Messages in this thread | | | Date | Thu, 19 May 2022 17:07:55 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 00/21] rcu/context-tracking: Merge RCU eqs-dynticks counter to context tracking v2 |
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On Wed, May 18, 2022 at 05:33:02PM +0200, Nicolas Saenz Julienne wrote: > On Tue, 2022-05-03 at 12:00 +0200, Frederic Weisbecker wrote: > > This mixes up the RCU dynticks counter and the context tracking state > > updates into a single atomic instruction. This may serve several > > purposes: > > > > 1) Improve CPU isolation with deferring some disturbances until sensitive > > userspace workload completes and goes to the kernel. This can take > > several forms, for example smp_call_function_housekeeping() or > > on_each_housekeeping_cpu() to enqueue and execute work on all > > housekeeping CPUs. Then an atomic operation on ct->state can defer > > the work on nohz_full CPUs until they run in kernel (or IPI them > > if they are in kernel mode), see this proposal by Peter: > > https://lore.kernel.org/all/20210929151723.162004989@infradead.org/#r > > > > 2) Unearth sysidle (https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git/commit/?h=sysidle.2017.05.11a&id=fe5ac724d81a3c7803e60c2232718f212f3f38d4) > > This feature allowed to shutdown the tick on the last housekeeping > > CPU once the rest of the system is fully idle. We needed some proper > > fully ordered context tracking for that. > > > > Inspired by Peterz: https://lore.kernel.org/all/20210929151723.162004989@infradead.org > > > > Passed 100 hours of TREE01. > > > > --- > > For the whole series: > > Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> > Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
I hesitated to apply these but the series has changed a little, although the fundamental bits remain.
I'll just wait for a confirmation from you on this v3.
Thanks!
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