[PATCH v2] IB/cq: Don't process more than the given budget

[PATCH v2] IB/cq: Don't process more than the given budget

[Sagi Grimberg]

The caller might not want this overhead.

Signed-off-by: Sagi Grimberg <sagi-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>
---
 drivers/infiniband/core/cq.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/core/cq.c b/drivers/infiniband/core/cq.c
index 2746d2eb3d52..21d1a38af489 100644
--- a/drivers/infiniband/core/cq.c
+++ b/drivers/infiniband/core/cq.c
@@ -29,7 +29,8 @@ static int __ib_process_cq(struct ib_cq *cq, int budget)
 {
 	int i, n, completed = 0;
 
-	while ((n = ib_poll_cq(cq, IB_POLL_BATCH, cq->wc)) > 0) {
+	while ((n = ib_poll_cq(cq, min_t(u32, IB_POLL_BATCH,
+			budget - completed), cq->wc)) > 0) {
 		for (i = 0; i < n; i++) {
 			struct ib_wc *wc = &cq->wc[i];
 
-- 
2.7.4

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Re: [PATCH v2] IB/cq: Don't process more than the given budget

[Bart Van Assche]

On Thu, 2017-03-09 at 01:05 +0200, Sagi Grimberg wrote:
> The caller might not want this overhead.
> 
> Signed-off-by: Sagi Grimberg <sagi-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>
> ---
>  drivers/infiniband/core/cq.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/infiniband/core/cq.c b/drivers/infiniband/core/cq.c
> index 2746d2eb3d52..21d1a38af489 100644
> --- a/drivers/infiniband/core/cq.c
> +++ b/drivers/infiniband/core/cq.c
> @@ -29,7 +29,8 @@ static int __ib_process_cq(struct ib_cq *cq, int budget)
>  {
>  	int i, n, completed = 0;
>  
> -	while ((n = ib_poll_cq(cq, IB_POLL_BATCH, cq->wc)) > 0) {
> +	while ((n = ib_poll_cq(cq, min_t(u32, IB_POLL_BATCH,
> +			budget - completed), cq->wc)) > 0) {
>  		for (i = 0; i < n; i++) {
>  			struct ib_wc *wc = &cq->wc[i];
>  

A comment that explains why min_t(u32, ...) is used would have been
welcome. Anyway:

Reviewed-by: Bart Van Assche <bart.vanassche-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>--
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Re: [PATCH v2] IB/cq: Don't process more than the given budget

[Leon Romanovsky]

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On Thu, Mar 09, 2017 at 01:05:58AM +0200, Sagi Grimberg wrote:
> The caller might not want this overhead.
>
> Signed-off-by: Sagi Grimberg <sagi-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>
> ---
>  drivers/infiniband/core/cq.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/infiniband/core/cq.c b/drivers/infiniband/core/cq.c
> index 2746d2eb3d52..21d1a38af489 100644
> --- a/drivers/infiniband/core/cq.c
> +++ b/drivers/infiniband/core/cq.c
> @@ -29,7 +29,8 @@ static int __ib_process_cq(struct ib_cq *cq, int budget)
>  {
>  	int i, n, completed = 0;
>
> -	while ((n = ib_poll_cq(cq, IB_POLL_BATCH, cq->wc)) > 0) {
> +	while ((n = ib_poll_cq(cq, min_t(u32, IB_POLL_BATCH,
> +			budget - completed), cq->wc)) > 0) {
>  		for (i = 0; i < n; i++) {
>  			struct ib_wc *wc = &cq->wc[i];
>

I agree with Bart, comment is welcome.
Not everyone will remember that budget can be -1 and (budget - completed) can be -1.

Anyway,
Reviewed-by: Leon Romanovsky <leonro-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>

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