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>
diff --git a/scripts/gfp-translate b/scripts/gfp-translate
new file mode 100644
index 0000000..073cb6d
--- /dev/null
+++ b/scripts/gfp-translate
@@ -0,0 +1,81 @@
+#!/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