linux-toradex.git/include/linux/lockdep.h, branch tegra-10.7.1

lockdep: Reintroduce generation count to make BFS faster

2009-08-02T13:41:37+00:00

We still can apply DaveM's generation count optimization to
BFS, based on the following idea:

 - before doing each BFS, increase the global generation id
   by 1

 - if one node in the graph has been visited, mark it as
   visited by storing the current global generation id into
   the node's dep_gen_id field

 - so we can decide if one node has been visited already, by
   comparing the node's dep_gen_id with the global generation id.

By applying DaveM's generation count optimization to current
implementation of BFS, we gain the following advantages:

 - we save MAX_LOCKDEP_ENTRIES/8 bytes memory;

 - we remove the bitmap_zero(bfs_accessed, MAX_LOCKDEP_ENTRIES);
   in each BFS, which is very time-consuming since
   MAX_LOCKDEP_ENTRIES may be very large.(16384UL)

Signed-off-by: Ming Lei 
Signed-off-by: Peter Zijlstra 
Cc: "David S. Miller" 
LKML-Reference: <1248274089-6358-1-git-send-email-tom.leiming@gmail.com>
Signed-off-by: Ingo Molnar

lockdep: Deal with many similar locks

2009-08-02T13:41:35+00:00

spin_lock_nest_lock() allows to take many instances of the same
class, this can easily lead to overflow of MAX_LOCK_DEPTH.

To avoid this overflow, we'll stop accounting instances but
start reference counting the class in the held_lock structure.

[ We could maintain a list of instances, if we'd move the hlock
  stuff into __lock_acquired(), but that would require
  significant modifications to the current code. ]

We restrict this mode to spin_lock_nest_lock() only, because it
degrades the lockdep quality due to lost of instance.

For lockstat this means we don't track lock statistics for any
but the first lock in the series.

Currently nesting is limited to 11 bits because that was the
spare space available in held_lock. This yields a 2048
instances maximium.

Signed-off-by: Peter Zijlstra 
Cc: Marcelo Tosatti 
Cc: Linus Torvalds 
Signed-off-by: Ingo Molnar

lockdep: Introduce lockdep_assert_held()

2009-08-02T13:41:34+00:00

Add a lockdep helper to validate that we indeed are the owner
of a lock.

Signed-off-by: Peter Zijlstra 
Signed-off-by: Ingo Molnar

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: 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

vfs: Set special lockdep map for dirs only if not set by fs

2009-06-22T21:34:22+00:00

Some filesystems need to set lockdep map for i_mutex differently for
different directories. For example OCFS2 has system directories (for
orphan inode tracking and for gathering all system files like journal
or quota files into a single place) which have different locking
locking rules than standard directories. For a filesystem setting
lockdep map is naturaly done when the inode is read but we have to
modify unlock_new_inode() not to overwrite the lockdep map the filesystem
has set.

Acked-by: peterz@infradead.org
CC: mingo@redhat.com
Signed-off-by: Jan Kara 
Signed-off-by: Joel Becker

Factor out #ifdefs from kernel/spinlock.c to LOCK_CONTENDED_FLAGS

2009-04-03T02:05:10+00:00

SGI has observed that on large systems, interrupts are not serviced for a
long period of time when waiting for a rwlock.  The following patch series
re-enables irqs while waiting for the lock, resembling the code which is
already there for spinlocks.

I only made the ia64 version, because the patch adds some overhead to the
fast path.  I assume there is currently no demand to have this for other
architectures, because the systems are not so large.  Of course, the
possibility to implement raw_{read|write}_lock_flags for any architecture
is still there.

This patch:

The new macro LOCK_CONTENDED_FLAGS expands to the correct implementation
depending on the config options, so that IRQ's are re-enabled when
possible, but they remain disabled if CONFIG_LOCKDEP is set.

Signed-off-by: Petr Tesarik 
Signed-off-by: Robin Holt 
Cc: 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: "Luck, Tony" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lockdep: move state bit definitions around

2009-02-14T22:27:59+00:00

For convenience later.

Signed-off-by: Peter Zijlstra 
Signed-off-by: Ingo Molnar

lockdep: sanitize reclaim bit names

2009-02-14T22:27:52+00:00

s/HELD_OVER/ENABLED/g

so that its similar to the hard and soft-irq names.

Signed-off-by: Peter Zijlstra 
Signed-off-by: Ingo Molnar

lockdep: sanitize bit names

2009-02-14T22:27:51+00:00

s/\(LOCKF\?_ENABLED_[^ ]*\)S\(_READ\)\?\>/\1\2/g

So that the USED_IN and ENABLED have the same names.

Signed-off-by: Peter Zijlstra 
Signed-off-by: Ingo Molnar