| Message ID | 1341494608-16591-3-git-send-email-daniel.lezcano@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thursday, July 05, 2012, Daniel Lezcano wrote: > The 'enter_dead' function is only used for processor_idle.c > and the same function is used several times. We fall into the > same abuse with the multiple callbacks for the same function. This isn't abuse, mind you. This is a normal practice. > This patch fixes that by moving the 'enter_dead' function to the > driver structure. A flag CPUIDLE_FLAG_DEAD_VALID has been added > to handle the callback conditional invokation. And how does that improve things? Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 07/05/2012 10:40 PM, Rafael J. Wysocki wrote: > On Thursday, July 05, 2012, Daniel Lezcano wrote: >> The 'enter_dead' function is only used for processor_idle.c >> and the same function is used several times. We fall into the >> same abuse with the multiple callbacks for the same function. > > This isn't abuse, mind you. This is a normal practice. Well, that depends :) I agree adding a callback per state is nice and flexible but if it is not used, it is a waste of memory, even if it is 32 bytes. >> This patch fixes that by moving the 'enter_dead' function to the >> driver structure. A flag CPUIDLE_FLAG_DEAD_VALID has been added >> to handle the callback conditional invokation. > > And how does that improve things? In order to check if the play_dead is enabled for a specific state, we check if the pointer is set. As it has been moved to a single function, we need to add a flag to replace this check. That is not an improvement, it replace a check by another check.
On Friday, July 06, 2012, Daniel Lezcano wrote: > On 07/05/2012 10:40 PM, Rafael J. Wysocki wrote: > > On Thursday, July 05, 2012, Daniel Lezcano wrote: > >> The 'enter_dead' function is only used for processor_idle.c > >> and the same function is used several times. We fall into the > >> same abuse with the multiple callbacks for the same function. > > > > This isn't abuse, mind you. This is a normal practice. > > Well, that depends :) > > I agree adding a callback per state is nice and flexible Yes, it is. > but if it is not used, it is a waste of memory, even if it is 32 bytes. 32 bits, perhaps? And how many of those are there in the whole system, actually? Is this a number that actually matters? > >> This patch fixes that by moving the 'enter_dead' function to the > >> driver structure. A flag CPUIDLE_FLAG_DEAD_VALID has been added > >> to handle the callback conditional invokation. > > > > And how does that improve things? > > In order to check if the play_dead is enabled for a specific state, we > check if the pointer is set. As it has been moved to a single function, > we need to add a flag to replace this check. That is not an improvement, Well, exactly. > it replace a check by another check. Sorry, but I don't really see the point. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 6d9ec3e..33310fb 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -1024,6 +1024,7 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev, struct cpuidle_driver acpi_idle_driver = { .name = "acpi_idle", .owner = THIS_MODULE, + .enter_dead = acpi_idle_play_dead, }; /** @@ -1132,16 +1133,14 @@ static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr) case ACPI_STATE_C1: if (cx->entry_method == ACPI_CSTATE_FFH) state->flags |= CPUIDLE_FLAG_TIME_VALID; - + state->flags |= CPUIDLE_FLAG_DEAD_VALID; state->enter = acpi_idle_enter_c1; - state->enter_dead = acpi_idle_play_dead; drv->safe_state_index = count; break; case ACPI_STATE_C2: - state->flags |= CPUIDLE_FLAG_TIME_VALID; + state->flags |= CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_DEAD_VALID; state->enter = acpi_idle_enter_simple; - state->enter_dead = acpi_idle_play_dead; drv->safe_state_index = count; break; diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index c064144..7dcfa45 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -81,14 +81,14 @@ int cpuidle_play_dead(void) for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) { struct cpuidle_state *s = &drv->states[i]; - if (s->power_usage < power_usage && s->enter_dead) { + if (s->power_usage < power_usage && (s->flags & CPUIDLE_FLAG_DEAD_VALID)) { power_usage = s->power_usage; dead_state = i; } } if (dead_state != -1) - return drv->states[dead_state].enter_dead(dev, dead_state); + return drv->enter_dead(dev, dead_state); return -ENODEV; } diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index 4d816c7..730e12e 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -52,14 +52,25 @@ struct cpuidle_state { int (*enter) (struct cpuidle_device *dev, struct cpuidle_driver *drv, int index); - - int (*enter_dead) (struct cpuidle_device *dev, int index); }; -/* Idle State Flags */ -#define CPUIDLE_FLAG_TIME_VALID (0x01) /* is residency time measurable? */ - -#define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000) +/******************************************************************************** + * Idle State Flags: * + * CPUIDLE_FLAG_TIME_VALID : the drivers could measure the state residency * + * time and store it in the 'target_residency'field. * + * This flag will tell the cpuidle core to use this * + * value to compute an accurate prediction. * + * * + * CPUIDLE_FLAG_COUPLED : state applies to multiple cpus * + * * + * CPUIDLE_FLAG_DEAD_VALID : the driver may want to deal with dead cpus, tell * + * the cpuidle core the specified state can use the * + * enter_dead function. * + * * + *******************************************************************************/ +#define CPUIDLE_FLAG_TIME_VALID (0x01) +#define CPUIDLE_FLAG_COUPLED (0x02) +#define CPUIDLE_FLAG_DEAD_VALID (0x04) /** * cpuidle_get_statedata - retrieves private driver state data @@ -132,6 +143,9 @@ struct cpuidle_driver { int state_count; int safe_state_index; int (*enter)(struct cpuidle_device *, struct cpuidle_driver *, int); +#ifdef CONFIG_ACPI + int (*enter_dead)(struct cpuidle_device *, int); +#endif }; #ifdef CONFIG_CPU_IDLE
The 'enter_dead' function is only used for processor_idle.c and the same function is used several times. We fall into the same abuse with the multiple callbacks for the same function. This patch fixes that by moving the 'enter_dead' function to the driver structure. A flag CPUIDLE_FLAG_DEAD_VALID has been added to handle the callback conditional invokation. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> --- drivers/acpi/processor_idle.c | 7 +++---- drivers/cpuidle/cpuidle.c | 4 ++-- include/linux/cpuidle.h | 26 ++++++++++++++++++++------ 3 files changed, 25 insertions(+), 12 deletions(-)