linux-toradex.git/kernel/locking/test-ww_mutex.c, branch v4.13-rc7

locking/ww-mutex: Limit stress test to 2 seconds

2017-03-30T07:49:47+00:00

Use a timeout rather than a fixed number of loops to avoid running for
very long periods, such as under the kbuilder VMs.

Reported-by: kernel test robot 
Signed-off-by: Chris Wilson 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Boqun Feng 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20170310105733.6444-1-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar

locking/ww_mutex: Improve test to cover acquire context changes

2017-03-16T08:57:09+00:00

Currently each thread starts an acquire context only once, and
performs all its loop iterations under it.

This means that the Wound/Wait relations between threads are fixed.

To make things a little more realistic and cover more of the
functionality with the test, open a new acquire context for each loop.

Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Chris Wilson 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Signed-off-by: Ingo Molnar

locking/ww_mutex: Adjust the lock number for stress test

2017-03-02T08:00:39+00:00

Because there are only 12 bits in held_lock::references, so we only
support 4095 nested lock held in the same time, adjust the lock number
for ww_mutex stress test to kill one lockdep splat:

  [ ] [ BUG: bad unlock balance detected! ]
  [ ] kworker/u2:0/5 is trying to release lock (ww_class_mutex) at:
  [ ] ww_mutex_unlock()
  [ ] but there are no more locks to release!
  ...

Signed-off-by: Boqun Feng 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Chris Wilson 
Cc: Fengguang Wu 
Cc: Linus Torvalds 
Cc: Nicolai Hähnle 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20170301150138.hdixnmafzfsox7nn@tardis.cn.ibm.com
Signed-off-by: Ingo Molnar

locking/ww_mutex: Replace cpu_relax() with cond_resched() for tests

2017-03-02T08:00:38+00:00

When busy-spinning on a ww_mutex_trylock(), we depend upon the other
thread advancing and releasing the lock. This can not happen on a single
CPU unless we relinquish it:

  [ ] NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [kworker/0:1:18]
  ...
  [ ] Call Trace:
  [ ]  mutex_trylock()
  [ ]  test_mutex_work+0x31/0x56
  [ ]  process_one_work+0x1b4/0x2f9
  [ ]  worker_thread+0x1b0/0x27c
  [ ]  kthread+0xd1/0xd3
  [ ]  ret_from_fork+0x19/0x30

Reported-by: Fengguang Wu 
Signed-off-by: Chris Wilson 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: f2a5fec17395 ("locking/ww_mutex: Begin kselftests for ww_mutex")
Link: http://lkml.kernel.org/r/20170228094011.2595-1-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar

locking/ww_mutex: Add kselftests for ww_mutex stress

2017-01-14T10:37:17+00:00

Signed-off-by: Chris Wilson 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Maarten Lankhorst 
Cc: Nicolai Hähnle 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20161201114711.28697-8-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar

locking/ww_mutex: Add kselftests for resolving ww_mutex cyclic deadlocks

2017-01-14T10:37:16+00:00

Check that ww_mutexes can detect cyclic deadlocks (generalised ABBA
cycles) and resolve them by lock reordering.

Signed-off-by: Chris Wilson 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Maarten Lankhorst 
Cc: Nicolai Hähnle 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20161201114711.28697-7-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar

locking/ww_mutex: Add kselftests for ww_mutex ABBA deadlock detection

2017-01-14T10:37:16+00:00

Signed-off-by: Chris Wilson 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Maarten Lankhorst 
Cc: Nicolai Hähnle 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20161201114711.28697-6-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar

locking/ww_mutex: Add kselftests for ww_mutex AA deadlock detection

2017-01-14T10:37:15+00:00

Signed-off-by: Chris Wilson 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Maarten Lankhorst 
Cc: Nicolai Hähnle 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20161201114711.28697-5-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar

locking/ww_mutex: Begin kselftests for ww_mutex

2017-01-14T10:37:14+00:00

Signed-off-by: Chris Wilson 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Maarten Lankhorst 
Cc: Nicolai Hähnle 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20161201114711.28697-4-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar