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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>
#include <linux/static_key.h>
DEFINE_STATIC_KEY_FALSE(housekeeping_overriden);
EXPORT_SYMBOL_GPL(housekeeping_overriden);
static cpumask_var_t housekeeping_mask;
static unsigned int housekeeping_flags;
int housekeeping_any_cpu(enum hk_flags flags)
{
if (static_branch_unlikely(&housekeeping_overriden))
if (housekeeping_flags & flags)
return cpumask_any_and(housekeeping_mask, cpu_online_mask);
return smp_processor_id();
}
EXPORT_SYMBOL_GPL(housekeeping_any_cpu);
const struct cpumask *housekeeping_cpumask(enum hk_flags flags)
{
if (static_branch_unlikely(&housekeeping_overriden))
if (housekeeping_flags & flags)
return housekeeping_mask;
return cpu_possible_mask;
}
EXPORT_SYMBOL_GPL(housekeeping_cpumask);
void housekeeping_affine(struct task_struct *t, enum hk_flags flags)
{
if (static_branch_unlikely(&housekeeping_overriden))
if (housekeeping_flags & flags)
set_cpus_allowed_ptr(t, housekeeping_mask);
}
EXPORT_SYMBOL_GPL(housekeeping_affine);
bool housekeeping_test_cpu(int cpu, enum hk_flags flags)
{
if (static_branch_unlikely(&housekeeping_overriden))
if (housekeeping_flags & flags)
return cpumask_test_cpu(cpu, housekeeping_mask);
return true;
}
EXPORT_SYMBOL_GPL(housekeeping_test_cpu);
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);
housekeeping_flags = HK_FLAG_TIMER | HK_FLAG_RCU | HK_FLAG_MISC;
static_branch_enable(&housekeeping_overriden);
/* We need at least one CPU to handle housekeeping work */
WARN_ON_ONCE(cpumask_empty(housekeeping_mask));
}
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