Messages in this thread | | | Date | Wed, 8 Apr 2015 10:04:43 -0400 | From | Chris Metcalf <> | Subject | Re: [PATCH v2 2/2] nohz: make nohz_full imply isolcpus |
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On 04/08/2015 05:41 AM, Peter Zijlstra wrote: > On Mon, Apr 06, 2015 at 02:16:45PM -0400, cmetcalf@ezchip.com wrote: >> From: Chris Metcalf <cmetcalf@ezchip.com> >> >> It's not clear that nohz_full is useful without isolcpus also >> set, since otherwise the scheduler has to run periodically to >> try to determine whether to steal work from other cores. > So the Changelog and the patch don't seem to agree with one another. > > The Changelog states that nohz_full should depend on isolcpus.
The git commit message says "make nohz_full imply isolcpus". That's consistent with the code.
> The patch implies nohz_full for isolcpus. > > These are not the same; and I don't see the argument for the former make > sense for the latter. > > In specific isolcpus without nohz_full does make sense. > >> Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com> >> Acked-by: Mike Galbraith <umgwanakikbuti@gmail.com> ["thumbs up!"] >> Acked-by: Rik van Riel <riel@redhat.com> >> --- >> kernel/sched/core.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/kernel/sched/core.c b/kernel/sched/core.c >> index f0f831e8a345..275f12c608f2 100644 >> --- a/kernel/sched/core.c >> +++ b/kernel/sched/core.c >> @@ -6836,6 +6836,7 @@ static int init_sched_domains(const struct cpumask *cpu_map) >> doms_cur = alloc_sched_domains(ndoms_cur); >> if (!doms_cur) >> doms_cur = &fallback_doms; >> + tick_nohz_full_set_cpus(cpu_isolated_map); >> cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); >> err = build_sched_domains(doms_cur[0], NULL); >> register_sched_domain_sysctl();
-- Chris Metcalf, EZChip Semiconductor http://www.ezchip.com
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