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

From: WANG Chao
Date: Mon Mar 25 2013 - 23:57:03 EST


On 03/25/2013 07:52 PM, åæä 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@xxxxxxxxx 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@xxxxxxxxx>
>> > ---
>> > 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".
>> >
>> >
>>
>
>
>
>

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