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Revert "ANDROID: cpu/hotplug: add pause/resume_cpus interface"

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This reverts commit 683010f555.

CPU Pause causes major merge conflicts with the 5.11 scheduler changes
(migrate-disable specifically), so lets revert Pause temporarily as it
is not needed urgently in android-mainline.

Signed-off-by: Quentin Perret <qperret@google.com>
Change-Id: I7f3f6003e962e61111831571602c380136a11d59
This commit is contained in:
Quentin Perret
2020-12-15 17:55:21 +00:00
parent 6a772b98a8
commit c7f998a0cd
4 changed files with 9 additions and 175 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/linux/cpu.h
-4
View File
@@ -122,8 +122,6 @@ extern void cpu_hotplug_disable(void);
extern void cpu_hotplug_enable(void);
void clear_tasks_mm_cpumask(int cpu);
int remove_cpu(unsigned int cpu);
int pause_cpus(struct cpumask *cpumask);
int resume_cpus(struct cpumask *cpumask);
int cpu_device_down(struct device *dev);
extern void smp_shutdown_nonboot_cpus(unsigned int primary_cpu);
@@ -137,8 +135,6 @@ static inline int cpus_read_trylock(void) { return true; }
static inline void lockdep_assert_cpus_held(void) { }
static inline void cpu_hotplug_disable(void) { }
static inline void cpu_hotplug_enable(void) { }
static inline int pause_cpus(struct cpumask *cpumask) { return -ENODEV; }
static inline int resume_cpus(struct cpumask *cpumask) { return -ENODEV; }
static inline void smp_shutdown_nonboot_cpus(unsigned int primary_cpu) { }
#endif /* !CONFIG_HOTPLUG_CPU */
include/linux/sched/hotplug.h
-2
View File
@@ -8,9 +8,7 @@
extern int sched_cpu_starting(unsigned int cpu);
extern int sched_cpu_activate(unsigned int cpu);
extern int sched_cpus_activate(struct cpumask *cpus);
extern int sched_cpu_deactivate(unsigned int cpu);
extern int sched_cpus_deactivate_nosync(struct cpumask *cpus);
#ifdef CONFIG_HOTPLUG_CPU
extern int sched_cpu_dying(unsigned int cpu);
kernel/cpu.c
-115
View File
@@ -1097,121 +1097,6 @@ int remove_cpu(unsigned int cpu)
}
EXPORT_SYMBOL_GPL(remove_cpu);
extern bool dl_cpu_busy(unsigned int cpu);
int pause_cpus(struct cpumask *cpus)
{
int err = 0;
int cpu;
cpu_maps_update_begin();
if (cpu_hotplug_disabled) {
err = -EBUSY;
goto err_cpu_maps_update;
}
/* Pausing an already inactive CPU isn't an error */
cpumask_and(cpus, cpus, cpu_active_mask);
for_each_cpu(cpu, cpus) {
if (!cpu_online(cpu) || dl_cpu_busy(cpu)) {
err = -EBUSY;
goto err_cpu_maps_update;
}
}
if (cpumask_weight(cpus) >= num_active_cpus()) {
err = -EBUSY;
goto err_cpu_maps_update;
}
if (cpumask_empty(cpus))
goto err_cpu_maps_update;
cpus_write_lock();
cpuhp_tasks_frozen = 0;
if (sched_cpus_deactivate_nosync(cpus)) {
err = -EBUSY;
goto err_cpus_write_unlock;
}
/*
* Even if living on the side of the regular HP path, pause is using
* one of the HP step (CPUHP_AP_ACTIVE). This should be reflected on the
* current state of the CPU.
*/
for_each_cpu(cpu, cpus) {
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
st->state = CPUHP_AP_ACTIVE - 1;
st->target = st->state;
}
err_cpus_write_unlock:
cpus_write_unlock();
err_cpu_maps_update:
cpu_maps_update_done();
return err;
}
EXPORT_SYMBOL_GPL(pause_cpus);
int resume_cpus(struct cpumask *cpus)
{
unsigned int cpu;
int err = 0;
cpu_maps_update_begin();
if (cpu_hotplug_disabled) {
err = -EBUSY;
goto err_cpu_maps_update;
}
/* Resuming an already active CPU isn't an error */
cpumask_andnot(cpus, cpus, cpu_active_mask);
for_each_cpu(cpu, cpus) {
if (!cpu_online(cpu)) {
err = -EBUSY;
goto err_cpu_maps_update;
}
}
if (cpumask_empty(cpus))
goto err_cpu_maps_update;
cpus_write_lock();
cpuhp_tasks_frozen = 0;
if (sched_cpus_activate(cpus)) {
err = -EBUSY;
goto err_cpus_write_unlock;
}
/*
* see pause_cpus.
*/
for_each_cpu(cpu, cpus) {
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
st->state = CPUHP_ONLINE;
st->target = st->state;
}
err_cpus_write_unlock:
cpus_write_unlock();
err_cpu_maps_update:
cpu_maps_update_done();
return err;
}
EXPORT_SYMBOL_GPL(resume_cpus);
void smp_shutdown_nonboot_cpus(unsigned int primary_cpu)
{
unsigned int cpu;
kernel/sched/core.c
+9 -54
View File
@@ -6979,27 +6979,19 @@ int sched_cpu_activate(unsigned int cpu)
return 0;
}
int sched_cpus_activate(struct cpumask *cpus)
{
unsigned int cpu;
for_each_cpu(cpu, cpus) {
if (sched_cpu_activate(cpu)) {
for_each_cpu_and(cpu, cpus, cpu_active_mask)
sched_cpu_deactivate(cpu);
return -EBUSY;
}
}
return 0;
}
int _sched_cpu_deactivate(unsigned int cpu)
int sched_cpu_deactivate(unsigned int cpu)
{
int ret;
set_cpu_active(cpu, false);
/*
* We've cleared cpu_active_mask, wait for all preempt-disabled and RCU
* users of this state to go away such that all new such users will
* observe it.
*
* Do sync before park smpboot threads to take care the rcu boost case.
*/
synchronize_rcu();
#ifdef CONFIG_SCHED_SMT
/*
@@ -7024,43 +7016,6 @@ int _sched_cpu_deactivate(unsigned int cpu)
return 0;
}
int sched_cpu_deactivate(unsigned int cpu)
{
int ret = _sched_cpu_deactivate(cpu);
if (ret)
return ret;
/*
* We've cleared cpu_active_mask, wait for all preempt-disabled and RCU
* users of this state to go away such that all new such users will
* observe it.
*
* Do sync before park smpboot threads to take care the rcu boost case.
*/
synchronize_rcu();
return 0;
}
int sched_cpus_deactivate_nosync(struct cpumask *cpus)
{
unsigned int cpu;
for_each_cpu(cpu, cpus) {
if (_sched_cpu_deactivate(cpu)) {
for_each_cpu(cpu, cpus) {
if (!cpu_active(cpu))
sched_cpu_activate(cpu);
}
return -EBUSY;
}
}
return 0;
}
static void sched_rq_cpu_starting(unsigned int cpu)
{
struct rq *rq = cpu_rq(cpu);