linux-dev/tools/testing/selftests/rcutorture/configs, branch master

Merge branches 'docs.2022.04.20a', 'fixes.2022.04.20a', 'nocb.2022.04.11b', 'rcu-tasks.2022.04.11b', 'srcu.2022.05.03a', 'torture.2022.04.11b', 'torture-tasks.2022.04.20a' and 'torturescript.2022.04.20a' into HEAD

2022-05-03T17:21:40Z

docs.2022.04.20a: Documentation updates. fixes.2022.04.20a: Miscellaneous fixes. nocb.2022.04.11b: Callback-offloading updates. rcu-tasks.2022.04.11b: RCU-tasks updates. srcu.2022.05.03a: Put SRCU on a memory diet. torture.2022.04.11b: Torture-test updates. torture-tasks.2022.04.20a: Avoid torture testing changing RCU configuration. torturescript.2022.04.20a: Torture-test scripting updates.

scftorture: Remove extraneous "scf" from per_version_boot_params

2022-04-20T23:55:03Z

There is an extraneous "scf" in the per_version_boot_params shell function used by scftorture. No harm done in that it is just passed as an argument to the /init program in initrd, but this commit nevertheless removes it. Signed-off-by: Paul E. McKenney

rcutorture: Adjust scenarios' Kconfig options for CONFIG_PREEMPT_DYNAMIC

2022-04-20T23:55:03Z

Now that CONFIG_PREEMPT_DYNAMIC=y is the default, kernels that are ostensibly built with CONFIG_PREEMPT_NONE=y or CONFIG_PREEMPT_VOLUNTARY=y are now actually built with CONFIG_PREEMPT=y, but are by default booted so as to disable preemption. Although this allows much more flexibility from a single kernel binary, it means that the current rcutorture scenarios won't find build errors that happen only when preemption is fully disabled at build time. This commit therefore adds CONFIG_PREEMPT_DYNAMIC=n to several scenarios, and while in the area switches one from CONFIG_PREEMPT_NONE=y to CONFIG_PREEMPT_VOLUNTARY=y to add coverage of this Kconfig option. Signed-off-by: Paul E. McKenney

scftorture: Adjust for TASKS_RCU Kconfig option being selected

2022-04-20T23:53:19Z

This commit adjusts the scftorture PREEMPT and NOPREEMPT scenarios to account for the TASKS_RCU Kconfig option being explicitly selected rather than computed in isolation. Signed-off-by: Paul E. McKenney

rcuscale: Allow rcuscale without RCU Tasks Rude/Trace

2022-04-20T23:53:19Z

Currently, a CONFIG_PREEMPT_NONE=y kernel substitutes normal RCU for RCU Tasks Rude and RCU Tasks Trace. Unless that kernel builds rcuscale, whether built-in or as a module, in which case these RCU Tasks flavors are (unnecessarily) built in. This both increases kernel size and increases the complexity of certain tracing operations. This commit therefore decouples the presence of rcuscale from the presence of RCU Tasks Rude and RCU Tasks Trace. Signed-off-by: Paul E. McKenney

rcuscale: Allow rcuscale without RCU Tasks

2022-04-20T23:53:19Z

Currently, a CONFIG_PREEMPT_NONE=y kernel substitutes normal RCU for RCU Tasks. Unless that kernel builds rcuscale, whether built-in or as a module, in which case RCU Tasks is (unnecessarily) built. This both increases kernel size and increases the complexity of certain tracing operations. This commit therefore decouples the presence of rcuscale from the presence of RCU Tasks. Signed-off-by: Paul E. McKenney

refscale: Allow refscale without RCU Tasks Rude/Trace

2022-04-20T23:53:19Z

Currently, a CONFIG_PREEMPT_NONE=y kernel substitutes normal RCU for RCU Tasks Rude and RCU Tasks Trace. Unless that kernel builds refscale, whether built-in or as a module, in which case these RCU Tasks flavors are (unnecessarily) built in. This both increases kernel size and increases the complexity of certain tracing operations. This commit therefore decouples the presence of refscale from the presence of RCU Tasks Rude and RCU Tasks Trace. Signed-off-by: Paul E. McKenney

refscale: Allow refscale without RCU Tasks

2022-04-20T23:53:19Z

Currently, a CONFIG_PREEMPT_NONE=y kernel substitutes normal RCU for RCU Tasks. Unless that kernel builds refscale, whether built-in or as a module, in which case RCU Tasks is (unnecessarily) built in. This both increases kernel size and increases the complexity of certain tracing operations. This commit therefore decouples the presence of refscale from the presence of RCU Tasks. Signed-off-by: Paul E. McKenney

rcutorture: Allow specifying per-scenario stat_interval

2022-04-20T23:53:19Z

The rcutorture test suite makes double use of the rcutorture.stat_interval module parameter. As its name suggests, it controls the frequency of statistics printing, but it also controls the rcu_torture_writer() stall timeout. The current setting of 15 seconds works surprisingly well. However, given that the RCU tasks stall-warning timeout is ten -minutes-, 15 seconds is too short for TASKS02, which runs a non-preemptible kernel on a single CPU. This commit therefore adds checks for per-scenario specification of the rcutorture.stat_interval module parameter. Signed-off-by: Paul E. McKenney

rcutorture: Add CONFIG_PREEMPT_DYNAMIC=n to TASKS02 scenario

2022-04-20T23:53:19Z

Now that CONFIG_PREEMPT_DYNAMIC=y is the default, TASKS02 no longer builds a pure non-preemptible kernel that uses Tiny RCU. This commit therefore fixes this new hole in rcutorture testing by adding CONFIG_PREEMPT_DYNAMIC=n to the TASKS02 rcutorture scenario. Signed-off-by: Paul E. McKenney