linux-toradex.git/kernel/lockdep_internals.h, branch v3.4.73

lockdep: No need to disable preemption in debug atomic ops

2010-05-04T03:38:16+00:00

No need to disable preemption in the debug_atomic_* ops, as
we ensure interrupts are disabled already.

So let's use the __this_cpu_ops() rather than this_cpu_ops() that
enclose the ops in a preempt disabled section.

Signed-off-by: Frederic Weisbecker 
Cc: Peter Zijlstra

lockdep: Actually _dec_ in debug_atomic_dec

2010-05-04T03:38:12+00:00

Fix a silly copy-paste mistake that was making debug_atomic_dec use
this_cpu_inc instead of this_cpu_dec.

Signed-off-by: Frederic Weisbecker 
Cc: Peter Zijlstra

lockdep: Provide off case for redundant_hardirqs_on increment

2010-05-04T03:37:28+00:00

We forgot to provide a !CONFIG_DEBUG_LOCKDEP case for the
redundant_hardirqs_on stat handling.

Manage that in the headers with a new __debug_atomic_inc() helper.

Fixes:

	kernel/lockdep.c:2306: error: 'lockdep_stats' undeclared (first use in this function)
	kernel/lockdep.c:2306: error: (Each undeclared identifier is reported only once
	kernel/lockdep.c:2306: error: for each function it appears in.)

Reported-by: Ingo Molnar 
Signed-off-by: Frederic Weisbecker 
Cc: Peter Zijlstra

lockdep: Simplify debug atomic ops

2010-04-30T17:15:56+00:00

Simplify debug_atomic_inc/dec by using this_cpu_inc/dec() instead
of doing it through an indirect get_cpu_var() and a manual
incrementation.

Signed-off-by: Frederic Weisbecker 
Cc: Peter Zijlstra

lockstat: Make lockstat counting per cpu

2010-04-05T22:15:37+00:00

Locking statistics are implemented using global atomic
variables. This is usually fine unless some path write them very
often.

This is the case for the function and function graph tracers
that disable irqs for each entry saved (except if the function
tracer is in preempt disabled only mode).
And calls to local_irq_save/restore() increment
hardirqs_on_events and hardirqs_off_events stats (or similar
stats for redundant versions).

Incrementing these global vars for each function ends up in too
much cache bouncing if lockstats are enabled.

To solve this, implement the debug_atomic_*() operations using
per cpu vars.

 -v2: Use per_cpu() instead of get_cpu_var() to fetch the desired
      cpu vars on debug_atomic_read()

 -v3: Store the stats in a structure. No need for local_t as we
      are NMI/irq safe.

 -v4: Fix tons of build errors. I thought I had tested it but I
      probably forgot to select the relevant config.

Suggested-by: Steven Rostedt 
Signed-off-by: Frederic Weisbecker 
Cc: Peter Zijlstra 
Cc: Steven Rostedt 
LKML-Reference: <1270505417-8144-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Steven Rostedt

lockdep: BFS cleanup

2009-07-24T08:53:29+00:00

Some cleanups of the lockdep code after the BFS series:

 - Remove the last traces of the generation id
 - Fixup comment style
 - Move the bfs routines into lockdep.c
 - Cleanup the bfs routines

[ tom.leiming@gmail.com: Fix crash ]
Signed-off-by: Peter Zijlstra 
LKML-Reference: <1246201486-7308-11-git-send-email-tom.leiming@gmail.com>
Signed-off-by: Ingo Molnar

lockdep: Add statistics info for max bfs queue depth

2009-07-24T08:52:03+00:00

Add BFS statistics to the existing lockdep stats.

Signed-off-by: Ming Lei 
Signed-off-by: Peter Zijlstra 
LKML-Reference: <1246201486-7308-10-git-send-email-tom.leiming@gmail.com>
Signed-off-by: Ingo Molnar

lockdep: Introduce print_shortest_lock_dependencies

2009-07-24T08:49:54+00:00

Since the shortest lock dependencies' path may be obtained by BFS,
we print the shortest one by print_shortest_lock_dependencies().

Signed-off-by: Ming Lei 
Signed-off-by: Peter Zijlstra 
LKML-Reference: <1246201486-7308-7-git-send-email-tom.leiming@gmail.com>
Signed-off-by: Ingo Molnar

lockdep: Improve implementation of BFS

2009-07-24T08:49:46+00:00

1,replace %MAX_CIRCULAR_QUE_SIZE with &(MAX_CIRCULAR_QUE_SIZE-1)
since we define MAX_CIRCULAR_QUE_SIZE as power of 2;

2,use bitmap to mark if a lock is accessed in BFS in order to
clear it quickly, because we may search a graph many times.

Signed-off-by: Ming Lei 
Signed-off-by: Peter Zijlstra 
LKML-Reference: <1246201486-7308-3-git-send-email-tom.leiming@gmail.com>
Signed-off-by: Ingo Molnar

lockdep: Print the shortest dependency chain if finding a circle

2009-07-24T08:49:44+00:00

Currently lockdep will print the 1st circle detected if it
exists when acquiring a new (next) lock.

This patch prints the shortest path from the next lock to be
acquired to the previous held lock if a circle is found.

The patch still uses the current method to check circle, and
once the circle is found, breadth-first search algorithem is
used to compute the shortest path from the next lock to the
previous lock in the forward lock dependency graph.

Printing the shortest path will shorten the dependency chain,
and make troubleshooting for possible circular locking easier.

Signed-off-by: Ming Lei 
Signed-off-by: Peter Zijlstra 
LKML-Reference: <1246201486-7308-2-git-send-email-tom.leiming@gmail.com>
Signed-off-by: Ingo Molnar