Messages in this thread | | | Subject | Re: [PATCH RFC: linux-next 1/2] irq: Add CPU mask affinity hint callback framework | From | Peter P Waskiewicz Jr <> | Date | Thu, 29 Apr 2010 13:28:50 -0700 |
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On Thu, 2010-04-29 at 12:48 -0700, Thomas Gleixner wrote: > 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 :)
Well, at this point we don't, but nothing says we can't.
> So it should be sufficient to set a pointer to that cpu_mask in > irq_desc and get rid of the callback completely.
So "register" would just assign the pointer, and "unregister" would make sure to NULL the mask pointer out. I like it. It'll sure clean things up too.
> 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.
Right.
> Thanks, > > tglx
Thanks for the additional inputs. Patches coming soon.
-PJ
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