Re: [PATCH 1/3] srcu: use cpu_online() instead custom check

2017-09-28 Thread Paul E. McKenney
On Thu, Sep 28, 2017 at 06:02:08PM +0200, Sebastian Andrzej Siewior wrote: > On 2017-09-22 11:43:14 [-0700], Paul E. McKenney wrote: > > On Fri, Sep 22, 2017 at 05:28:04PM +0200, Sebastian Andrzej Siewior wrote: > > > The current check via srcu_online is slightly racy because after looking > > > at

Re: [PATCH 1/3] srcu: use cpu_online() instead custom check

2017-09-28 Thread Sebastian Andrzej Siewior
On 2017-09-22 11:43:14 [-0700], Paul E. McKenney wrote: > On Fri, Sep 22, 2017 at 05:28:04PM +0200, Sebastian Andrzej Siewior wrote: > > The current check via srcu_online is slightly racy because after looking > > at srcu_online there could be an interrupt that interrupted us long > > enough until

Re: [PATCH 1/3] srcu: use cpu_online() instead custom check

2017-09-22 Thread Paul E. McKenney
On Fri, Sep 22, 2017 at 05:28:04PM +0200, Sebastian Andrzej Siewior wrote: > The current check via srcu_online is slightly racy because after looking > at srcu_online there could be an interrupt that interrupted us long > enough until the CPU we checked against went offline. But in that case, woul

[PATCH 1/3] srcu: use cpu_online() instead custom check

2017-09-22 Thread Sebastian Andrzej Siewior
The current check via srcu_online is slightly racy because after looking at srcu_online there could be an interrupt that interrupted us long enough until the CPU we checked against went offline. An alternative would be to hold the hotplug rwsem (so the CPUs don't change their state) and then check