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locking/Kconfig: Restructure the lock debugging menu 

Two config options in the lock debugging menu that are probably the most
frequently used, as far as I am concerned, is the PROVE_LOCKING and
LOCK_STAT. From a UI perspective, they should be front and center. So
these two options are now moved to the top of the lock debugging menu.

The DEBUG_WW_MUTEX_SLOWPATH option is also added to the PROVE_LOCKING
umbrella.

Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1522445280-7767-4-git-send-email-longman@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Waiman Long 2018-03-30 17:28:00 -04:00 committed by Ingo Molnar
parent f07cbebb6d
commit 19193bcad8
1 changed files with 68 additions and 67 deletions
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135
lib/Kconfig.debug
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@ -1039,6 +1039,74 @@ config LOCK_DEBUGGING_SUPPORT
depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
default y
config PROVE_LOCKING
bool "Lock debugging: prove locking correctness"
depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
select LOCKDEP
select DEBUG_SPINLOCK
select DEBUG_MUTEXES
select DEBUG_RT_MUTEXES if RT_MUTEXES
select DEBUG_RWSEMS if RWSEM_SPIN_ON_OWNER
select DEBUG_WW_MUTEX_SLOWPATH
select DEBUG_LOCK_ALLOC
select TRACE_IRQFLAGS
default n
help
This feature enables the kernel to prove that all locking
that occurs in the kernel runtime is mathematically
correct: that under no circumstance could an arbitrary (and
not yet triggered) combination of observed locking
sequences (on an arbitrary number of CPUs, running an
arbitrary number of tasks and interrupt contexts) cause a
deadlock.
In short, this feature enables the kernel to report locking
related deadlocks before they actually occur.
The proof does not depend on how hard and complex a
deadlock scenario would be to trigger: how many
participant CPUs, tasks and irq-contexts would be needed
for it to trigger. The proof also does not depend on
timing: if a race and a resulting deadlock is possible
theoretically (no matter how unlikely the race scenario
is), it will be proven so and will immediately be
reported by the kernel (once the event is observed that
makes the deadlock theoretically possible).
If a deadlock is impossible (i.e. the locking rules, as
observed by the kernel, are mathematically correct), the
kernel reports nothing.
NOTE: this feature can also be enabled for rwlocks, mutexes
and rwsems - in which case all dependencies between these
different locking variants are observed and mapped too, and
the proof of observed correctness is also maintained for an
arbitrary combination of these separate locking variants.
For more details, see Documentation/locking/lockdep-design.txt.
config LOCK_STAT
bool "Lock usage statistics"
depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
select LOCKDEP
select DEBUG_SPINLOCK
select DEBUG_MUTEXES
select DEBUG_RT_MUTEXES if RT_MUTEXES
select DEBUG_LOCK_ALLOC
default n
help
This feature enables tracking lock contention points
For more details, see Documentation/locking/lockstat.txt
This also enables lock events required by "perf lock",
subcommand of perf.
If you want to use "perf lock", you also need to turn on
CONFIG_EVENT_TRACING.
CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
(CONFIG_LOCKDEP defines "acquire" and "release" events.)
config DEBUG_RT_MUTEXES
bool "RT Mutex debugging, deadlock detection"
depends on DEBUG_KERNEL && RT_MUTEXES
@ -1102,51 +1170,6 @@ config DEBUG_LOCK_ALLOC
spin_lock_init()/mutex_init()/etc., or whether there is any lock
held during task exit.
config PROVE_LOCKING
bool "Lock debugging: prove locking correctness"
depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
select LOCKDEP
select DEBUG_SPINLOCK
select DEBUG_MUTEXES
select DEBUG_RT_MUTEXES if RT_MUTEXES
select DEBUG_RWSEMS if RWSEM_SPIN_ON_OWNER
select DEBUG_LOCK_ALLOC
select TRACE_IRQFLAGS
default n
help
This feature enables the kernel to prove that all locking
that occurs in the kernel runtime is mathematically
correct: that under no circumstance could an arbitrary (and
not yet triggered) combination of observed locking
sequences (on an arbitrary number of CPUs, running an
arbitrary number of tasks and interrupt contexts) cause a
deadlock.
In short, this feature enables the kernel to report locking
related deadlocks before they actually occur.
The proof does not depend on how hard and complex a
deadlock scenario would be to trigger: how many
participant CPUs, tasks and irq-contexts would be needed
for it to trigger. The proof also does not depend on
timing: if a race and a resulting deadlock is possible
theoretically (no matter how unlikely the race scenario
is), it will be proven so and will immediately be
reported by the kernel (once the event is observed that
makes the deadlock theoretically possible).
If a deadlock is impossible (i.e. the locking rules, as
observed by the kernel, are mathematically correct), the
kernel reports nothing.
NOTE: this feature can also be enabled for rwlocks, mutexes
and rwsems - in which case all dependencies between these
different locking variants are observed and mapped too, and
the proof of observed correctness is also maintained for an
arbitrary combination of these separate locking variants.
For more details, see Documentation/locking/lockdep-design.txt.
config LOCKDEP
bool
depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
@ -1158,28 +1181,6 @@ config LOCKDEP
config LOCKDEP_SMALL
bool
config LOCK_STAT
bool "Lock usage statistics"
depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
select LOCKDEP
select DEBUG_SPINLOCK
select DEBUG_MUTEXES
select DEBUG_RT_MUTEXES if RT_MUTEXES
select DEBUG_LOCK_ALLOC
default n
help
This feature enables tracking lock contention points
For more details, see Documentation/locking/lockstat.txt
This also enables lock events required by "perf lock",
subcommand of perf.
If you want to use "perf lock", you also need to turn on
CONFIG_EVENT_TRACING.
CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
(CONFIG_LOCKDEP defines "acquire" and "release" events.)
config DEBUG_LOCKDEP
bool "Lock dependency engine debugging"
depends on DEBUG_KERNEL && LOCKDEP