On Wed, Sep 11, 2013 at 01:52:37PM -0400, Steven Rostedt wrote:
> On Wed, 11 Sep 2013 13:25:52 -0400
> Konrad Rzeszutek Wilk <konrad.w...@oracle.com> wrote:
>
>
> > commit 97ce2c88f9ad42e3c60a9beb9fca87abf3639faa
> > Author: Jeremy Fitzhardinge <jeremy.fitzhardi...@citrix.com>
> > Date: Wed Oct 12 16:17:54 2011 -0700
> >
> > jump-label: initialize jump-label subsystem much earlier
> >
> > Initialize jump_labels much, much earlier, so they're available for use
> > during system setup.
> >
> > Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardi...@citrix.com>
> > Acked-by: Peter Zijlstra <a.p.zijls...@chello.nl>
> >
> >
> > implies that yes.
>
> Unfortunately it does not. All that patch did was move
> jump_label_init() up more. If anything, it implies "no".
>
> The question is, can we enable jump_labels before jump_label_init()?
>
> Note, we may still be able to (as it seems to work), the thing is, the
> only thing that static_key_slow_inc() does is to tell jump_label_init()
> to enable it. Before jump_label_init() is called, nothing has changed.
> No code modification, all users of paravirt_ticketlocks_enabled are
> still off.
<confused>
I am thins would still work:
47 static __always_inline void arch_spin_unlock(arch_spinlock_t *lock)
148 {
149 if (TICKET_SLOWPATH_FLAG &&
150 static_key_false(¶virt_ticketlocks_enabled)) {
(from arch/x86/include/asm/spinlock.h) as the static_key_false
would check the key->enabled. Which had been incremented?
Granted there are no patching done yet, but that should still allow
this code path to be taken?
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