Merge tag 'core-rcu-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU updates from Ingo Molnar:

 - Support for "N" as alias for last bit in bitmap parsing library (eg
   using syntax like "nohz_full=2-N")

 - kvfree_rcu updates

 - mm_dump_obj() updates. (One of these is to mm, but was suggested by
   Andrew Morton.)

 - RCU callback offloading update

 - Polling RCU grace-period interfaces

 - Realtime-related RCU updates

 - Tasks-RCU updates

 - Torture-test updates

 - Torture-test scripting updates

 - Miscellaneous fixes

* tag 'core-rcu-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (77 commits)
  rcutorture: Test start_poll_synchronize_rcu() and poll_state_synchronize_rcu()
  rcu: Provide polling interfaces for Tiny RCU grace periods
  torture: Fix kvm.sh --datestamp regex check
  torture: Consolidate qemu-cmd duration editing into kvm-transform.sh
  torture: Print proper vmlinux path for kvm-again.sh runs
  torture: Make TORTURE_TRUST_MAKE available in kvm-again.sh environment
  torture: Make kvm-transform.sh update jitter commands
  torture: Add --duration argument to kvm-again.sh
  torture: Add kvm-again.sh to rerun a previous torture-test
  torture: Create a "batches" file for build reuse
  torture: De-capitalize TORTURE_SUITE
  torture: Make upper-case-only no-dot no-slash scenario names official
  torture: Rename SRCU-t and SRCU-u to avoid lowercase characters
  torture: Remove no-mpstat error message
  torture: Record kvm-test-1-run.sh and kvm-test-1-run-qemu.sh PIDs
  torture: Record jitter start/stop commands
  torture: Extract kvm-test-1-run-qemu.sh from kvm-test-1-run.sh
  torture: Record TORTURE_KCONFIG_GDB_ARG in qemu-cmd
  torture: Abstract jitter.sh start/stop into scripts
  rcu: Provide polling interfaces for Tree RCU grace periods
  ...

1 files changed, 37 insertions, 0 deletions

diff --git a/tools/testing/selftests/rcutorture/bin/jitterstart.sh b/tools/testing/selftests/rcutorture/bin/jitterstart.sh
new file mode 100644
index 000000000000..3d710ad291c3
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/bin/jitterstart.sh
@@ -0,0 +1,37 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Start up the specified number of jitter.sh scripts in the background.
+#
+# Usage: . jitterstart.sh n jittering-dir duration [ sleepmax [ spinmax ] ]
+#
+# n: Number of jitter.sh scripts to start up.
+# jittering-dir: Directory in which to put "jittering" file.
+# duration: Time to run in seconds.
+# sleepmax: Maximum microseconds to sleep, defaults to one second.
+# spinmax: Maximum microseconds to spin, defaults to one millisecond.
+#
+# Copyright (C) 2021 Facebook, Inc.
+#
+# Authors: Paul E. McKenney <paulmck@kernel.org>
+
+jitter_n=$1
+if test -z "$jitter_n"
+then
+	echo jitterstart.sh: Missing count of jitter.sh scripts to start.
+	exit 33
+fi
+jittering_dir=$2
+if test -z "$jittering_dir"
+then
+	echo jitterstart.sh: Missing directory in which to place jittering file.
+	exit 34
+fi
+shift
+shift
+
+touch ${jittering_dir}/jittering
+for ((jitter_i = 1; jitter_i <= $jitter_n; jitter_i++))
+do
+	jitter.sh $jitter_i "${jittering_dir}/jittering" "$@" &
+done