* [PATCH v2] memory/samsung: reduce unnecessary mutex lock area
@ 2020-05-12 11:08 Bernard Zhao
0 siblings, 0 replies; 3+ messages in thread
From: Bernard Zhao @ 2020-05-12 11:08 UTC (permalink / raw)
To: Lukasz Luba, Kukjin Kim, Krzysztof Kozlowski, linux-pm,
linux-samsung-soc, linux-arm-kernel, linux-kernel
Cc: opensource.kernel, Bernard Zhao
Maybe dmc->df->lock seems not needed to protect "if (ret)
& dev_warn" branch. Maybe this change speed up the code a bit.
Signed-off-by: Bernard Zhao <bernard@vivo.com>
----
Changes since v1:
*change release lock before the if statement.
*revert dmc->df->lock mutex lock to protect function
exynos5_dmc_perf_events_check
Link for V1:
*https://lore.kernel.org/patchwork/patch/1238888/
---
drivers/memory/samsung/exynos5422-dmc.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/memory/samsung/exynos5422-dmc.c b/drivers/memory/samsung/exynos5422-dmc.c
index 22a43d662833..25196d6268e2 100644
--- a/drivers/memory/samsung/exynos5422-dmc.c
+++ b/drivers/memory/samsung/exynos5422-dmc.c
@@ -1346,15 +1346,13 @@ static irqreturn_t dmc_irq_thread(int irq, void *priv)
struct exynos5_dmc *dmc = priv;
mutex_lock(&dmc->df->lock);
-
exynos5_dmc_perf_events_check(dmc);
-
res = update_devfreq(dmc->df);
+ mutex_unlock(&dmc->df->lock);
+
if (res)
dev_warn(dmc->dev, "devfreq failed with %d\n", res);
- mutex_unlock(&dmc->df->lock);
-
return IRQ_HANDLED;
}
--
2.26.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] memory/samsung: reduce unnecessary mutex lock area
2020-05-12 11:40 Markus Elfring
@ 2020-05-12 11:56 ` Lukasz Luba
0 siblings, 0 replies; 3+ messages in thread
From: Lukasz Luba @ 2020-05-12 11:56 UTC (permalink / raw)
To: Markus Elfring, Bernard Zhao, linux-arm-kernel, linux-pm,
linux-samsung-soc
Cc: linux-kernel, opensource.kernel, Krzysztof Kozlowski, Kukjin Kim
On 5/12/20 12:40 PM, Markus Elfring wrote:
>> Maybe dmc->df->lock seems not needed to protect "if (ret)
>> & dev_warn" branch. Maybe this change speed up the code a bit.
>
> I suggest to improve also this commit message.
>
> * Please reduce uncertainty.
>
> * An imperative wording is probably preferred, isn't it?
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?id=152036d1379ffd6985262743dcf6b0f9c75f83a4#n151
>
> * Will it be more appropriate to refer to the transformation “Reduce the lock scope”?
>
> * Would you like to add the tag “Fixes” to the change description?
>
> Regards,
> Markus
>
Thank you Markus for providing to Bernard helpful suggestions.
@Bernard please read the link above and send v3
Something like: 'memory/samsung: reduce protected code area in IRQ
handler' for the subject header would be better.
Then in the message explain (without 'maybe') that it will speed-up a
bit this IRQ processing and there is no need to protect return value or
printing.
Regards,
Lukasz
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] memory/samsung: reduce unnecessary mutex lock area
@ 2020-05-12 11:40 Markus Elfring
2020-05-12 11:56 ` Lukasz Luba
0 siblings, 1 reply; 3+ messages in thread
From: Markus Elfring @ 2020-05-12 11:40 UTC (permalink / raw)
To: Bernard Zhao, linux-arm-kernel, linux-pm, linux-samsung-soc
Cc: linux-kernel, opensource.kernel, Krzysztof Kozlowski, Kukjin Kim,
Lukasz Luba
> Maybe dmc->df->lock seems not needed to protect "if (ret)
> & dev_warn" branch. Maybe this change speed up the code a bit.
I suggest to improve also this commit message.
* Please reduce uncertainty.
* An imperative wording is probably preferred, isn't it?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?id=152036d1379ffd6985262743dcf6b0f9c75f83a4#n151
* Will it be more appropriate to refer to the transformation “Reduce the lock scope”?
* Would you like to add the tag “Fixes” to the change description?
Regards,
Markus
^ permalink raw reply [flat|nested] 3+ messages in thread
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