Messages in this thread | | | Date | Thu, 26 Feb 2015 08:45:59 +0100 | From | Peter Zijlstra <> | Subject | Re: [RFC][PATCH v2] sched/rt: Use IPI to trigger RT task push migration instead of pulling |
| |
On Wed, Feb 25, 2015 at 12:50:15PM -0500, Steven Rostedt wrote: > It can't be used for state? > > If one CPU writes "zero", and the other CPU wants to decide if the > system is in the state to do something, isn't a rmb() fine to use? > > > CPU 1: > > x = 0; > /* Tell other CPUs they can now do something */ > smp_wmb(); > > CPU 2: > /* Make sure we see current state of x */ > smp_rmb(); > if (x == 0) > do_something(); > > The above situation is not acceptable?
Acceptable is just not the word. It plain doesn't work that way.
> Otherwise, we fail to be able to do_something() when it is perfectly > fine to do so.
Can't be helped.
| |