From cb0982e205e2368b5a5d148a6929fda735422727 Mon Sep 17 00:00:00 2001
From: "Paul E. McKenney" <paulmck@kernel.org>
Date: Tue, 30 Aug 2022 11:52:13 -0700
Subject: [PATCH] rcutorture: Avoid torture.sh compressing identical files

Currently, torture.sh will compress the vmlinux files for KASAN and
KCSAN runs.  But it will compress all of the files, including those
copied verbatim by the kvm-again.sh script.  Compression takes around ten
minutes, so this is not a good thing.  This commit therefore compresses
only one of a given set of identical vmlinux files, and then hard-links
it to the directories produced by kvm-again.sh.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 tools/testing/selftests/rcutorture/bin/torture.sh | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/rcutorture/bin/torture.sh b/tools/testing/selftests/rcutorture/bin/torture.sh
index b376688..a0be345 100755
--- a/tools/testing/selftests/rcutorture/bin/torture.sh
+++ b/tools/testing/selftests/rcutorture/bin/torture.sh
@@ -536,7 +536,10 @@ if test -n "$tdir" && test $compress_concurrency -gt 0
 then
 	# KASAN vmlinux files can approach 1GB in size, so compress them.
 	echo Looking for K[AC]SAN files to compress: `date` > "$tdir/log-xz" 2>&1
-	find "$tdir" -type d -name '*-k[ac]san' -print > $T/xz-todo
+	find "$tdir" -type d -name '*-k[ac]san' -print > $T/xz-todo-all
+	find "$tdir" -type f -name 're-run' -print | sed -e 's,/re-run,,' |
+		grep -e '-k[ac]san$' > $T/xz-todo-copy
+	sort $T/xz-todo-all $T/xz-todo-copy | uniq -u > $T/xz-todo
 	ncompresses=0
 	batchno=1
 	if test -s $T/xz-todo
@@ -568,6 +571,24 @@ then
 			echo Waiting for final batch $batchno of $ncompresses compressions `date` | tee -a "$tdir/log-xz" | tee -a $T/log
 		fi
 		wait
+		if test -s $T/xz-todo-copy
+		then
+			# The trick here is that we need corresponding
+			# vmlinux files from corresponding scenarios.
+			echo Linking vmlinux.xz files to re-use scenarios `date` | tee -a "$tdir/log-xz" | tee -a $T/log
+			dirstash="`pwd`"
+			for i in `cat $T/xz-todo-copy`
+			do
+				cd $i
+				find . -name vmlinux -print > $T/xz-todo-copy-vmlinux
+				for v in `cat $T/xz-todo-copy-vmlinux`
+				do
+					rm -f "$v"
+					cp -l `cat $i/re-run`/"$i/$v".xz "`dirname "$v"`"
+				done
+				cd "$dirstash"
+			done
+		fi
 		echo Size after compressing $n2compress files: `du -sh $tdir | awk '{ print $1 }'` `date` 2>&1 | tee -a "$tdir/log-xz" | tee -a $T/log
 		echo Total duration `get_starttime_duration $starttime`. | tee -a $T/log
 	else
-- 
2.7.4