Commit de201559 authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar

sched/isolation: Introduce housekeeping flags

Before we implement isolcpus under housekeeping, we need the isolation
features to be more finegrained. For example some people want NOHZ_FULL
without the full scheduler isolation, others want full scheduler
isolation without NOHZ_FULL.

So let's cut all these isolation features piecewise, at the risk of
overcutting it right now. We can still merge some flags later if they
always make sense together.
Signed-off-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Acked-by: default avatarThomas 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/1509072159-31808-9-git-send-email-frederic@kernel.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 5c4991e2
......@@ -2270,8 +2270,8 @@ static int __init tile_net_init_module(void)
tile_net_dev_init(name, mac);
if (!network_cpus_init())
cpumask_and(&network_cpus_map, housekeeping_cpumask(),
cpu_online_mask);
cpumask_and(&network_cpus_map,
housekeeping_cpumask(HK_FLAG_MISC), cpu_online_mask);
return 0;
}
......
......@@ -5,35 +5,43 @@
#include <linux/init.h>
#include <linux/tick.h>
enum hk_flags {
HK_FLAG_TIMER = 1,
HK_FLAG_RCU = (1 << 1),
HK_FLAG_MISC = (1 << 2),
HK_FLAG_SCHED = (1 << 3),
};
#ifdef CONFIG_CPU_ISOLATION
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);
extern bool housekeeping_test_cpu(int cpu);
extern int housekeeping_any_cpu(enum hk_flags flags);
extern const struct cpumask *housekeeping_cpumask(enum hk_flags flags);
extern void housekeeping_affine(struct task_struct *t, enum hk_flags flags);
extern bool housekeeping_test_cpu(int cpu, enum hk_flags flags);
extern void __init housekeeping_init(void);
#else
static inline int housekeeping_any_cpu(void)
static inline int housekeeping_any_cpu(enum hk_flags flags)
{
return smp_processor_id();
}
static inline const struct cpumask *housekeeping_cpumask(void)
static inline const struct cpumask *housekeeping_cpumask(enum hk_flags flags)
{
return cpu_possible_mask;
}
static inline void housekeeping_affine(struct task_struct *t) { }
static inline void housekeeping_affine(struct task_struct *t,
enum hk_flags flags) { }
static inline void housekeeping_init(void) { }
#endif /* CONFIG_CPU_ISOLATION */
static inline bool housekeeping_cpu(int cpu)
static inline bool housekeeping_cpu(int cpu, enum hk_flags flags)
{
#ifdef CONFIG_CPU_ISOLATION
if (static_branch_unlikely(&housekeeping_overriden))
return housekeeping_test_cpu(cpu);
return housekeeping_test_cpu(cpu, flags);
#endif
return true;
}
......
......@@ -2584,7 +2584,7 @@ static void rcu_bind_gp_kthread(void)
if (!tick_nohz_full_enabled())
return;
housekeeping_affine(current);
housekeeping_affine(current, HK_FLAG_RCU);
}
/* Record the current task on dyntick-idle entry. */
......
......@@ -719,7 +719,7 @@ static int __noreturn rcu_tasks_kthread(void *arg)
LIST_HEAD(rcu_tasks_holdouts);
/* Run on housekeeping CPUs by default. Sysadm can move if desired. */
housekeeping_affine(current);
housekeeping_affine(current, HK_FLAG_RCU);
/*
* Each pass through the following loop makes one check for
......
......@@ -527,7 +527,7 @@ int get_nohz_timer_target(void)
int i, cpu = smp_processor_id();
struct sched_domain *sd;
if (!idle_cpu(cpu) && housekeeping_cpu(cpu))
if (!idle_cpu(cpu) && housekeeping_cpu(cpu, HK_FLAG_TIMER))
return cpu;
rcu_read_lock();
......@@ -536,15 +536,15 @@ int get_nohz_timer_target(void)
if (cpu == i)
continue;
if (!idle_cpu(i) && housekeeping_cpu(i)) {
if (!idle_cpu(i) && housekeeping_cpu(i, HK_FLAG_TIMER)) {
cpu = i;
goto unlock;
}
}
}
if (!housekeeping_cpu(cpu))
cpu = housekeeping_any_cpu();
if (!housekeeping_cpu(cpu, HK_FLAG_TIMER))
cpu = housekeeping_any_cpu(HK_FLAG_TIMER);
unlock:
rcu_read_unlock();
return cpu;
......
......@@ -9027,7 +9027,7 @@ void nohz_balance_enter_idle(int cpu)
return;
/* Spare idle load balancing on CPUs that don't want to be disturbed: */
if (!housekeeping_cpu(cpu))
if (!housekeeping_cpu(cpu, HK_FLAG_SCHED))
return;
if (test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))
......
......@@ -15,37 +15,39 @@
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(void)
int housekeeping_any_cpu(enum hk_flags flags)
{
if (static_branch_unlikely(&housekeeping_overriden))
return cpumask_any_and(housekeeping_mask, cpu_online_mask);
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(void)
const struct cpumask *housekeeping_cpumask(enum hk_flags flags)
{
if (static_branch_unlikely(&housekeeping_overriden))
return housekeeping_mask;
if (housekeeping_flags & flags)
return housekeeping_mask;
return cpu_possible_mask;
}
EXPORT_SYMBOL_GPL(housekeeping_cpumask);
void housekeeping_affine(struct task_struct *t)
void housekeeping_affine(struct task_struct *t, enum hk_flags flags)
{
if (static_branch_unlikely(&housekeeping_overriden))
set_cpus_allowed_ptr(t, housekeeping_mask);
if (housekeeping_flags & flags)
set_cpus_allowed_ptr(t, housekeeping_mask);
}
EXPORT_SYMBOL_GPL(housekeeping_affine);
bool housekeeping_test_cpu(int cpu)
bool housekeeping_test_cpu(int cpu, enum hk_flags flags)
{
if (static_branch_unlikely(&housekeeping_overriden))
return cpumask_test_cpu(cpu, housekeeping_mask);
if (housekeeping_flags & flags)
return cpumask_test_cpu(cpu, housekeeping_mask);
return true;
}
EXPORT_SYMBOL_GPL(housekeeping_test_cpu);
......@@ -65,6 +67,8 @@ void __init housekeeping_init(void)
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 */
......
......@@ -777,7 +777,8 @@ void __init lockup_detector_init(void)
if (tick_nohz_full_enabled())
pr_info("Disabling watchdog on nohz_full cores by default\n");
cpumask_copy(&watchdog_cpumask, housekeeping_cpumask());
cpumask_copy(&watchdog_cpumask,
housekeeping_cpumask(HK_FLAG_TIMER));
if (!watchdog_nmi_probe())
nmi_watchdog_available = true;
......
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