Re: [PATCH 00/16] dyn_array and nr_irqs support v2

From: Eric W. Biederman
Date: Fri Aug 01 2008 - 16:53:19 EST


Yinghai Lu <yhlu.kernel@xxxxxxxxx> writes:

> Please check dyn_array support for x86

YH you have not addressed any of my core concerns and this exceeds my review limit.
Unfortunately I don't feel like this is a productive process.

My core concerns are:
- You have not separated out and separately pushed the regression patch. So that we can
fix the current rc release. Simply tuning NR_IRQS is all I feel comfortable with for
fixing things in the post merge window period.

- The generic code has no business with dealing with NR_IRQS sized arrays.
Since we don't have a generic problem I don't see why we should have a generic dyn_array solution.

- The dyn_array infrastructure does not provide for per numa node allocation of
irq_desc structures, limiting NUMA scalability.

- You appear to be papering over problems instead of digging in and actually fixing them.

YH Here is what I was suggesting when the topic of killing NR_IRQs came up a week or so
ago.
http://lkml.org/lkml/2008/7/10/439
http://lkml.org/lkml/2008/7/10/532

Which essentially boils down to:
- Removing NR_IRQS from the non-irq infrastructure code.
- Add a config option for architectures that are not going to use an array
- In the genirq code have a lookup function that goes from irq number to irq_desc *.

The rest we should be able to handle in a arch dependent fashion.

When we are done we should be able to create a stable irq number for msi interrupts
that is something like: bus:dev:fun:vector_no which is 8+5+3+12=28 bits long.

Eric
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