Re: [PATCH v4 1/5] getcpu_cache system call: cache CPU number of running thread

From: Linus Torvalds
Date: Sat Feb 27 2016 - 19:57:40 EST

On Sat, Feb 27, 2016 at 4:39 PM, Mathieu Desnoyers
<mathieu.desnoyers@xxxxxxxxxxxx> wrote:
> I'm particularly interested to know what are the best practices to
> deal with an extensible bitfield (the features mask). cpu_set_t
> and sigmask each seem to do their own thing.

Quite frankly, why would the kernel ever touch anything else?

And if the kernel doesn't touch anything else, why make it part of the ABI?

I don't see why the kernel would ever want to have a more complex
interface. Explain.