From 46bcfad7a819bd17ac4e831b04405152d59784ab Mon Sep 17 00:00:00 2001 From: Deepthi Dharwar Date: Fri, 28 Oct 2011 16:20:42 +0530 Subject: cpuidle: Single/Global registration of idle states This patch makes the cpuidle_states structure global (single copy) instead of per-cpu. The statistics needed on per-cpu basis by the governor are kept per-cpu. This simplifies the cpuidle subsystem as state registration is done by single cpu only. Having single copy of cpuidle_states saves memory. Rare case of asymmetric C-states can be handled within the cpuidle driver and architectures such as POWER do not have asymmetric C-states. Having single/global registration of all the idle states, dynamic C-state transitions on x86 are handled by the boot cpu. Here, the boot cpu would disable all the devices, re-populate the states and later enable all the devices, irrespective of the cpu that would receive the notification first. Reference: https://lkml.org/lkml/2011/4/25/83 Signed-off-by: Deepthi Dharwar Signed-off-by: Trinabh Gupta Tested-by: Jean Pihet Reviewed-by: Kevin Hilman Acked-by: Arjan van de Ven Acked-by: Kevin Hilman Signed-off-by: Len Brown --- drivers/idle/intel_idle.c | 80 ++++++++++++++++++++++++++++++++++++----------- 1 file changed, 61 insertions(+), 19 deletions(-) (limited to 'drivers/idle/intel_idle.c') diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 3aa8d4cb6dca..5be9d599ff6b 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -81,7 +81,8 @@ static unsigned int mwait_substates; static unsigned int lapic_timer_reliable_states = (1 << 1); /* Default to only C1 */ static struct cpuidle_device __percpu *intel_idle_cpuidle_devices; -static int intel_idle(struct cpuidle_device *dev, int index); +static int intel_idle(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int index); static struct cpuidle_state *cpuidle_state_table; @@ -227,13 +228,15 @@ static int get_driver_data(int cstate) /** * intel_idle * @dev: cpuidle_device + * @drv: cpuidle driver * @index: index of cpuidle state * */ -static int intel_idle(struct cpuidle_device *dev, int index) +static int intel_idle(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int index) { unsigned long ecx = 1; /* break on interrupt flag */ - struct cpuidle_state *state = &dev->states[index]; + struct cpuidle_state *state = &drv->states[index]; struct cpuidle_state_usage *state_usage = &dev->states_usage[index]; unsigned long eax = (unsigned long)cpuidle_get_statedata(state_usage); unsigned int cstate; @@ -419,6 +422,60 @@ static void intel_idle_cpuidle_devices_uninit(void) free_percpu(intel_idle_cpuidle_devices); return; } +/* + * intel_idle_cpuidle_driver_init() + * allocate, initialize cpuidle_states + */ +static int intel_idle_cpuidle_driver_init(void) +{ + int cstate; + struct cpuidle_driver *drv = &intel_idle_driver; + + drv->state_count = 1; + + for (cstate = 1; cstate < MWAIT_MAX_NUM_CSTATES; ++cstate) { + int num_substates; + + if (cstate > max_cstate) { + printk(PREFIX "max_cstate %d reached\n", + max_cstate); + break; + } + + /* does the state exist in CPUID.MWAIT? */ + num_substates = (mwait_substates >> ((cstate) * 4)) + & MWAIT_SUBSTATE_MASK; + if (num_substates == 0) + continue; + /* is the state not enabled? */ + if (cpuidle_state_table[cstate].enter == NULL) { + /* does the driver not know about the state? */ + if (*cpuidle_state_table[cstate].name == '\0') + pr_debug(PREFIX "unaware of model 0x%x" + " MWAIT %d please" + " contact lenb@kernel.org", + boot_cpu_data.x86_model, cstate); + continue; + } + + if ((cstate > 2) && + !boot_cpu_has(X86_FEATURE_NONSTOP_TSC)) + mark_tsc_unstable("TSC halts in idle" + " states deeper than C2"); + + drv->states[drv->state_count] = /* structure copy */ + cpuidle_state_table[cstate]; + + drv->state_count += 1; + } + + if (auto_demotion_disable_flags) + smp_call_function(auto_demotion_disable, NULL, 1); + + return 0; +} + + /* * intel_idle_cpuidle_devices_init() * allocate, initialize, register cpuidle_devices @@ -453,23 +510,9 @@ static int intel_idle_cpuidle_devices_init(void) continue; /* is the state not enabled? */ if (cpuidle_state_table[cstate].enter == NULL) { - /* does the driver not know about the state? */ - if (*cpuidle_state_table[cstate].name == '\0') - pr_debug(PREFIX "unaware of model 0x%x" - " MWAIT %d please" - " contact lenb@kernel.org", - boot_cpu_data.x86_model, cstate); continue; } - if ((cstate > 2) && - !boot_cpu_has(X86_FEATURE_NONSTOP_TSC)) - mark_tsc_unstable("TSC halts in idle" - " states deeper than C2"); - - dev->states[dev->state_count] = /* structure copy */ - cpuidle_state_table[cstate]; - dev->states_usage[dev->state_count].driver_data = (void *)get_driver_data(cstate); @@ -484,8 +527,6 @@ static int intel_idle_cpuidle_devices_init(void) return -EIO; } } - if (auto_demotion_disable_flags) - smp_call_function(auto_demotion_disable, NULL, 1); return 0; } @@ -503,6 +544,7 @@ static int __init intel_idle_init(void) if (retval) return retval; + intel_idle_cpuidle_driver_init(); retval = cpuidle_register_driver(&intel_idle_driver); if (retval) { printk(KERN_DEBUG PREFIX "intel_idle yielding to %s", -- cgit v1.2.3