mm: add a gfp-translate script to help understand page allocation failure reports

#!/bin/bash

# Translate the bits making up a GFP mask

# (c) 2009, Mel Gorman <mel@csn.ul.ie>

# Licensed under the terms of the GNU GPL License version 2

SOURCE=

GFPMASK=none

# Helper function to report failures and exit

die() {

	echo ERROR: $@

	if [ "$TMPFILE" != "" ]; then

		rm -f $TMPFILE

	fi

	exit -1

}

usage() {

	echo "usage: gfp-translate [-h] [ --source DIRECTORY ] gfpmask"

	exit 0

}

# Parse command-line arguements

while [ $# -gt 0 ]; do

	case $1 in

		--source)

			SOURCE=$2

			shift 2

			;;

		-h)

			usage

			;;

		--help)

			usage

			;;

		*)

			GFPMASK=$1

			shift

			;;

	esac

done

# Guess the kernel source directory if it's not set. Preference is in order of

# o current directory

# o /usr/src/linux

if [ "$SOURCE" = "" ]; then

	if [ -r "/usr/src/linux/Makefile" ]; then

		SOURCE=/usr/src/linux

	fi

	if [ -r "`pwd`/Makefile" ]; then

		SOURCE=`pwd`

	fi

fi

# Confirm that a source directory exists

if [ ! -r "$SOURCE/Makefile" ]; then

	die "Could not locate kernel source directory or it is invalid"

fi

# Confirm that a GFP mask has been specified

if [ "$GFPMASK" = "none" ]; then

	usage

fi

# Extract GFP flags from the kernel source

TMPFILE=`mktemp -t gfptranslate-XXXXXX` || exit 1

grep "^#define __GFP" $SOURCE/include/linux/gfp.h | sed -e 's/(__force gfp_t)//' | sed -e 's/u)/)/' | grep -v GFP_BITS | sed -e 's/)\//) \//' > $TMPFILE

# Parse the flags

IFS="

"

echo Source: $SOURCE

echo Parsing: $GFPMASK

for LINE in `cat $TMPFILE`; do

	MASK=`echo $LINE | awk '{print $3}'`

	if [ $(($GFPMASK&$MASK)) -ne 0 ]; then

		echo $LINE

	fi

done

rm -f $TMPFILE

exit 0