On Tue, Nov 08, 2016 at 11:15:51AM +0000, Mathieu Desnoyers wrote: > ----- On Nov 7, 2016, at 3:03 PM, Paul E. McKenney paulmck@xxxxxxxxxxxxxxxxxx wrote: > > > On Mon, Nov 07, 2016 at 06:10:14PM +0000, Mathieu Desnoyers wrote: > >> > >> ----- On Nov 7, 2016, at 1:06 PM, Paul E. McKenney paulmck@xxxxxxxxxxxxxxxxxx > >> wrote: > >> > >> > On Mon, Nov 07, 2016 at 05:08:59PM +0000, Mathieu Desnoyers wrote: > >> >> ----- On Nov 3, 2016, at 1:49 PM, Paul E. McKenney paulmck@xxxxxxxxxxxxxxxxxx > >> >> wrote: > >> >> > >> >> > On Thu, Nov 03, 2016 at 10:29:28AM -0600, Mathieu Desnoyers wrote: > >> >> >> Userspace applications should be allowed to expect the membarrier system > >> >> >> call with MEMBARRIER_CMD_SHARED command to issue memory barriers on > >> >> >> nohz_full CPUs, but synchronize_sched() does not take those into > >> >> >> account. > >> >> >> > >> >> >> Given that we do not want unrelated processes to be able to affect > >> >> >> real-time sensitive nohz_full CPUs, simply return ENOSYS when membarrier > >> >> >> is invoked on a kernel with enabled nohz_full CPUs. > >> >> >> > >> >> >> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> > >> >> >> CC: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> > >> >> > > >> >> > Acked-by: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> > >> >> > >> >> Hi Paul, > >> >> > >> >> Do you plan to pick it up through your tree, or I should sent > >> >> it directly to Linus ? > >> > > >> > Your choice. I believe that the original went some other way, but I > >> > would be fine carrying this one. > >> > >> Not sure what you mean by "the original" ? And which other way ? > >> I have not been notified about this. > > > > If I remember correctly, you sent the original sys_membarrier() > > patch through akpm or similar. > > Ah right, the original implementation, yes. > > > > >> If you can carry this patch it would be very much appreciated, > > > > Will do! > > Especially since the regression is somewhat related to RCU > behavior wrt nohz_full, getting it through your tree seems > relevant. I have it queued for 4.11, thank you! Thanx, Paul -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html