Re: [PATCH] nvme-pci: Fix incorrect use of CMB size to calculate q_depth

[Stephen Bates]

> On Feb 6, 2018, at 8:02 AM, Keith Busch  wrote:
> 
>> On Mon, Feb 05, 2018 at 03:32:23PM -0700, sba...@raithlin.com wrote:
>> 
>> -if (dev->cmb && (dev->cmbsz & NVME_CMBSZ_SQS)) {
>> +if (dev->cmb && use_cmb_sqes && (dev->cmbsz & NVME_CMBSZ_SQS)) {
> 
> Is this a prep patch for something coming later? dev->cmb is already
> NULL if use_cmb_sqes is false.

Thanks Keith. 

Not sure how I missed this. I was working on OOT patches to enable WDS and RDS 
in the CMB. I *thought* I’d confirmed this patch was applicable to upstream. 
Looks like I did not do that correctly. 

Sorry for the churn. We can leave this patch out for now. Thanks for the prompt 
feedback everyone!

Stephen 

Re: [PATCH] nvme-pci: Fix incorrect use of CMB size to calculate q_depth

[Stephen Bates]

> On Feb 6, 2018, at 8:02 AM, Keith Busch  wrote:
> 
>> On Mon, Feb 05, 2018 at 03:32:23PM -0700, sba...@raithlin.com wrote:
>> 
>> -if (dev->cmb && (dev->cmbsz & NVME_CMBSZ_SQS)) {
>> +if (dev->cmb && use_cmb_sqes && (dev->cmbsz & NVME_CMBSZ_SQS)) {
> 
> Is this a prep patch for something coming later? dev->cmb is already
> NULL if use_cmb_sqes is false.

Thanks Keith. 

Not sure how I missed this. I was working on OOT patches to enable WDS and RDS 
in the CMB. I *thought* I’d confirmed this patch was applicable to upstream. 
Looks like I did not do that correctly. 

Sorry for the churn. We can leave this patch out for now. Thanks for the prompt 
feedback everyone!

Stephen 

Re: [PATCH] nvme-pci: Fix incorrect use of CMB size to calculate q_depth

[Keith Busch]

On Mon, Feb 05, 2018 at 03:32:23PM -0700, sba...@raithlin.com wrote:
>  
> - if (dev->cmb && (dev->cmbsz & NVME_CMBSZ_SQS)) {
> + if (dev->cmb && use_cmb_sqes && (dev->cmbsz & NVME_CMBSZ_SQS)) {

Is this a prep patch for something coming later? dev->cmb is already
NULL if use_cmb_sqes is false.

Re: [PATCH] nvme-pci: Fix incorrect use of CMB size to calculate q_depth

[Keith Busch]

On Mon, Feb 05, 2018 at 03:32:23PM -0700, sba...@raithlin.com wrote:
>  
> - if (dev->cmb && (dev->cmbsz & NVME_CMBSZ_SQS)) {
> + if (dev->cmb && use_cmb_sqes && (dev->cmbsz & NVME_CMBSZ_SQS)) {

Is this a prep patch for something coming later? dev->cmb is already
NULL if use_cmb_sqes is false.

Re: [PATCH] nvme-pci: Fix incorrect use of CMB size to calculate q_depth

[Max Gurtovoy]

On 2/6/2018 11:48 AM, Sagi Grimberg wrote:

Looks good,

Reviewed-by: Sagi Grimberg 

I'll pick this one up unless someone thinks I shouldn't..


Looks good to me (I can imagine what scenario failed this :) ),

Reviewed-by: Max Gurtovoy 



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Re: [PATCH] nvme-pci: Fix incorrect use of CMB size to calculate q_depth

[Max Gurtovoy]

On 2/6/2018 11:48 AM, Sagi Grimberg wrote:

Looks good,

Reviewed-by: Sagi Grimberg 

I'll pick this one up unless someone thinks I shouldn't..


Looks good to me (I can imagine what scenario failed this :) ),

Reviewed-by: Max Gurtovoy 



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Re: [PATCH] nvme-pci: Fix incorrect use of CMB size to calculate q_depth

[Sagi Grimberg]

Looks good,

Reviewed-by: Sagi Grimberg 

I'll pick this one up unless someone thinks I shouldn't..

Re: [PATCH] nvme-pci: Fix incorrect use of CMB size to calculate q_depth

[Sagi Grimberg]

Looks good,

Reviewed-by: Sagi Grimberg 

I'll pick this one up unless someone thinks I shouldn't..

[PATCH] nvme-pci: Fix incorrect use of CMB size to calculate q_depth

[sbates]

From: Stephen Bates 

We should not be using the CMB to determine the permissable q_depth
when we don't plan to place any queues in the CMB. In the case of a
small CMB or large numbers of queues this could lead to shallow queues
when they don't need to be.

Signed-off-by: Stephen Bates 
---
 drivers/nvme/host/pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 0bc6a9e..0d099e9 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1913,7 +1913,7 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
if (nr_io_queues == 0)
return 0;
 
-   if (dev->cmb && (dev->cmbsz & NVME_CMBSZ_SQS)) {
+   if (dev->cmb && use_cmb_sqes && (dev->cmbsz & NVME_CMBSZ_SQS)) {
result = nvme_cmb_qdepth(dev, nr_io_queues,
sizeof(struct nvme_command));
if (result > 0)
-- 
2.7.4

[PATCH] nvme-pci: Fix incorrect use of CMB size to calculate q_depth

[sbates]

From: Stephen Bates 

We should not be using the CMB to determine the permissable q_depth
when we don't plan to place any queues in the CMB. In the case of a
small CMB or large numbers of queues this could lead to shallow queues
when they don't need to be.

Signed-off-by: Stephen Bates 
---
 drivers/nvme/host/pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 0bc6a9e..0d099e9 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1913,7 +1913,7 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
if (nr_io_queues == 0)
return 0;
 
-   if (dev->cmb && (dev->cmbsz & NVME_CMBSZ_SQS)) {
+   if (dev->cmb && use_cmb_sqes && (dev->cmbsz & NVME_CMBSZ_SQS)) {
result = nvme_cmb_qdepth(dev, nr_io_queues,
sizeof(struct nvme_command));
if (result > 0)
-- 
2.7.4