torture: Make the build machine control N in "make -jN"

Given remote rcutorture runs, it is quite possible that the build system
will have fewer CPUs than the system(s) running the actual test scenarios.
In such cases, using the number of CPUs on the test systems can overload
the build system, slowing down the build or, worse, OOMing the build
system.  This commit therefore uses the build system's CPU count to set
N in "make -jN", and by tradition sets "N" to double the CPU count.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/tools/testing/selftests/rcutorture/bin/kvm-build.sh b/tools/testing/selftests/rcutorture/bin/kvm-build.sh
index 115e1822b26f27301cfc5d2970fa42e682d7119d..55f4fc10262458867a3f35e2ca657f6c3b424e95 100755 (executable)
--- a/tools/testing/selftests/rcutorture/bin/kvm-build.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-build.sh
@@ -40,8 +40,10 @@ if test $retval -gt 1
 then
        exit 2
 fi
-ncpus=`cpus2use.sh`
-make -j$ncpus $TORTURE_KMAKE_ARG > $resdir/Make.out 2>&1
+
+# Tell "make" to use double the number of real CPUs on the build system.
+ncpus="`lscpu | grep '^CPU(' | awk '{ print $2 }'`"
+make -j$((2 * ncpus)) $TORTURE_KMAKE_ARG > $resdir/Make.out 2>&1
 retval=$?
 if test $retval -ne 0 || grep "rcu[^/]*": < $resdir/Make.out | egrep -q "Stop|Error|error:|warning:" || egrep -q "Stop|Error|error:" < $resdir/Make.out
 then