rcutorture: Adjust scenarios' Kconfig options for CONFIG_PREEMPT_DYNAMIC

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 <paulmck@kernel.org>

torture: Remove RCU_FAST_NO_HZ from rcu scenarios

All of the rcu scenarios that mentioning CONFIG_RCU_FAST_NO_HZ disable it.
But this Kconfig option is disabled by default, so this commit removes
the pointless "CONFIG_RCU_FAST_NO_HZ=n" lines from these scenarios.

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

sched/isolation: Eliminate NO_HZ_FULL_ALL

Commit 6f1982fedd59 ("sched/isolation: Handle the nohz_full= parameter")
broke CONFIG_NO_HZ_FULL_ALL=y kernels. This breakage is due to the code
under CONFIG_NO_HZ_FULL_ALL failing to invoke the shiny new housekeeping
functions. This means that rcutorture scenario TREE04 now emits RCU CPU
stall warnings due to the RCU grace-period kthreads not being awakened
at a time of their choosing, or perhaps even not at all:

[ 27.731422] rcu_bh kthread starved for 21001 jiffies! g18446744073709551369 c18446744073709551368 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x402 ->cpu=3
[ 27.731423] rcu_bh I14936 9 2 0x80080000
[ 27.731435] Call Trace:
[ 27.731440] __schedule+0x31a/0x6d0
[ 27.731442] schedule+0x31/0x80
[ 27.731446] schedule_timeout+0x15a/0x320
[ 27.731453] ? call_timer_fn+0x130/0x130
[ 27.731457] rcu_gp_kthread+0x66c/0xea0
[ 27.731458] ? rcu_gp_kthread+0x66c/0xea0

Because no one has complained about CONFIG_NO_HZ_FULL_ALL=y being broken,
I hypothesize that no one is in fact using it, other than rcutorture.
This commit therefore eliminates CONFIG_NO_HZ_FULL_ALL and updates
rcutorture's config files to instead use the nohz_full= kernel parameter
to put the desired CPUs into nohz_full mode.

Fixes: 6f1982fedd59 ("sched/isolation: Handle the nohz_full= parameter")

Reported-by: kernel test robot <xiaolong.ye@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wanpeng Li <kernellwp@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Jonathan Corbet <corbet@lwn.net>

rcu: Remove nohz_full full-system-idle state machine

The NO_HZ_FULL_SYSIDLE full-system-idle capability was added in 2013
by commit 0edd1b1784cb ("nohz_full: Add full-system-idle state machine"),
but has not been used. This commit therefore removes it.

If it turns out to be needed later, this commit can always be reverted.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>

rcu: Remove *_SLOW_* Kconfig options

The RCU_TORTURE_TEST_SLOW_PREINIT, RCU_TORTURE_TEST_SLOW_PREINIT_DELAY,
RCU_TORTURE_TEST_SLOW_PREINIT_DELAY, RCU_TORTURE_TEST_SLOW_INIT,
RCU_TORTURE_TEST_SLOW_INIT_DELAY, RCU_TORTURE_TEST_SLOW_CLEANUP,
and RCU_TORTURE_TEST_SLOW_CLEANUP_DELAY Kconfig options are only
useful for torture testing, and there are the rcutree.gp_cleanup_delay,
rcutree.gp_init_delay, and rcutree.gp_preinit_delay kernel boot parameters
that rcutorture can use instead. The effect of these parameters is to
artificially slow down grace period initialization and cleanup in order
to make some types of race conditions happen more often.

This commit therefore simplifies Tree RCU a bit by removing the Kconfig
options and adding the corresponding kernel parameters to rcutorture's
.boot files instead. However, this commit also leaves out the kernel
parameters for TREE02, TREE04, and TREE07 in order to have about the
same number of tests slowed as not slowed. TREE01, TREE03, TREE05,
and TREE06 are slowed, and the rest are not slowed.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

rcutorture: Update test scenarios based on new Kconfig dependencies

A number of the rcutorture test scenarios were not using the desired
Kconfig options because dependencies were preventing the selections in the
Kconfig-fragment files from being honored. This commit therefore updates
the Kconfig-fragment files to account for these changes in dependencies.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

torture: Add tests without slow grace period setup/cleanup

This commit moves CONFIG_RCU_TORTURE_TEST_SLOW_CLEANUP,
CONFIG_RCU_TORTURE_TEST_SLOW_INIT, and CONFIG_RCU_TORTURE_TEST_SLOW_PREINIT
from CFcommon to all of the TREE scenarios other than TREE08 and TREE09
in order to do at least some testing without these Kconfig options set.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

rcu: Remove CONFIG_RCU_CPU_STALL_INFO

The CONFIG_RCU_CPU_STALL_INFO has been default-y for a couple of
releases with no complaints, so it is time to eliminate this Kconfig
option entirely, so that the long-form RCU CPU stall warnings cannot
be disabled. This commit does just that.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

rcutorture: Update TREE_RCU-kconfig.txt

This commit updates TREE_RCU-kconfig.txt to reflect changes in RCU's
Kconfig setup. This commit also updates rcutorture's Kconfig fragments
to account for Kconfig parameters that are now driven directly off of
other Kconfig parameters.

The #CHECK# prefix tells the rcutorture scripts to take no action to try
to set the Kconfig parameter, but to check that it does in fact get set.
This is useful for verifying that Kconfig parameters that are supposed
to be automatically set do in fact get set to the required values.

Reported-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

rcutorture: Make rcutorture scripts force RCU_EXPERT

This commit causes the rcutorture scripts to force RCU_EXPERT so that
these scripts can cause rcutorture to torture RCU in the various required
configurations. However, SRCU-P, TASKS03, and TREE09 retain !RCU_EXPERT
in order to ensure testing of the vanilla configuration.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

rcutorture: Update configuration fragments for rcutree.rcu_fanout_exact

This commit updates rcutortures configuration-fragment files to account
for the move from the CONFIG_RCU_FANOUT_EXACT Kconfig parameter to the
new rcutree.rcu_fanout_exact= boot parameter.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

rcu: Remove CONFIG_RCU_CPU_STALL_VERBOSE

The CONFIG_RCU_CPU_STALL_VERBOSE Kconfig parameter causes preemptible
RCU's CPU stall warnings to dump out any preempted tasks that are blocking
the current RCU grace period. This information is useful, and the default
has been CONFIG_RCU_CPU_STALL_VERBOSE=y for some years. It is therefore
time for this commit to remove this Kconfig parameter, so that future
kernel builds will always act as if CONFIG_RCU_CPU_STALL_VERBOSE=y.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

rcutorture: Specify CONFIG_CPUMASK_OFFSTACK=y for TREE07

This commit specifies offstack cpumasks in TREE07 in order to catch
references to unallocated cpumask_var_t variables.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>

rcutorture: Test partial nohz_full= configuration

The current set of tests covers only cases where either all possible CPUs
are nohz_full= CPUs or none of them are. Because there have been some
recent bug escapes in cases where only some of the CPUs are nohz_full=
CPUs, this commit add a configuration where only half of the CPUs are
nohz_full= CPUs.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>

rcu: Remove CONFIG_PROVE_RCU_DELAY

The CONFIG_PROVE_RCU_DELAY Kconfig parameter doesn't appear to be very
effective at finding race conditions, so this commit removes it.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
[ paulmck: Remove definition and uses as noted by Paul Bolle. ]

rcutorture: Introduce "rcu" directory level underneath configs

This commit uses the standard software ploy of introducing another
level of indirection below the configs directory. This allows each
torture-test suite to have its own set of Kconfig files, boot parameters,
and version-specific scripts. Initially, we have only rcu, but lock
will follow soonish.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>