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author | Deepthi Dharwar <deepthi@linux.vnet.ibm.com> | 2011-10-28 10:50:42 (GMT) |
---|---|---|
committer | Len Brown <len.brown@intel.com> | 2011-11-07 02:13:58 (GMT) |
commit | 46bcfad7a819bd17ac4e831b04405152d59784ab (patch) | |
tree | 20041e788154d103edff2699f88d4a30320e3ee2 /drivers/idle/intel_idle.c | |
parent | 4202735e8ab6ecfb0381631a0d0b58fefe0bd4e2 (diff) | |
download | linux-46bcfad7a819bd17ac4e831b04405152d59784ab.tar.xz |
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 <deepthi@linux.vnet.ibm.com>
Signed-off-by: Trinabh Gupta <g.trinabh@gmail.com>
Tested-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/idle/intel_idle.c')
-rw-r--r-- | drivers/idle/intel_idle.c | 80 |
1 files changed, 61 insertions, 19 deletions
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 3aa8d4c..5be9d59 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; @@ -420,6 +423,60 @@ static void intel_idle_cpuidle_devices_uninit(void) 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", |