Re: [PATCH 3/3] early_printk: Add simple serialization to early_vprintk()

[Paul E. McKenney]

On Wed, Oct 04, 2017 at 04:52:47PM +0200, Peter Zijlstra wrote:
> On Wed, Oct 04, 2017 at 10:43:54AM -0400, Steven Rostedt wrote:
> > 
> > My question is not about ordering, but about coherency. Can you have
> > one CPU read a variable that goes into cache, and keep using the cached
> > variable every time the program asks to read it, instead of going out
> > to memory.
> 
> No, not on a coherent system.

What Peter said.  And if you use READ_ONCE() for the reads, than as
far as I know, all the systems that the Linux kernel supports are
coherent systems.

							Thanx, Paul