Messages in this thread | | | Date | Thu, 29 Apr 2010 21:48:24 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH RFC: linux-next 1/2] irq: Add CPU mask affinity hint callback framework |
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B1;2005;0cPeter,
On Thu, 29 Apr 2010, Peter P Waskiewicz Jr wrote: > On Wed, 2010-04-28 at 09:45 -0700, Thomas Gleixner wrote: > > So you need a reference to your device, so what about the following: > > > > struct irq_affinity_hint; > > > > struct irq_affinity_hint { > > unsigned int (*callback)(unsigned int irq, struct irq_affinity_hint *hint, > > cpumask_var_t *mask); > > } > > > > Now you embed that struct into your device private data structure and > > you get the reference to it back in the callback function. No extra > > kmalloc/kfree, less code. > > Good idea! I'll roll that into my new version.
Thinking more about it, I wonder whether you have a cpu_mask in your driver/device private data anyway. I bet you have :)
So it should be sufficient to set a pointer to that cpu_mask in irq_desc and get rid of the callback completely.
Any access to desc->affinity_hint needs to be protected by desc->lock. For setting the pointer to a real mask resp. NULL that's fine. The copy which you need to do in the proc-read function is not going to introduce huge latencies either.
Thanks,
tglx
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