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SubjectRe: [PATCH 1/2] PPC: powernv: remove redundant cpuidle_idle_call()
Hi Deepthi,

On 02/07/2014 03:15 PM, Deepthi Dharwar wrote:
> Hi Preeti,
>
> Thanks for the patch.
>
> On 02/07/2014 12:31 PM, Preeti U Murthy wrote:
>> Hi Nicolas,
>>
>> Find below the patch that will need to be squashed with this one.
>> This patch is based on the mainline.Adding Deepthi, the author of
>> the patch which introduced the powernv cpuidle driver. Deepthi,
>> do you think the below patch looks right? We do not need to do an
>> explicit local_irq_enable() since we are in the call path of
>> cpuidle driver and that explicitly enables irqs on exit from
>> idle states.
>
> Yes, We enable irqs explicitly while entering snooze loop and we always
> have interrupts enabled in the snooze state.
> For NAP state, we exit out of this state with interrupts enabled so we
> do not need an explicit enable of irqs.
>
>> On 02/07/2014 06:47 AM, Nicolas Pitre wrote:
>>> On Thu, 6 Feb 2014, Preeti U Murthy wrote:
>>>
>>>> Hi Daniel,
>>>>
>>>> On 02/06/2014 09:55 PM, Daniel Lezcano wrote:
>>>>> Hi Nico,
>>>>>
>>>>>
>>>>> On 6 February 2014 14:16, Nicolas Pitre <nicolas.pitre@linaro.org> wrote:
>>>>>
>>>>>> The core idle loop now takes care of it.
>>>>>>
>>>>>> Signed-off-by: Nicolas Pitre <nico@linaro.org>
>>>>>> ---
>>>>>> arch/powerpc/platforms/powernv/setup.c | 13 +------------
>>>>>> 1 file changed, 1 insertion(+), 12 deletions(-)
>>>>>>
>>>>>> diff --git a/arch/powerpc/platforms/powernv/setup.c
>>>>>> b/arch/powerpc/platforms/powernv/setup.c
>>>>>> index 21166f65c9..a932feb290 100644
>>>>>> --- a/arch/powerpc/platforms/powernv/setup.c
>>>>>> +++ b/arch/powerpc/platforms/powernv/setup.c
>>>>>> @@ -26,7 +26,6 @@
>>>>>> #include <linux/of_fdt.h>
>>>>>> #include <linux/interrupt.h>
>>>>>> #include <linux/bug.h>
>>>>>> -#include <linux/cpuidle.h>
>>>>>>
>>>>>> #include <asm/machdep.h>
>>>>>> #include <asm/firmware.h>
>>>>>> @@ -217,16 +216,6 @@ static int __init pnv_probe(void)
>>>>>> return 1;
>>>>>> }
>>>>>>
>>>>>> -void powernv_idle(void)
>>>>>> -{
>>>>>> - /* Hook to cpuidle framework if available, else
>>>>>> - * call on default platform idle code
>>>>>> - */
>>>>>> - if (cpuidle_idle_call()) {
>>>>>> - power7_idle();
>>>>>> - }
>>>>>>
>>
>> drivers/cpuidle/cpuidle-powernv.c | 4 ++++
>> 1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
>> index 78fd174..130f081 100644
>> --- a/drivers/cpuidle/cpuidle-powernv.c
>> +++ b/drivers/cpuidle/cpuidle-powernv.c
>> @@ -31,11 +31,13 @@ static int snooze_loop(struct cpuidle_device *dev,
>> set_thread_flag(TIF_POLLING_NRFLAG);
>>
>> while (!need_resched()) {
>> + ppc64_runlatch_off();
> ^^^^^^^^^^^^^^^
> We could move this before the while() loop.
> It would ideal to turn off latch when we enter snooze and
> turn it on when we are about to exit, rather than doing
> it over and over in the while loop.

You are right, this can be moved out of the loop.

Thanks

Regards
Preeti U Murthy



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