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

[Peter Zijlstra]

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@xxxxxxxxxxxxxxxxxx>

Then imagine someone doing:

 while (1)
  sys_membarrier();

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

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