Commit 8cb9764f authored May 06, 2015 by Chris Metcalf Committed by Ingo Molnar May 07, 2015

nohz: Set isolcpus when nohz_full is set



nohz_full is only useful with isolcpus are 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.

Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Jones <davej@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1430928266-24888-5-git-send-email-fweisbec@gmail.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 83dedea8

kernel/sched/core.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -7036,6 +7036,9 @@ 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();

		/*

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