kernel/sched/isolation.c


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/*
 *  Housekeeping management. Manage the targets for routine code that can run on
 *  any CPU: unbound workqueues, timers, kthreads and any offloadable work.
 *
 * Copyright (C) 2017 Red Hat, Inc., Frederic Weisbecker
 *
 */

#include <linux/sched/isolation.h>
#include <linux/tick.h>
#include <linux/init.h>
#include <linux/kernel.h>

cpumask_var_t housekeeping_mask;

void __init housekeeping_init(void)
{
	if (!tick_nohz_full_enabled())
		return;

	if (!alloc_cpumask_var(&housekeeping_mask, GFP_KERNEL)) {
		WARN(1, "NO_HZ: Can't allocate not-full dynticks cpumask\n");
		cpumask_clear(tick_nohz_full_mask);
		tick_nohz_full_running = false;
		return;
	}

	cpumask_andnot(housekeeping_mask,
		       cpu_possible_mask, tick_nohz_full_mask);

	/* We need at least one CPU to handle housekeeping work */
	WARN_ON_ONCE(cpumask_empty(housekeeping_mask));
}