Subject: Re: [PATCH 1/3] powerpc - Initialize the irq radix tree earlier
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reply-To: benh@kernel.crashing.org
To: Sebastien Dugue <sebastien.dugue@bull.net>
Cc: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org,
       linux-rt-users@vger.kernel.org, paulus@samba.org,
       michael@ellerman.id.au, jean-pierre.dion@bull.net,
       gilles.carry@ext.bull.net, tinytim@us.ibm.com, tglx@linutronix.de,
       rostedt@goodmis.org
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Date: Tue, 05 Aug 2008 11:05:03 +1000
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>  - Remove the populating of the tree from the revmap function as
>    you already do
>  - Move it to irq_create_mapping() for the normal case
>  - For pre-existing interrupt, have the generic code that initializes
>    the radix tree walk through all interrupts and setup the revmap for
>    them. If that needs locking vs. concurrent irq_create_mapping, it's
>    easy to use one of the available spinlocks for that.

And in fact, you may even be able to avoid GFP_ATOMIC completely here
and switch it to GFP_KERNEL since irq_create_mapping() can sleep afaik,
provided that you avoid the spinlocking.

Ben.


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