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>

diff --git a/tools/testing/selftests/rcutorture/bin/torture.sh b/tools/testing/selftests/rcutorture/bin/torture.sh
index b376688..a0be345 100755 (executable)
--- 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