On Mon, 2015-05-11 at 15:25 -0400, Chris Metcalf wrote: > On 05/11/2015 03:19 PM, Mike Galbraith wrote: > > I really shouldn't have acked nohz_full -> isolcpus. Beside the fact > > that old static isolcpus was_supposed_ to crawl off and die, I know > > beyond doubt that having isolated a cpu as well as you can definitely > > does NOT imply that said cpu should become tickless. > > True, at a high level, I agree that it would be better to have a > top-level concept like Frederic's proposed ISOLATION that includes > isolcpus and nohz_cpu (and other stuff as needed). > > That said, what you wrote above is wrong; even with the patch you > acked, setting isolcpus does not automatically turn on nohz_full for > a given cpu. The patch made it true the other way around: when > you say nohz_full, you automatically get isolcpus on that cpu too. > That does, at least, make sense for the semantics of nohz_full. I didn't write that, I wrote nohz_full implies (spelled '->') isolcpus. Yes, with nohz_full currently being static, the old allegedly dying but also static isolcpus scheduler off switch is a convenient thing to wire the nohz_full CPU SET (<- hint;) property to. -Mike -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
