Re: [PATCH 00/10] jump label: introduce very_[un]likely + cleanups +docs

[Ingo Molnar]

* Ingo Molnar <mingo@xxxxxxx> wrote:

> But it is fundamentally mixing execution and *data type* and 
> it is not conveying the build time bias properly.
> 
> So the best high level naming would be something like:
> 
> 	struct static_condition static_flag = STATIC_COND_FALSE;
> 
> 
> 	if (very_unlikely(&static_flag)) {
> 		...
> 	}
> 
> 	...
> 
> 	static_cond_inc(&static_flag);
> 	...
> 	static_cond_dec(&static_flag);

Btw., I think the modification path could also carry the high 
cost of modification (stopping all cpus, modifying code, etc.).

This could be done via:

	static_cond_slow_inc(&static_flag);
	...
	static_cond_slow_dec(&static_flag);

And if a developer does not notice that 'slow' implies a 
performance cost, then he probably would have doubly missed this 
aspect of jump_label_inc()/jump_label_dec().

Thanks,

	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/