From 3b253ad6890af0fda91fed8b67ad0805b6ff1a3d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Mon, 11 Jun 2018 15:58:09 +0200
Subject: [PATCH] cocinelle: use GNU parallel to run spatch

spatch is single-threaded, i.e. slow. On my machine it allocates 5 GB of memory
and starts swapping, which makes it even slower. Using parallel makes the whole
thing pleasantly fast.
---
 coccinelle/run-coccinelle.sh | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/coccinelle/run-coccinelle.sh b/coccinelle/run-coccinelle.sh
index a18da58a3e..22ab66d3dd 100755
--- a/coccinelle/run-coccinelle.sh
+++ b/coccinelle/run-coccinelle.sh
@@ -11,11 +11,17 @@ case "$1" in
                 ;;
 esac
 
+if ! parallel -h >/dev/null; then
+        echo 'Please install GNU parallel (package "parallel")'
+        exit 1
+fi
+
 for SCRIPT in ${@-$top/coccinelle/*.cocci} ; do
         echo "--x-- Processing $SCRIPT --x--"
         TMPFILE=`mktemp`
         echo "+ spatch --sp-file $SCRIPT $args ..."
-        spatch --sp-file $SCRIPT $args $files 2>"$TMPFILE" || cat "$TMPFILE"
-        rm "$TMPFILE"
+        parallel --halt now,fail=1 --keep-order --noswap --max-args=20 \
+                 spatch --sp-file $SCRIPT $args ::: $files \
+                 2>"$TMPFILE" || cat "$TMPFILE"
         echo -e "--x-- Processed $SCRIPT --x--\n"
 done