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Subject: Re: [PATCH 3/4] perf-events: Add support for supplementary event
 registers v3
From: Peter Zijlstra <peterz@infradead.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: eranian@google.com, linux-kernel@vger.kernel.org, x86@kernel.org,
        Andi Kleen <ak@linux.intel.com>, Ingo Molnar <mingo@elte.hu>
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Date: Fri, 26 Nov 2010 16:30:24 +0100
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On Fri, 2010-11-26 at 16:28 +0100, Peter Zijlstra wrote:
> On Thu, 2010-11-18 at 12:46 +0100, Peter Zijlstra wrote:
> > On Thu, 2010-11-18 at 12:16 +0100, Andi Kleen wrote:
> > > 
> > > > > + * Runs later because per cpu allocations don't work early on.
> > > > > + */
> > > > > +__initcall(init_intel_percore);
> > > > 
> > > > I've got a patch moving the whole pmu init to early_initcall(), which is
> > > > after mm_init() so it would actually work.
> > > 
> > > So do you want to make  this patchkit depend on that patch?
> > > Or just integrate it and then change later? 
> > 
> > Doesn't really matter, I can fix it up afterwards, just wanted to let
> > you know.. I can also flip that enable thing.
> > 
> > I'll take these 4 patches and fixup these things and then see what falls
> > out ;-)
> 
> OK, that initcall patch hit -tip and Ingo wants that allocation stuff
> fixed up before committing those patches.
> 
> Could you run another version of these patches (you can ignore the
> checkpatch output that results from the non-std struct initialization
> layout)?
> 
> Just make the allocation path like the AMD NB stuff, use the cpu_prepare
> and cpu_dead hooks to alloc/free and add a refcount in the percpu
> object.

While looking at the AMD code, I think we can do away with amd_nb_lock,
all the hotplug stuff is serialized on the hotplug mutex anyway.