kernel cmdline: Remove hugepage allocations

2nd kernel has very limited memory. Allocating huge pages will probably
trigger OOM. So let's remove hugepages and hugepagesz kernel parameters
for 2nd kernel when 1st kernel are using them.

If user wants huge pages cmdline in 2nd kernel, he/she can still specify
it through KERNEL_COMMANDLINE_APPEND in /etc/sysconfig/kdump.

This patch adds a new function remove_cmdline_param(). It takes a list
of kernel parameters as its arguments and remove them from given kernel
cmdline.

update:
1. Add description of remove_cmdline_param() per Vivek.
2. Remove_cmdline_param() will take kernel cmdline as $1, then strip it
   and print the result.

Signed-off-by: WANG Chao <chaowang@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>

kdumpctl

@@ -16,6 +16,23 @@ if [ -f /etc/sysconfig/kdump ]; then
 	. /etc/sysconfig/kdump
 fi
 
+# remove_cmdline_param <kernel cmdline> <param1> [<param2>] ... [<paramN>]
+# Remove a list of kernel parameters from a given kernel cmdline and print the result.
+# For each "arg" in the removing params list, "arg" and "arg=xxx" will be removed if exists.
+function remove_cmdline_param()
+{
+	local cmdline=$1
+	shift
+
+	for arg in $@; do
+		cmdline=`echo $cmdline | \
+			 sed -e "s/\b$arg=[^ ]*\b//g" \
+			     -e "s/\b$arg\b//g" \
+			     -e "s/\s\+/ /g"`
+	done
+	echo $cmdline
+}
+
 function save_core()
 {
 	coredir="/var/crash/`date +"%Y-%m-%d-%H:%M"`"
@@ -221,8 +238,8 @@ function load_kdump()
 	then
 		KDUMP_COMMANDLINE=`cat /proc/cmdline`
 	fi
+	KDUMP_COMMANDLINE=`remove_cmdline_param "$KDUMP_COMMANDLINE" crashkernel hugepages hugepagesz`
 
-	KDUMP_COMMANDLINE=`echo $KDUMP_COMMANDLINE | sed -e 's/crashkernel=[^ ]*//'`
 	KDUMP_COMMANDLINE="${KDUMP_COMMANDLINE} ${KDUMP_COMMANDLINE_APPEND}"
 
 	$KEXEC $KEXEC_ARGS $standard_kexec_args \