android/android_kernel_asus_sm8350
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Revert "hrtimers: Push pending hrtimers away from outgoing CPU earlier"

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This reverts commit 54d0d83a53 which is
commit 5c0930ccaad5a74d74e8b18b648c5eb21ed2fe94 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: Ifdc5474de6e7488eb24959df1697b61b2e3e7880
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Greg Kroah-Hartman 2023-12-18 18:58:40 +00:00
parent af6deae771
commit 5c9845d8c6
4 changed files with 24 additions and 22 deletions
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1
include/linux/cpuhotplug.h
View File

@ -140,7 +140,6 @@ enum cpuhp_state {
CPUHP_AP_ARM_CORESIGHT_STARTING,
CPUHP_AP_ARM64_ISNDEP_STARTING,
CPUHP_AP_SMPCFD_DYING,
CPUHP_AP_HRTIMERS_DYING,
CPUHP_AP_X86_TBOOT_DYING,
CPUHP_AP_ARM_CACHE_B15_RAC_DYING,
CPUHP_AP_ONLINE,

4
include/linux/hrtimer.h
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@ -529,9 +529,9 @@ extern void sysrq_timer_list_show(void);
int hrtimers_prepare_cpu(unsigned int cpu);
#ifdef CONFIG_HOTPLUG_CPU
int hrtimers_cpu_dying(unsigned int cpu);
int hrtimers_dead_cpu(unsigned int cpu);
#else
#define hrtimers_cpu_dying NULL
#define hrtimers_dead_cpu NULL
#endif
#endif

8
kernel/cpu.c
View File

@ -1491,7 +1491,7 @@ static struct cpuhp_step cpuhp_hp_states[] = {
[CPUHP_HRTIMERS_PREPARE] = {
.name = "hrtimers:prepare",
.startup.single = hrtimers_prepare_cpu,
.teardown.single = NULL,
.teardown.single = hrtimers_dead_cpu,
},
[CPUHP_SMPCFD_PREPARE] = {
.name = "smpcfd:prepare",
@ -1558,12 +1558,6 @@ static struct cpuhp_step cpuhp_hp_states[] = {
.startup.single = NULL,
.teardown.single = smpcfd_dying_cpu,
},
[CPUHP_AP_HRTIMERS_DYING] = {
.name = "hrtimers:dying",
.startup.single = NULL,
.teardown.single = hrtimers_cpu_dying,
},
/* Entry state on starting. Interrupts enabled from here on. Transient
* state for synchronsization */
[CPUHP_AP_ONLINE] = {

33
kernel/time/hrtimer.c
View File

@ -2105,22 +2105,29 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
}
}
int hrtimers_cpu_dying(unsigned int dying_cpu)
int hrtimers_dead_cpu(unsigned int scpu)
{
struct hrtimer_cpu_base *old_base, *new_base;
int i, ncpu = cpumask_first(cpu_active_mask);
int i;
tick_cancel_sched_timer(dying_cpu);
old_base = this_cpu_ptr(&hrtimer_bases);
new_base = &per_cpu(hrtimer_bases, ncpu);
BUG_ON(cpu_online(scpu));
tick_cancel_sched_timer(scpu);
/*
* this BH disable ensures that raise_softirq_irqoff() does
* not wakeup ksoftirqd (and acquire the pi-lock) while
* holding the cpu_base lock
*/
local_bh_disable();
local_irq_disable();
old_base = &per_cpu(hrtimer_bases, scpu);
new_base = this_cpu_ptr(&hrtimer_bases);
/*
* The caller is globally serialized and nobody else
* takes two locks at once, deadlock is not possible.
*/
raw_spin_lock(&old_base->lock);
raw_spin_lock_nested(&new_base->lock, SINGLE_DEPTH_NESTING);
raw_spin_lock(&new_base->lock);
raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
migrate_hrtimer_list(&old_base->clock_base[i],
@ -2131,13 +2138,15 @@ int hrtimers_cpu_dying(unsigned int dying_cpu)
* The migration might have changed the first expiring softirq
* timer on this CPU. Update it.
*/
__hrtimer_get_next_event(new_base, HRTIMER_ACTIVE_SOFT);
/* Tell the other CPU to retrigger the next event */
smp_call_function_single(ncpu, retrigger_next_event, NULL, 0);
hrtimer_update_softirq_timer(new_base, false);
raw_spin_unlock(&new_base->lock);
raw_spin_unlock(&old_base->lock);
raw_spin_unlock(&new_base->lock);
/* Check, if we got expired work to do */
__hrtimer_peek_ahead_timers();
local_irq_enable();
local_bh_enable();
return 0;
}