| Message ID | 1413822343-1972-3-git-send-email-daniel.lezcano@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Mon, 20 Oct 2014, Daniel Lezcano wrote: > In the current code, the check to reflect or not the outcoming state is done > against the idle state which has been choose and its value. s/choose/chosen/ > Instead of doing a check in each of the reflect functions, just don't call reflect > if something went wrong in the idle path. > > Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Acked-by: Nicolas Pitre <nico@linaro.org> > --- > drivers/cpuidle/governors/ladder.c | 3 +-- > drivers/cpuidle/governors/menu.c | 4 +--- > kernel/sched/idle.c | 3 ++- > 3 files changed, 4 insertions(+), 6 deletions(-) > > diff --git a/drivers/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c > index fb396d6..c0b36a8 100644 > --- a/drivers/cpuidle/governors/ladder.c > +++ b/drivers/cpuidle/governors/ladder.c > @@ -165,8 +165,7 @@ static int ladder_enable_device(struct cpuidle_driver *drv, > static void ladder_reflect(struct cpuidle_device *dev, int index) > { > struct ladder_device *ldev = &__get_cpu_var(ladder_devices); > - if (index > 0) > - ldev->last_state_idx = index; > + ldev->last_state_idx = index; > } > > static struct cpuidle_governor ladder_governor = { > diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c > index a17515f..3907301 100644 > --- a/drivers/cpuidle/governors/menu.c > +++ b/drivers/cpuidle/governors/menu.c > @@ -365,9 +365,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev, > static void menu_reflect(struct cpuidle_device *dev, int index) > { > struct menu_device *data = &__get_cpu_var(menu_devices); > - data->last_state_idx = index; > - if (index >= 0) > - data->needs_update = 1; > + data->needs_update = 1; > } > > /** > diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c > index f439161..9ac7322 100644 > --- a/kernel/sched/idle.c > +++ b/kernel/sched/idle.c > @@ -162,7 +162,8 @@ use_default: > /* > * Give the governor an opportunity to reflect on the outcome > */ > - cpuidle_reflect(dev, entered_state); > + if (entered_state >= 0) > + cpuidle_reflect(dev, entered_state); > > exit_idle: > __current_set_polling(); > -- > 1.9.1 > > -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Oct 20, 2014 at 06:25:41PM +0200, Daniel Lezcano wrote: > - if (index > 0) > - if (index >= 0) That's not the same condition. -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 10/24/2014 03:24 PM, Peter Zijlstra wrote: > On Mon, Oct 20, 2014 at 06:25:41PM +0200, Daniel Lezcano wrote: >> - if (index > 0) >> - if (index >= 0) > > That's not the same condition. Yes and it is wrong. That is the result of the CPUIDLE_DRIVER_STATE_START dance. The ladder governor is avoiding to use the POLL state as it was running on x86. But on, eg. ARM, we will never reflect the state 0 because CPUIDLE_DRIVER_STATE_START is equal to zero for all non-x86 platform. If I am not wrong the ladder select function will never choose the state 0 for x86, so it will never reflect the state 0 (after applying the patch 1/5). For the other arch it will reflect the state 0 as it should.
On Mon, Oct 20, 2014 at 06:25:41PM +0200, Daniel Lezcano wrote: > +++ b/kernel/sched/idle.c > @@ -162,7 +162,8 @@ use_default: > /* > * Give the governor an opportunity to reflect on the outcome > */ > - cpuidle_reflect(dev, entered_state); > + if (entered_state >= 0) > + cpuidle_reflect(dev, entered_state); > Given we'll do use_default: when next_state < 0, we actually never get here unless this is true. -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 10/24/2014 03:38 PM, Peter Zijlstra wrote: > On Mon, Oct 20, 2014 at 06:25:41PM +0200, Daniel Lezcano wrote: >> +++ b/kernel/sched/idle.c >> @@ -162,7 +162,8 @@ use_default: >> /* >> * Give the governor an opportunity to reflect on the outcome >> */ >> - cpuidle_reflect(dev, entered_state); >> + if (entered_state >= 0) >> + cpuidle_reflect(dev, entered_state); >> > > Given we'll do use_default: when next_state < 0, we actually never get > here unless this is true. There is the 'cpuidle_enter' call in between which may fail.
On Fri, Oct 24, 2014 at 03:43:53PM +0200, Daniel Lezcano wrote: > On 10/24/2014 03:38 PM, Peter Zijlstra wrote: > >On Mon, Oct 20, 2014 at 06:25:41PM +0200, Daniel Lezcano wrote: > >>+++ b/kernel/sched/idle.c > >>@@ -162,7 +162,8 @@ use_default: > >> /* > >> * Give the governor an opportunity to reflect on the outcome > >> */ > >>- cpuidle_reflect(dev, entered_state); > >>+ if (entered_state >= 0) > >>+ cpuidle_reflect(dev, entered_state); > >> > > > >Given we'll do use_default: when next_state < 0, we actually never get > >here unless this is true. > > There is the 'cpuidle_enter' call in between which may fail. Hmm, indeed there is. I had not expected that one to fail like this. -- To unsubscribe from this list: send the line "unsubscribe linux-pm" 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/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c index fb396d6..c0b36a8 100644 --- a/drivers/cpuidle/governors/ladder.c +++ b/drivers/cpuidle/governors/ladder.c @@ -165,8 +165,7 @@ static int ladder_enable_device(struct cpuidle_driver *drv, static void ladder_reflect(struct cpuidle_device *dev, int index) { struct ladder_device *ldev = &__get_cpu_var(ladder_devices); - if (index > 0) - ldev->last_state_idx = index; + ldev->last_state_idx = index; } static struct cpuidle_governor ladder_governor = { diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c index a17515f..3907301 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -365,9 +365,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev, static void menu_reflect(struct cpuidle_device *dev, int index) { struct menu_device *data = &__get_cpu_var(menu_devices); - data->last_state_idx = index; - if (index >= 0) - data->needs_update = 1; + data->needs_update = 1; } /** diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index f439161..9ac7322 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -162,7 +162,8 @@ use_default: /* * Give the governor an opportunity to reflect on the outcome */ - cpuidle_reflect(dev, entered_state); + if (entered_state >= 0) + cpuidle_reflect(dev, entered_state); exit_idle: __current_set_polling();
In the current code, the check to reflect or not the outcoming state is done against the idle state which has been choose and its value. Instead of doing a check in each of the reflect functions, just don't call reflect if something went wrong in the idle path. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> --- drivers/cpuidle/governors/ladder.c | 3 +-- drivers/cpuidle/governors/menu.c | 4 +--- kernel/sched/idle.c | 3 ++- 3 files changed, 4 insertions(+), 6 deletions(-)