Hi!
Recently I started getting multiple errors like this:
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
... and so on
This is all happening on a PPC64 "powernv" platform machine. To trigger the
error state, it is enough to _flood_ ping CXGB3 card from another machine
(which has Emulex 10Gb NIC + Cisco switch). Just do "ping -f 172.20.1.2"
and wait 10-15 seconds.
The messages are coming from arch/powerpc/kernel/iommu.c and basically
mean that the driver requested more pages than the DMA window has which is
normally 1GB (there could be another possible source of errors -
ppc_md.tce_build callback - but on powernv platform it always succeeds).
The patch after which it broke is:
commit f83331bab149e29fa2c49cf102c0cd8c3f1ce9f9
Author: Santosh Rastapur [off-list ref]
Date: Tue May 21 04:21:29 2013 +0000
cxgb3: Check and handle the dma mapping errors
Any quick ideas? Thanks!
--
Alexey
From: Jay Fenlason <hidden> Date: 2013-08-05 18:41:18
On Mon, Aug 05, 2013 at 12:59:04PM +1000, Alexey Kardashevskiy wrote:
Hi!
Recently I started getting multiple errors like this:
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
... and so on
This is all happening on a PPC64 "powernv" platform machine. To trigger the
error state, it is enough to _flood_ ping CXGB3 card from another machine
(which has Emulex 10Gb NIC + Cisco switch). Just do "ping -f 172.20.1.2"
and wait 10-15 seconds.
The messages are coming from arch/powerpc/kernel/iommu.c and basically
mean that the driver requested more pages than the DMA window has which is
normally 1GB (there could be another possible source of errors -
ppc_md.tce_build callback - but on powernv platform it always succeeds).
The patch after which it broke is:
commit f83331bab149e29fa2c49cf102c0cd8c3f1ce9f9
Author: Santosh Rastapur [off-list ref]
Date: Tue May 21 04:21:29 2013 +0000
cxgb3: Check and handle the dma mapping errors
Any quick ideas? Thanks!
That patch adds error checking to detect failed dma mapping requests.
Before it, the code always assumed that dma mapping requests succeded,
whether they actually do or not, so the fact that the older kernel
does not log errors only means that the failures are being ignored,
and any appearance of working is through pure luck. The machine could
have just crashed at that point.
What is the observed behavior of the system by the machine initiating
the ping flood? Do the older and newer kernels differ in the
percentage of pings that do not receive replies? O the newer kernel,
when the mapping errors are detected, the packet that it is trying to
transmit is dropped, but I'm not at all sure what happens on the older
kernel after the dma mapping fails. As I mentioned earlier, I'm
surprised it does not crash. Perhaps the folks from Chelsio have a
better idea what happens after a dma mapping error is ignored?
-- JF
On Mon, Aug 05, 2013 at 12:59:04PM +1000, Alexey Kardashevskiy wrote:
quoted
Hi!
Recently I started getting multiple errors like this:
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
... and so on
This is all happening on a PPC64 "powernv" platform machine. To trigger the
error state, it is enough to _flood_ ping CXGB3 card from another machine
(which has Emulex 10Gb NIC + Cisco switch). Just do "ping -f 172.20.1.2"
and wait 10-15 seconds.
The messages are coming from arch/powerpc/kernel/iommu.c and basically
mean that the driver requested more pages than the DMA window has which is
normally 1GB (there could be another possible source of errors -
ppc_md.tce_build callback - but on powernv platform it always succeeds).
The patch after which it broke is:
commit f83331bab149e29fa2c49cf102c0cd8c3f1ce9f9
Author: Santosh Rastapur [off-list ref]
Date: Tue May 21 04:21:29 2013 +0000
cxgb3: Check and handle the dma mapping errors
Any quick ideas? Thanks!
That patch adds error checking to detect failed dma mapping requests.
Before it, the code always assumed that dma mapping requests succeded,
whether they actually do or not, so the fact that the older kernel
does not log errors only means that the failures are being ignored,
and any appearance of working is through pure luck. The machine could
have just crashed at that point.
From what I see, the patch adds map_skb() function which is called in two
new places, so the patch does not just mechanically replace
skb_frag_dma_map() to map_skb() or something like that.
What is the observed behavior of the system by the machine initiating
the ping flood? Do the older and newer kernels differ in the
percentage of pings that do not receive replies?
The other machine stops receiving replies. It is using different adapter,
not Chelsio and the kernel version does not really matter.
O the newer kernel,
when the mapping errors are detected, the packet that it is trying to
transmit is dropped, but I'm not at all sure what happens on the older
kernel after the dma mapping fails. As I mentioned earlier, I'm
surprised it does not crash. Perhaps the folks from Chelsio have a
better idea what happens after a dma mapping error is ignored?
Any kernel cannot avoid platform's iommu_alloc() on ppc64/powernv so if
there was a problem, we would have seen messages (and yes, kernel would
have crashed).
--
Alexey
From: Divy Le ray <hidden> Date: 2013-08-07 17:01:31
On 08/05/2013 11:41 AM, Jay Fenlason wrote:
On Mon, Aug 05, 2013 at 12:59:04PM +1000, Alexey Kardashevskiy wrote:
quoted
Hi!
Recently I started getting multiple errors like this:
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
... and so on
This is all happening on a PPC64 "powernv" platform machine. To trigger the
error state, it is enough to _flood_ ping CXGB3 card from another machine
(which has Emulex 10Gb NIC + Cisco switch). Just do "ping -f 172.20.1.2"
and wait 10-15 seconds.
The messages are coming from arch/powerpc/kernel/iommu.c and basically
mean that the driver requested more pages than the DMA window has which is
normally 1GB (there could be another possible source of errors -
ppc_md.tce_build callback - but on powernv platform it always succeeds).
The patch after which it broke is:
commit f83331bab149e29fa2c49cf102c0cd8c3f1ce9f9
Author: Santosh Rastapur [off-list ref]
Date: Tue May 21 04:21:29 2013 +0000
cxgb3: Check and handle the dma mapping errors
Any quick ideas? Thanks!
That patch adds error checking to detect failed dma mapping requests.
Before it, the code always assumed that dma mapping requests succeded,
whether they actually do or not, so the fact that the older kernel
does not log errors only means that the failures are being ignored,
and any appearance of working is through pure luck. The machine could
have just crashed at that point.
What is the observed behavior of the system by the machine initiating
the ping flood? Do the older and newer kernels differ in the
percentage of pings that do not receive replies? O the newer kernel,
when the mapping errors are detected, the packet that it is trying to
transmit is dropped, but I'm not at all sure what happens on the older
kernel after the dma mapping fails. As I mentioned earlier, I'm
surprised it does not crash. Perhaps the folks from Chelsio have a
better idea what happens after a dma mapping error is ignored?
Hi,
It should definitely not be ignored. It should not happen this reliably
either.
I wonder if we are not hitting a leak of iommu entries.
Cheers,
Divy
On Mon, Aug 05, 2013 at 12:59:04PM +1000, Alexey Kardashevskiy wrote:
quoted
Hi!
Recently I started getting multiple errors like this:
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
... and so on
This is all happening on a PPC64 "powernv" platform machine. To trigger the
error state, it is enough to _flood_ ping CXGB3 card from another machine
(which has Emulex 10Gb NIC + Cisco switch). Just do "ping -f 172.20.1.2"
and wait 10-15 seconds.
The messages are coming from arch/powerpc/kernel/iommu.c and basically
mean that the driver requested more pages than the DMA window has which is
normally 1GB (there could be another possible source of errors -
ppc_md.tce_build callback - but on powernv platform it always succeeds).
The patch after which it broke is:
commit f83331bab149e29fa2c49cf102c0cd8c3f1ce9f9
Author: Santosh Rastapur [off-list ref]
Date: Tue May 21 04:21:29 2013 +0000
cxgb3: Check and handle the dma mapping errors
Any quick ideas? Thanks!
That patch adds error checking to detect failed dma mapping requests.
Before it, the code always assumed that dma mapping requests succeded,
whether they actually do or not, so the fact that the older kernel
does not log errors only means that the failures are being ignored,
and any appearance of working is through pure luck. The machine could
have just crashed at that point.
What is the observed behavior of the system by the machine initiating
the ping flood? Do the older and newer kernels differ in the
percentage of pings that do not receive replies? O the newer kernel,
when the mapping errors are detected, the packet that it is trying to
transmit is dropped, but I'm not at all sure what happens on the older
kernel after the dma mapping fails. As I mentioned earlier, I'm
surprised it does not crash. Perhaps the folks from Chelsio have a
better idea what happens after a dma mapping error is ignored?
Hi,
It should definitely not be ignored. It should not happen this reliably
either.
I wonder if we are not hitting a leak of iommu entries.
Yes we do. I did some more tests with socklib from here
http://junkcode.samba.org/ftp/unpacked/junkcode/socklib/
The test is basically sock_source sending packets to sock_sink. If block
size is >=512 bytes, there is no leak, if I set packet size to <=256 bytes,
it starts leaking, smaller block size means faster leak. The type of the
other adapter does not really matter, can be the same Emulex adapter.
I am attaching a small patch which I made in order to detect the leak.
Without the patch, no leak happens, I double checked.
--
Alexey
Ping, anyone?
On 08/08/2013 03:38 PM, Alexey Kardashevskiy wrote:
On 08/08/2013 02:55 AM, Divy Le ray wrote:
quoted
On 08/05/2013 11:41 AM, Jay Fenlason wrote:
quoted
On Mon, Aug 05, 2013 at 12:59:04PM +1000, Alexey Kardashevskiy wrote:
quoted
Hi!
Recently I started getting multiple errors like this:
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
cxgb3 0006:01:00.0: iommu_alloc failed, tbl c000000003067980 vaddr
c000001fbdaaa882 npages 1
... and so on
This is all happening on a PPC64 "powernv" platform machine. To trigger the
error state, it is enough to _flood_ ping CXGB3 card from another machine
(which has Emulex 10Gb NIC + Cisco switch). Just do "ping -f 172.20.1.2"
and wait 10-15 seconds.
The messages are coming from arch/powerpc/kernel/iommu.c and basically
mean that the driver requested more pages than the DMA window has which is
normally 1GB (there could be another possible source of errors -
ppc_md.tce_build callback - but on powernv platform it always succeeds).
The patch after which it broke is:
commit f83331bab149e29fa2c49cf102c0cd8c3f1ce9f9
Author: Santosh Rastapur [off-list ref]
Date: Tue May 21 04:21:29 2013 +0000
cxgb3: Check and handle the dma mapping errors
Any quick ideas? Thanks!
That patch adds error checking to detect failed dma mapping requests.
Before it, the code always assumed that dma mapping requests succeded,
whether they actually do or not, so the fact that the older kernel
does not log errors only means that the failures are being ignored,
and any appearance of working is through pure luck. The machine could
have just crashed at that point.
What is the observed behavior of the system by the machine initiating
the ping flood? Do the older and newer kernels differ in the
percentage of pings that do not receive replies? O the newer kernel,
when the mapping errors are detected, the packet that it is trying to
transmit is dropped, but I'm not at all sure what happens on the older
kernel after the dma mapping fails. As I mentioned earlier, I'm
surprised it does not crash. Perhaps the folks from Chelsio have a
better idea what happens after a dma mapping error is ignored?
Hi,
It should definitely not be ignored. It should not happen this reliably
either.
I wonder if we are not hitting a leak of iommu entries.
Yes we do. I did some more tests with socklib from here
http://junkcode.samba.org/ftp/unpacked/junkcode/socklib/
The test is basically sock_source sending packets to sock_sink. If block
size is >=512 bytes, there is no leak, if I set packet size to <=256 bytes,
it starts leaking, smaller block size means faster leak. The type of the
other adapter does not really matter, can be the same Emulex adapter.
I am attaching a small patch which I made in order to detect the leak.
Without the patch, no leak happens, I double checked.