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

Peter Zijlstra
2019-07-01T14:10:52Z

On Mon, Jul 01, 2019 at 12:39:35PM +0200, John Ogness wrote:

> Thanks. I overlooked that subtle detail. Can I assume NMIs do not exist
> on architectures that need to implement locking for cmpxchg()? Or did I
> just hit a major obstacle?

I think that is a fair assumption, I'm not aware of anybody having NMIs
_and_ 'broken' atomics.

Then again, we also have ARCH_HAVE_NMI_SAFE_CMPXCHG.