linux-toradex.git/include/linux/torture.h, branch v5.12-rc5

torture: Maintain torture-specific set of CPUs-online books

2021-01-07T01:17:22+00:00

The TREE01 rcutorture scenario intentionally creates confusion as to the
number of available CPUs by specifying the "maxcpus=8 nr_cpus=43" kernel
boot parameters.  This can disable rcutorture's load shedding, which
currently uses num_online_cpus(), which would count the extra 35 CPUs.
However, the rcutorture guest OS will be provisioned with only 8 CPUs,
which means that rcutorture will present full load even when all but one
of the original 8 CPUs are offline.  This can result in spurious errors
due to extreme overloading of that single remaining CPU.

This commit therefore keeps a separate set of books on the number of
usable online CPUs, so that torture_num_online_cpus() is used for load
shedding instead of num_online_cpus().  Note that initial sizing must
use num_online_cpus() because torture_num_online_cpus() will return
NR_CPUS until shortly after torture_onoff_init() is invoked.

Reported-by: Frederic Weisbecker 
[ paulmck: Apply feedback from kernel test robot. ]
Signed-off-by: Paul E. McKenney

torture: Throttle VERBOSE_TOROUT_*() output

2021-01-07T01:17:21+00:00

This commit adds kernel boot parameters torture.verbose_sleep_frequency
and torture.verbose_sleep_duration, which allow VERBOSE_TOROUT_*() output
to be throttled with periodic sleeps on large systems.

Signed-off-by: Paul E. McKenney

torture: Add fuzzed hrtimer-based sleep functions

2021-01-07T01:17:19+00:00

This commit adds torture_hrtimeout_ns(), torture_hrtimeout_us(),
torture_hrtimeout_ms(), torture_hrtimeout_jiffies(), and
torture_hrtimeout_s(), each of which uses hrtimers to block for a fuzzed
time interval.  These functions are intended to be used by the various
torture tests to decouple wakeups from the timer wheel, thus providing
more opportunity for Murphy to insert destructive race conditions.

Signed-off-by: Paul E. McKenney

rcutorture: Add races with task-exit processing

2020-06-29T19:01:44+00:00

Several variants of Linux-kernel RCU interact with task-exit processing,
including preemptible RCU, Tasks RCU, and Tasks Trace RCU.  This commit
therefore adds testing of this interaction to rcutorture by adding
rcutorture.read_exit_burst and rcutorture.read_exit_delay kernel-boot
parameters.  These kernel parameters control the frequency and spacing
of special read-then-exit kthreads that are spawned.

[ paulmck: Apply feedback from Dan Carpenter's static checker. ]
[ paulmck: Reduce latency to avoid false-positive shutdown hangs. ]
Signed-off-by: Paul E. McKenney

locktorture.c: Fix if-statement empty body warnings

2020-04-27T18:05:13+00:00

When using -Wextra, gcc complains about torture_preempt_schedule()
when its definition is empty (i.e., when CONFIG_PREEMPTION is not
set/enabled).  Fix these warnings by adding an empty do-while block
for that macro when CONFIG_PREEMPTION is not set.
Fixes these build warnings:

../kernel/locking/locktorture.c:119:29: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
../kernel/locking/locktorture.c:166:29: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
../kernel/locking/locktorture.c:337:29: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
../kernel/locking/locktorture.c:490:29: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
../kernel/locking/locktorture.c:528:29: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
../kernel/locking/locktorture.c:553:29: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]

I have verified that there is no object code change (with gcc 7.5.0).

Signed-off-by: Randy Dunlap 
Cc: Davidlohr Bueso 
Cc: Josh Triplett 
Signed-off-by: "Paul E. McKenney"

rcu: Use CONFIG_PREEMPTION

2019-07-31T17:03:35+00:00

CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by
CONFIG_PREEMPT_RT. Both PREEMPT and PREEMPT_RT require the same
functionality which today depends on CONFIG_PREEMPT.

Switch the conditionals in RCU to use CONFIG_PREEMPTION.

That's the first step towards RCU on RT. The further tweaks are work in
progress. This neither touches the selftest bits which need a closer look
by Paul.

Signed-off-by: Thomas Gleixner 
Acked-by: Peter Zijlstra (Intel) 
Cc: Linus Torvalds 
Cc: Masami Hiramatsu 
Cc: Paolo Bonzini 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Steven Rostedt 
Link: http://lkml.kernel.org/r/20190726212124.210156346@linutronix.de
Signed-off-by: Ingo Molnar

torture: Allow inter-stutter interval to be specified

2019-05-28T16:06:09+00:00

Currently, the inter-stutter interval is the same as the stutter duration,
that is, whatever number of jiffies is passed into torture_stutter_init().
This has worked well for quite some time, but the addition of
forward-progress testing to rcutorture can delay processes for several
seconds, which can triple the time that they are stuttered.

This commit therefore adds a second argument to torture_stutter_init()
that specifies the inter-stutter interval.  While locktorture preserves
the current behavior, rcutorture uses the RCU CPU stall warning interval
to provide a wider inter-stutter interval.

Signed-off-by: Paul E. McKenney

Merge branches 'doc.2019.01.26a', 'fixes.2019.01.26a', 'sil.2019.01.26a', 'spdx.2019.02.09a', 'srcu.2019.01.26a' and 'torture.2019.01.26a' into HEAD

2019-02-09T16:47:52+00:00

doc.2019.01.26a:  Documentation updates.
fixes.2019.01.26a:  Miscellaneous fixes.
sil.2019.01.26a:  Removal of a few more spin_is_locked() instances.
spdx.2019.02.09a:  Add SPDX identifiers to RCU files
srcu.2019.01.26a:  SRCU updates.
torture.2019.01.26a: Torture-test updates.

linux/torture: Convert to SPDX license identifier

2019-02-09T16:46:31+00:00

Replace the license boiler plate with a SPDX license identifier.
While in the area, update an email address.

Signed-off-by: Paul E. McKenney 
[ paulmck: Update .h SPDX format per Joe Perches. ]
Reviewed-by: Thomas Gleixner

rcutorture: Add grace period after CPU offline

2019-01-25T23:37:10+00:00

Beyond a certain point in the CPU-hotplug offline process, timers get
stranded on the outgoing CPU, and won't fire until that CPU comes back
online, which might well be never.  This commit therefore adds a hook
in torture_onoff_init() that is invoked from torture_offline(), which
rcutorture uses to occasionally wait for a grace period.  This should
result in failures for RCU implementations that rely on stranded timers
eventually firing in the absence of the CPU coming back online.

Reported-by: Sebastian Andrzej Siewior 
Signed-off-by: Paul E. McKenney