Re: Regression :-) Re: [GIT PULL RESEND] x86/jumpmplabel changesfor v3.12-rc1

From: Steven Rostedt
Date: Wed Sep 11 2013 - 11:47:16 EST


On Wed, 11 Sep 2013 11:21:49 -0400
Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> wrote:
> >
> > I'm trying to understand how this will fix it for you. Are you sure you
> > removed 'xen_nopvspin'?
>
> Yes.
> >
> > If you are calling static_key_slow_inc() before jump_label_init(), then
> > it should still fail. The static_key_slow_inc() eventually calls
> > arch_jump_label_transform(), which calls __jump_label_transform() with
> > init == 0.
>
> Perhaps I am misreading the code, but I believe init is set to one.
> That is due to us calling:
>
> arch_jump_label_transform (.., JUMP_LABEL_ENABLE)
>
> which calls __jump_label_transform(.., 1)
> ?

>From what I'm looking at, only arch_jump_label_transform_static() calls
__jump_label_transform() with a 1 for init. arch_jump_label_transform()
calls it with 0 for init, which is what eventually gets called by
xen_init_spinlocks().

>
> Perhaps the 'init' and 'enable' parameters have different meanings?

Yes they do.

-- Steve

>
> >
> > The below code looks to me that it would still compare the contents
> > with the ideal_nop, which hasn't been set yet.
>
> In the !init case - sure.
>
> In the init case - just with default_nop.
>
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