[PATCH] interconnect: Do not skip aggregation for disabled paths

[PATCH] interconnect: Do not skip aggregation for disabled paths

[Georgi Djakov]

When an interconnect path is being disabled, currently we don't aggregate
the requests for it afterwards. But the re-aggregation step shouldn't be
skipped, as it may leave the nodes with outdated bandwidth data. This
outdated data may actually keep the path still enabled and prevent the
device from going into lower power states.

Reported-by: Atul Dhudase <adhudase@codeaurora.org>
Fixes: 7d374b209083 ("interconnect: Add helpers for enabling/disabling a path")
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
---
 drivers/interconnect/core.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c
index 37d5ec970cc1..5174dcb31ab7 100644
--- a/drivers/interconnect/core.c
+++ b/drivers/interconnect/core.c
@@ -243,6 +243,7 @@ static int aggregate_requests(struct icc_node *node)
 {
 	struct icc_provider *p = node->provider;
 	struct icc_req *r;
+	u32 avg_bw, peak_bw;
 
 	node->avg_bw = 0;
 	node->peak_bw = 0;
@@ -251,9 +252,14 @@ static int aggregate_requests(struct icc_node *node)
 		p->pre_aggregate(node);
 
 	hlist_for_each_entry(r, &node->req_list, req_node) {
-		if (!r->enabled)
-			continue;
-		p->aggregate(node, r->tag, r->avg_bw, r->peak_bw,
+		if (r->enabled) {
+			avg_bw = r->avg_bw;
+			peak_bw = r->peak_bw;
+		} else {
+			avg_bw = 0;
+			peak_bw = 0;
+		}
+		p->aggregate(node, r->tag, avg_bw, peak_bw,
 			     &node->avg_bw, &node->peak_bw);
 	}
 

Re: [PATCH] interconnect: Do not skip aggregation for disabled paths

[Sibi Sankar]

Hey Georgi,
Thanks for the patch!

On 2020-07-21 17:37, Georgi Djakov wrote:
> When an interconnect path is being disabled, currently we don't 
> aggregate
> the requests for it afterwards. But the re-aggregation step shouldn't 
> be
> skipped, as it may leave the nodes with outdated bandwidth data. This
> outdated data may actually keep the path still enabled and prevent the
> device from going into lower power states.
> 
> Reported-by: Atul Dhudase <adhudase@codeaurora.org>
> Fixes: 7d374b209083 ("interconnect: Add helpers for enabling/disabling 
> a path")
> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
> ---

Reviewed-by: Sibi Sankar <sibis@codeaurora.org>

>  drivers/interconnect/core.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c
> index 37d5ec970cc1..5174dcb31ab7 100644
> --- a/drivers/interconnect/core.c
> +++ b/drivers/interconnect/core.c
> @@ -243,6 +243,7 @@ static int aggregate_requests(struct icc_node 
> *node)
>  {
>  	struct icc_provider *p = node->provider;
>  	struct icc_req *r;
> +	u32 avg_bw, peak_bw;
> 
>  	node->avg_bw = 0;
>  	node->peak_bw = 0;
> @@ -251,9 +252,14 @@ static int aggregate_requests(struct icc_node 
> *node)
>  		p->pre_aggregate(node);
> 
>  	hlist_for_each_entry(r, &node->req_list, req_node) {
> -		if (!r->enabled)
> -			continue;
> -		p->aggregate(node, r->tag, r->avg_bw, r->peak_bw,
> +		if (r->enabled) {
> +			avg_bw = r->avg_bw;
> +			peak_bw = r->peak_bw;
> +		} else {
> +			avg_bw = 0;
> +			peak_bw = 0;
> +		}
> +		p->aggregate(node, r->tag, avg_bw, peak_bw,
>  			     &node->avg_bw, &node->peak_bw);
>  	}

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project.

Re: [PATCH] interconnect: Do not skip aggregation for disabled paths

[adhudase]

On 2020-07-21 17:37, Georgi Djakov wrote:
> When an interconnect path is being disabled, currently we don't 
> aggregate
> the requests for it afterwards. But the re-aggregation step shouldn't 
> be
> skipped, as it may leave the nodes with outdated bandwidth data. This
> outdated data may actually keep the path still enabled and prevent the
> device from going into lower power states.
> 
> Reported-by: Atul Dhudase <adhudase@codeaurora.org>
> Fixes: 7d374b209083 ("interconnect: Add helpers for enabling/disabling 
> a path")
> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
> ---

Tested-by: Atul Dhudase <adhudase@codeaurora.org>
Reviewed-by: Atul Dhudase <adhudase@codeaurora.org>

>  drivers/interconnect/core.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c
> index 37d5ec970cc1..5174dcb31ab7 100644
> --- a/drivers/interconnect/core.c
> +++ b/drivers/interconnect/core.c
> @@ -243,6 +243,7 @@ static int aggregate_requests(struct icc_node 
> *node)
>  {
>  	struct icc_provider *p = node->provider;
>  	struct icc_req *r;
> +	u32 avg_bw, peak_bw;
> 
>  	node->avg_bw = 0;
>  	node->peak_bw = 0;
> @@ -251,9 +252,14 @@ static int aggregate_requests(struct icc_node 
> *node)
>  		p->pre_aggregate(node);
> 
>  	hlist_for_each_entry(r, &node->req_list, req_node) {
> -		if (!r->enabled)
> -			continue;
> -		p->aggregate(node, r->tag, r->avg_bw, r->peak_bw,
> +		if (r->enabled) {
> +			avg_bw = r->avg_bw;
> +			peak_bw = r->peak_bw;
> +		} else {
> +			avg_bw = 0;
> +			peak_bw = 0;
> +		}
> +		p->aggregate(node, r->tag, avg_bw, peak_bw,
>  			     &node->avg_bw, &node->peak_bw);
>  	}