[PATCH 1/1 v1] the recommended crash memory reservation is too small for x86_64.

[PATCH 1/1 v1] the recommended crash memory reservation is too small for x86_64.

[zhouzhouyi]

From: root <root@zzy-Lenovo.(none)>


 On Documentation/kdump/kdump.txt, section Boot into  System Kernel: On x86 and x86_64, use
 "crashkernel=64M@16M", but some OSes like ubuntu 12.10 use ram fs larger than 64M, so in these cases the
 memory reserved for crashkernel should be at least 128M.


Signed-off-by: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
---
 Documentation/kdump/kdump.txt |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index 13f1aa0..1e850e0 100644
--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -290,7 +290,9 @@ Boot into System Kernel
    "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory
    starting at physical address 0x01000000 (16MB) for the dump-capture kernel.
 
-   On x86 and x86_64, use "crashkernel=64M@16M".
+   On x86 and x86_64, use "crashkernel=64M@16M" (some OSes use init ram fs larger
+than 64M, for example ubuntu-12.10, use crashkernel=128M@16M instead, or dump-capture
+kernel will out of memory).
 
    On ppc64, use "crashkernel=128M@32M".
 
-- 
1.7.10.4

Re: [PATCH 1/1 v1] the recommended crash memory reservation is too small for x86_64.

[WANG Chao]

On 03/25/2013 06:56 PM, zhouzhouyi@gmail.com wrote:
> From: root <root@zzy-Lenovo.(none)>
> 
> 
>  On Documentation/kdump/kdump.txt, section Boot into  System Kernel: On x86 and x86_64, use
>  "crashkernel=64M@16M", but some OSes like ubuntu 12.10 use ram fs larger than 64M, so in these cases the
>  memory reserved for crashkernel should be at least 128M.

People use different initramfs generators for different purpose. That means
the size of initramfs and also its memory consuming can vary very much from
each other. You just can't list all these generators and their recommended
reserved memory here. Though I have to say crashkernel=128M is good choice.

I think it would be better to leave this to user or distribution itself to
determine how much memory should be reserved for crash kernel, then export
this value to kernel in some ways.

Thanks,
WANG Chao

> 
> 
> Signed-off-by: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
> ---
>  Documentation/kdump/kdump.txt |    4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
> index 13f1aa0..1e850e0 100644
> --- a/Documentation/kdump/kdump.txt
> +++ b/Documentation/kdump/kdump.txt
> @@ -290,7 +290,9 @@ Boot into System Kernel
>     "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory
>     starting at physical address 0x01000000 (16MB) for the dump-capture kernel.
>  
> -   On x86 and x86_64, use "crashkernel=64M@16M".
> +   On x86 and x86_64, use "crashkernel=64M@16M" (some OSes use init ram fs larger
> +than 64M, for example ubuntu-12.10, use crashkernel=128M@16M instead, or dump-capture
> +kernel will out of memory).
>  
>     On ppc64, use "crashkernel=128M@32M".
>  
> 

Re: Re: [PATCH 1/1 v1] the recommended crash memory reservation is too small for x86_64.

[周洲仪]

Thanks for reviewing
  Is it sounds good to add following line into section "Boot into System Kernel":

  The memory reserved for crash kernel should be no less than the unpacked init ram disk size
that loaded with dump-capture kernel plus wired memory used by kernel itself.

  #################
  After all, I have been trapped into "hang after capture" problem when sticking strictly to this document.
Cheers
Zhouyi  

> 
> On 03/25/2013 06:56 PM, zhouzhouyi@gmail.com wrote:
> > From: root <root@zzy-Lenovo.(none)>
> > 
> > 
> >  On Documentation/kdump/kdump.txt, section Boot into  System Kernel: On x86 and x86_64, use
> >  "crashkernel=64M@16M", but some OSes like ubuntu 12.10 use ram fs larger than 64M, so in these cases the
> >  memory reserved for crashkernel should be at least 128M.
> 
> People use different initramfs generators for different purpose. That means
> the size of initramfs and also its memory consuming can vary very much from
> each other. You just can't list all these generators and their recommended
> reserved memory here. Though I have to say crashkernel=128M is good choice.
> 
> I think it would be better to leave this to user or distribution itself to
> determine how much memory should be reserved for crash kernel, then export
> this value to kernel in some ways.
> 
> Thanks,
> WANG Chao
> 
> > 
> > 
> > Signed-off-by: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
> > ---
> >  Documentation/kdump/kdump.txt |    4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
> > index 13f1aa0..1e850e0 100644
> > --- a/Documentation/kdump/kdump.txt
> > +++ b/Documentation/kdump/kdump.txt
> > @@ -290,7 +290,9 @@ Boot into System Kernel
> >     "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory
> >     starting at physical address 0x01000000 (16MB) for the dump-capture kernel.
> >  
> > -   On x86 and x86_64, use "crashkernel=64M@16M".
> > +   On x86 and x86_64, use "crashkernel=64M@16M" (some OSes use init ram fs larger
> > +than 64M, for example ubuntu-12.10, use crashkernel=128M@16M instead, or dump-capture
> > +kernel will out of memory).
> >  
> >     On ppc64, use "crashkernel=128M@32M".
> >  
> > 
> 

Re: [PATCH 1/1 v1] the recommended crash memory reservation is too small for x86_64.

[WANG Chao]

On 03/25/2013 07:52 PM, 周洲仪 wrote:
> Thanks for reviewing
>   Is it sounds good to add following line into section "Boot into System Kernel":
> 
>   The memory reserved for crash kernel should be no less than the unpacked init ram disk size
> that loaded with dump-capture kernel plus wired memory used by kernel itself.

Sorry, that is just basic knowledge for everyone.

> 
>   #################
>   After all, I have been trapped into "hang after capture" problem when sticking strictly to this document.
> Cheers
> Zhouyi  
> 
>>  
>>  On 03/25/2013 06:56 PM, zhouzhouyi@gmail.com wrote:
>>  > From: root <root@zzy-Lenovo.(none)>
>>  > 
>>  > 
>>  >  On Documentation/kdump/kdump.txt, section Boot into  System Kernel: On x86 and x86_64, use
>>  >  "crashkernel=64M@16M", but some OSes like ubuntu 12.10 use ram fs larger than 64M, so in these cases the
>>  >  memory reserved for crashkernel should be at least 128M.
>>  
>>  People use different initramfs generators for different purpose. That means
>>  the size of initramfs and also its memory consuming can vary very much from
>>  each other. You just can't list all these generators and their recommended
>>  reserved memory here. Though I have to say crashkernel=128M is good choice.
>>  
>>  I think it would be better to leave this to user or distribution itself to
>>  determine how much memory should be reserved for crash kernel, then export
>>  this value to kernel in some ways.
>>  
>>  Thanks,
>>  WANG Chao
>>  
>>  > 
>>  > 
>>  > Signed-off-by: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
>>  > ---
>>  >  Documentation/kdump/kdump.txt |    4 +++-
>>  >  1 file changed, 3 insertions(+), 1 deletion(-)
>>  > 
>>  > diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
>>  > index 13f1aa0..1e850e0 100644
>>  > --- a/Documentation/kdump/kdump.txt
>>  > +++ b/Documentation/kdump/kdump.txt
>>  > @@ -290,7 +290,9 @@ Boot into System Kernel
>>  >     "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory
>>  >     starting at physical address 0x01000000 (16MB) for the dump-capture kernel.
>>  >  
>>  > -   On x86 and x86_64, use "crashkernel=64M@16M".
>>  > +   On x86 and x86_64, use "crashkernel=64M@16M" (some OSes use init ram fs larger
>>  > +than 64M, for example ubuntu-12.10, use crashkernel=128M@16M instead, or dump-capture
>>  > +kernel will out of memory).
>>  >  
>>  >     On ppc64, use "crashkernel=128M@32M".
>>  >  
>>  > 
>>  
> 
> 
> 
> 

Re: [PATCH 1/1 v1] the recommended crash memory reservation is too small for x86_64.

[Simon Horman]

On Mon, Mar 25, 2013 at 06:56:49PM +0800, zhouzhouyi@gmail.com wrote:
> From: root <root@zzy-Lenovo.(none)>

The above line is bogus.

>  On Documentation/kdump/kdump.txt, section Boot into  System Kernel: On x86 and x86_64, use
>  "crashkernel=64M@16M", but some OSes like ubuntu 12.10 use ram fs larger than 64M, so in these cases the
>  memory reserved for crashkernel should be at least 128M.

The above lines are way to wide. Something less than 80 columns is normal.

> Signed-off-by: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
> ---
>  Documentation/kdump/kdump.txt |    4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
> index 13f1aa0..1e850e0 100644
> --- a/Documentation/kdump/kdump.txt
> +++ b/Documentation/kdump/kdump.txt
> @@ -290,7 +290,9 @@ Boot into System Kernel
>     "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory
>     starting at physical address 0x01000000 (16MB) for the dump-capture kernel.
>  
> -   On x86 and x86_64, use "crashkernel=64M@16M".
> +   On x86 and x86_64, use "crashkernel=64M@16M" (some OSes use init ram fs larger
> +than 64M, for example ubuntu-12.10, use crashkernel=128M@16M instead, or dump-capture
> +kernel will out of memory).

I believe lines of kdmump.txt should also be 80 columns wide or less.

>     On ppc64, use "crashkernel=128M@32M".
>  
> -- 
> 1.7.10.4
> 
> 
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