Re: [block IO crash] Re: 2.6.39-rc5-git2 boot crashs

[Ingo Molnar]

* Christoph Lameter <cl@xxxxxxxxx> wrote:

> On Wed, 4 May 2011, Tejun Heo wrote:
> 
> > The cmpxchg_double optimization made the fast path go quite faster
> > when CPU supports it but it may as well slow things down considerably
> > if CPU doesn't, due to extra irq on/off's.  Anyways, here's hoping
> > that the slow down is acceptable compared to the base code without
> > cmpxchg_double and the ugliness can be removed.
> 
> I think we are all in agreement. First path to fix the percpu macros:
> 
> 
> Subject: percpu: Fix irqsafe_cpu_cmpxchg_double
> 
> The function in the macro was not updated when the function was given a bool return value.
> 
> Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>

Note, the final commit needs to have a proper Reported-by and explanation about 
how this was triggered, to fairly credit all the hard work done by Werner ...

Thanks,

	Ingo
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