Messages in this thread | | | Date | Sat, 18 Jul 2015 15:36:03 +0200 | From | Frederic Weisbecker <> | Subject | Re: [RFC] workqueue: avoiding unbounded wq on isolated CPUs by default |
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On Fri, Jul 17, 2015 at 07:15:48PM +0200, Mike Galbraith wrote: > On Fri, 2015-07-17 at 11:27 -0400, Tejun Heo wrote: > > > I'm just curious whether there was any specific reason we didn't do > > this before (ISTR people discussing it back then too). > > I'm dead set against all this auto-presume nonsense fwtw Allocating a > pool of no_hz_full _capable_ CPUs should not entice the kernel to make > any rash assumptions. Let users do the button poking, they know what > they want, and when they want it.
We need to make a choice then. Either we do all the affinity tuning from userspace with a common tool, which is what I had wished before everybody asked for pre-settings.
Or we do it in the kernel, now we should define some kind of CONFIG_ISOLATION to make that proper and rule the various kinds of isolation people are interested in.
But we can't leave it half-way like it is currently with everything preset on top of nohz: rcu nocb mask, watchdog mask, cpu_isolation_map and exclude workqueue.
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