From e179f5a04ba46ee5c5439480c2bfd68c358168b7 Mon Sep 17 00:00:00 2001
From: Frederic Weisbecker <frederic@kernel.org>
Date: Fri, 27 Oct 2017 04:42:32 +0200
Subject: [PATCH] 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>
---
include/linux/sched/isolation.h | 3 ++-
kernel/sched/isolation.c | 13 +++++++++----
2 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h
index ed935ffc6ffa..194c586fbb12 100644
--- a/include/linux/sched/isolation.h
+++ b/include/linux/sched/isolation.h
@@ -6,6 +6,7 @@
#include <linux/tick.h>
#ifdef CONFIG_NO_HZ_FULL
+DECLARE_STATIC_KEY_FALSE(housekeeping_overriden);
extern int housekeeping_any_cpu(void);
extern const struct cpumask *housekeeping_cpumask(void);
extern void housekeeping_affine(struct task_struct *t);
@@ -31,7 +32,7 @@ static inline void housekeeping_init(void) { }
static inline bool is_housekeeping_cpu(int cpu)
{
#ifdef CONFIG_NO_HZ_FULL
- if (tick_nohz_full_enabled())
+ if (static_branch_unlikely(&housekeeping_overriden))
return housekeeping_test_cpu(cpu);
#endif
return true;
diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
index 16445097eb25..bb8ba19a0235 100644
--- a/kernel/sched/isolation.c
+++ b/kernel/sched/isolation.c
@@ -10,12 +10,15 @@
#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 (tick_nohz_full_enabled())
+ if (static_branch_unlikely(&housekeeping_overriden))
return cpumask_any_and(housekeeping_mask, cpu_online_mask);
return smp_processor_id();
@@ -24,7 +27,7 @@ EXPORT_SYMBOL_GPL(housekeeping_any_cpu);
const struct cpumask *housekeeping_cpumask(void)
{
- if (tick_nohz_full_enabled())
+ if (static_branch_unlikely(&housekeeping_overriden))
return housekeeping_mask;
return cpu_possible_mask;
@@ -33,14 +36,14 @@ EXPORT_SYMBOL_GPL(housekeeping_cpumask);
void housekeeping_affine(struct task_struct *t)
{
- if (tick_nohz_full_enabled())
+ 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 (tick_nohz_full_enabled())
+ if (static_branch_unlikely(&housekeeping_overriden))
return cpumask_test_cpu(cpu, housekeeping_mask);
return true;
@@ -62,6 +65,8 @@ void __init housekeeping_init(void)
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));
}
--
2.30.9