Hello, Paul. On Wed, Jul 13, 2016 at 02:18:41PM -0700, Paul E. McKenney wrote: > On Wed, Jul 13, 2016 at 05:05:26PM -0400, Tejun Heo wrote: > > On Wed, Jul 13, 2016 at 02:03:15PM -0700, Paul E. McKenney wrote: > > > Take the patch that I just sent out and make the choice of normal > > > vs. expedited depend on CONFIG_PREEMPT_RT or whatever the -rt guys are > > > calling it these days. Is there a low-latency Kconfig option other > > > than CONFIG_NO_HZ_FULL? > > > > Sounds like a plan to me. > > I like the way we like each other's idea. Mutually assured laziness? ;-)
Heh, indeed. :) Technically, I think the lglock approach would be better here given the combination of requirements; however, it's quite a bit more code which would likely require some sophistications down the line (like blocking new readers first at the start of down_write). If we have to go there, we'll go there but for now I think it'd be simpler to conditionally switch to the expedited operations. It can be a config option which is selected by !RT as you suggested. If anyone hits an actual issue with that, we can go for the lglock thing. Thanks. -- tejun
