[ofa-general] Re: [PATCH] IB/ehca: Serialize HCA-related hCalls on POWER5
Arnd Bergmann
arnd at arndb.de
Fri Dec 7 01:58:37 PST 2007
On Thursday 06 December 2007, Roland Dreier wrote:
> > Regarding the performance problem, have you checked whether converting all
> > your spin_lock_irqsave to spin_lock/spin_lock_irq improves your performance
> > on the older machines? Maybe it's already fast enough that way.
>
> It does seem that the only places that the hcall_lock is taken also
> use msleep, so they must always be in process context. So you can
> safely just use spin_lock(), right?
I think it needs some more inspection. The msleep in there is only called
for hcalls that return H_IS_LONG_BUSY(). In theory, you can call
ehca_plpar_hcall_norets() from inside an interrupt handler if the
hcall in question never returns long busy.
Arnd <><
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