From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: Query: Boot time allocation of irq descriptors
Date: Wed, 11 Feb 2015 14:55:51 +0000
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To: Vijay Kilari <vijay.kilari@gmail.com>, Ian Campbell <Ian.Campbell@citrix.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: manish.jaggi@caviumnetworks.com, Julien Grall <julien.grall@linaro.org>, Stefano Stabellini <stefano.stabellini@citrix.com>, "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
List-Id: xen-devel@lists.xenproject.org

On 11/02/15 14:50, Vijay Kilari wrote:
> Hi ,
>
>   I just glaced at the x86 code, here nr_irqs are set to 1024, which includes
> normal irq's and MSI's. Memory for these descriptors are allocated at boot time.
> is it correct?
>
> int __init init_irq_data(void)
> {
>
> ...
>     for (vector = 0; vector < NR_VECTORS; ++vector)
>         this_cpu(vector_irq)[vector] = INT_MIN;
>
>     irq_desc = xzalloc_array(struct irq_desc, nr_irqs);
>
> ...
> }
>
>
> In xen/include/asm-x86/irq.h
>
> #define MSI_IRQ(irq)       ((irq) >= nr_irqs_gsi && (irq) < nr_irqs)

What do you think is incorrect about it?

~Andrew