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Commit 1bda3f80 authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar
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sched/isolation: Isolate workqueues when "nohz_full=" is set 



As we prepare for offloading the residual 1hz scheduler ticks to
workqueue, let's affine those to housekeepers so that they don't
interrupt the CPUs that don't want to be disturbed.

Signed-off-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wanpeng Li <kernellwp@gmail.com>
Link: http://lkml.kernel.org/r/1519186649-3242-5-git-send-email-frederic@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 22ab8bc0

include/linux/sched/isolation.h

+1 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ enum hk_flags { 
	HK_FLAG_SCHED		= (1 << 3),

	HK_FLAG_TICK		= (1 << 4),

	HK_FLAG_DOMAIN		= (1 << 5),

	HK_FLAG_WQ		= (1 << 6),

};



#ifdef CONFIG_CPU_ISOLATION

kernel/sched/isolation.c

+2 −1
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
 *  any CPU: unbound workqueues, timers, kthreads and any offloadable work.

 *

 * Copyright (C) 2017 Red Hat, Inc., Frederic Weisbecker

 * Copyright (C) 2017-2018 SUSE, Frederic Weisbecker

 *

 */
@@ -119,7 +120,7 @@ static int __init housekeeping_nohz_full_setup(char *str) 
{

	unsigned int flags;



	flags = HK_FLAG_TICK | HK_FLAG_TIMER | HK_FLAG_RCU | HK_FLAG_MISC;

	flags = HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU | HK_FLAG_MISC;



	return housekeeping_setup(str, flags);

}

kernel/workqueue.c

+2 −1
Original line number Diff line number Diff line
@@ -5565,12 +5565,13 @@ static void __init wq_numa_init(void) 
int __init workqueue_init_early(void)

{

	int std_nice[NR_STD_WORKER_POOLS] = { 0, HIGHPRI_NICE_LEVEL };

	int hk_flags = HK_FLAG_DOMAIN | HK_FLAG_WQ;

	int i, cpu;



	WARN_ON(__alignof__(struct pool_workqueue) < __alignof__(long long));



	BUG_ON(!alloc_cpumask_var(&wq_unbound_cpumask, GFP_KERNEL));

	cpumask_copy(wq_unbound_cpumask, housekeeping_cpumask(HK_FLAG_DOMAIN));

	cpumask_copy(wq_unbound_cpumask, housekeeping_cpumask(hk_flags));



	pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC);