This commit adds the rcutorture.preempt_duration module parameter to
rcutorture's TREE03.boot parameter list in order to better test preemption
of RCU read-side critical sections.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
This commit adds the rcutree.nohz_full_patience_delay=1000 kernel boot
parameter to the TREE07 scenario, on the observation that "if it ain't
tested, it don't work".
Signed-off-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
The TREE09 rcutorture scenario exhausts memory from time to time, and
this is due to a reader being preempted and blocking grace periods,
thus preventing recycling of the memory used in callback-flooding tests.
This commit therefore enables RCU priority boosting and sets the boosting
delay to 100 milliseconds after grace-period start.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
There is code in rcu_implicit_dynticks_qs() that checks for the current
grace period being halfway to the RCU CPU stall timeout, but rcutorture
currently does not test this code. This commit therefore adds a 14-second
stall to the TREE07 scenario in order to test this code given the default
RCU CPU stall warning timeout of 21 seconds.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>
This commit adds CONFIG_DEBUG_OBJECTS=y to the TRACE02 rcutorture scenario
to catch any further RCU Tasks bugs involving this Kconfig option.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Currently, the kernel boot parameters specified by the kvm.sh --bootargs
parameter are placed near the beginning of the -append list that is
passed to qemu. This means that in the not-uncommon case of a kernel
boot parameter where the last argument wins, the --bootargs list overrides
neither the list in the .boot file nor the additional parameters supplied
by the rcutorture scripting.
This commit therefore places the kernel boot parameters specified by
the kvm.sh --bootargs parameter at the end of qemu's -append list.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The TASKS03 scenario specifies both CONFIG_RCU_EXPERT=y and
removes #CHECK#CONFIG_RCU_EXPERT=n in order to be consistent with
CONFIG_RCU_EXPERT=y prerequisites.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The BUSTED-BOOST and TREE03 scenarios specify a mythical tree.use_softirq
module parameter, which means a failure to get full test coverage. This
commit therefore corrects the name to rcutree.use_softirq.
Fixes: e2b949d543 ("rcutorture: Make TREE03 use real-time tree.use_softirq setting")
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
This commit enables the RCU_LAZY Kconfig option in scenario TREE04 in
order to provide some ongoing testing of this configuration.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
There is now a BOOTPARAM_HOTPLUG_CPU0 Kconfig option that allows CPU 0
to be offlined on x86 systems. This commit therefore sets this option in
the TREE01 rcutorture scenario in order to regularly test this capability.
Reported-by: "Zhang, Qiang1" <qiang1.zhang@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
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>
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 <paulmck@kernel.org>
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 <paulmck@kernel.org>
Unless a kernel builds rcutorture, whether built-in or as a module, that
kernel is also built with CONFIG_TASKS_RUDE_RCU, whether anything else
needs Tasks Rude RCU or not. This unnecessarily increases kernel size.
This commit therefore decouples the presence of rcutorture from the
presence of RCU Tasks Rude.
However, there is a need to select CONFIG_TASKS_RUDE_RCU for testing
purposes. Except that casual users must not be bothered with
questions -- for them, this needs to be fully automated. There is
thus a CONFIG_FORCE_TASKS_RUDE_RCU that selects CONFIG_TASKS_RUDE_RCU,
is user-selectable, but which depends on CONFIG_RCU_EXPERT.
[ paulmck: Apply kernel test robot feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Currently, a CONFIG_PREEMPT_NONE=y kernel substitutes normal RCU for
RCU Tasks. Unless that kernel builds rcutorture, whether built-in or as
a module, in which case RCU Tasks is (unnecessarily) used. This both
increases kernel size and increases the complexity of certain tracing
operations. This commit therefore decouples the presence of rcutorture
from the presence of RCU Tasks.
However, there is a need to select CONFIG_TASKS_RCU for testing purposes.
Except that casual users must not be bothered with questions -- for them,
this needs to be fully automated. There is thus a CONFIG_FORCE_TASKS_RCU
that selects CONFIG_TASKS_RCU, is user-selectable, but which depends
on CONFIG_RCU_EXPERT.
[ paulmck: Apply kernel test robot feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Unless a kernel builds rcutorture, whether built-in or as a module, that
kernel is also built with CONFIG_TASKS_TRACE_RCU, whether anything else
needs Tasks Trace RCU or not. This unnecessarily increases kernel size.
This commit therefore decouples the presence of rcutorture from the
presence of RCU Tasks Trace.
However, there is a need to select CONFIG_TASKS_TRACE_RCU for
testing purposes. Except that casual users must not be bothered with
questions -- for them, this needs to be fully automated. There is thus
a CONFIG_FORCE_TASKS_TRACE_RCU that selects CONFIG_TASKS_TRACE_RCU,
is user-selectable, but which depends on CONFIG_RCU_EXPERT.
[ paulmck: Apply kernel test robot feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Currently, any kernel built with CONFIG_PREEMPTION=y also gets
CONFIG_TASKS_RCU=y, which is not helpful to people trying to build
preemptible kernels of minimal size.
Because CONFIG_TASKS_RCU=y is needed only in kernels doing tracing of
one form or another, this commit moves from TASKS_RCU deciding when it
should be enabled to the tracing Kconfig options explicitly selecting it.
This allows building preemptible kernels without TASKS_RCU, if desired.
This commit also updates the SRCU-N and TREE09 rcutorture scenarios
in order to avoid Kconfig errors that would otherwise result from
CONFIG_TASKS_RCU being selected without its CONFIG_RCU_EXPERT dependency
being met.
[ paulmck: Apply BPF_SYSCALL feedback from Andrii Nakryiko. ]
Reported-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit adjusts RUDE01 to 3 CPUs and TRACE01 to 5 CPUs in order to
test Tasks RCU's ability to handle non-power-of-two numbers of CPUs.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Thie commit adds kernel boot parameters to the SRCU-N and SRCU-P
rcutorture scenarios to cause SRCU-N to test contention-based resizing
and SRCU-P to test init_srcu_struct()-time resizing. Note that this
also tests never-resizing because the contention-based resizing normally
takes some minutes to make the shift.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit modifies the TASKS01 scenario to use four callback queues
and the TRACE01 scenario to use two queues, thus providing testing of
multiple queues by default.
Cc: Neeraj Upadhyay <neeraj.iitr10@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit adjusts the TRACE02 scenario to use a pair of callback-flood
kthreads. This in turn forces lock contention on the single RCU Tasks
Trace callback queue, which forces use of all CPUs' queues, thus testing
this transition. (No, there is not yet any way to transition back.
Cc: Neeraj Upadhyay <neeraj.iitr10@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit enables two callback-flood kthreads for the TREE02 scenario
and 28 for the TREE10 scenario.
Cc: Neeraj Upadhyay <neeraj.iitr10@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
All of the uses of CONFIG_RCU_FAST_NO_HZ=y that I have seen involve
systems with RCU callbacks offloaded. In this situation, all that this
Kconfig option does is slow down idle entry/exit with an additional
allways-taken early exit. If this is the only use case, then this
Kconfig option nothing but an attractive nuisance that needs to go away.
This commit therefore removes the RCU_FAST_NO_HZ Kconfig option.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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>
With CONFIG_PREEMPT_DYNAMIC=y, the kernel builds with CONFIG_PREEMPTION=y
because preemption can be enabled at runtime. This prevents any tests
of Tiny RCU or Tiny SRCU from running correctly. This commit therefore
explicitly sets CONFIG_PREEMPT_DYNAMIC=n for those scenarios.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
There is no way to place the vCPUs in a two-CPU rcutorture scenario to
get variable memory latency. This commit therefore upgrades the current
two-CPU rcutorture scenarios to four CPUs.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit adds the BUSTED-BOOST rcutorture scenario, which can be
used to test rcutorture's ability to test RCU priority boosting.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The convention that scenario names are all uppercase has two exceptions,
SRCU-t and SRCU-u. This commit therefore renames them to SRCU-T and
SRCU-U, respectively, to bring them in line with this convention. This in
turn permits tighter argument checking in the torture-test scripting.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
TREE03 tests RCU priority boosting, which is a real-time feature.
It would also be good if it tested something closer to what is
actually used by the real-time folks. This commit therefore adds
tree.use_softirq=0 to the TREE03 kernel boot parameters in TREE03.boot.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit uses the shiny new "all" and "N" cpumask options to decouple
the "nohz_full" and "rcu_nocbs" kernel boot parameters in the TREE04.boot
and TREE08.boot files from the CONFIG_NR_CPUS options in the TREE04 and
TREE08 files.
Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
RCU's rcutree.use_softirq=0 kernel boot parameter substitutes the per-CPU
rcuc kthreads for softirq, which is used in real-time installations.
However, none of the rcutorture scenarios test this parameter.
This commit therefore adds rcutree.use_softirq=0 to the RUDE01 and
TASKS01 rcutorture scenarios, both of which indirectly exercise RCU.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The SRCU-u scenario expects to enable lockdep but to also disable the
CONFIG_PREEMPT_COUNT kconfig option. This no longer works. This commit
therefore instead enables lockdep in SRCU-t, which then allows SRCU-u
to disable CONFIG_PREEMPT_COUNT.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Currently, the CONFIG_PREEMPT_NONE=y rcutorture TRACE01 rcutorture
scenario enables lockdep. This limits its ability to find bugs due to
non-preemptible sections of code being RCU readers, and pretty much all
code thus appearing to lockdep to be an RCU reader. This commit therefore
moves lockdep testing to the CONFIG_PREEMPT=y rcutorture TRACE02 scenario.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Currently, the CONFIG_PROVE_RCU_LIST=y case is untested. This commit
therefore adds CONFIG_PROVE_RCU_LIST=y to rcutorture's TREE05 scenario.
Cc: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
fixes.2020.04.27a: Miscellaneous fixes.
kfree_rcu.2020.04.27a: Changes related to kfree_rcu().
rcu-tasks.2020.04.27a: Addition of new RCU-tasks flavors.
stall.2020.04.27a: RCU CPU stall-warning updates.
torture.2020.05.07a: Torture-test updates.
The number of CPUs is tuned to allow "4*CFLIST TREE10" on a large system,
up from "3*CFLIST TREE10" previously.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit adds a TRACE02 scenario which enables preemption and RCU
Tasks Trace IPIs, more specifically, disabling heavyweight readers.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit enables the KCSAN Kconfig options that (1) detect data
races between reads and writes even when the writes do not change the
variable's value and (2) detect data races involving plain C-language
writes. These changes only affect scripted rcutorture runs and can be
overridden using the kvm.sh --kconfig argument.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The small-system rcutorture configurations have served us well for a great
many years, but it is now time to add a larger one. This commit does
just that, but does not add it to the defaults in CFLIST. This allows
the kvm.sh argument '--configs "4*CFLIST TREE10" to run four instances
of each of the default configurations concurrently with one instance of
the large configuration.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
