linux/Documentation/litmus-tests
Linus Torvalds 60eb450742 LKMM scripting updates for v6.4
This update improves litmus-test documentation and improves the ability
 to do before/after tests on the https://github.com/paulmckrcu/litmus repo.
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Merge tag 'lkmm-scripting.2023.04.07a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull Linux Kernel Memory Model scripting updates from Paul McKenney:
 "This improves litmus-test documentation and improves the ability to do
  before/after tests on the https://github.com/paulmckrcu/litmus repo"

* tag 'lkmm-scripting.2023.04.07a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (32 commits)
  tools/memory-model: Remove out-of-date SRCU documentation
  tools/memory-model: Document LKMM test procedure
  tools/memory-model: Use "grep -E" instead of "egrep"
  tools/memory-model: Use "-unroll 0" to keep --hw runs finite
  tools/memory-model: Make judgelitmus.sh handle scripted Result: tag
  tools/memory-model: Add data-race capabilities to judgelitmus.sh
  tools/memory-model: Add checktheselitmus.sh to run specified litmus tests
  tools/memory-model: Repair parseargs.sh header comment
  tools/memory-model:  Add "--" to parseargs.sh for additional arguments
  tools/memory-model: Make history-check scripts use mselect7
  tools/memory-model: Make checkghlitmus.sh use mselect7
  tools/memory-model: Fix scripting --jobs argument
  tools/memory-model: Implement --hw support for checkghlitmus.sh
  tools/memory-model: Add -v flag to jingle7 runs
  tools/memory-model: Make runlitmus.sh check for jingle errors
  tools/memory-model: Allow herd to deduce CPU type
  tools/memory-model: Keep assembly-language litmus tests
  tools/memory-model: Move from .AArch64.litmus.out to .litmus.AArch.out
  tools/memory-model: Make runlitmus.sh generate .litmus.out for --hw
  tools/memory-model: Split runlitmus.sh out of checklitmus.sh
  ...
2023-04-24 12:02:25 -07:00
..
atomic
locking tools/memory-model: Document locking corner cases 2023-03-24 10:22:25 -07:00
rcu
README Documentation: litmus-tests: Correct spelling 2023-03-22 12:02:21 -07:00

============
LITMUS TESTS
============

Each subdirectory contains litmus tests that are typical to describe the
semantics of respective kernel APIs.
For more information about how to "run" a litmus test or how to generate
a kernel test module based on a litmus test, please see
tools/memory-model/README.


atomic (/atomic directory)
--------------------------

Atomic-RMW+mb__after_atomic-is-stronger-than-acquire.litmus
    Test that an atomic RMW followed by a smp_mb__after_atomic() is
    stronger than a normal acquire: both the read and write parts of
    the RMW are ordered before the subsequential memory accesses.

Atomic-RMW-ops-are-atomic-WRT-atomic_set.litmus
    Test that atomic_set() cannot break the atomicity of atomic RMWs.
    NOTE: Require herd7 7.56 or later which supports "(void)expr".


RCU (/rcu directory)
--------------------

MP+onceassign+derefonce.litmus (under tools/memory-model/litmus-tests/)
    Demonstrates the use of rcu_assign_pointer() and rcu_dereference() to
    ensure that an RCU reader will not see pre-initialization garbage.

RCU+sync+read.litmus
RCU+sync+free.litmus
    Both the above litmus tests demonstrate the RCU grace period guarantee
    that an RCU read-side critical section can never span a grace period.