support for crashkernel= in 10_linux.in

[Michael Vogt <mvo@ubuntu.com>]

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Hello,

in ubuntu we are working on making it easier to capture kernel
crashes. The system we use is based around kdump and it works by
triggering a kexec of a special crashdump kernel if the regular
kernels crashes. In order for this to work the normal kernel needs a
additional commandline option "crashkernel=".

Attached is a very simple patch that adds this option automatically if
kexec and makedumpfile are available.

If its not general enough for inclusion into the default grub2, may a
mechanism to pass additional kernel commandline paramters via some
sort of defaults.d/ directory would be the right apporoach? Then I
could just ship a config file in kexec-tools that looks like this:

GRUB_LINUX_CMDLINE_EXTRA="$GRUB_LINUX_CMDLINE_EXTRA crashkernel=384M-2G:64M,2G-:128M"


Thanks,
 Michael

P.S. I also put the patch in the bugtracker at
https://savannah.gnu.org/bugs/?26874

[-- Attachment #2: 10_crashkernel.patch --]
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diff -Nur -x '*.orig' -x '*~' grub2-1.96+20090611/util/grub.d/10_linux.in grub2-1.96+20090611.new/util/grub.d/10_linux.in
--- grub2-1.96+20090611/util/grub.d/10_linux.in	2009-06-24 10:17:45.202761012 +0200
+++ grub2-1.96+20090611.new/util/grub.d/10_linux.in	2009-06-24 10:19:11.198757708 +0200
@@ -43,6 +43,11 @@
   LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}
 fi
 
+# add crashkernel option if we have the requierd tools
+if [ -x "/usr/bin/makedumpfile" ] && [ -x "/sbin/kexec" ]; then
+    GRUB_CMDLINE_EXTRA="$GRUB_CMDLINE_EXTRA crashkernel=384M-2G:64M,2G-:128M"
+fi
+
 test_numeric ()
 {
   local a=$1
@@ -143,7 +148,7 @@
   fi
 
   linux_entry "${OS}, Linux ${version}" \
-      "${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT}"
+      "${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT} ${GRUB_CMDLINE_EXTRA}"
   linux_entry "${OS}, Linux ${version} (recovery mode)" \
       "single ${GRUB_CMDLINE_LINUX}"