* SWIOTLB on 32-bit PAE
@ 2015-10-05 8:31 Christian Melki
[not found] ` <561254A7.4000805@t2data.com>
0 siblings, 1 reply; 4+ messages in thread
From: Christian Melki @ 2015-10-05 8:31 UTC (permalink / raw)
To: linux-kernel; +Cc: konrad.wilk
[-- Attachment #1: Type: text/plain, Size: 1232 bytes --]
Hi,
I discovered that my 32-bit PAE 4.2.0 kernel (no IOMMU code) would hang
when writing to my USB disk. The kernel spews million(-ish messages per
sec) to syslog, effectively "hanging" userspace with my kernel.
Oct 2 14:33:06 voodoochild kernel: [ 223.287447] nommu_map_sg:
overflow 25dcac000+1024 of device mask ffffffff
Oct 2 14:33:06 voodoochild kernel: [ 223.287448] nommu_map_sg:
overflow 25dcac000+1024 of device mask ffffffff
Oct 2 14:33:06 voodoochild kernel: [ 223.287449] nommu_map_sg:
overflow 25dcac000+1024 of device mask ffffffff
... etc ...
In my kernel config I noticed that SWIOTLB was not on. It seems SWIOTLB
is provided for 64-bit and 32-bit with IOMMU/AGPGART code. But if I
compiled the kernel with PAE and no IOMMU and no other GART code, I
would not get SWIOTLB. I'd like to think that SWIOTLB should be selected
for 32-bit PAE as default.
I have attached a oneliner patch which does that.
The patch works for me. The issue where the kernel more or less runs
endless bashing of (nommu_?)map_sg when failing is another problem I
guess. I expected the kernel/drivers to have some more graceful
handling, but I know to little about this area to have a proper opinion.
Regards,
Christian
[-- Attachment #2: swiotlb.patch --]
[-- Type: text/x-patch, Size: 481 bytes --]
diff -urN linux-4.2.orig/arch/x86/Kconfig linux-4.2/arch/x86/Kconfig
--- linux-4.2.orig/arch/x86/Kconfig 2015-10-05 08:56:58.933313678 +0200
+++ linux-4.2/arch/x86/Kconfig 2015-10-05 09:00:00.916306025 +0200
@@ -1282,6 +1282,7 @@
config X86_PAE
bool "PAE (Physical Address Extension) Support"
depends on X86_32 && !HIGHMEM4G
+ select SWIOTLB
---help---
PAE is required for NX support, and furthermore enables
larger swapspace support for non-overcommit purposes. It
^ permalink raw reply [flat|nested] 4+ messages in thread[parent not found: <561254A7.4000805@t2data.com>]
* Re: Fwd: SWIOTLB on 32-bit PAE [not found] ` <561254A7.4000805@t2data.com> @ 2015-10-05 14:21 ` Konrad Rzeszutek Wilk 2015-10-05 15:31 ` Christian Melki 0 siblings, 1 reply; 4+ messages in thread From: Konrad Rzeszutek Wilk @ 2015-10-05 14:21 UTC (permalink / raw) To: Christian Melki; +Cc: joro, linux-kernel On Mon, Oct 05, 2015 at 12:44:55PM +0200, Christian Melki wrote: > Joerg, > > I already sent the patch for Kconfig change to the list. > But I discovered something even more disturbing which I mailed Konrad about. > With the change my machine does not hang any more, but instead corrupts data > which is written. The data however is readable on the machine which > corrupted it, unreadable on the other machine without the patch. I don't > understand what is going on. I have never encountered "selective" file > corruption of fs on different machines. The fs itself checks out cleanly > with badblock control (ext4). I fail to understand what is happening. And I believe this ended up being an operator error? With the patch you sent, you didn't include your SoB (Signed-off-By). I would like to include your patch but I cannot with your SoB. It is matter of reading to Documentation/SubmittingPatches and just consenting to the Certificate in there. If you are uncomfortable with that - that is OK, I can make this patch myself (a one liner :-)) but I figured it owuld be nice for you to have all the credit. > > Regards, > Christian > > -------- Forwarded Message -------- > Subject: SWIOTLB on 32-bit PAE > Date: Mon, 5 Oct 2015 10:31:39 +0200 > From: Christian Melki <christian.melki@t2data.com> > To: linux-kernel@vger.kernel.org > CC: konrad.wilk@oracle.com > > Hi, > > I discovered that my 32-bit PAE 4.2.0 kernel (no IOMMU code) would hang > when writing to my USB disk. The kernel spews million(-ish messages per > sec) to syslog, effectively "hanging" userspace with my kernel. > > Oct 2 14:33:06 voodoochild kernel: [ 223.287447] nommu_map_sg: > overflow 25dcac000+1024 of device mask ffffffff > Oct 2 14:33:06 voodoochild kernel: [ 223.287448] nommu_map_sg: > overflow 25dcac000+1024 of device mask ffffffff > Oct 2 14:33:06 voodoochild kernel: [ 223.287449] nommu_map_sg: > overflow 25dcac000+1024 of device mask ffffffff > ... etc ... > > In my kernel config I noticed that SWIOTLB was not on. It seems SWIOTLB > is provided for 64-bit and 32-bit with IOMMU/AGPGART code. But if I > compiled the kernel with PAE and no IOMMU and no other GART code, I > would not get SWIOTLB. I'd like to think that SWIOTLB should be selected > for 32-bit PAE as default. > > I have attached a oneliner patch which does that. > The patch works for me. The issue where the kernel more or less runs > endless bashing of (nommu_?)map_sg when failing is another problem I > guess. I expected the kernel/drivers to have some more graceful > handling, but I know to little about this area to have a proper opinion. > > Regards, > Christian > > > > diff -urN linux-4.2.orig/arch/x86/Kconfig linux-4.2/arch/x86/Kconfig > --- linux-4.2.orig/arch/x86/Kconfig 2015-10-05 08:56:58.933313678 +0200 > +++ linux-4.2/arch/x86/Kconfig 2015-10-05 09:00:00.916306025 +0200 > @@ -1282,6 +1282,7 @@ > config X86_PAE > bool "PAE (Physical Address Extension) Support" > depends on X86_32 && !HIGHMEM4G > + select SWIOTLB > ---help--- > PAE is required for NX support, and furthermore enables > larger swapspace support for non-overcommit purposes. It > ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Fwd: SWIOTLB on 32-bit PAE 2015-10-05 14:21 ` Fwd: " Konrad Rzeszutek Wilk @ 2015-10-05 15:31 ` Christian Melki 2015-10-07 19:45 ` Konrad Rzeszutek Wilk 0 siblings, 1 reply; 4+ messages in thread From: Christian Melki @ 2015-10-05 15:31 UTC (permalink / raw) To: Konrad Rzeszutek Wilk; +Cc: joro, linux-kernel [-- Attachment #1: Type: text/plain, Size: 3391 bytes --] Yes. Operator error indeed. Thanks for asking. Included is the same patch with the SoB. On 10/05/2015 04:21 PM, Konrad Rzeszutek Wilk wrote: > On Mon, Oct 05, 2015 at 12:44:55PM +0200, Christian Melki wrote: >> Joerg, >> >> I already sent the patch for Kconfig change to the list. >> But I discovered something even more disturbing which I mailed Konrad about. >> With the change my machine does not hang any more, but instead corrupts data >> which is written. The data however is readable on the machine which >> corrupted it, unreadable on the other machine without the patch. I don't >> understand what is going on. I have never encountered "selective" file >> corruption of fs on different machines. The fs itself checks out cleanly >> with badblock control (ext4). I fail to understand what is happening. > > And I believe this ended up being an operator error? > > With the patch you sent, you didn't include your SoB > (Signed-off-By). I would like to include your patch but I cannot > with your SoB. It is matter of reading to Documentation/SubmittingPatches > and just consenting to the Certificate in there. > > If you are uncomfortable with that - that is OK, I can make this > patch myself (a one liner :-)) but I figured it owuld be nice > for you to have all the credit. >> >> Regards, >> Christian >> >> -------- Forwarded Message -------- >> Subject: SWIOTLB on 32-bit PAE >> Date: Mon, 5 Oct 2015 10:31:39 +0200 >> From: Christian Melki <christian.melki@t2data.com> >> To: linux-kernel@vger.kernel.org >> CC: konrad.wilk@oracle.com >> >> Hi, >> >> I discovered that my 32-bit PAE 4.2.0 kernel (no IOMMU code) would hang >> when writing to my USB disk. The kernel spews million(-ish messages per >> sec) to syslog, effectively "hanging" userspace with my kernel. >> >> Oct 2 14:33:06 voodoochild kernel: [ 223.287447] nommu_map_sg: >> overflow 25dcac000+1024 of device mask ffffffff >> Oct 2 14:33:06 voodoochild kernel: [ 223.287448] nommu_map_sg: >> overflow 25dcac000+1024 of device mask ffffffff >> Oct 2 14:33:06 voodoochild kernel: [ 223.287449] nommu_map_sg: >> overflow 25dcac000+1024 of device mask ffffffff >> ... etc ... >> >> In my kernel config I noticed that SWIOTLB was not on. It seems SWIOTLB >> is provided for 64-bit and 32-bit with IOMMU/AGPGART code. But if I >> compiled the kernel with PAE and no IOMMU and no other GART code, I >> would not get SWIOTLB. I'd like to think that SWIOTLB should be selected >> for 32-bit PAE as default. >> >> I have attached a oneliner patch which does that. >> The patch works for me. The issue where the kernel more or less runs >> endless bashing of (nommu_?)map_sg when failing is another problem I >> guess. I expected the kernel/drivers to have some more graceful >> handling, but I know to little about this area to have a proper opinion. >> >> Regards, >> Christian >> >> >> > >> diff -urN linux-4.2.orig/arch/x86/Kconfig linux-4.2/arch/x86/Kconfig >> --- linux-4.2.orig/arch/x86/Kconfig 2015-10-05 08:56:58.933313678 +0200 >> +++ linux-4.2/arch/x86/Kconfig 2015-10-05 09:00:00.916306025 +0200 >> @@ -1282,6 +1282,7 @@ >> config X86_PAE >> bool "PAE (Physical Address Extension) Support" >> depends on X86_32 && !HIGHMEM4G >> + select SWIOTLB >> ---help--- >> PAE is required for NX support, and furthermore enables >> larger swapspace support for non-overcommit purposes. It >> > [-- Attachment #2: swiotlb.patch --] [-- Type: text/plain, Size: 542 bytes --] diff -urN linux-4.2.orig/arch/x86/Kconfig linux-4.2/arch/x86/Kconfig --- linux-4.2.orig/arch/x86/Kconfig 2015-10-05 08:56:58.933313678 +0200 +++ linux-4.2/arch/x86/Kconfig 2015-10-05 09:00:00.916306025 +0200 @@ -1282,6 +1282,7 @@ config X86_PAE bool "PAE (Physical Address Extension) Support" depends on X86_32 && !HIGHMEM4G + select SWIOTLB ---help--- PAE is required for NX support, and furthermore enables larger swapspace support for non-overcommit purposes. It Signed-off-by: Christian Melki <christian.melki@t2data.com> ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Fwd: SWIOTLB on 32-bit PAE 2015-10-05 15:31 ` Christian Melki @ 2015-10-07 19:45 ` Konrad Rzeszutek Wilk 0 siblings, 0 replies; 4+ messages in thread From: Konrad Rzeszutek Wilk @ 2015-10-07 19:45 UTC (permalink / raw) To: Christian Melki; +Cc: joro, linux-kernel On Mon, Oct 05, 2015 at 05:31:33PM +0200, Christian Melki wrote: > Yes. Operator error indeed. > > Thanks for asking. Included is the same patch with the SoB. I've stuck it at https://git.kernel.org/cgit/linux/kernel/git/konrad/swiotlb.git/ #stable/for-linus-4.3 Will send it out tomorrow if there are no #linux-next issues. > > On 10/05/2015 04:21 PM, Konrad Rzeszutek Wilk wrote: > >On Mon, Oct 05, 2015 at 12:44:55PM +0200, Christian Melki wrote: > >>Joerg, > >> > >>I already sent the patch for Kconfig change to the list. > >>But I discovered something even more disturbing which I mailed Konrad about. > >>With the change my machine does not hang any more, but instead corrupts data > >>which is written. The data however is readable on the machine which > >>corrupted it, unreadable on the other machine without the patch. I don't > >>understand what is going on. I have never encountered "selective" file > >>corruption of fs on different machines. The fs itself checks out cleanly > >>with badblock control (ext4). I fail to understand what is happening. > > > >And I believe this ended up being an operator error? > > > >With the patch you sent, you didn't include your SoB > >(Signed-off-By). I would like to include your patch but I cannot > >with your SoB. It is matter of reading to Documentation/SubmittingPatches > >and just consenting to the Certificate in there. > > > >If you are uncomfortable with that - that is OK, I can make this > >patch myself (a one liner :-)) but I figured it owuld be nice > >for you to have all the credit. > >> > >>Regards, > >>Christian > >> > >>-------- Forwarded Message -------- > >>Subject: SWIOTLB on 32-bit PAE > >>Date: Mon, 5 Oct 2015 10:31:39 +0200 > >>From: Christian Melki <christian.melki@t2data.com> > >>To: linux-kernel@vger.kernel.org > >>CC: konrad.wilk@oracle.com > >> > >>Hi, > >> > >>I discovered that my 32-bit PAE 4.2.0 kernel (no IOMMU code) would hang > >>when writing to my USB disk. The kernel spews million(-ish messages per > >>sec) to syslog, effectively "hanging" userspace with my kernel. > >> > >>Oct 2 14:33:06 voodoochild kernel: [ 223.287447] nommu_map_sg: > >>overflow 25dcac000+1024 of device mask ffffffff > >>Oct 2 14:33:06 voodoochild kernel: [ 223.287448] nommu_map_sg: > >>overflow 25dcac000+1024 of device mask ffffffff > >>Oct 2 14:33:06 voodoochild kernel: [ 223.287449] nommu_map_sg: > >>overflow 25dcac000+1024 of device mask ffffffff > >>... etc ... > >> > >>In my kernel config I noticed that SWIOTLB was not on. It seems SWIOTLB > >>is provided for 64-bit and 32-bit with IOMMU/AGPGART code. But if I > >>compiled the kernel with PAE and no IOMMU and no other GART code, I > >>would not get SWIOTLB. I'd like to think that SWIOTLB should be selected > >>for 32-bit PAE as default. > >> > >>I have attached a oneliner patch which does that. > >>The patch works for me. The issue where the kernel more or less runs > >>endless bashing of (nommu_?)map_sg when failing is another problem I > >>guess. I expected the kernel/drivers to have some more graceful > >>handling, but I know to little about this area to have a proper opinion. > >> > >>Regards, > >>Christian > >> > >> > >> > > > >>diff -urN linux-4.2.orig/arch/x86/Kconfig linux-4.2/arch/x86/Kconfig > >>--- linux-4.2.orig/arch/x86/Kconfig 2015-10-05 08:56:58.933313678 +0200 > >>+++ linux-4.2/arch/x86/Kconfig 2015-10-05 09:00:00.916306025 +0200 > >>@@ -1282,6 +1282,7 @@ > >> config X86_PAE > >> bool "PAE (Physical Address Extension) Support" > >> depends on X86_32 && !HIGHMEM4G > >>+ select SWIOTLB > >> ---help--- > >> PAE is required for NX support, and furthermore enables > >> larger swapspace support for non-overcommit purposes. It > >> > > > > diff -urN linux-4.2.orig/arch/x86/Kconfig linux-4.2/arch/x86/Kconfig > --- linux-4.2.orig/arch/x86/Kconfig 2015-10-05 08:56:58.933313678 +0200 > +++ linux-4.2/arch/x86/Kconfig 2015-10-05 09:00:00.916306025 +0200 > @@ -1282,6 +1282,7 @@ > config X86_PAE > bool "PAE (Physical Address Extension) Support" > depends on X86_32 && !HIGHMEM4G > + select SWIOTLB > ---help--- > PAE is required for NX support, and furthermore enables > larger swapspace support for non-overcommit purposes. It > > Signed-off-by: Christian Melki <christian.melki@t2data.com> ^ permalink raw reply [flat|nested] 4+ messages in thread
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2015-10-05 8:31 SWIOTLB on 32-bit PAE Christian Melki
[not found] ` <561254A7.4000805@t2data.com>
2015-10-05 14:21 ` Fwd: " Konrad Rzeszutek Wilk
2015-10-05 15:31 ` Christian Melki
2015-10-07 19:45 ` Konrad Rzeszutek Wilk
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