On Fri, Apr 14, 2017 at 11:51:07AM +0200, Thomas Gleixner wrote: > On Fri, 14 Apr 2017, Peter Zijlstra wrote: > > > On Wed, Apr 12, 2017 at 10:07:28PM +0200, Thomas Gleixner wrote: > > > +long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg) > > > +{ > > > + long ret = -ENODEV; > > > + > > > + get_online_cpus(); > > > + if (cpu_online(cpu)) > > > + ret = work_on_cpu(cpu, fn, arg); > > > + put_online_cpus(); > > > + return ret; > > > +} > > > > But doesn't workqueue have this lovelt 'feature' where it will unbind > > per-cpu work and run it on random CPUs when hotplug happens? > > > > That is, I think you need a flush_work() before put_online_cpus() if you > > want to guarantee anything. > > work_on_cpu() is sychnronous, it flushes already.
So much for being awake ...