[BUG] mellanox IB driver fails to load on large config

[BUG] mellanox IB driver fails to load on large config

[andrew banman]

I'm seeing a large number of allocation errors originating from the Mellanox IB
driver when booting the 4.2-rc1 kernel on a 4096cpu 32TB memory system:

8<---
<mlx4_ib> mlx4_ib_alloc_eqs: Can't allocate EQ 64; reverting to legacy
<mlx4_ib> mlx4_ib_alloc_eqs: Can't allocate EQ 65; reverting to legacy
<mlx4_ib> mlx4_ib_alloc_eqs: Can't allocate EQ 66; reverting to legacy
<mlx4_ib> mlx4_ib_alloc_eqs: Can't allocate EQ 67; reverting to legacy
<mlx4_ib> mlx4_ib_alloc_eqs: Can't allocate EQ 68; reverting to legacy
<mlx4_ib> mlx4_ib_alloc_eqs: Can't allocate EQ 69; reverting to legacy
<mlx4_ib> mlx4_ib_alloc_eqs: Can't allocate EQ 70; reverting to legacy
<mlx4_ib> mlx4_ib_alloc_eqs: Can't allocate EQ 71; reverting to legacy
......
<mlx4_ib> mlx4_ib_alloc_eqs: Can't allocate EQ 123; reverting to legacy
--->8

Where the failing function is in drivers/infiniband/hw/mlx4/main.c:

8<---
2042 static void mlx4_ib_alloc_eqs(struct mlx4_dev *dev, struct mlx4_ib_dev *ibdev)
...
2075                         /* Set IRQ for specific name (per ring) */
2076                         if (mlx4_assign_eq(dev, name, NULL,
2077                                            &ibdev->eq_table[eq])) {
2078                                 /* Use legacy (same as mlx4_en driver) */
2079                                 pr_warn("Can't allocate EQ %d; reverting to legacy\n", eq);
2080                                 ibdev->eq_table[eq] =
2081                                         (eq % dev->caps.num_comp_vectors);
2082                         }
--->8

The problem doesn't appear to be fatal. At this point I am unsure if this is
actually expected behavior, so I'm looking for some insight into the issue.

At first we believed the problem to be with request_irq, but after writing in
some debug code that mlx4_assign_eq returned -28, indicating that vec was
never assigned:

8<---
@@ -1401,6 +1402,7 @@ int mlx4_assign_eq(struct mlx4_dev *dev, char *name, struct cpu_rmap *rmap,
        if (vec) {
                *vector = vec;
        } else {
+               pr_crit("!!! debug: mlx4_assign_eq - last err %d\n", err);
                *vector = 0;
                err = (i == dev->caps.comp_pool) ? -ENOSPC : err;
        }
--->8

8<---
 [ 1565.416273] !!! debug: mlx4_assign_eq - last err 0
 [ 1565.416275] <mlx4_ib> mlx4_ib_alloc_eqs: !!! debug: mlx4_assign_eq returned -28
 [ 1565.416277] <mlx4_ib> mlx4_ib_alloc_eqs: Can't allocate EQ 64; reverting to legacy
--->8


Any help would be greatly appreciated!

Andrew Banman

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Re: [BUG] mellanox IB driver fails to load on large config

[Or Gerlitz]

On Fri, Jul 10, 2015 at 10:15 PM, andrew banman <abanman-sJ/iWh9BUns@public.gmane.org> wrote:
> I'm seeing a large number of allocation errors originating from the Mellanox IB
> driver when booting the 4.2-rc1 kernel on a 4096cpu 32TB memory system:

Just to make sure, mlx4 works fine on this small (...) system with 4.1
and 4.2-rc1 breaks, or 4.2-rc1 is the 1st time you're trying that
config?
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Re: [BUG] mellanox IB driver fails to load on large config

[andrew banman]

On Sat, Jul 11, 2015 at 11:20:19PM +0300, Or Gerlitz wrote:
> On Fri, Jul 10, 2015 at 10:15 PM, andrew banman <abanman-sJ/iWh9BUns@public.gmane.org> wrote:
> > I'm seeing a large number of allocation errors originating from the Mellanox IB
> > driver when booting the 4.2-rc1 kernel on a 4096cpu 32TB memory system:
> 
> Just to make sure, mlx4 works fine on this small (...) system with 4.1
> and 4.2-rc1 breaks, or 4.2-rc1 is the 1st time you're trying that
> config?

I'll let Alex comment on that, he did some testing on that.

-Andrew
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Re: [BUG] mellanox IB driver fails to load on large config

[Alex Thorlton]

On Tue, Jul 14, 2015 at 01:22:34PM -0500, andrew banman wrote:
> On Sat, Jul 11, 2015 at 11:20:19PM +0300, Or Gerlitz wrote:
> > On Fri, Jul 10, 2015 at 10:15 PM, andrew banman <abanman-sJ/iWh9BUns@public.gmane.org> wrote:
> > > I'm seeing a large number of allocation errors originating from the Mellanox IB
> > > driver when booting the 4.2-rc1 kernel on a 4096cpu 32TB memory system:
> > 
> > Just to make sure, mlx4 works fine on this small (...) system with 4.1
> > and 4.2-rc1 breaks, or 4.2-rc1 is the 1st time you're trying that
> > config?
> 
> I'll let Alex comment on that, he did some testing on that.

I started seeing this on a 4.1-rc8 kernel, so it's been around for a
little while.  It may have been around before 4.1-rc8, but I haven't run
any kernels older than that on the big machine for some time.

- Alex
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Re: [BUG] mellanox IB driver fails to load on large config

[Or Gerlitz]

On Tue, Jul 14, 2015 at 9:48 PM, Alex Thorlton <athorlton@sgi.com> wrote:
> On Tue, Jul 14, 2015 at 01:22:34PM -0500, andrew banman wrote:
>> On Sat, Jul 11, 2015 at 11:20:19PM +0300, Or Gerlitz wrote:
>> > On Fri, Jul 10, 2015 at 10:15 PM, andrew banman <abanman@sgi.com> wrote:
>> > > I'm seeing a large number of allocation errors originating from the Mellanox IB
>> > > driver when booting the 4.2-rc1 kernel on a 4096cpu 32TB memory system:
>> >
>> > Just to make sure, mlx4 works fine on this small (...) system with 4.1
>> > and 4.2-rc1 breaks, or 4.2-rc1 is the 1st time you're trying that
>> > config?
>>
>> I'll let Alex comment on that, he did some testing on that.
>
> I started seeing this on a 4.1-rc8 kernel, so it's been around for a
> little while.  It may have been around before 4.1-rc8, but I haven't run
> any kernels older than that on the big machine for some time.

To make sure I am correctly following, on 4.1-rc8  you also see
something, right? are these the same messages or different ones? if
the latter send to us.

Or.

Re: [BUG] mellanox IB driver fails to load on large config

[Alex Thorlton]

On Tue, Jul 14, 2015 at 11:06:26PM +0300, Or Gerlitz wrote:
> On Tue, Jul 14, 2015 at 9:48 PM, Alex Thorlton <athorlton-sJ/iWh9BUns@public.gmane.org> wrote:
> > On Tue, Jul 14, 2015 at 01:22:34PM -0500, andrew banman wrote:
> >> On Sat, Jul 11, 2015 at 11:20:19PM +0300, Or Gerlitz wrote:
> >> > On Fri, Jul 10, 2015 at 10:15 PM, andrew banman <abanman-sJ/iWh9BUns@public.gmane.org> wrote:
> >> > > I'm seeing a large number of allocation errors originating from the Mellanox IB
> >> > > driver when booting the 4.2-rc1 kernel on a 4096cpu 32TB memory system:
> >> >
> >> > Just to make sure, mlx4 works fine on this small (...) system with 4.1
> >> > and 4.2-rc1 breaks, or 4.2-rc1 is the 1st time you're trying that
> >> > config?
> >>
> >> I'll let Alex comment on that, he did some testing on that.
> >
> > I started seeing this on a 4.1-rc8 kernel, so it's been around for a
> > little while.  It may have been around before 4.1-rc8, but I haven't run
> > any kernels older than that on the big machine for some time.
> 
> To make sure I am correctly following, on 4.1-rc8  you also see
> something, right?

Yes, that's correct.

> are these the same messages or different ones? if the latter send to us.

We see the same exact messages on 4.1-rc8.

Thanks for looking into this!

- Alex
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Re: [BUG] mellanox IB driver fails to load on large config

[Matan Barak]

On 7/14/2015 11:28 PM, Alex Thorlton wrote:
> On Tue, Jul 14, 2015 at 11:06:26PM +0300, Or Gerlitz wrote:
>> On Tue, Jul 14, 2015 at 9:48 PM, Alex Thorlton <athorlton-sJ/iWh9BUns@public.gmane.org> wrote:
>>> On Tue, Jul 14, 2015 at 01:22:34PM -0500, andrew banman wrote:
>>>> On Sat, Jul 11, 2015 at 11:20:19PM +0300, Or Gerlitz wrote:
>>>>> On Fri, Jul 10, 2015 at 10:15 PM, andrew banman <abanman-sJ/iWh9BUns@public.gmane.org> wrote:
>>>>>> I'm seeing a large number of allocation errors originating from the Mellanox IB
>>>>>> driver when booting the 4.2-rc1 kernel on a 4096cpu 32TB memory system:
>>>>>
>>>>> Just to make sure, mlx4 works fine on this small (...) system with 4.1
>>>>> and 4.2-rc1 breaks, or 4.2-rc1 is the 1st time you're trying that
>>>>> config?
>>>>
>>>> I'll let Alex comment on that, he did some testing on that.
>>>
>>> I started seeing this on a 4.1-rc8 kernel, so it's been around for a
>>> little while.  It may have been around before 4.1-rc8, but I haven't run
>>> any kernels older than that on the big machine for some time.
>>
>> To make sure I am correctly following, on 4.1-rc8  you also see
>> something, right?
>
> Yes, that's correct.
>
>> are these the same messages or different ones? if the latter send to us.
>
> We see the same exact messages on 4.1-rc8.

Hi,

We don't recall getting those error with 32cpu machines, but we'll try 
to reproduce this issue.

Matan

>
> Thanks for looking into this!
>
> - Alex
>
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Re: [BUG] mellanox IB driver fails to load on large config

[Or Gerlitz]

On 7/14/2015 11:28 PM, Alex Thorlton wrote:
>
> We see the same exact messages on 4.1-rc8.
>
>

does this solves the problem?


diff --git a/include/linux/mlx4/device.h b/include/linux/mlx4/device.h
index ad31e47..c8ae3b9 100644
--- a/include/linux/mlx4/device.h
+++ b/include/linux/mlx4/device.h
@@ -45,7 +45,7 @@
  #include <linux/timecounter.h>

  #define MAX_MSIX_P_PORT                17
-#define MAX_MSIX               64
+#define MAX_MSIX               1024
  #define MIN_MSIX_P_PORT                5
  #define MLX4_IS_LEGACY_EQ_MODE(dev_cap) ((dev_cap).num_comp_vectors < \
(dev_cap).num_ports * MIN_MSIX_P_PORT)
--

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Re: [BUG] mellanox IB driver fails to load on large config

[Alex Thorlton]

On Thu, Jul 16, 2015 at 09:25:37AM +0300, Or Gerlitz wrote:
> On 7/14/2015 11:28 PM, Alex Thorlton wrote:
>>
>> We see the same exact messages on 4.1-rc8.
>>
>>
>
> does this solves the problem?
>
>
> diff --git a/include/linux/mlx4/device.h b/include/linux/mlx4/device.h
> index ad31e47..c8ae3b9 100644
> --- a/include/linux/mlx4/device.h
> +++ b/include/linux/mlx4/device.h
> @@ -45,7 +45,7 @@
>  #include <linux/timecounter.h>
>
>  #define MAX_MSIX_P_PORT                17
> -#define MAX_MSIX               64
> +#define MAX_MSIX               1024
>  #define MIN_MSIX_P_PORT                5
>  #define MLX4_IS_LEGACY_EQ_MODE(dev_cap) ((dev_cap).num_comp_vectors < \
> (dev_cap).num_ports * MIN_MSIX_P_PORT)
> --
>

I've got some time on the large machine later today.  I'll give this a
try then.

Thanks, Or!

- Alex
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Re: [BUG] mellanox IB driver fails to load on large config

[Alex Thorlton]

On Mon, Jul 20, 2015 at 11:28:03AM -0500, Alex Thorlton wrote:
> I've got some time on the large machine later today.  I'll give this a
> try then.

I ran a boot with this patch applied:

diff --git a/include/linux/mlx4/device.h b/include/linux/mlx4/device.h
index 83e80ab..c84aea0 100644
--- a/include/linux/mlx4/device.h
+++ b/include/linux/mlx4/device.h
@@ -45,7 +45,7 @@
 #include <linux/timecounter.h>

 #define MAX_MSIX_P_PORT                17
-#define MAX_MSIX               64
+#define MAX_MSIX               8192
 #define MSIX_LEGACY_SZ         4
 #define MIN_MSIX_P_PORT                5

I went for a max of 8192, since I was actually booting the machine with
6144 cores (not 4096) for this run.  It doesn't look like this fixed the
problem.  I still saw the same errors during boot.

FWIW, the module does appear to still successfully load:

8<---
# lsmod | grep mlx
mlx4_ib               151552  0
ib_sa                  32768  1 mlx4_ib
ib_mad                 49152  2 ib_sa,mlx4_ib
ib_core               102400  3 ib_sa,mlx4_ib,ib_mad
mlx4_core             278528  1 mlx4_ib
--->8

If the module loading is good enough, and we should just ignore the
errors, then I'm fine with that.  Just wanting to make sure that
everything is behaving correctly.

- Alex
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Re: [BUG] mellanox IB driver fails to load on large config

[Matan Barak]

On Tue, Jul 21, 2015 at 5:56 AM, Alex Thorlton <athorlton-sJ/iWh9BUns@public.gmane.org> wrote:
> On Mon, Jul 20, 2015 at 11:28:03AM -0500, Alex Thorlton wrote:
>> I've got some time on the large machine later today.  I'll give this a
>> try then.
>
> I ran a boot with this patch applied:
>
> diff --git a/include/linux/mlx4/device.h b/include/linux/mlx4/device.h
> index 83e80ab..c84aea0 100644
> --- a/include/linux/mlx4/device.h
> +++ b/include/linux/mlx4/device.h
> @@ -45,7 +45,7 @@
>  #include <linux/timecounter.h>
>
>  #define MAX_MSIX_P_PORT                17
> -#define MAX_MSIX               64
> +#define MAX_MSIX               8192
>  #define MSIX_LEGACY_SZ         4
>  #define MIN_MSIX_P_PORT                5
>
> I went for a max of 8192, since I was actually booting the machine with
> 6144 cores (not 4096) for this run.  It doesn't look like this fixed the
> problem.  I still saw the same errors during boot.
>
> FWIW, the module does appear to still successfully load:
>
> 8<---
> # lsmod | grep mlx
> mlx4_ib               151552  0
> ib_sa                  32768  1 mlx4_ib
> ib_mad                 49152  2 ib_sa,mlx4_ib
> ib_core               102400  3 ib_sa,mlx4_ib,ib_mad
> mlx4_core             278528  1 mlx4_ib
> --->8
>
> If the module loading is good enough, and we should just ignore the
> errors, then I'm fine with that.  Just wanting to make sure that
> everything is behaving correctly.

It shouldn't be a problem,  as all unused/erroneous EQs get "-1".
We'll try to reproduce the problem here, it might take awhile though.

Thanks for checking this,
Matan

>
> - Alex
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