linux_dsm_epyc7002/kernel/sched/isolation.c
Frederic Weisbecker e179f5a04b sched/isolation: Use its own static key
Housekeeping code still depends on the nohz_full static key. Since we want
to decouple housekeeping from NOHZ, let's create a housekeeping specific
static key.

It's mostly relevant for calls to is_housekeeping_cpu() from the scheduler.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
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: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wanpeng Li <kernellwp@gmail.com>
Link: http://lkml.kernel.org/r/1509072159-31808-6-git-send-email-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-27 09:55:27 +02:00

73 lines
1.8 KiB
C

/*
* 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;
int housekeeping_any_cpu(void)
{
if (static_branch_unlikely(&housekeeping_overriden))
return cpumask_any_and(housekeeping_mask, cpu_online_mask);
return smp_processor_id();
}
EXPORT_SYMBOL_GPL(housekeeping_any_cpu);
const struct cpumask *housekeeping_cpumask(void)
{
if (static_branch_unlikely(&housekeeping_overriden))
return housekeeping_mask;
return cpu_possible_mask;
}
EXPORT_SYMBOL_GPL(housekeeping_cpumask);
void housekeeping_affine(struct task_struct *t)
{
if (static_branch_unlikely(&housekeeping_overriden))
set_cpus_allowed_ptr(t, housekeeping_mask);
}
EXPORT_SYMBOL_GPL(housekeeping_affine);
bool housekeeping_test_cpu(int cpu)
{
if (static_branch_unlikely(&housekeeping_overriden))
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);
static_branch_enable(&housekeeping_overriden);
/* We need at least one CPU to handle housekeeping work */
WARN_ON_ONCE(cpumask_empty(housekeeping_mask));
}