From: Chanwoo Choi <cw00.choi@samsung.com>
To: Dong Aisheng <dongas86@gmail.com>, Chanwoo Choi <cwchoi00@gmail.com>
Cc: Dong Aisheng <aisheng.dong@nxp.com>,
Linux PM <linux-pm@vger.kernel.org>,
"moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE"
<linux-arm-kernel@lists.infradead.org>,
Sascha Hauer <kernel@pengutronix.de>,
Shawn Guo <shawnguo@kernel.org>, dl-linux-imx <linux-imx@nxp.com>,
open list <linux-kernel@vger.kernel.org>,
myungjoo.ham@samsung.com, kyungmin.park@samsung.com,
Abel Vesa <abel.vesa@nxp.com>
Subject: Re: [PATCH 07/11] PM / devfreq: check get_dev_status before start monitor
Date: Wed, 10 Mar 2021 12:25:31 +0900 [thread overview]
Message-ID: <31be2267-8988-f162-f5a6-6e6389bbf1fb@samsung.com> (raw)
In-Reply-To: <CAA+hA=QZbxE-aFh2UnH6wHBUStj8SAtW8C4SEZtGcxQwsOO=Aw@mail.gmail.com>
On 3/10/21 11:56 AM, Dong Aisheng wrote:
> On Wed, Mar 10, 2021 at 12:12 AM Chanwoo Choi <cwchoi00@gmail.com> wrote:
>>
>> On 21. 3. 10. 오전 12:58, Chanwoo Choi wrote:
>>> On 21. 3. 9. 오후 9:58, Dong Aisheng wrote:
>>>> The devfreq monitor depends on the device to provide load information
>>>> by .get_dev_status() to calculate the next target freq.
>>>>
>>>> And this will cause changing governor to simple ondemand fail
>>>> if device can't support.
>>>>
>>>> Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
>>>> ---
>>>> drivers/devfreq/devfreq.c | 10 +++++++---
>>>> drivers/devfreq/governor.h | 2 +-
>>>> drivers/devfreq/governor_simpleondemand.c | 3 +--
>>>> 3 files changed, 9 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>>>> index 7231fe6862a2..d1787b6c7d7c 100644
>>>> --- a/drivers/devfreq/devfreq.c
>>>> +++ b/drivers/devfreq/devfreq.c
>>>> @@ -482,10 +482,13 @@ static void devfreq_monitor(struct work_struct
>>>> *work)
>>>> * to be called from governor in response to DEVFREQ_GOV_START
>>>> * event when device is added to devfreq framework.
>>>> */
>>>> -void devfreq_monitor_start(struct devfreq *devfreq)
>>>> +int devfreq_monitor_start(struct devfreq *devfreq)
>>>> {
>>>> if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
>>>> - return;
>>>> + return 0;
>>>> +
>>>> + if (!devfreq->profile->get_dev_status)
>>>> + return -EINVAL;
>>
>> Again, I think that get_dev_status is not used for all governors.
>> So that it cause the governor start fail. Don't check whether
>> .get_dev_status is NULL or not.
>>
>
> I'm not quite understand your point.
> it is used by governor_simpleondemand.c and tegra_devfreq_governor.
> get_target_freq -> devfreq_update_stats -> get_dev_status
The devfreq can add the new governor by anyone.
So these functions like devfreq_monitor_* have to support
the governors and also must support the governor to be added
in the future.
>
> Without checking, device can switch to ondemand governor if it does not support.
>
> Am i missed something?
>
> Regards
> Aisheng
>
>>>> switch (devfreq->profile->timer) {
>>>> case DEVFREQ_TIMER_DEFERRABLE:
>>>> @@ -495,12 +498,13 @@ void devfreq_monitor_start(struct devfreq *devfreq)
>>>> INIT_DELAYED_WORK(&devfreq->work, devfreq_monitor);
>>>> break;
>>>> default:
>>>> - return;
>>>> + return -EINVAL;
>>>> }
>>>> if (devfreq->profile->polling_ms)
>>>> queue_delayed_work(devfreq_wq, &devfreq->work,
>>>> msecs_to_jiffies(devfreq->profile->polling_ms));
>>>> + return 0;
>>>> }
>>>> EXPORT_SYMBOL(devfreq_monitor_start);
>>>> diff --git a/drivers/devfreq/governor.h b/drivers/devfreq/governor.h
>>>> index 5cee3f64fe2b..31af6d072a10 100644
>>>> --- a/drivers/devfreq/governor.h
>>>> +++ b/drivers/devfreq/governor.h
>>>> @@ -75,7 +75,7 @@ struct devfreq_governor {
>>>> unsigned int event, void *data);
>>>> };
>>>> -void devfreq_monitor_start(struct devfreq *devfreq);
>>>> +int devfreq_monitor_start(struct devfreq *devfreq);
>>>> void devfreq_monitor_stop(struct devfreq *devfreq);
>>>> void devfreq_monitor_suspend(struct devfreq *devfreq);
>>>> void devfreq_monitor_resume(struct devfreq *devfreq);
>>>> diff --git a/drivers/devfreq/governor_simpleondemand.c
>>>> b/drivers/devfreq/governor_simpleondemand.c
>>>> index d57b82a2b570..ea287b57cbf3 100644
>>>> --- a/drivers/devfreq/governor_simpleondemand.c
>>>> +++ b/drivers/devfreq/governor_simpleondemand.c
>>>> @@ -89,8 +89,7 @@ static int devfreq_simple_ondemand_handler(struct
>>>> devfreq *devfreq,
>>>> {
>>>> switch (event) {
>>>> case DEVFREQ_GOV_START:
>>>> - devfreq_monitor_start(devfreq);
>>>> - break;
>>>> + return devfreq_monitor_start(devfreq);
>>>> case DEVFREQ_GOV_STOP:
>>>> devfreq_monitor_stop(devfreq);
>>>>
>>>
>>> Need to handle the all points of devfreq_monitor_start() usage.
>>> please check the tegra30-devfreq.c for this update.
>>>
>>> $ grep -rn "devfreq_monitor_start" drivers/
>>> drivers/devfreq/governor_simpleondemand.c:92:
>>> devfreq_monitor_start(devfreq);
>>> drivers/devfreq/tegra30-devfreq.c:744:
>>> devfreq_monitor_start(devfreq);
>>> ......
>>>
>>
>>
>> --
>> Best Regards,
>> Samsung Electronics
>> Chanwoo Choi
>
>
--
Best Regards,
Chanwoo Choi
Samsung Electronics
next prev parent reply other threads:[~2021-03-10 3:09 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-09 12:58 [PATCH 00/11] PM / devfreq: a few small fixes and improvements Dong Aisheng
2021-03-09 12:58 ` [PATCH 01/11] doc: ABI: devfreq: remove invalid central_polling description Dong Aisheng
2021-03-09 15:01 ` Chanwoo Choi
2021-03-09 12:58 ` [PATCH 02/11] PM / devfreq: remove the invalid description for get_target_freq Dong Aisheng
2021-03-09 15:02 ` Chanwoo Choi
2021-03-09 15:14 ` Dong Aisheng
2021-03-09 12:58 ` [PATCH 03/11] PM / devfreq: fix the wrong set_freq path for userspace governor Dong Aisheng
2021-03-09 15:13 ` Chanwoo Choi
2021-03-09 15:16 ` Dong Aisheng
2021-03-09 12:58 ` [PATCH 04/11] PM / devfreq: bail out early if no freq changes in devfreq_set_target Dong Aisheng
2021-03-09 15:47 ` Chanwoo Choi
2021-03-10 2:42 ` Dong Aisheng
2021-03-09 12:58 ` [PATCH 05/11] PM / devfreq: use more accurate returned new_freq as resume_freq Dong Aisheng
2021-03-09 15:53 ` Chanwoo Choi
2021-03-10 2:43 ` Dong Aisheng
2021-03-10 3:07 ` Chanwoo Choi
2021-03-10 3:04 ` Dong Aisheng
2021-03-09 12:58 ` [PATCH 06/11] PM / devfreq: drop the unnecessary low variable initialization Dong Aisheng
2021-03-09 12:58 ` [PATCH 07/11] PM / devfreq: check get_dev_status before start monitor Dong Aisheng
2021-03-09 15:58 ` Chanwoo Choi
2021-03-09 16:12 ` Chanwoo Choi
2021-03-10 2:56 ` Dong Aisheng
2021-03-10 3:25 ` Chanwoo Choi [this message]
2021-03-10 4:56 ` Dong Aisheng
2021-03-11 7:10 ` Chanwoo Choi
2021-03-12 10:57 ` Dong Aisheng
2021-03-12 16:09 ` Chanwoo Choi
2021-03-13 6:45 ` Dong Aisheng
2021-03-18 8:03 ` Dong Aisheng
2021-03-18 9:54 ` Chanwoo Choi
2021-03-18 9:59 ` Chanwoo Choi
2021-03-18 10:51 ` Dong Aisheng
2021-03-10 2:51 ` Dong Aisheng
2021-03-09 12:58 ` [PATCH 08/11] PM / devfreq: check get_dev_status in devfreq_update_stats Dong Aisheng
2021-03-09 16:02 ` Chanwoo Choi
2021-03-09 16:20 ` Chanwoo Choi
2021-03-10 3:00 ` Dong Aisheng
2021-03-11 7:01 ` Chanwoo Choi
2021-03-09 12:58 ` [PATCH 09/11] PM / devfreq: governor: optimize simpleondemand get_target_freq Dong Aisheng
2021-03-09 16:09 ` Chanwoo Choi
2021-03-10 3:02 ` Dong Aisheng
2021-03-09 12:58 ` [PATCH 10/11] PM / devfreq: imx8m-ddrc: remove imx8m_ddrc_get_dev_status Dong Aisheng
2021-03-09 16:22 ` Chanwoo Choi
2021-03-09 12:58 ` [PATCH 11/11] PM / devfreq: imx8m-ddrc: drop polling_ms Dong Aisheng
2021-03-09 16:23 ` Chanwoo Choi
2021-03-10 3:03 ` Dong Aisheng
2021-03-09 12:58 ` [PATCH 00/11] PM / devfreq: a few small fixes and improvements Dong Aisheng
2021-03-09 12:58 ` [PATCH 01/11] doc: ABI: devfreq: remove invalid central_polling description Dong Aisheng
2021-03-09 12:58 ` [PATCH 02/11] PM / devfreq: remove the invalid description for get_target_freq Dong Aisheng
2021-03-09 12:58 ` [PATCH 03/11] PM / devfreq: fix the wrong set_freq path for userspace governor Dong Aisheng
2021-03-09 12:58 ` [PATCH 04/11] PM / devfreq: bail out early if no freq changes in devfreq_set_target Dong Aisheng
2021-03-09 12:58 ` [PATCH 05/11] PM / devfreq: use more accurate returned new_freq as resume_freq Dong Aisheng
2021-03-09 12:58 ` [PATCH 06/11] PM / devfreq: drop the unnecessary low variable initialization Dong Aisheng
2021-03-09 12:58 ` [PATCH 07/11] PM / devfreq: check get_dev_status before start monitor Dong Aisheng
2021-03-09 12:58 ` [PATCH 08/11] PM / devfreq: check get_dev_status in devfreq_update_stats Dong Aisheng
2021-03-09 12:58 ` [PATCH 09/11] PM / devfreq: governor: optimize simpleondemand get_target_freq Dong Aisheng
2021-03-09 12:58 ` [PATCH 10/11] PM / devfreq: imx8m-ddrc: remove imx8m_ddrc_get_dev_status Dong Aisheng
2021-03-09 12:58 ` [PATCH 11/11] PM / devfreq: imx8m-ddrc: drop polling_ms Dong Aisheng
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