Re: [RFC PATCH] introduce sys_membarrier(): process-wide memory barrier

Peter Zijlstra
2010-01-07T08:32:59Z

On Wed, 2010-01-06 at 21:02 -0800, Paul E. McKenney wrote:
>
> Beats the heck out of user-mode signal handlers!!! And it is hard
> to imagine groveling through runqueues ever being a win, even on very
> large systems. The only reasonable optimization I can imagine is to
> turn this into a no-op for a single-threaded process, but there are
> other ways to do that optimization.
>
> Reviewed-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>

Then imagine someone doing:

while (1)
sys_membarrier();

on your multi node machine, see how happy you are then.