linux-kernel - Re: [PATCH v6 2/3] soc: qcom: rpmh: Update dirty flag only when data changes

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Date:   Mon, 24 Feb 2020 12:13:39 +0530
From:   Srinivas Rao L <lsrao@...eaurora.org>
To:     Maulik Shah <mkshah@...eaurora.org>, swboyd@...omium.org,
        mka@...omium.org, evgreen@...omium.org, bjorn.andersson@...aro.org
Cc:     linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        agross@...nel.org, dianders@...omium.org, rnayak@...eaurora.org,
        ilina@...eaurora.org
Subject: Re: [PATCH v6 2/3] soc: qcom: rpmh: Update dirty flag only when data
 changes

Reviewed-by: Srinivas Rao L <lsrao@...eaurora.org>

Regards,
Srinivas.

On 2/21/2020 3:02 PM, Maulik Shah wrote:
> Currently rpmh ctrlr dirty flag is set for all cases regardless
> of data is really changed or not. Add changes to update it when
> data is updated to newer values.
>
> Also move dirty flag updates to happen from within cache_lock.
>
> Signed-off-by: Maulik Shah <mkshah@...eaurora.org>
> ---
>   drivers/soc/qcom/rpmh.c | 21 ++++++++++++++++-----
>   1 file changed, 16 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
> index eb0ded0..83ba4e0 100644
> --- a/drivers/soc/qcom/rpmh.c
> +++ b/drivers/soc/qcom/rpmh.c
> @@ -139,20 +139,27 @@ static struct cache_req *cache_rpm_request(struct rpmh_ctrlr *ctrlr,
>   existing:
>   	switch (state) {
>   	case RPMH_ACTIVE_ONLY_STATE:
> -		if (req->sleep_val != UINT_MAX)
> +		if (req->sleep_val != UINT_MAX) {
>   			req->wake_val = cmd->data;
> +			ctrlr->dirty = true;
> +		}
>   		break;
>   	case RPMH_WAKE_ONLY_STATE:
> -		req->wake_val = cmd->data;
> +		if (req->wake_val != cmd->data) {
> +			req->wake_val = cmd->data;
> +			ctrlr->dirty = true;
> +		}
>   		break;
>   	case RPMH_SLEEP_STATE:
> -		req->sleep_val = cmd->data;
> +		if (req->sleep_val != cmd->data) {
> +			req->sleep_val = cmd->data;
> +			ctrlr->dirty = true;
> +		}
>   		break;
>   	default:
>   		break;
>   	}
>   
> -	ctrlr->dirty = true;
>   unlock:
>   	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
>   
> @@ -287,6 +294,7 @@ static void cache_batch(struct rpmh_ctrlr *ctrlr, struct batch_cache_req *req)
>   
>   	spin_lock_irqsave(&ctrlr->cache_lock, flags);
>   	list_add_tail(&req->list, &ctrlr->batch_cache);
> +	ctrlr->dirty = true;
>   	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
>   }
>   
> @@ -323,6 +331,7 @@ static void invalidate_batch(struct rpmh_ctrlr *ctrlr)
>   	list_for_each_entry_safe(req, tmp, &ctrlr->batch_cache, list)
>   		kfree(req);
>   	INIT_LIST_HEAD(&ctrlr->batch_cache);
> +	ctrlr->dirty = true;
>   	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
>   }
>   
> @@ -456,6 +465,7 @@ static int send_single(struct rpmh_ctrlr *ctrlr, enum rpmh_state state,
>   int rpmh_flush(struct rpmh_ctrlr *ctrlr)
>   {
>   	struct cache_req *p;
> +	unsigned long flags;
>   	int ret;
>   
>   	if (!ctrlr->dirty) {
> @@ -488,7 +498,9 @@ int rpmh_flush(struct rpmh_ctrlr *ctrlr)
>   			return ret;
>   	}
>   
> +	spin_lock_irqsave(&ctrlr->cache_lock, flags);
>   	ctrlr->dirty = false;
> +	spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
>   
>   	return 0;
>   }
> @@ -507,7 +519,6 @@ int rpmh_invalidate(const struct device *dev)
>   	int ret;
>   
>   	invalidate_batch(ctrlr);
> -	ctrlr->dirty = true;
>   
>   	do {
>   		ret = rpmh_rsc_invalidate(ctrlr_to_drv(ctrlr));

-- 
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