From: Matt Turner on
On Thu, Jun 24, 2010 at 5:51 AM, Michael Cree <mcree(a)orcon.net.nz> wrote:
> On 22/06/10 20:32, Dave Airlie wrote:
>>
>> On Tue, Jun 22, 2010 at 3:59 PM, FUJITA Tomonori
>> <fujita.tomonori(a)lab.ntt.co.jp> �wrote:
>>>
>>> On Mon, 21 Jun 2010 17:19:43 -0400
>>> Matt Turner<mattst88(a)gmail.com> �wrote:
>>>
>>>> Michael Cree and I have been debugging FDO bug 26403 [1]. I tried
>>>> booting with `radeon.test=1` and found this, which I think is related:
>
> Note that my radeon card is PCI whereas I think Matt may be using an AGP
> card.

Actually, I'm using a plain Radeon 9100 PCI.

> My logs are very similar to Matt's except I don't see the following line:
>
>>>>> pci_map_single failed: could not allocate dma page tables
>
>
>>> This happens in the latest git, right?
>
> Indeed, testing 2.6.35-rc3 (plus a couple or so extra patches to fix
> unrelated compile errors).
>
>>> Is this a regression (what kernel version worked)?
>>>
>>> Seems that the IOMMU can't find 128 pages. It's likely due to:
>>>
>>> - out of the IOMMU space (possibly someone doesn't free the IOMMU
>>> �space).
>>>
>>> or
>>>
>>> - the mapping parameters (such as align) aren't appropriate so the
>>> �IOMMU can't find space.
>>
>> I don't think KMS drivers have ever worked on alpha so its not a
>> regression, they are working fine on x86 + powerpc and sparc has been
>> run at least once.
>
> KMS on the console boot up has worked since about 2.6.32, but starting up
> the X server has always failed and, in my case, the system becomes unstable
> and eventually OOPs.
>
>> I suspect we are simply hitting the limits of the iommu, how big an
>> address space does it handle? since generally graphics drivers try to
>> bind a lot of things to the GART.
>
> No idea on the address space limit. �I applied the patch of Fujita that logs
> all IOMMU allocations, and also inserted some extra printks in the ttm
> kernel code so that I could see which routines failed and the error code
> returned. �Running the radeon test on boot exhibits the following:
>
> [ �238.712768] [drm] Tested GTT->VRAM and VRAM->GTT copy for GTT offset
> 0x1a312000
> [ �239.281127] [drm] Tested GTT->VRAM and VRAM->GTT copy for GTT offset
> 0x1a412000
> [ �239.281127] ttm_tt_bind belched -12
> [ �239.282104] ttm_bo_handle_move_mem belched -12
> [ �239.282104] ttm_bo_move_buffer belched -12
> [ �239.282104] ttm_bo_validate belched -12
> [ �239.282104] radeon 0000:01:00.0: object_init failed for (1048576,
> 0x00000002) err=-12
> [ �239.282104] [drm:radeon_test_moves] *ERROR* Failed to create GTT object
> 419
> [ �239.399291] Error while testing BO move.
>
> Note that no IOMMU allocations are printed while radeon_test_moves is
> running so iommu_arena_alloc doesn't appear to be called. �Also the error
> code returned up to radeon_test_moves is -12 which is ENOMEM. �So does
> appear to be some memory limit.

I confirm that we're getting -ENOMEM. I don't know if it's coming from
radeon_gart_bind(), but if it is there's an interesting comment
immediately after the call to pci_map_page:

if (pci_dma_mapping_error(rdev->pdev, rdev->gart.pages_addr[p])) {
/* FIXME: failed to map page (return -ENOMEM?) */
radeon_gart_unbind(rdev, offset, pages);
return -ENOMEM;
}

>> It might be worth limiting the PCIGART in radeon to 32MB to see if the
>> lower limit helps.
>
> So, how does one do that?

Boot with `radeon.test=1 radeon.gartsize=<size in MB>`.
> Cheers
> Michael.

Thanks,
Matt
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From: FUJITA Tomonori on
On Thu, 24 Jun 2010 21:51:40 +1200
Michael Cree <mcree(a)orcon.net.nz> wrote:

> >> Is this a regression (what kernel version worked)?
> >>
> >> Seems that the IOMMU can't find 128 pages. It's likely due to:
> >>
> >> - out of the IOMMU space (possibly someone doesn't free the IOMMU
> >> space).
> >>
> >> or
> >>
> >> - the mapping parameters (such as align) aren't appropriate so the
> >> IOMMU can't find space.
> >
> > I don't think KMS drivers have ever worked on alpha so its not a
> > regression, they are working fine on x86 + powerpc and sparc has been
> > run at least once.
>
> KMS on the console boot up has worked since about 2.6.32, but starting
> up the X server has always failed and, in my case, the system becomes
> unstable and eventually OOPs.
>
> > I suspect we are simply hitting the limits of the iommu, how big an
> > address space does it handle? since generally graphics drivers try to
> > bind a lot of things to the GART.
>
> No idea on the address space limit. I applied the patch of Fujita that
> logs all IOMMU allocations, and also inserted some extra printks in the
> ttm kernel code so that I could see which routines failed and the error
> code returned. Running the radeon test on boot exhibits the following:
>
> [ 238.712768] [drm] Tested GTT->VRAM and VRAM->GTT copy for GTT offset
> 0x1a312000
> [ 239.281127] [drm] Tested GTT->VRAM and VRAM->GTT copy for GTT offset
> 0x1a412000
> [ 239.281127] ttm_tt_bind belched -12
> [ 239.282104] ttm_bo_handle_move_mem belched -12
> [ 239.282104] ttm_bo_move_buffer belched -12
> [ 239.282104] ttm_bo_validate belched -12
> [ 239.282104] radeon 0000:01:00.0: object_init failed for (1048576,
> 0x00000002) err=-12
> [ 239.282104] [drm:radeon_test_moves] *ERROR* Failed to create GTT
> object 419
> [ 239.399291] Error while testing BO move.
>
> Note that no IOMMU allocations are printed while radeon_test_moves is
> running so iommu_arena_alloc doesn't appear to be called. Also the
> error code returned up to radeon_test_moves is -12 which is ENOMEM. So
> does appear to be some memory limit.

Hmm, not related with IOMMU? looks like ttm_tt_populate could return
ENOMEM too. Can we locate where we hit ENOMEM first?
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From: Matt Turner on
On Sun, Jun 27, 2010 at 12:20 AM, FUJITA Tomonori
<fujita.tomonori(a)lab.ntt.co.jp> wrote:
> On Thu, 24 Jun 2010 10:53:52 -0400
> Matt Turner <mattst88(a)gmail.com> wrote:
>
>> > Seems that the IOMMU can't find 128 pages. It's likely due to:
>> >
>> > - out of the IOMMU space (possibly someone doesn't free the IOMMU
>> > �space).
>> >
>> > or
>> >
>> > - the mapping parameters (such as align) aren't appropriate so the
>> > �IOMMU can't find space.
>> >
>> >
>> >> Is this the cause of the bug we're seeing in the report [1]?
>> >>
>> >> Anyone know what's going wrong here?
>> >
>> >
>> > I've attached a patch to print the debug info about the mapping
>> > parameters.
>> >
>> >
>> > diff --git a/arch/alpha/kernel/pci_iommu.c b/arch/alpha/kernel/pci_iommu.c
>> > index d1dbd9a..17cf0d8 100644
>> > --- a/arch/alpha/kernel/pci_iommu.c
>> > +++ b/arch/alpha/kernel/pci_iommu.c
>> > @@ -187,6 +187,10 @@ iommu_arena_alloc(struct device *dev, struct pci_iommu_arena *arena, long n,
>> > � � � �/* Search for N empty ptes */
>> > � � � �ptes = arena->ptes;
>> > � � � �mask = max(align, arena->align_entry) - 1;
>> > +
>> > + � � � printk("%s: %p, %p, %d, %ld, %lx, %u\n", __func__, dev, arena, arena->size,
>> > + � � � � � � �n, mask, align);
>> > +
>> > � � � �p = iommu_arena_find_pages(dev, arena, n, mask);
>> > � � � �if (p < 0) {
>> > � � � � � � � �spin_unlock_irqrestore(&arena->lock, flags);
>>
>> Using this patch, I log the attached output.
>
> Your system has 1GB iommu address space. I guess that it's enough for
> KSM?

I would definitely think so. The video card I'm using here is a 64MB
Radeon 9100 PCI, with a 128MB BAR.

> The parameters in the log looks good. But you got this log before you
> started X?

Yes, that's right.

I'll see if I can isolate where the first -ENOMEM is coming from.

Thanks Fujita for helping with this!

Matt
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From: Michael Cree on
On 27/06/10 16:20, FUJITA Tomonori wrote:
> On Thu, 24 Jun 2010 21:51:40 +1200
> Michael Cree<mcree(a)orcon.net.nz> wrote:
>
>>>> Is this a regression (what kernel version worked)?
>>>>
>>>> Seems that the IOMMU can't find 128 pages. It's likely due to:
>>>>
>>>> - out of the IOMMU space (possibly someone doesn't free the IOMMU
>>>> space).
>>>>
>>>> or
>>>>
>>>> - the mapping parameters (such as align) aren't appropriate so the
>>>> IOMMU can't find space.
>>>
>>> I don't think KMS drivers have ever worked on alpha so its not a
>>> regression, they are working fine on x86 + powerpc and sparc has been
>>> run at least once.
>>
>> KMS on the console boot up has worked since about 2.6.32, but starting
>> up the X server has always failed and, in my case, the system becomes
>> unstable and eventually OOPs.
>>
>>> I suspect we are simply hitting the limits of the iommu, how big an
>>> address space does it handle? since generally graphics drivers try to
>>> bind a lot of things to the GART.
>>
>> No idea on the address space limit. I applied the patch of Fujita that
>> logs all IOMMU allocations, and also inserted some extra printks in the
>> ttm kernel code so that I could see which routines failed and the error
>> code returned. Running the radeon test on boot exhibits the following:
>>
>> [ 238.712768] [drm] Tested GTT->VRAM and VRAM->GTT copy for GTT offset
>> 0x1a312000
>> [ 239.281127] [drm] Tested GTT->VRAM and VRAM->GTT copy for GTT offset
>> 0x1a412000
>> [ 239.281127] ttm_tt_bind belched -12
>> [ 239.282104] ttm_bo_handle_move_mem belched -12
>> [ 239.282104] ttm_bo_move_buffer belched -12
>> [ 239.282104] ttm_bo_validate belched -12
>> [ 239.282104] radeon 0000:01:00.0: object_init failed for (1048576,
>> 0x00000002) err=-12
>> [ 239.282104] [drm:radeon_test_moves] *ERROR* Failed to create GTT
>> object 419
>> [ 239.399291] Error while testing BO move.
>>
>> Note that no IOMMU allocations are printed while radeon_test_moves is
>> running so iommu_arena_alloc doesn't appear to be called. Also the
>> error code returned up to radeon_test_moves is -12 which is ENOMEM. So
>> does appear to be some memory limit.
>
> Hmm, not related with IOMMU? looks like ttm_tt_populate could return
> ENOMEM too. Can we locate where we hit ENOMEM first?

Yeah, in ttm_mem_global_reserve while it is walking glob->zones:

[ 239.303588] [drm] Tested GTT->VRAM and VRAM->GTT copy for GTT offset
0x1a412000
[ 239.304564] ttm_mem_global_reserve zone used_mem (0x1a5f0000) exceeds
limit (0x1a5ef000)
[ 239.304564] ttm_mem_global_reserve zone used_mem (0x1a5f0000) exceeds
limit (0x1a5ef000)
[ 239.304564] ttm_mem_global_reserve zone used_mem (0x1a5f0000) exceeds
limit (0x1a5ef000)
[ 239.304564] ttm_mem_global_reserve zone used_mem (0x1a5f0000) exceeds
limit (0x1a5ef000)
[ 239.304564] ttm_mem_global_reserve zone used_mem (0x1a5f0000) exceeds
limit (0x1a5ef000)
[ 239.304564] ttm_mem_global_reserve return non-zero count decs to zero
[ 239.304564] ttm_mem_global_alloc_page belched -12
[ 239.304564] __ttm_tt_get_page coughed NULL
[ 239.304564] ttm_tt_populate belched -12
[ 239.304564] ttm_tt_bind belched -12
[ 239.304564] ttm_bo_handle_move_mem belched -12
[ 239.304564] ttm_bo_move_buffer belched -12
[ 239.304564] ttm_bo_validate belched -12

On a hunch that we are chasing a red herring I installed another 256MB
of memory into the machine (was 576MB for the test reported above) for a
total of 832MB.

Now radeon_test_moves runs to completion without error.

OK, now a test of starting up the X server - ah, a bus error again but
now it looks like it's in the radeon driver:

[ 1435.014] (II) EXA(0): Driver allocated offscreen pixmaps
[ 1435.014] (II) EXA(0): Driver registered support for the following
operations:
[ 1435.014] (II) Solid
[ 1435.014] (II) Copy
[ 1435.014] (II) Composite (RENDER acceleration)
[ 1435.014] (II) UploadToScreen
[ 1435.014] (II) DownloadFromScreen
[ 1435.030]
Backtrace:
[ 1435.032] 0: /opt/xorg-ev56/bin/X (xorg_backtrace+0x54) [0x120070884]
[ 1435.032] 1: /opt/xorg-ev56/bin/X (0x120000000+0x65608) [0x120065608]
[ 1435.033] 2: /lib/libc.so.6.1 (0x20000310000+0x3d610) [0x2000034d610]
[ 1435.034] 3: /opt/xorg-ev56/lib/xorg/modules/drivers/radeon_drv.so
(0x20000758000+0x15b890) [0x200008b3890]
[ 1435.034] 4: /opt/xorg-ev56/lib/xorg/modules/drivers/radeon_drv.so
(0x20000758000+0x1392a0) [0x200008912a0]
[ 1435.034] 5: /opt/xorg-ev56/lib/xorg/modules/drivers/radeon_drv.so
(0x20000758000+0x139bec) [0x20000891bec]
[ 1435.034] 6: /opt/xorg-ev56/lib/xorg/modules/drivers/radeon_drv.so
(0x20000758000+0x4f088) [0x200007a7088]
[ 1435.035] 7: /opt/xorg-ev56/lib/xorg/modules/drivers/radeon_drv.so
(0x20000758000+0x16f0f8) [0x200008c70f8]
[ 1435.035] 8: /opt/xorg-ev56/bin/X (AddScreen+0x1c0) [0x1200532b0]
[ 1435.036] 9: /opt/xorg-ev56/bin/X (InitOutput+0x29c) [0x12008c6ec]
[ 1435.036] 10: /opt/xorg-ev56/bin/X (0x120000000+0x24b48) [0x120024b48]
[ 1435.037] 11: /lib/libc.so.6.1 (__libc_start_main+0xec) [0x2000033267c]
[ 1435.037] 12: /opt/xorg-ev56/bin/X (__start+0x38) [0x120024788]
[ 1435.038] Bus error at address 0x20000030000

And nothing in dmesg. Now I'm not triggering the nasty page alloc errors.

Cheers
Michael.
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From: Dave Airlie on
On Sun, Jun 27, 2010 at 8:46 PM, Michael Cree <mcree(a)orcon.net.nz> wrote:
> On 27/06/10 16:20, FUJITA Tomonori wrote:
>>
>> On Thu, 24 Jun 2010 21:51:40 +1200
>> Michael Cree<mcree(a)orcon.net.nz> �wrote:
>>
>>>>> Is this a regression (what kernel version worked)?
>>>>>
>>>>> Seems that the IOMMU can't find 128 pages. It's likely due to:
>>>>>
>>>>> - out of the IOMMU space (possibly someone doesn't free the IOMMU
>>>>> � space).
>>>>>
>>>>> or
>>>>>
>>>>> - the mapping parameters (such as align) aren't appropriate so the
>>>>> � IOMMU can't find space.
>>>>
>>>> I don't think KMS drivers have ever worked on alpha so its not a
>>>> regression, they are working fine on x86 + powerpc and sparc has been
>>>> run at least once.
>>>
>>> KMS on the console boot up has worked since about 2.6.32, but starting
>>> up the X server has always failed and, in my case, the system becomes
>>> unstable and eventually OOPs.
>>>
>>>> I suspect we are simply hitting the limits of the iommu, how big an
>>>> address space does it handle? since generally graphics drivers try to
>>>> bind a lot of things to the GART.
>>>
>>> No idea on the address space limit. �I applied the patch of Fujita that
>>> logs all IOMMU allocations, and also inserted some extra printks in the
>>> ttm kernel code so that I could see which routines failed and the error
>>> code returned. �Running the radeon test on boot exhibits the following:
>>>
>>> [ �238.712768] [drm] Tested GTT->VRAM and VRAM->GTT copy for GTT offset
>>> 0x1a312000
>>> [ �239.281127] [drm] Tested GTT->VRAM and VRAM->GTT copy for GTT offset
>>> 0x1a412000
>>> [ �239.281127] ttm_tt_bind belched -12
>>> [ �239.282104] ttm_bo_handle_move_mem belched -12
>>> [ �239.282104] ttm_bo_move_buffer belched -12
>>> [ �239.282104] ttm_bo_validate belched -12
>>> [ �239.282104] radeon 0000:01:00.0: object_init failed for (1048576,
>>> 0x00000002) err=-12
>>> [ �239.282104] [drm:radeon_test_moves] *ERROR* Failed to create GTT
>>> object 419
>>> [ �239.399291] Error while testing BO move.
>>>
>>> Note that no IOMMU allocations are printed while radeon_test_moves is
>>> running so iommu_arena_alloc doesn't appear to be called. �Also the
>>> error code returned up to radeon_test_moves is -12 which is ENOMEM. �So
>>> does appear to be some memory limit.
>>
>> Hmm, not related with IOMMU? looks like ttm_tt_populate could return
>> ENOMEM too. Can we locate where we hit ENOMEM first?
>
> Yeah, in ttm_mem_global_reserve while it is walking glob->zones:
>
> [ �239.303588] [drm] Tested GTT->VRAM and VRAM->GTT copy for GTT offset
> 0x1a412000
> [ �239.304564] ttm_mem_global_reserve zone used_mem (0x1a5f0000) exceeds
> limit (0x1a5ef000)
> [ �239.304564] ttm_mem_global_reserve zone used_mem (0x1a5f0000) exceeds
> limit (0x1a5ef000)
> [ �239.304564] ttm_mem_global_reserve zone used_mem (0x1a5f0000) exceeds
> limit (0x1a5ef000)
> [ �239.304564] ttm_mem_global_reserve zone used_mem (0x1a5f0000) exceeds
> limit (0x1a5ef000)
> [ �239.304564] ttm_mem_global_reserve zone used_mem (0x1a5f0000) exceeds
> limit (0x1a5ef000)
> [ �239.304564] ttm_mem_global_reserve return non-zero count decs to zero
> [ �239.304564] ttm_mem_global_alloc_page belched -12
> [ �239.304564] __ttm_tt_get_page coughed NULL
> [ �239.304564] ttm_tt_populate belched -12
> [ �239.304564] ttm_tt_bind belched -12
> [ �239.304564] ttm_bo_handle_move_mem belched -12
> [ �239.304564] ttm_bo_move_buffer belched -12
> [ �239.304564] ttm_bo_validate belched -12
>
> On a hunch that we are chasing a red herring I installed another 256MB of
> memory into the machine (was 576MB for the test reported above) for a total
> of 832MB.
>
> Now radeon_test_moves runs to completion without error.
>
> OK, now a test of starting up the X server - ah, a bus error again but now
> it looks like it's in the radeon driver:
>
> [ �1435.014] (II) EXA(0): Driver allocated offscreen pixmaps
> [ �1435.014] (II) EXA(0): Driver registered support for the following
> operations:
> [ �1435.014] (II) � � � � Solid
> [ �1435.014] (II) � � � � Copy
> [ �1435.014] (II) � � � � Composite (RENDER acceleration)
> [ �1435.014] (II) � � � � UploadToScreen
> [ �1435.014] (II) � � � � DownloadFromScreen
> [ �1435.030]
> Backtrace:
> [ �1435.032] 0: /opt/xorg-ev56/bin/X (xorg_backtrace+0x54) [0x120070884]
> [ �1435.032] 1: /opt/xorg-ev56/bin/X (0x120000000+0x65608) [0x120065608]
> [ �1435.033] 2: /lib/libc.so.6.1 (0x20000310000+0x3d610) [0x2000034d610]
> [ �1435.034] 3: /opt/xorg-ev56/lib/xorg/modules/drivers/radeon_drv.so
> (0x20000758000+0x15b890) [0x200008b3890]
> [ �1435.034] 4: /opt/xorg-ev56/lib/xorg/modules/drivers/radeon_drv.so
> (0x20000758000+0x1392a0) [0x200008912a0]
> [ �1435.034] 5: /opt/xorg-ev56/lib/xorg/modules/drivers/radeon_drv.so
> (0x20000758000+0x139bec) [0x20000891bec]
> [ �1435.034] 6: /opt/xorg-ev56/lib/xorg/modules/drivers/radeon_drv.so
> (0x20000758000+0x4f088) [0x200007a7088]
> [ �1435.035] 7: /opt/xorg-ev56/lib/xorg/modules/drivers/radeon_drv.so
> (0x20000758000+0x16f0f8) [0x200008c70f8]
> [ �1435.035] 8: /opt/xorg-ev56/bin/X (AddScreen+0x1c0) [0x1200532b0]
> [ �1435.036] 9: /opt/xorg-ev56/bin/X (InitOutput+0x29c) [0x12008c6ec]
> [ �1435.036] 10: /opt/xorg-ev56/bin/X (0x120000000+0x24b48) [0x120024b48]
> [ �1435.037] 11: /lib/libc.so.6.1 (__libc_start_main+0xec) [0x2000033267c]
> [ �1435.037] 12: /opt/xorg-ev56/bin/X (__start+0x38) [0x120024788]
> [ �1435.038] Bus error at address 0x20000030000
>
> And nothing in dmesg. �Now I'm not triggering the nasty page alloc errors.

The bus error is caused by the kernel, its something alpha specific
with how mmap works,
I'm not sure if alpha needs some special mmap flags or something,

Dave.
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