global variable true/false and never changes after boot. And found jump_table
> > > > is larger than expected. This patch is a trial to allow to place jump_table
> > > > in .init section. How do you think ?
> > > >
> > >
> > > Remeber too, that 'static_branch()' is inherently biased. That is, the
> > > 'false' path is assumed to be the the most likely path. Thus, the 'true'
> > > path is move out-of-line. Thus, if the 'true' branch is potentially
> > > used all the time, we would want to make sure that the savings of not
> > > having to check a variable is still worth it. I should probably rename
> > > static_branch() -> 'static_branch_default_false()' to make that clear.
> > >
> > Thank you for pointing out.
> >
> > My assumption is that it's disabled at boot by few people because sane
> > people will not config memcg if they don't want. Most of distro users
> > will not turn off it...
>
> I think that's a bad assumption. I see a lot of cgroup_disable=memory
> command lines, and _always_ add it to grub when installing "everything
> plus the kitchen sink" distro kernels on my boxen.
>
Ok, I stop this work.

Thanks,
-Kame

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