[PATCHv3 0/9] Support Xen versions up to xen-4.1

[PATCHv3 0/9] Support Xen versions up to xen-4.1

[Petr Tesarik]

Hello everybody,

this is version 3 of my patch set. I'm very much indebted to Norbert
Trapp for his extensive testing of my previous patch set, which
revealed that Xen hypervisor static data was not kept with the previous
version of the patch set.

I could also add the performance improvements, but I'm afraid it would
make for an incremental patch, so let's wait until the filtering is
finally right.

I have re-tested this patch set with the same result as v2:

  - Xen-3.2.3 - WORKS
  - Xen-4.0.1 - WORKS (only with --xen-syms)
  - Xen-4.0.2 - WORKS
  - Xen-4.1.2 - WORKS

Filtering free pages (-d16 and above) doesn't work (even after I manually
provided the missing "max_pfn" symbol), but that seems unrelated, so I'm
going to address it in a subsequent patch set.

Norbert, if you test these patches, please send your comments to the
mailing list.

Atsushi-san, if the patch set passes Norbert's testing, what else do you
need to accept the changes in upstream?

Regards,
Petr Tesarik
SUSE Linux



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Re: [PATCHv3 0/9] Support Xen versions up to xen-4.1

[Atsushi Kumagai]

Hello Petr,

On Fri, 24 Aug 2012 17:41:27 +0200
Petr Tesařík <petr@tesarici.cz> wrote:

> Hello everybody,
> 
> this is version 3 of my patch set. I'm very much indebted to Norbert
> Trapp for his extensive testing of my previous patch set, which
> revealed that Xen hypervisor static data was not kept with the previous
> version of the patch set.

Thank you for your hard work, Petr and Norbert.

> 
> I could also add the performance improvements, but I'm afraid it would
> make for an incremental patch, so let's wait until the filtering is
> finally right.
> 
> I have re-tested this patch set with the same result as v2:
> 
>   - Xen-3.2.3 - WORKS
>   - Xen-4.0.1 - WORKS (only with --xen-syms)
>   - Xen-4.0.2 - WORKS
>   - Xen-4.1.2 - WORKS
> 
> Filtering free pages (-d16 and above) doesn't work (even after I manually
> provided the missing "max_pfn" symbol), but that seems unrelated, so I'm
> going to address it in a subsequent patch set.
> 
> Norbert, if you test these patches, please send your comments to the
> mailing list.
> 
> Atsushi-san, if the patch set passes Norbert's testing, what else do you
> need to accept the changes in upstream?

I'll review your v3 patch set as best I can.
If I can't see any problem, then I'll merge them into v1.5.1.
Now, I plan to release v1.5.1 before the end of September.


Thanks
Atsushi Kumagai

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Re: [PATCHv3 0/9] Support Xen versions up to xen-4.1

[Trapp, Norbert]

Hello Petr,

> -----Original Message-----
> From: Petr Tesarik [mailto:ptesarik@suse.cz]
> Sent: Friday, August 24, 2012 5:46 PM
> To: kexec@lists.infradead.org
> Cc: Trapp, Norbert
> Subject: [PATCHv3 0/9] Support Xen versions up to xen-4.1
> 
> Hello everybody,
> 
> this is version 3 of my patch set. I'm very much indebted to Norbert
> Trapp for his extensive testing of my previous patch set, which
> revealed that Xen hypervisor static data was not kept with the previous
> version of the patch set.

Thank you, Petr. I also admire your patches for all sorts of versions.

> 
> I could also add the performance improvements, but I'm afraid it would
> make for an incremental patch, so let's wait until the filtering is
> finally right.

Alright to abandon the performance improvements for the time being
but I would vote for adding the 1GB page recognition. That is:
...(pgd_entry & _PAGE_PSE)... in kvto_xen_x86_64. I think you would need
a huge amount of memory to recognize this problem.
  
With kind regards,
	Norbert Trapp


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Re: [PATCHv3 0/9] Support Xen versions up to xen-4.1

[Petr Tesarik]

Dne Po 27. srpna 2012 18:19:20 Trapp, Norbert napsal(a):
> Hello Petr,
> 
> > -----Original Message-----
> > From: Petr Tesarik [mailto:ptesarik@suse.cz]
> > Sent: Friday, August 24, 2012 5:46 PM
> > To: kexec@lists.infradead.org
> > Cc: Trapp, Norbert
> > Subject: [PATCHv3 0/9] Support Xen versions up to xen-4.1
> > 
> > Hello everybody,
> > 
> > this is version 3 of my patch set. I'm very much indebted to Norbert
> > Trapp for his extensive testing of my previous patch set, which
> > revealed that Xen hypervisor static data was not kept with the previous
> > version of the patch set.
> 
> Thank you, Petr. I also admire your patches for all sorts of versions.
> 
> > I could also add the performance improvements, but I'm afraid it would
> > make for an incremental patch, so let's wait until the filtering is
> > finally right.
> 
> Alright to abandon the performance improvements for the time being
> but I would vote for adding the 1GB page recognition. That is:
> ...(pgd_entry & _PAGE_PSE)... in kvto_xen_x86_64. I think you would need
> a huge amount of memory to recognize this problem.

It would still be good to get it into the next release. So, if we finally got 
everything right here, I'll be posting the improvements right away.

Petr Tesarik
SUSE Linux

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Re: [PATCHv3 0/9] Support Xen versions up to xen-4.1

[Petr Tesarik]

Dne Po 27. srpna 2012 18:19:20 Trapp, Norbert napsal(a):
>[...]
> > I could also add the performance improvements, but I'm afraid it would
> > make for an incremental patch, so let's wait until the filtering is
> > finally right.
> 
> Alright to abandon the performance improvements for the time being
> but I would vote for adding the 1GB page recognition. That is:
> ...(pgd_entry & _PAGE_PSE)... in kvto_xen_x86_64. I think you would need
> a huge amount of memory to recognize this problem.

Oh! I missed the part that adds support for 1G pages. This is not merely 
performance improvement, but a bugfix - the routine is not able to translate 
1G mappings without the change.

The thing with 1G pages is that they are not available on all platforms (AFAIK 
only AMD has them).

Anyway, it should be two patches, in fact. Please stay tuned.

Petr Tesarik
SUSE Linux

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[PATCHv3 0/9] Support Xen versions up to xen-4.1

[Petr Tesařík]

Hello everybody,

this is version 3 of my patch set. I'm very much indebted to Norbert
Trapp for his extensive testing of my previous patch set, which
revealed that Xen hypervisor static data was not kept with the previous
version of the patch set.

I could also add the performance improvements, but I'm afraid it would
make for an incremental patch, so let's wait until the filtering is
finally right.

I have re-tested this patch set with the same result as v2:

  - Xen-3.2.3 - WORKS
  - Xen-4.0.1 - WORKS (only with --xen-syms)
  - Xen-4.0.2 - WORKS
  - Xen-4.1.2 - WORKS

Filtering free pages (-d16 and above) doesn't work (even after I manually
provided the missing "max_pfn" symbol), but that seems unrelated, so I'm
going to address it in a subsequent patch set.

Norbert, if you test these patches, please send your comments to the
mailing list.

Atsushi-san, if the patch set passes Norbert's testing, what else do you
need to accept the changes in upstream?

Regards,
Petr Tesarik
SUSE Linux



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http://lists.infradead.org/mailman/listinfo/kexec

Re: [PATCHv3 0/9] Support Xen versions up to xen-4.1

[Trapp, Norbert]

> -----Original Message-----
> From: Petr Tesařík [mailto:petr@tesarici.cz]
> Sent: Friday, August 24, 2012 5:41 PM
> To: kexec@lists.infradead.org
> Cc: Trapp, Norbert
> Subject: [PATCHv3 0/9] Support Xen versions up to xen-4.1
> 
> Hello everybody,
> 
> this is version 3 of my patch set. I'm very much indebted to Norbert
> Trapp for his extensive testing of my previous patch set, which
> revealed that Xen hypervisor static data was not kept with the previous
> version of the patch set.
> 
> I could also add the performance improvements, but I'm afraid it would
> make for an incremental patch, so let's wait until the filtering is
> finally right.
> 
> I have re-tested this patch set with the same result as v2:
> 
>   - Xen-3.2.3 - WORKS
>   - Xen-4.0.1 - WORKS (only with --xen-syms)
>   - Xen-4.0.2 - WORKS
>   - Xen-4.1.2 - WORKS
> 
> Filtering free pages (-d16 and above) doesn't work (even after I manually
> provided the missing "max_pfn" symbol), but that seems unrelated, so I'm
> going to address it in a subsequent patch set.
> 
> Norbert, if you test these patches, please send your comments to the
> mailing list.

Hello Petr et al.,

after testing Petr's patches PATCHv3 plus "support for x86_64 1GB pages",
"add missing return statement" and "keep dumpfile pages in a cache" on a
machine with Xen 4.0.3 and 1GB pages there is only one comment I have:
It all worked nicely!

With kind regards,

	Norbert

Norbert Trapp
PBG PDG ES&S SWE OS 6

FUJITSU
Fujitsu Technology Solutions GmbH
Domagkstraße 28, D-80807 München, Germany
E-mail: Norbert.Trapp@ts.fujitsu.com
Web: ts.fujitsu.com
Company details: ts.fujitsu.com/imprint
 
> Atsushi-san, if the patch set passes Norbert's testing, what else do you
> need to accept the changes in upstream?
> 
> Regards,
> Petr Tesarik
> SUSE Linux
> 


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Re: [PATCHv3 0/9] Support Xen versions up to xen-4.1

[Atsushi Kumagai]

Hello Norbert and Petr,

On Fri, 31 Aug 2012 17:05:01 +0200
"Trapp, Norbert" <norbert.trapp@ts.fujitsu.com> wrote:

> 
> > -----Original Message-----
> > From: Petr Tesařík [mailto:petr@tesarici.cz]
> > Sent: Friday, August 24, 2012 5:41 PM
> > To: kexec@lists.infradead.org
> > Cc: Trapp, Norbert
> > Subject: [PATCHv3 0/9] Support Xen versions up to xen-4.1
> > 
> > Hello everybody,
> > 
> > this is version 3 of my patch set. I'm very much indebted to Norbert
> > Trapp for his extensive testing of my previous patch set, which
> > revealed that Xen hypervisor static data was not kept with the previous
> > version of the patch set.
> > 
> > I could also add the performance improvements, but I'm afraid it would
> > make for an incremental patch, so let's wait until the filtering is
> > finally right.
> > 
> > I have re-tested this patch set with the same result as v2:
> > 
> >   - Xen-3.2.3 - WORKS
> >   - Xen-4.0.1 - WORKS (only with --xen-syms)
> >   - Xen-4.0.2 - WORKS
> >   - Xen-4.1.2 - WORKS
> > 
> > Filtering free pages (-d16 and above) doesn't work (even after I manually
> > provided the missing "max_pfn" symbol), but that seems unrelated, so I'm
> > going to address it in a subsequent patch set.
> > 
> > Norbert, if you test these patches, please send your comments to the
> > mailing list.
> 
> Hello Petr et al.,
> 
> after testing Petr's patches PATCHv3 plus "support for x86_64 1GB pages",
> "add missing return statement" and "keep dumpfile pages in a cache" on a
> machine with Xen 4.0.3 and 1GB pages there is only one comment I have:
> It all worked nicely!

Thank you for your report, that's good.
So, I'll review these patches for makedumpfile-1.5.1.


Thanks
Atsushi Kumagai

> With kind regards,
> 
> 	Norbert
> 
> Norbert Trapp
> PBG PDG ES&S SWE OS 6
> 
> FUJITSU
> Fujitsu Technology Solutions GmbH
> Domagkstraße 28, D-80807 München, Germany
> E-mail: Norbert.Trapp@ts.fujitsu.com
> Web: ts.fujitsu.com
> Company details: ts.fujitsu.com/imprint
>  
> > Atsushi-san, if the patch set passes Norbert's testing, what else do you
> > need to accept the changes in upstream?
> > 
> > Regards,
> > Petr Tesarik
> > SUSE Linux
> > 
> 
> 
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec

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Re: [PATCHv3 0/9] Support Xen versions up to xen-4.1

[Trapp, Norbert]

Hello Atsushi, Petr, Stefan et al.,

When applying the makedumpfile Xen4 patches to the makedumpfile 1.5.0
version and using it for a crash file to save just the dom0 and xen pages
it again worked splendid in that makedumpfile was much faster than without
the Xen4 patches. Alas I had to remove the OFFSET_IN_UNION_INIT(page._domain,
"page_info", "domain") call because OFFSET_IN_UNION_INIT was no longer present.
It didn't matter much because the call is only needed for makedumpfile -g or when
using the /boot/xen-syms file. In the current 1.5.0  makedumpfile.c version you
see

    OFFSET_INIT(page_info._domain, "page_info", "u").

The Xen4 patch modified this because the _domain structure member is in different
unions for different version (x86, ia64) and may also not be the first entry in
the union depending on the Xen version.

    OFFSET_IN_UNION_INIT(page_info._domain, "page_info", "_domain");

As an experiment I tried to use

    OFFSET_INIT(page_info._domain, "page_info", "domain")

with makedumpfile 1.5.0. To get the correct offset I had to
modify the dwarf_info.c code:

--- ../makedumpfile-1.5.0/dwarf_info.c  2012-09-06 07:30:23.000000000 +0200
+++ dwarf_info.c        2012-09-12 15:49:23.000000000 +0200
@@ -449,8 +449,8 @@
 static int
 is_anonymous_container(Dwarf_Die *die)
 {
-       if (dwarf_diename(die))
-               return FALSE;
+       //if (dwarf_diename(die))
+       //      return FALSE;
        if (dwarf_tag(die) == DW_TAG_structure_type)
                return TRUE;
        if (dwarf_info.cmd != DWARF_INFO_GET_MEMBER_OFFSET_1ST_UNION
@@ -495,7 +495,7 @@
                 * Descend into anonymous members and search for member
                 * there.
                 */
-               if (!name) {
+               if ((!name) || (strcmp(name, dwarf_info.member_name) != 0)) {
                        if (!get_die_type(walker, &die_type))
                                continue;
                        if (is_anonymous_container(&die_type))


This is not a patch but just a description of what I modified for a test.
The underlying question is why only the anonymous unions are used and not the
ones with a name.

With kind regards

	Norbert

Norbert Trapp
PDG ES&S SWE OS 6

FUJITSU
Fujitsu Technology Solutions GmbH
Domagkstraße 28, D-80807 München, Germany
E-mail: Norbert.Trapp at ts.fujitsu.com
Web: ts.fujitsu.com
Company details: ts.fujitsu.com/imprint

> -----Original Message-----
> From: Atsushi Kumagai [mailto:kumagai-atsushi@mxc.nes.nec.co.jp]
> Sent: Monday, September 03, 2012 7:01 AM
> To: Trapp, Norbert; petr@tesarici.cz
> Cc: kexec@lists.infradead.org
> Subject: Re: [PATCHv3 0/9] Support Xen versions up to xen-4.1
> 
...
> 
> Thank you for your report, that's good.
> So, I'll review these patches for makedumpfile-1.5.1.
> 
> 
> Thanks
> Atsushi Kumagai

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Re: [PATCHv3 0/9] Support Xen versions up to xen-4.1

[Stefan Bader]

[-- Attachment #1.1: Type: text/plain, Size: 3615 bytes --]

On 12.09.2012 16:39, Trapp, Norbert wrote:
> Hello Atsushi, Petr, Stefan et al.,
> 

Hi Norbert,

> When applying the makedumpfile Xen4 patches to the makedumpfile 1.5.0
> version and using it for a crash file to save just the dom0 and xen pages
> it again worked splendid in that makedumpfile was much faster than without
> the Xen4 patches. Alas I had to remove the OFFSET_IN_UNION_INIT(page._domain,
> "page_info", "domain") call because OFFSET_IN_UNION_INIT was no longer present.
> It didn't matter much because the call is only needed for makedumpfile -g or when
> using the /boot/xen-syms file. In the current 1.5.0  makedumpfile.c version you
> see
> 
>     OFFSET_INIT(page_info._domain, "page_info", "u").
> 
> The Xen4 patch modified this because the _domain structure member is in different
> unions for different version (x86, ia64) and may also not be the first entry in
> the union depending on the Xen version.
> 
>     OFFSET_IN_UNION_INIT(page_info._domain, "page_info", "_domain");
> 
> As an experiment I tried to use
> 

>     OFFSET_INIT(page_info._domain, "page_info", "domain")

Just to make sure and since I am a bit lazy: with the Xen patch the page_info
structure has a member (somewhere) named domain? (or _domain)?

> 
> with makedumpfile 1.5.0. To get the correct offset I had to
> modify the dwarf_info.c code:
> 
> --- ../makedumpfile-1.5.0/dwarf_info.c  2012-09-06 07:30:23.000000000 +0200
> +++ dwarf_info.c        2012-09-12 15:49:23.000000000 +0200
> @@ -449,8 +449,8 @@
>  static int
>  is_anonymous_container(Dwarf_Die *die)
>  {
> -       if (dwarf_diename(die))
> -               return FALSE;
> +       //if (dwarf_diename(die))
> +       //      return FALSE;
>         if (dwarf_tag(die) == DW_TAG_structure_type)
>                 return TRUE;
>         if (dwarf_info.cmd != DWARF_INFO_GET_MEMBER_OFFSET_1ST_UNION
> @@ -495,7 +495,7 @@
>                  * Descend into anonymous members and search for member
>                  * there.
>                  */
> -               if (!name) {
> +               if ((!name) || (strcmp(name, dwarf_info.member_name) != 0)) {
>                         if (!get_die_type(walker, &die_type))
>                                 continue;
>                         if (is_anonymous_container(&die_type))
> 
> 
> This is not a patch but just a description of what I modified for a test.
> The underlying question is why only the anonymous unions are used and not the
> ones with a name.

I made the patch because one element in some anonymous structure/union combo was
not found in newer kernels and the previous exceptions for such a thing were
hard coded. But as far as the dwarf info I was looking at the named
structures/unions were handled and I did not want to modify that case without a
way to test.

-Stefan
> 
> With kind regards
> 
> 	Norbert
> 
> Norbert Trapp
> PDG ES&S SWE OS 6
> 
> FUJITSU
> Fujitsu Technology Solutions GmbH
> Domagkstraße 28, D-80807 München, Germany
> E-mail: Norbert.Trapp at ts.fujitsu.com
> Web: ts.fujitsu.com
> Company details: ts.fujitsu.com/imprint
> 
>> -----Original Message-----
>> From: Atsushi Kumagai [mailto:kumagai-atsushi@mxc.nes.nec.co.jp]
>> Sent: Monday, September 03, 2012 7:01 AM
>> To: Trapp, Norbert; petr@tesarici.cz
>> Cc: kexec@lists.infradead.org
>> Subject: Re: [PATCHv3 0/9] Support Xen versions up to xen-4.1
>>
> ...
>>
>> Thank you for your report, that's good.
>> So, I'll review these patches for makedumpfile-1.5.1.
>>
>>
>> Thanks
>> Atsushi Kumagai
> 



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[-- Attachment #2: Type: text/plain, Size: 143 bytes --]

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Re: [PATCHv3 0/9] Support Xen versions up to xen-4.1

[Trapp, Norbert]

Hello Stefan,

> -----Original Message-----
> From: Stefan Bader [mailto:stefan.bader@canonical.com]
> Sent: Monday, September 17, 2012 2:38 PM
> To: Trapp, Norbert
> Cc: Atsushi Kumagai; petr@tesarici.cz; kexec@lists.infradead.org
> Subject: Re: [PATCHv3 0/9] Support Xen versions up to xen-4.1
> 
> On 12.09.2012 16:39, Trapp, Norbert wrote:
> > Hello Atsushi, Petr, Stefan et al.,
> >
> 
> Hi Norbert,
> 
> > When applying the makedumpfile Xen4 patches to the makedumpfile 1.5.0
> > version and using it for a crash file to save just the dom0 and xen pages
> > it again worked splendid in that makedumpfile was much faster than without
> > the Xen4 patches. Alas I had to remove the OFFSET_IN_UNION_INIT(page._domain,
> > "page_info", "domain") call because OFFSET_IN_UNION_INIT was no longer present.
> > It didn't matter much because the call is only needed for makedumpfile -g or when
> > using the /boot/xen-syms file. In the current 1.5.0  makedumpfile.c version you
> > see
> >
> >     OFFSET_INIT(page_info._domain, "page_info", "u").
> >
> > The Xen4 patch modified this because the _domain structure member is in different
> > unions for different version (x86, ia64) and may also not be the first entry in
> > the union depending on the Xen version.
> >
> >     OFFSET_IN_UNION_INIT(page_info._domain, "page_info", "_domain");
> >
> > As an experiment I tried to use
> >
> 
> >     OFFSET_INIT(page_info._domain, "page_info", "domain")
> 
> Just to make sure and since I am a bit lazy: with the Xen patch the page_info
> structure has a member (somewhere) named domain? (or _domain)?
> 

Just to get you on the right track, the struct page_info in the Xen code is meant.
Not the one in the makedumpfile code.

For example in xen-4.1.3/xen/common/kexec.c:
#ifdef __ia64__
    VMCOREINFO_OFFSET_SUB(page_info, u.inuse, _domain);
#else
    VMCOREINFO_OFFSET_SUB(page_info, v.inuse, _domain);
#endif

And the different page_info structures you find in:
xen-4.1.3/xen/include/asm-ia64/mm.h
xen-4.1.3/xen/include/asm-x86/mm.h

And also the structures can be different depending on the Xen version.

> >
> > with makedumpfile 1.5.0. To get the correct offset I had to
> > modify the dwarf_info.c code:
> >
> > --- ../makedumpfile-1.5.0/dwarf_info.c  2012-09-06 07:30:23.000000000 +0200
> > +++ dwarf_info.c        2012-09-12 15:49:23.000000000 +0200
> > @@ -449,8 +449,8 @@
> >  static int
> >  is_anonymous_container(Dwarf_Die *die)
> >  {
> > -       if (dwarf_diename(die))
> > -               return FALSE;
> > +       //if (dwarf_diename(die))
> > +       //      return FALSE;
> >         if (dwarf_tag(die) == DW_TAG_structure_type)
> >                 return TRUE;
> >         if (dwarf_info.cmd != DWARF_INFO_GET_MEMBER_OFFSET_1ST_UNION
> > @@ -495,7 +495,7 @@
> >                  * Descend into anonymous members and search for member
> >                  * there.
> >                  */
> > -               if (!name) {
> > +               if ((!name) || (strcmp(name, dwarf_info.member_name) != 0)) {
> >                         if (!get_die_type(walker, &die_type))
> >                                 continue;
> >                         if (is_anonymous_container(&die_type))
> >
> >
> > This is not a patch but just a description of what I modified for a test.
> > The underlying question is why only the anonymous unions are used and not the
> > ones with a name.
> 
> I made the patch because one element in some anonymous structure/union combo was
> not found in newer kernels and the previous exceptions for such a thing were
> hard coded. But as far as the dwarf info I was looking at the named
> structures/unions were handled and I did not want to modify that case without a
> way to test.
> 
> -Stefan

With kind regards

	Norbert

Norbert Trapp
PBG PDG ES&S SWE OS 6

FUJITSU
Fujitsu Technology Solutions GmbH
Domagkstraße 28, D-80807 München, Germany
E-mail: Norbert.Trapp@ts.fujitsu.com
Web: ts.fujitsu.com
Company details: ts.fujitsu.com/imprint


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Re: [PATCHv3 0/9] Support Xen versions up to xen-4.1

[Atsushi Kumagai]

Hello Norbert,

On Mon, 17 Sep 2012 18:52:57 +0200
"Trapp, Norbert" <norbert.trapp@ts.fujitsu.com> wrote:

> > Hi Norbert,
> > 
> > > When applying the makedumpfile Xen4 patches to the makedumpfile 1.5.0
> > > version and using it for a crash file to save just the dom0 and xen pages
> > > it again worked splendid in that makedumpfile was much faster than without
> > > the Xen4 patches. Alas I had to remove the OFFSET_IN_UNION_INIT(page._domain,
> > > "page_info", "domain") call because OFFSET_IN_UNION_INIT was no longer present.
> > > It didn't matter much because the call is only needed for makedumpfile -g or when
> > > using the /boot/xen-syms file. In the current 1.5.0  makedumpfile.c version you
> > > see
> > >
> > >     OFFSET_INIT(page_info._domain, "page_info", "u").
> > >
> > > The Xen4 patch modified this because the _domain structure member is in different
> > > unions for different version (x86, ia64) and may also not be the first entry in
> > > the union depending on the Xen version.
> > >
> > >     OFFSET_IN_UNION_INIT(page_info._domain, "page_info", "_domain");
> > >
> > > As an experiment I tried to use
> > >
> > 
> > >     OFFSET_INIT(page_info._domain, "page_info", "domain")

Sorry for my carelessness.
However, I still think that to integrate OFFSET_IN_UNION_INIT into OFFSET_INIT
is reasonable. So, please use OFFSET_INIT in v1.5.0 or later.

> > 
> > Just to make sure and since I am a bit lazy: with the Xen patch the page_info
> > structure has a member (somewhere) named domain? (or _domain)?
> > 
> 
> Just to get you on the right track, the struct page_info in the Xen code is meant.
> Not the one in the makedumpfile code.
> 
> For example in xen-4.1.3/xen/common/kexec.c:
> #ifdef __ia64__
>     VMCOREINFO_OFFSET_SUB(page_info, u.inuse, _domain);
> #else
>     VMCOREINFO_OFFSET_SUB(page_info, v.inuse, _domain);
> #endif
> 
> And the different page_info structures you find in:
> xen-4.1.3/xen/include/asm-ia64/mm.h
> xen-4.1.3/xen/include/asm-x86/mm.h
> 
> And also the structures can be different depending on the Xen version.
> 
> > >
> > > with makedumpfile 1.5.0. To get the correct offset I had to
> > > modify the dwarf_info.c code:
> > >
> > > --- ../makedumpfile-1.5.0/dwarf_info.c  2012-09-06 07:30:23.000000000 +0200
> > > +++ dwarf_info.c        2012-09-12 15:49:23.000000000 +0200
> > > @@ -449,8 +449,8 @@
> > >  static int
> > >  is_anonymous_container(Dwarf_Die *die)
> > >  {
> > > -       if (dwarf_diename(die))
> > > -               return FALSE;
> > > +       //if (dwarf_diename(die))
> > > +       //      return FALSE;
> > >         if (dwarf_tag(die) == DW_TAG_structure_type)
> > >                 return TRUE;
> > >         if (dwarf_info.cmd != DWARF_INFO_GET_MEMBER_OFFSET_1ST_UNION
> > > @@ -495,7 +495,7 @@
> > >                  * Descend into anonymous members and search for member
> > >                  * there.
> > >                  */
> > > -               if (!name) {
> > > +               if ((!name) || (strcmp(name, dwarf_info.member_name) != 0)) {
> > >                         if (!get_die_type(walker, &die_type))
> > >                                 continue;
> > >                         if (is_anonymous_container(&die_type))
> > >
> > >
> > > This is not a patch but just a description of what I modified for a test.
> > > The underlying question is why only the anonymous unions are used and not the
> > > ones with a name.
> > 
> > I made the patch because one element in some anonymous structure/union combo was
> > not found in newer kernels and the previous exceptions for such a thing were
> > hard coded. But as far as the dwarf info I was looking at the named
> > structures/unions were handled and I did not want to modify that case without a
> > way to test.

As for getting the offset, it is necessary to descend into structures/unions even
which are named.
So, I'll modify dwarf_info.c as below in the next version.


diff --git a/dwarf_info.c b/dwarf_info.c
index fb11e49..0c18dd1 100644
--- a/dwarf_info.c
+++ b/dwarf_info.c
@@ -447,10 +447,8 @@ get_dwarf_base_type(Dwarf_Die *die)
 }

 static int
-is_anonymous_container(Dwarf_Die *die)
+is_container(Dwarf_Die *die)
 {
-       if (dwarf_diename(die))
-               return FALSE;
        if (dwarf_tag(die) == DW_TAG_structure_type)
                return TRUE;
        if (dwarf_info.cmd != DWARF_INFO_GET_MEMBER_OFFSET_1ST_UNION
@@ -492,13 +490,13 @@ search_member(Dwarf_Die *die)
                        continue;

                /*
-                * Descend into anonymous members and search for member
+                * Descend into structures/unions and search for member
                 * there.
                 */
-               if (!name) {
+               if ((!name) || (strcmp(name, dwarf_info.member_name) != 0)) {
                        if (!get_die_type(walker, &die_type))
                                continue;
-                       if (is_anonymous_container(&die_type))
+                       if (is_container(&die_type))
                                if (search_member(&die_type)) {
                                        adjust_member_offset(walker);
                                        return TRUE;
@@ -1047,9 +1045,13 @@ get_member_offset(char *structname, char *membername, int cmd)
        dwarf_info.cmd = cmd;
        dwarf_info.struct_name = structname;
        dwarf_info.struct_size = NOT_FOUND_STRUCTURE;
-       dwarf_info.member_name = membername;
        dwarf_info.member_offset = NOT_FOUND_STRUCTURE;

+       if (dwarf_info.cmd == DWARF_INFO_GET_MEMBER_OFFSET_1ST_UNION)
+               dwarf_info.member_name = "";
+       else
+               dwarf_info.member_name = membername;
+
        if (!get_debug_info())
                return FAILED_DWARFINFO;

Thanks
Atsushi Kumagai

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