Messages in this thread Patch in this message | | | From | Frederic Weisbecker <> | Subject | [PATCH 4/4] nohz: Set isolcpus when nohz_full is set | Date | Tue, 21 Apr 2015 14:23:09 +0200 |
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From: Chris Metcalf <cmetcalf@ezchip.com>
nohz_full is only useful with isolcpus also set, since otherwise the scheduler has to run periodically to try to determine whether to steal work from other cores.
Accordingly, when booting with nohz_full=xxx on the command line, we should act as if isolcpus=xxx was also set, and set (or extend) the isolcpus set to include the nohz_full cpus.
Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Mike Galbraith <umgwanakikbuti@gmail.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> --- kernel/sched/core.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 8414a6a..ee4f735 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7051,6 +7051,9 @@ void __init sched_init_smp(void) alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); alloc_cpumask_var(&fallback_doms, GFP_KERNEL); + /* nohz_full won't take effect without isolating the cpus. */ + tick_nohz_full_add_cpus_to(cpu_isolated_map); + sched_init_numa(); /* -- 2.1.4
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