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Diffstat (limited to 'kernel/smpboot.c')
-rw-r--r--kernel/smpboot.c59
1 files changed, 34 insertions, 25 deletions
diff --git a/kernel/smpboot.c b/kernel/smpboot.c
index 02fc5c933673..4503b60ce9bd 100644
--- a/kernel/smpboot.c
+++ b/kernel/smpboot.c
@@ -1,13 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* Common SMP CPU bringup/teardown functions
*/
#include <linux/cpu.h>
#include <linux/err.h>
#include <linux/smp.h>
+#include <linux/delay.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/sched.h>
+#include <linux/sched/task.h>
#include <linux/export.h>
#include <linux/percpu.h>
#include <linux/kthread.h>
@@ -15,8 +18,6 @@
#include "smpboot.h"
-#ifdef CONFIG_SMP
-
#ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
/*
* For the hotplug case we keep the task structs around and reuse
@@ -24,13 +25,12 @@
*/
static DEFINE_PER_CPU(struct task_struct *, idle_threads);
-struct task_struct * __cpuinit idle_thread_get(unsigned int cpu)
+struct task_struct *idle_thread_get(unsigned int cpu)
{
struct task_struct *tsk = per_cpu(idle_threads, cpu);
if (!tsk)
return ERR_PTR(-ENOMEM);
- init_idle(tsk, cpu);
return tsk;
}
@@ -45,7 +45,7 @@ void __init idle_thread_set_boot_cpu(void)
*
* Creates the thread if it does not exist.
*/
-static inline void idle_init(unsigned int cpu)
+static __always_inline void idle_init(unsigned int cpu)
{
struct task_struct *tsk = per_cpu(idle_threads, cpu);
@@ -74,8 +74,6 @@ void __init idle_threads_init(void)
}
#endif
-#endif /* #ifdef CONFIG_SMP */
-
static LIST_HEAD(hotplug_threads);
static DEFINE_MUTEX(smpboot_threads_lock);
@@ -110,9 +108,10 @@ static int smpboot_thread_fn(void *data)
set_current_state(TASK_INTERRUPTIBLE);
preempt_disable();
if (kthread_should_stop()) {
- set_current_state(TASK_RUNNING);
+ __set_current_state(TASK_RUNNING);
preempt_enable();
- if (ht->cleanup)
+ /* cleanup must mirror setup */
+ if (ht->cleanup && td->status != HP_THREAD_NONE)
ht->cleanup(td->cpu, cpu_online(td->cpu));
kfree(td);
return 0;
@@ -136,26 +135,27 @@ static int smpboot_thread_fn(void *data)
/* Check for state change setup */
switch (td->status) {
case HP_THREAD_NONE:
+ __set_current_state(TASK_RUNNING);
preempt_enable();
if (ht->setup)
ht->setup(td->cpu);
td->status = HP_THREAD_ACTIVE;
- preempt_disable();
- break;
+ continue;
+
case HP_THREAD_PARKED:
+ __set_current_state(TASK_RUNNING);
preempt_enable();
if (ht->unpark)
ht->unpark(td->cpu);
td->status = HP_THREAD_ACTIVE;
- preempt_disable();
- break;
+ continue;
}
if (!ht->thread_should_run(td->cpu)) {
- preempt_enable();
+ preempt_enable_no_resched();
schedule();
} else {
- set_current_state(TASK_RUNNING);
+ __set_current_state(TASK_RUNNING);
preempt_enable();
ht->thread_fn(td->cpu);
}
@@ -183,6 +183,12 @@ __smpboot_create_thread(struct smp_hotplug_thread *ht, unsigned int cpu)
kfree(td);
return PTR_ERR(tsk);
}
+ kthread_set_per_cpu(tsk, cpu);
+ /*
+ * Park the thread so that it could start right on the CPU
+ * when it is available.
+ */
+ kthread_park(tsk);
get_task_struct(tsk);
*per_cpu_ptr(ht->store, cpu) = tsk;
if (ht->create) {
@@ -219,12 +225,11 @@ static void smpboot_unpark_thread(struct smp_hotplug_thread *ht, unsigned int cp
{
struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
- if (ht->pre_unpark)
- ht->pre_unpark(cpu);
- kthread_unpark(tsk);
+ if (!ht->selfparking)
+ kthread_unpark(tsk);
}
-void smpboot_unpark_threads(unsigned int cpu)
+int smpboot_unpark_threads(unsigned int cpu)
{
struct smp_hotplug_thread *cur;
@@ -232,6 +237,7 @@ void smpboot_unpark_threads(unsigned int cpu)
list_for_each_entry(cur, &hotplug_threads, list)
smpboot_unpark_thread(cur, cpu);
mutex_unlock(&smpboot_threads_lock);
+ return 0;
}
static void smpboot_park_thread(struct smp_hotplug_thread *ht, unsigned int cpu)
@@ -242,7 +248,7 @@ static void smpboot_park_thread(struct smp_hotplug_thread *ht, unsigned int cpu)
kthread_park(tsk);
}
-void smpboot_park_threads(unsigned int cpu)
+int smpboot_park_threads(unsigned int cpu)
{
struct smp_hotplug_thread *cur;
@@ -250,6 +256,7 @@ void smpboot_park_threads(unsigned int cpu)
list_for_each_entry_reverse(cur, &hotplug_threads, list)
smpboot_park_thread(cur, cpu);
mutex_unlock(&smpboot_threads_lock);
+ return 0;
}
static void smpboot_destroy_threads(struct smp_hotplug_thread *ht)
@@ -261,15 +268,15 @@ static void smpboot_destroy_threads(struct smp_hotplug_thread *ht)
struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
if (tsk) {
- kthread_stop(tsk);
- put_task_struct(tsk);
+ kthread_stop_put(tsk);
*per_cpu_ptr(ht->store, cpu) = NULL;
}
}
}
/**
- * smpboot_register_percpu_thread - Register a per_cpu thread related to hotplug
+ * smpboot_register_percpu_thread - Register a per_cpu thread related
+ * to hotplug
* @plug_thread: Hotplug thread descriptor
*
* Creates and starts the threads on all online cpus.
@@ -279,6 +286,7 @@ int smpboot_register_percpu_thread(struct smp_hotplug_thread *plug_thread)
unsigned int cpu;
int ret = 0;
+ cpus_read_lock();
mutex_lock(&smpboot_threads_lock);
for_each_online_cpu(cpu) {
ret = __smpboot_create_thread(plug_thread, cpu);
@@ -291,6 +299,7 @@ int smpboot_register_percpu_thread(struct smp_hotplug_thread *plug_thread)
list_add(&plug_thread->list, &hotplug_threads);
out:
mutex_unlock(&smpboot_threads_lock);
+ cpus_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(smpboot_register_percpu_thread);
@@ -303,11 +312,11 @@ EXPORT_SYMBOL_GPL(smpboot_register_percpu_thread);
*/
void smpboot_unregister_percpu_thread(struct smp_hotplug_thread *plug_thread)
{
- get_online_cpus();
+ cpus_read_lock();
mutex_lock(&smpboot_threads_lock);
list_del(&plug_thread->list);
smpboot_destroy_threads(plug_thread);
mutex_unlock(&smpboot_threads_lock);
- put_online_cpus();
+ cpus_read_unlock();
}
EXPORT_SYMBOL_GPL(smpboot_unregister_percpu_thread);
generated by cgit (git 2.34.1) at 2025-12-21 21:33:56 +0000