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Mel Gorman 608e8e66a1 mm: add a gfp-translate script to help understand page allocation failure reports

The page allocation failure messages include a line that looks like

page allocation failure. order:1, mode:0x4020

The mode is easy to translate but irritating for the lazy and a bit error
prone.  This patch adds a very simple helper script gfp-translate for the
mode: portion of the page allocation failure messages.  An example usage
looks like

  mel@machina:~/linux-2.6 $ scripts/gfp-translate 0x4020
  Source: /home/mel/linux-2.6
  Parsing: 0x4020
  #define __GFP_HIGH	(0x20)	/* Should access emergency pools? */
  #define __GFP_COMP	(0x4000) /* Add compound page metadata */

The script is not a work of art but it has come in handy for me a few
times so I thought I would share.

[akpm@linux-foundation.org: clarify an error message]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2009-06-16 19:47:44 -07:00

1.5 KiB

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#!/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

1.5 KiB Raw Blame History