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    SubjectRe: [Fastboot] Stupid kexec/kdump question...
    On Tue, Sep 26, 2006 at 10:10:29PM -0700, Andrew Morton wrote:
    > On Tue, 26 Sep 2006 11:25:06 -0400
    > wrote:
    > > OK, I'm running a Fedora Core 6 (rawhide actually) box with -18-mm1 kernel.
    > > I've installed kexec-tools and similar, and am trying to get the kernels
    > > built following the hints in Documentation/kdump/kdump.txt, but a few
    > > questions arise:
    > >
    > > 1) Other than the fact that the Fedora userspace looks for a
    > > ${kernelvers}kdump kernel, is there any reason the kdump kernel has
    > > to match the running one, or can an older kernel be used?

    The post-crash kernel is not realy dependant on the pre-crash kernel.
    What is important is that either the kernel is relocatable
    (which is being worked on for x86 and i386), or it is compiled to
    run at a non-default address and that address corresponds
    to the region reserved by the crashkernel command line parameter
    passed to the pre-crash kernel.

    The post-crash kernel will also need CONFIG_CRASH_DUMP
    and likely CONFIG_PROC_VMCORE

    > > 2) I'm presuming that a massively stripped down kernel (no sound support,
    > > no netfilter, no etc) that just has what's needed to mount the dump location
    > > is sufficient?


    > > 3) The docs recommend 'crashkernel=64M@16M', but that's 8% of my memory.
    > > What will happen if I try '16M@16M' instead? Just slower copying due to
    > > a smaller buffer cache space, or something more evil?

    There is a lower bound to how small you can make the space, which
    is basically how little memory space your post-crash kernel needs.
    16M is probably pushing it, but 32M should be more than possible.
    Experimentation is really the order of the day here.


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      Last update: 2006-09-27 07:31    [W:0.020 / U:7.744 seconds]
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