diff options
Diffstat (limited to 'drivers/acpi/processor_idle.c')
| -rw-r--r-- | drivers/acpi/processor_idle.c | 38 |
1 files changed, 34 insertions, 4 deletions
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 71066066d626b..0a395fca843b4 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -38,6 +38,7 @@ #include <linux/dmi.h> #include <linux/moduleparam.h> #include <linux/sched.h> /* need_resched() */ +#include <linux/latency.h> #include <asm/io.h> #include <asm/uaccess.h> @@ -453,7 +454,8 @@ static void acpi_processor_idle(void) */ if (cx->promotion.state && ((cx->promotion.state - pr->power.states) <= max_cstate)) { - if (sleep_ticks > cx->promotion.threshold.ticks) { + if (sleep_ticks > cx->promotion.threshold.ticks && + cx->promotion.state->latency <= system_latency_constraint()) { cx->promotion.count++; cx->demotion.count = 0; if (cx->promotion.count >= @@ -494,8 +496,10 @@ static void acpi_processor_idle(void) end: /* * Demote if current state exceeds max_cstate + * or if the latency of the current state is unacceptable */ - if ((pr->power.state - pr->power.states) > max_cstate) { + if ((pr->power.state - pr->power.states) > max_cstate || + pr->power.state->latency > system_latency_constraint()) { if (cx->demotion.state) next_state = cx->demotion.state; } @@ -1009,9 +1013,11 @@ static int acpi_processor_power_seq_show(struct seq_file *seq, void *offset) seq_printf(seq, "active state: C%zd\n" "max_cstate: C%d\n" - "bus master activity: %08x\n", + "bus master activity: %08x\n" + "maximum allowed latency: %d usec\n", pr->power.state ? pr->power.state - pr->power.states : 0, - max_cstate, (unsigned)pr->power.bm_activity); + max_cstate, (unsigned)pr->power.bm_activity, + system_latency_constraint()); seq_puts(seq, "states:\n"); @@ -1077,6 +1083,28 @@ static const struct file_operations acpi_processor_power_fops = { .release = single_release, }; +static void smp_callback(void *v) +{ + /* we already woke the CPU up, nothing more to do */ +} + +/* + * This function gets called when a part of the kernel has a new latency + * requirement. This means we need to get all processors out of their C-state, + * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that + * wakes them all right up. + */ +static int acpi_processor_latency_notify(struct notifier_block *b, + unsigned long l, void *v) +{ + smp_call_function(smp_callback, NULL, 0, 1); + return NOTIFY_OK; +} + +static struct notifier_block acpi_processor_latency_notifier = { + .notifier_call = acpi_processor_latency_notify, +}; + int acpi_processor_power_init(struct acpi_processor *pr, struct acpi_device *device) { @@ -1093,6 +1121,7 @@ int acpi_processor_power_init(struct acpi_processor *pr, "ACPI: processor limited to max C-state %d\n", max_cstate); first_run++; + register_latency_notifier(&acpi_processor_latency_notifier); } if (!pr) @@ -1164,6 +1193,7 @@ int acpi_processor_power_exit(struct acpi_processor *pr, * copies of pm_idle before proceeding. */ cpu_idle_wait(); + unregister_latency_notifier(&acpi_processor_latency_notifier); } return 0; |