Re: [PATCH] sparse_irq aka dyn_irq v13

From: Yinghai Lu
Date: Sun Nov 16 2008 - 18:45:26 EST


Benjamin Herrenschmidt wrote:
>
> In any case, the patch is too big and unless I missed something, totally
> under-documented in what it does, why it does it, how it does it, etc...
> with a bit more of that, I might take more time to look closely and find
> out that indeed it's something I can make use of, maybe with a few
> tweaks.

will cut it to smaller ones. try to have one big one to make review more easy.

starting case
1. IBM x3950 have io apic pins > 224?
2. SGI big box need 8192 irqs

want to make same kernel with NR_CPUS = 4096 can be used with regular sized system.

points are
1. removing irq_desc array and NR_IRQS. for small system will have less wasting ram in that array, and for big system will get more irqs like system have 8 pcie cards and every card need 40 MSI vector or a lot of IO apic controllers etc.
2. make irq number is bus/devfn/idx, and every dev func will use 12bit range, irq number is relatively fixed not like current MSI irq creating is some kind of floating from NR_IRQS too.
3. irq_desc is going with /proc/irq/xxx/smp_affinity.

YH
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/