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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen staging] x86/cpuidle: push parked CPUs into deeper sleep states when possible
commit 685151829e7577383051baa63d57d5f0ac8e2006
Author: Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue May 21 08:31:09 2019 +0200
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue May 21 08:31:09 2019 +0200
x86/cpuidle: push parked CPUs into deeper sleep states when possible
When the mwait-idle driver isn't used, C-state information becomes
available only in the course of Dom0 starting up. Use the provided data
to allow parked CPUs to sleep in a more energy efficient way, by waking
them briefly (via NMI) once the data has been recorded.
This involves re-arranging how/when the governor's ->enable() hook gets
invoked. The changes there include addition of so far missing error
handling in the respective CPU notifier handlers.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
xen/arch/x86/acpi/cpu_idle.c | 68 ++++++++++++++++++++++++++++++----------
xen/arch/x86/acpi/cpuidle_menu.c | 3 --
xen/arch/x86/cpu/mwait-idle.c | 11 ++++---
3 files changed, 59 insertions(+), 23 deletions(-)
diff --git a/xen/arch/x86/acpi/cpu_idle.c b/xen/arch/x86/acpi/cpu_idle.c
index cc388a27cc..13459ab8d8 100644
--- a/xen/arch/x86/acpi/cpu_idle.c
+++ b/xen/arch/x86/acpi/cpu_idle.c
@@ -349,12 +349,22 @@ static void dump_cx(unsigned char key)
unsigned int cpu;
printk("'%c' pressed -> printing ACPI Cx structures\n", key);
- for_each_online_cpu ( cpu )
- if (processor_powers[cpu])
- {
- print_acpi_power(cpu, processor_powers[cpu]);
- process_pending_softirqs();
- }
+ for_each_present_cpu ( cpu )
+ {
+ struct acpi_processor_power *power = processor_powers[cpu];
+
+ if ( !power )
+ continue;
+
+ if ( cpu_online(cpu) )
+ print_acpi_power(cpu, power);
+ else if ( park_offline_cpus )
+ printk("CPU%u parked in state %u (C%u)\n", cpu,
+ power->last_state ? power->last_state->idx : 1,
+ power->last_state ? power->last_state->type : 1);
+
+ process_pending_softirqs();
+ }
}
static int __init cpu_idle_key_init(void)
@@ -764,6 +774,7 @@ void acpi_dead_idle(void)
goto default_halt;
cx = &power->states[power->count - 1];
+ power->last_state = cx;
if ( cx->entry_method == ACPI_CSTATE_EM_FFH )
{
@@ -1225,9 +1236,30 @@ long set_cx_pminfo(uint32_t acpi_id, struct
xen_processor_power *power)
set_cx(acpi_power, &xen_cx);
}
- if ( cpuidle_current_governor->enable &&
- cpuidle_current_governor->enable(acpi_power) )
- return -EFAULT;
+ if ( !cpu_online(cpu_id) )
+ {
+ uint32_t apic_id = x86_cpu_to_apicid[cpu_id];
+
+ /*
+ * If we've just learned of more available C states, wake the CPU if
+ * it's parked, so it can go back to sleep in perhaps a deeper state.
+ */
+ if ( park_offline_cpus && apic_id != BAD_APICID )
+ {
+ unsigned long flags;
+
+ local_irq_save(flags);
+ apic_wait_icr_idle();
+ apic_icr_write(APIC_DM_NMI | APIC_DEST_PHYSICAL, apic_id);
+ local_irq_restore(flags);
+ }
+ }
+ else if ( cpuidle_current_governor->enable )
+ {
+ ret = cpuidle_current_governor->enable(acpi_power);
+ if ( ret < 0 )
+ return ret;
+ }
/* FIXME: C-state dependency is not supported by far */
@@ -1387,19 +1419,22 @@ static int cpu_callback(
struct notifier_block *nfb, unsigned long action, void *hcpu)
{
unsigned int cpu = (unsigned long)hcpu;
+ int rc = 0;
- /* Only hook on CPU_ONLINE because a dead cpu may utilize the info to
- * to enter deep C-state */
+ /*
+ * Only hook on CPU_UP_PREPARE because a dead cpu may utilize the info
+ * to enter deep C-state.
+ */
switch ( action )
{
- case CPU_ONLINE:
- (void)cpuidle_init_cpu(cpu);
- break;
- default:
+ case CPU_UP_PREPARE:
+ rc = cpuidle_init_cpu(cpu);
+ if ( !rc && cpuidle_current_governor->enable )
+ rc = cpuidle_current_governor->enable(processor_powers[cpu]);
break;
}
- return NOTIFY_DONE;
+ return !rc ? NOTIFY_DONE : notifier_from_errno(rc);
}
static struct notifier_block cpu_nfb = {
@@ -1414,6 +1449,7 @@ static int __init cpuidle_presmp_init(void)
return 0;
mwait_idle_init(&cpu_nfb);
+ cpu_nfb.notifier_call(&cpu_nfb, CPU_UP_PREPARE, cpu);
cpu_nfb.notifier_call(&cpu_nfb, CPU_ONLINE, cpu);
register_cpu_notifier(&cpu_nfb);
return 0;
diff --git a/xen/arch/x86/acpi/cpuidle_menu.c b/xen/arch/x86/acpi/cpuidle_menu.c
index 20f4f5fcf4..bae16f81da 100644
--- a/xen/arch/x86/acpi/cpuidle_menu.c
+++ b/xen/arch/x86/acpi/cpuidle_menu.c
@@ -277,9 +277,6 @@ static void menu_reflect(struct acpi_processor_power *power)
static int menu_enable_device(struct acpi_processor_power *power)
{
- if (!cpu_online(power->cpu))
- return -1;
-
memset(&per_cpu(menu_devices, power->cpu), 0, sizeof(struct menu_device));
return 0;
diff --git a/xen/arch/x86/cpu/mwait-idle.c b/xen/arch/x86/cpu/mwait-idle.c
index dab2be0f07..24b757b8c1 100644
--- a/xen/arch/x86/cpu/mwait-idle.c
+++ b/xen/arch/x86/cpu/mwait-idle.c
@@ -1166,12 +1166,17 @@ static int mwait_idle_cpu_init(struct notifier_block
*nfb,
struct acpi_processor_power *dev = processor_powers[cpu];
switch (action) {
+ int rc;
+
default:
return NOTIFY_DONE;
case CPU_UP_PREPARE:
- cpuidle_init_cpu(cpu);
- return NOTIFY_DONE;
+ rc = cpuidle_init_cpu(cpu);
+ dev = processor_powers[cpu];
+ if (!rc && cpuidle_current_governor->enable)
+ rc = cpuidle_current_governor->enable(dev);
+ return !rc ? NOTIFY_DONE : notifier_from_errno(rc);
case CPU_ONLINE:
if (!dev)
@@ -1260,8 +1265,6 @@ int __init mwait_idle_init(struct notifier_block *nfb)
}
if (!err) {
nfb->notifier_call = mwait_idle_cpu_init;
- mwait_idle_cpu_init(nfb, CPU_UP_PREPARE, NULL);
-
pm_idle_save = pm_idle;
pm_idle = mwait_idle;
dead_idle = acpi_dead_idle;
--
generated by git-patchbot for /home/xen/git/xen.git#staging
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