In performance tests, it can be counter-productive to spread torture-test
guest OSes across sockets.  Plus the experimenter might have ideas about
what CPUs individual guest OSes are to run on.  This commit therefore
adds a --no-affinity parameter to kvm.sh to prevent it from running
taskset on its guest OSes.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>

This commit adds an rcutorture scenario that tests light-weight SRCU
readers.  While in the area, it adjusts the size of the TREE10 scenario.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <bpf@vger.kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>

This commit adds a TINY scenario in order to support tests of Tiny RCU
and Tiny SRCU.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>

Some servers have limitations on the number of CPUs a given guest OS
can use.  In my earlier experience, such limitations have been at least
half of the host's CPUs, but in a recent example, this limit is less
than 40%.  This commit therefore adds a --guest-cpu-limit argument that
allows such low limits to be made known to torture.sh.

Signed-off-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>

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>

Add CFcommon.arch for arch-specific Kconfig options.

In accordance with [1], [2] and [3], move the x86-specific kernel option
CONFIG_HYPERVISOR_GUEST to CFcommon.i686 and CFcommon.x86_64, and also
move the x86/PowerPC CONFIG_KVM_GUEST Kconfig option to CFcommon.i686,
CFcommon.x86_64, and CFcommon.ppc64le.

The "arch" in CFcommon.arch is taken from the "uname -m" command.

[1] https://lore.kernel.org/all/20240427005626.1365935-1-zhouzhouyi@gmail.com/
[2] https://lore.kernel.org/all/059d36ce-6453-42be-a31e-895abd35d590@paulmck-laptop/
[3] https://lore.kernel.org/all/ZnBkHosMDhsh4H8g@J2N7QTR9R3/

Tested in x86_64 and PPC VM of Open Source Lab of Oregon State University.

Fixes: a6fda6dab93c ("rcutorture: Tweak kvm options")
Suggested-by: Paul E. McKenney <paulmck@kernel.org>
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>

Currently, the torture.sh --do-kvfree testing is hard-coded to ten
minutes, ignoring the --duration argument.  This commit therefore scales
this test duration the same as for the rcutorture tests.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

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>