2021-01-21 03:29:10

by Ivan Babrou

[permalink] [raw]
Subject: [PATCH net-next] sfc: reduce the number of requested xdp ev queues

Without this change the driver tries to allocate too many queues,
breaching the number of available msi-x interrupts on machines
with many logical cpus and default adapter settings:

Insufficient resources for 12 XDP event queues (24 other channels, max 32)

Which in turn triggers EINVAL on XDP processing:

sfc 0000:86:00.0 ext0: XDP TX failed (-22)

Signed-off-by: Ivan Babrou <[email protected]>
---
drivers/net/ethernet/sfc/efx_channels.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/sfc/efx_channels.c b/drivers/net/ethernet/sfc/efx_channels.c
index a4a626e9cd9a..1bfeee283ea9 100644
--- a/drivers/net/ethernet/sfc/efx_channels.c
+++ b/drivers/net/ethernet/sfc/efx_channels.c
@@ -17,6 +17,7 @@
#include "rx_common.h"
#include "nic.h"
#include "sriov.h"
+#include "workarounds.h"

/* This is the first interrupt mode to try out of:
* 0 => MSI-X
@@ -137,6 +138,7 @@ static int efx_allocate_msix_channels(struct efx_nic *efx,
{
unsigned int n_channels = parallelism;
int vec_count;
+ int tx_per_ev;
int n_xdp_tx;
int n_xdp_ev;

@@ -149,9 +151,9 @@ static int efx_allocate_msix_channels(struct efx_nic *efx,
* multiple tx queues, assuming tx and ev queues are both
* maximum size.
*/
-
+ tx_per_ev = EFX_MAX_EVQ_SIZE / EFX_TXQ_MAX_ENT(efx);
n_xdp_tx = num_possible_cpus();
- n_xdp_ev = DIV_ROUND_UP(n_xdp_tx, EFX_MAX_TXQ_PER_CHANNEL);
+ n_xdp_ev = DIV_ROUND_UP(n_xdp_tx, tx_per_ev);

vec_count = pci_msix_vec_count(efx->pci_dev);
if (vec_count < 0)
--
2.29.2


2021-01-21 16:17:04

by Edward Cree

[permalink] [raw]
Subject: Re: [PATCH net-next] sfc: reduce the number of requested xdp ev queues

On 20/01/2021 21:27, Ivan Babrou wrote:
> Without this change the driver tries to allocate too many queues,
> breaching the number of available msi-x interrupts on machines
> with many logical cpus and default adapter settings:
>
> Insufficient resources for 12 XDP event queues (24 other channels, max 32)
>
> Which in turn triggers EINVAL on XDP processing:
>
> sfc 0000:86:00.0 ext0: XDP TX failed (-22)
>
> Signed-off-by: Ivan Babrou <[email protected]>

Acked-by: Edward Cree <[email protected]>

2021-01-21 17:17:05

by Jesper Dangaard Brouer

[permalink] [raw]
Subject: Re: [PATCH net-next] sfc: reduce the number of requested xdp ev queues

On Wed, 20 Jan 2021 13:27:59 -0800
Ivan Babrou <[email protected]> wrote:

> Without this change the driver tries to allocate too many queues,
> breaching the number of available msi-x interrupts on machines
> with many logical cpus and default adapter settings:
>
> Insufficient resources for 12 XDP event queues (24 other channels, max 32)
>
> Which in turn triggers EINVAL on XDP processing:
>
> sfc 0000:86:00.0 ext0: XDP TX failed (-22)
>
> Signed-off-by: Ivan Babrou <[email protected]>
> ---

I guess the patch is good in itself due to available msi-x interrupts.

Per earlier discussion: What will happen if a CPU with an ID higher
than available XDP TX-queues redirect a packet out this driver?


> drivers/net/ethernet/sfc/efx_channels.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/sfc/efx_channels.c b/drivers/net/ethernet/sfc/efx_channels.c
> index a4a626e9cd9a..1bfeee283ea9 100644
> --- a/drivers/net/ethernet/sfc/efx_channels.c
> +++ b/drivers/net/ethernet/sfc/efx_channels.c
> @@ -17,6 +17,7 @@
> #include "rx_common.h"
> #include "nic.h"
> #include "sriov.h"
> +#include "workarounds.h"
>
> /* This is the first interrupt mode to try out of:
> * 0 => MSI-X
> @@ -137,6 +138,7 @@ static int efx_allocate_msix_channels(struct efx_nic *efx,
> {
> unsigned int n_channels = parallelism;
> int vec_count;
> + int tx_per_ev;
> int n_xdp_tx;
> int n_xdp_ev;
>
> @@ -149,9 +151,9 @@ static int efx_allocate_msix_channels(struct efx_nic *efx,
> * multiple tx queues, assuming tx and ev queues are both
> * maximum size.
> */
> -
> + tx_per_ev = EFX_MAX_EVQ_SIZE / EFX_TXQ_MAX_ENT(efx);
> n_xdp_tx = num_possible_cpus();
> - n_xdp_ev = DIV_ROUND_UP(n_xdp_tx, EFX_MAX_TXQ_PER_CHANNEL);
> + n_xdp_ev = DIV_ROUND_UP(n_xdp_tx, tx_per_ev);
>
> vec_count = pci_msix_vec_count(efx->pci_dev);
> if (vec_count < 0)



--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer

2021-01-21 17:27:53

by Maciej Fijalkowski

[permalink] [raw]
Subject: Re: [PATCH net-next] sfc: reduce the number of requested xdp ev queues

On Thu, Jan 21, 2021 at 06:11:30PM +0100, Jesper Dangaard Brouer wrote:
> On Wed, 20 Jan 2021 13:27:59 -0800
> Ivan Babrou <[email protected]> wrote:
>
> > Without this change the driver tries to allocate too many queues,
> > breaching the number of available msi-x interrupts on machines
> > with many logical cpus and default adapter settings:
> >
> > Insufficient resources for 12 XDP event queues (24 other channels, max 32)
> >
> > Which in turn triggers EINVAL on XDP processing:
> >
> > sfc 0000:86:00.0 ext0: XDP TX failed (-22)

Please mention in commit message *how* you are addressing/fixing this
issue.

> >
> > Signed-off-by: Ivan Babrou <[email protected]>
> > ---
>
> I guess the patch is good in itself due to available msi-x interrupts.
>
> Per earlier discussion: What will happen if a CPU with an ID higher
> than available XDP TX-queues redirect a packet out this driver?

+1 on that question

>
>
> > drivers/net/ethernet/sfc/efx_channels.c | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/sfc/efx_channels.c b/drivers/net/ethernet/sfc/efx_channels.c
> > index a4a626e9cd9a..1bfeee283ea9 100644
> > --- a/drivers/net/ethernet/sfc/efx_channels.c
> > +++ b/drivers/net/ethernet/sfc/efx_channels.c
> > @@ -17,6 +17,7 @@
> > #include "rx_common.h"
> > #include "nic.h"
> > #include "sriov.h"
> > +#include "workarounds.h"
> >
> > /* This is the first interrupt mode to try out of:
> > * 0 => MSI-X
> > @@ -137,6 +138,7 @@ static int efx_allocate_msix_channels(struct efx_nic *efx,
> > {
> > unsigned int n_channels = parallelism;
> > int vec_count;
> > + int tx_per_ev;
> > int n_xdp_tx;
> > int n_xdp_ev;
> >
> > @@ -149,9 +151,9 @@ static int efx_allocate_msix_channels(struct efx_nic *efx,
> > * multiple tx queues, assuming tx and ev queues are both
> > * maximum size.
> > */
> > -
> > + tx_per_ev = EFX_MAX_EVQ_SIZE / EFX_TXQ_MAX_ENT(efx);
> > n_xdp_tx = num_possible_cpus();
> > - n_xdp_ev = DIV_ROUND_UP(n_xdp_tx, EFX_MAX_TXQ_PER_CHANNEL);
> > + n_xdp_ev = DIV_ROUND_UP(n_xdp_tx, tx_per_ev);
> >
> > vec_count = pci_msix_vec_count(efx->pci_dev);
> > if (vec_count < 0)
>
>
>
> --
> Best regards,
> Jesper Dangaard Brouer
> MSc.CS, Principal Kernel Engineer at Red Hat
> LinkedIn: http://www.linkedin.com/in/brouer
>

2021-01-23 03:32:53

by patchwork-bot+netdevbpf

[permalink] [raw]
Subject: Re: [PATCH net-next] sfc: reduce the number of requested xdp ev queues

Hello:

This patch was applied to netdev/net-next.git (refs/heads/master):

On Wed, 20 Jan 2021 13:27:59 -0800 you wrote:
> Without this change the driver tries to allocate too many queues,
> breaching the number of available msi-x interrupts on machines
> with many logical cpus and default adapter settings:
>
> Insufficient resources for 12 XDP event queues (24 other channels, max 32)
>
> Which in turn triggers EINVAL on XDP processing:
>
> [...]

Here is the summary with links:
- [net-next] sfc: reduce the number of requested xdp ev queues
https://git.kernel.org/netdev/net-next/c/e26ca4b53582

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html


2021-02-06 10:53:42

by Martin Habets

[permalink] [raw]
Subject: Re: [PATCH net-next] sfc: reduce the number of requested xdp ev queues

On Wed, Jan 20, 2021 at 01:27:59PM -0800, Ivan Babrou wrote:
> Without this change the driver tries to allocate too many queues,
> breaching the number of available msi-x interrupts on machines
> with many logical cpus and default adapter settings:
>
> Insufficient resources for 12 XDP event queues (24 other channels, max 32)
>
> Which in turn triggers EINVAL on XDP processing:
>
> sfc 0000:86:00.0 ext0: XDP TX failed (-22)
>
> Signed-off-by: Ivan Babrou <[email protected]>

Acked-by: Martin Habets <[email protected]>

> ---
> drivers/net/ethernet/sfc/efx_channels.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/sfc/efx_channels.c b/drivers/net/ethernet/sfc/efx_channels.c
> index a4a626e9cd9a..1bfeee283ea9 100644
> --- a/drivers/net/ethernet/sfc/efx_channels.c
> +++ b/drivers/net/ethernet/sfc/efx_channels.c
> @@ -17,6 +17,7 @@
> #include "rx_common.h"
> #include "nic.h"
> #include "sriov.h"
> +#include "workarounds.h"
>
> /* This is the first interrupt mode to try out of:
> * 0 => MSI-X
> @@ -137,6 +138,7 @@ static int efx_allocate_msix_channels(struct efx_nic *efx,
> {
> unsigned int n_channels = parallelism;
> int vec_count;
> + int tx_per_ev;
> int n_xdp_tx;
> int n_xdp_ev;
>
> @@ -149,9 +151,9 @@ static int efx_allocate_msix_channels(struct efx_nic *efx,
> * multiple tx queues, assuming tx and ev queues are both
> * maximum size.
> */
> -
> + tx_per_ev = EFX_MAX_EVQ_SIZE / EFX_TXQ_MAX_ENT(efx);
> n_xdp_tx = num_possible_cpus();
> - n_xdp_ev = DIV_ROUND_UP(n_xdp_tx, EFX_MAX_TXQ_PER_CHANNEL);
> + n_xdp_ev = DIV_ROUND_UP(n_xdp_tx, tx_per_ev);
>
> vec_count = pci_msix_vec_count(efx->pci_dev);
> if (vec_count < 0)
> --
> 2.29.2