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sched/hotplug: Convert cpu_[in]active notifiers to state machine 

Now that we reduced everything into single notifiers, it's simple to move them
into the hotplug state machine space.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: rt@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner 2016-03-10 12:54:13 +01:00
parent c6d2c7475c
commit 40190a78f8
5 changed files with 30 additions and 60 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
include/linux/cpu.h
View File

@ -59,18 +59,6 @@ struct notifier_block;
* CPU notifier priorities.
*/
enum {
/*
* SCHED_ACTIVE marks a cpu which is coming up active during
* CPU_ONLINE and CPU_DOWN_FAILED and must be the first notifier. Is
* also cpuset according to cpu_active mask right after activating the
* cpu. During CPU_DOWN_PREPARE, SCHED_INACTIVE reversed the operation.
*
* This ordering guarantees consistent cpu_active mask and
* migration behavior to all cpu notifiers.
*/
CPU_PRI_SCHED_ACTIVE = INT_MAX,
CPU_PRI_SCHED_INACTIVE = INT_MIN,
/* migration should happen before other stuff but after perf */
CPU_PRI_PERF = 20,
CPU_PRI_MIGRATION = 10,

1
include/linux/cpuhotplug.h
View File

@ -13,6 +13,7 @@ enum cpuhp_state {
CPUHP_AP_ONLINE,
CPUHP_TEARDOWN_CPU,
CPUHP_AP_ONLINE_IDLE,
CPUHP_AP_ACTIVE,
CPUHP_AP_SMPBOOT_THREADS,
CPUHP_AP_NOTIFY_ONLINE,
CPUHP_AP_ONLINE_DYN,

2
include/linux/sched.h
View File

@ -373,6 +373,8 @@ extern void trap_init(void);
extern void update_process_times(int user);
extern void scheduler_tick(void);
extern int sched_cpu_starting(unsigned int cpu);
extern int sched_cpu_activate(unsigned int cpu);
extern int sched_cpu_deactivate(unsigned int cpu);
extern void sched_show_task(struct task_struct *p);

8
kernel/cpu.c
View File

@ -923,8 +923,6 @@ void cpuhp_online_idle(enum cpuhp_state state)
st->state = CPUHP_AP_ONLINE_IDLE;
/* The cpu is marked online, set it active now */
set_cpu_active(cpu, true);
/* Unpark the stopper thread and the hotplug thread of this cpu */
stop_machine_unpark(cpu);
kthread_unpark(st->thread);
@ -1259,6 +1257,12 @@ static struct cpuhp_step cpuhp_ap_states[] = {
[CPUHP_AP_ONLINE] = {
.name = "ap:online",
},
/* First state is scheduler control. Interrupts are enabled */
[CPUHP_AP_ACTIVE] = {
.name = "sched:active",
.startup = sched_cpu_activate,
.teardown = sched_cpu_deactivate,
},
/* Handle smpboot threads park/unpark */
[CPUHP_AP_SMPBOOT_THREADS] = {
.name = "smpboot:threads",

67
kernel/sched/core.c
View File

@ -6634,9 +6634,6 @@ static void sched_domains_numa_masks_set(unsigned int cpu)
int node = cpu_to_node(cpu);
int i, j;
if (!sched_smp_initialized)
return;
for (i = 0; i < sched_domains_numa_levels; i++) {
for (j = 0; j < nr_node_ids; j++) {
if (node_distance(j, node) <= sched_domains_numa_distance[i])
@ -6649,9 +6646,6 @@ static void sched_domains_numa_masks_clear(unsigned int cpu)
{
int i, j;
if (!sched_smp_initialized)
return;
for (i = 0; i < sched_domains_numa_levels; i++) {
for (j = 0; j < nr_node_ids; j++)
cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]);
@ -7051,12 +7045,9 @@ static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */
* If we come here as part of a suspend/resume, don't touch cpusets because we
* want to restore it back to its original state upon resume anyway.
*/
static void cpuset_cpu_active(bool frozen)
static void cpuset_cpu_active(void)
{
if (!sched_smp_initialized)
return;
if (frozen) {
if (cpuhp_tasks_frozen) {
/*
* num_cpus_frozen tracks how many CPUs are involved in suspend
* resume sequence. As long as this is not the last online
@ -7077,17 +7068,14 @@ static void cpuset_cpu_active(bool frozen)
cpuset_update_active_cpus(true);
}
static int cpuset_cpu_inactive(unsigned int cpu, bool frozen)
static int cpuset_cpu_inactive(unsigned int cpu)
{
unsigned long flags;
struct dl_bw *dl_b;
bool overflow;
int cpus;
if (!sched_smp_initialized)
return 0;
if (!frozen) {
if (!cpuhp_tasks_frozen) {
rcu_read_lock_sched();
dl_b = dl_bw_of(cpu);
@ -7108,42 +7096,33 @@ static int cpuset_cpu_inactive(unsigned int cpu, bool frozen)
return 0;
}
static int sched_cpu_active(struct notifier_block *nfb, unsigned long action,
void *hcpu)
int sched_cpu_activate(unsigned int cpu)
{
unsigned int cpu = (unsigned long)hcpu;
set_cpu_active(cpu, true);
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_DOWN_FAILED:
case CPU_ONLINE:
set_cpu_active(cpu, true);
if (sched_smp_initialized) {
sched_domains_numa_masks_set(cpu);
cpuset_cpu_active(action & CPU_TASKS_FROZEN);
return NOTIFY_OK;
default:
return NOTIFY_DONE;
cpuset_cpu_active();
}
return 0;
}
static int sched_cpu_inactive(struct notifier_block *nfb,
unsigned long action, void *hcpu)
int sched_cpu_deactivate(unsigned int cpu)
{
unsigned int cpu = (unsigned long)hcpu;
int ret;
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_DOWN_PREPARE:
set_cpu_active(cpu, false);
ret = cpuset_cpu_inactive(cpu, action & CPU_TASKS_FROZEN);
if (ret) {
set_cpu_active(cpu, true);
return notifier_from_errno(ret);
}
sched_domains_numa_masks_clear(cpu);
return NOTIFY_OK;
default:
return NOTIFY_DONE;
set_cpu_active(cpu, false);
if (!sched_smp_initialized)
return 0;
ret = cpuset_cpu_inactive(cpu);
if (ret) {
set_cpu_active(cpu, true);
return ret;
}
sched_domains_numa_masks_clear(cpu);
return 0;
}
int sched_cpu_starting(unsigned int cpu)
@ -7197,10 +7176,6 @@ static int __init migration_init(void)
migration_call(&migration_notifier, CPU_ONLINE, cpu);
register_cpu_notifier(&migration_notifier);
/* Register cpu active notifiers */
cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE);
cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE);
return 0;
}
early_initcall(migration_init);