Re: [PATCH] perf_counter: extensible perf_counter_attr

[Ingo Molnar]

* Corey Ashford <cjashfor@xxxxxxxxxxxxxxxxxx> wrote:

> Peter Zijlstra wrote:
>> On Mon, 2009-06-08 at 14:18 -0700, Corey Ashford wrote:
>>> pca.ext_attrs = &feature.head; /* secretly know that there's data 
>>> that lies past the attr struct header */
>>
>> Right, except its not so very secret since we have the type field
>> telling us.
>
> I see.  Thanks for the explanation.  Looks like a good plan to me!

i think we'd have a much simpler implementation by changing 
__reserved_1 to attr_size. When the kernel adds new attributes, the 
size will increase - old user-space will use the old size which the 
kernel detects and adopts to (by zeroing out that attribute space).

That way we'll always have a nice flat attributes structure, with no 
quirky chaining that has field-dependent data types ...

	Ingo
--
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/