Re: [RFC PATCH v2 1/2] printk-rb: add a new printk ringbuffer implementation

Andrea Parri
2019-06-21T12:17:04Z

> > FWIW (and as anticipated time ago in a private email), when I see code
> > like this I tend to look elsewhere... ;-/
>
> Do you really mean "code" or are you just referring to "code comments"?
> If you really mean code, then I'd appreciate some feedback about what
> should change.

I really just meant "uncommented code". ;-) I do plan to read your:

https://lkml.kernel.org/r/87k1df28x4.fsf@linutronix.de

(and the code it's referring to) with due calm in the following days.
Thank you in advance for these remarks.

[Trying to address your question about herd7,]

A list of supported primitives is available from:

tools/memory-model/linux-kernel.def (left column)

This includes cmpxchg() (and its variants: _relaxed(), _acquire() and
_release()), however, herd7 can currently only parse statements like:

loc_var = cmpxchg(addr, old, new);

(and it will complain loudly without that "loc_var = " part...); this
is something that could be improved, or at least it seems this way...

A similar consideration holds for all the value-returning primitives.

Thanks,
Andrea