Re: [PATCH 2/2] powerpc - Make the irq reverse mapping radix treelockless

From: Sebastien Dugue
Date: Wed Sep 03 2008 - 09:41:35 EST


On Wed, 20 Aug 2008 15:23:01 +1000 Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> wrote:

> BTW. It would be good to try to turn the GFP_ATOMIC into GFP_KERNEL,

That would be nice indeed

> maybe using a semaphore instead of a lock to protect insertion vs.
> initialisation.

a semaphore? are you meaning a mutex? If not, I fail to understand what you're
implying.

> The old scheme was fine because if the atomic allocation
> failed, it could fallback to the linear search and try again on the next
> interrupt. Not anymore.

Right, that's the problem with this new scheme and I'm still trying
to find a way to handle memory allocation failures be it for GFP_ATOMIC or
GFP_KERNEL.

I could not think of anything simple so far and I'm open for suggestions.

Thanks,

Sebastien.

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