cext: fix memory leak in phases computation
Without this a buffer whose size in bytes is the number of
changesets in the repository is leaked each time the repository is
opened and changeset phases are computed.
Impact: the current code in hgwebdir creates a new `localrepository`
instance for each HTTP request. Since any pull or push is made of several
requests, a team of 100 people can easily produce thousands of such
requests per day.
Being a low-level malloc, this leak can't be seen with the gc module and
tools relying on that, but was spotted by valgrind immediately.
Reproduction
------------
for i in range(cl_args.iterations):
repo = hg.repository(baseui, repo_path)
rev = repo.revs(rev).first()
ctx = repo[rev]
del ctx
del repo
# avoid any pollution by other type of leak
# (that should be fixed in 5.8)
repoview._filteredrepotypes.clear()
gc.collect()
Measurements
------------
Resident Set Size (RSS), taken on a clone of
mozilla-central for performance analysis (440 000
changesets).
before:
5.8+hg19.5ac0f2a8ba72 1000 iterations: 1606MB
5.8+hg19.5ac0f2a8ba72 10000 iterations: 5723MB
after:
5.8+hg20.e2084d39e145 1000 iterations: 555MB
5.8+hg20.e2084d39e145 10000 iterations: 555MB
(double checked, not a copy/paste error)
(e2084d39e14 is the present changeset, before amendment
of the message to add the measurements)
#!/bin/sh
#
# This is an example of using HGEDITOR to create of diff to review the
# changes while committing.
# If you want to pass your favourite editor some other parameters
# only for Mercurial, modify this:
case "${EDITOR}" in
"")
EDITOR="vi"
;;
emacs)
EDITOR="$EDITOR -nw"
;;
gvim|vim)
EDITOR="$EDITOR -f -o"
;;
esac
HGTMP=""
cleanup_exit() {
rm -rf "$HGTMP"
}
# Remove temporary files even if we get interrupted
trap "cleanup_exit" 0 # normal exit
trap "exit 255" HUP INT QUIT ABRT TERM
HGTMP=$(mktemp -d ${TMPDIR-/tmp}/hgeditor.XXXXXX)
[ x$HGTMP != x -a -d $HGTMP ] || {
echo "Could not create temporary directory! Exiting." 1>&2
exit 1
}
(
grep '^HG: changed' "$1" | cut -b 13- | while read changed; do
"$HG" diff "$changed" >> "$HGTMP/diff"
done
)
cat "$1" > "$HGTMP/msg"
MD5=$(which md5sum 2>/dev/null) || \
MD5=$(which md5 2>/dev/null)
[ -x "${MD5}" ] && CHECKSUM=`${MD5} "$HGTMP/msg"`
if [ -s "$HGTMP/diff" ]; then
$EDITOR "$HGTMP/msg" "$HGTMP/diff" || exit $?
else
$EDITOR "$HGTMP/msg" || exit $?
fi
[ -x "${MD5}" ] && (echo "$CHECKSUM" | ${MD5} -c >/dev/null 2>&1 && exit 13)
mv "$HGTMP/msg" "$1"
exit $?