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  1. 14 Feb, 2009 4 commits
    • Peter Zijlstra's avatar
      lockstat: warn about disabled lock debugging · 9833f8cb
      Peter Zijlstra authored
      Avoid confusion and clearly state lock debugging got disabled.
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      9833f8cb
    • Peter Zijlstra's avatar
      lockdep: get_user_chars() redo · f510b233
      Peter Zijlstra authored
      Generic, states independent, get_user_chars().
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      f510b233
    • Peter Zijlstra's avatar
      lockdep: sanitize bit names · 4fc95e86
      Peter Zijlstra authored
      s/\(LOCKF\?_ENABLED_[^ ]*\)S\(_READ\)\?\>/\1\2/g
      
      So that the USED_IN and ENABLED have the same names.
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      4fc95e86
    • Nick Piggin's avatar
      lockdep: annotate reclaim context (__GFP_NOFS) · cf40bd16
      Nick Piggin authored
      Here is another version, with the incremental patch rolled up, and
      added reclaim context annotation to kswapd, and allocation tracing
      to slab allocators (which may only ever reach the page allocator
      in rare cases, so it is good to put annotations here too).
      
      Haven't tested this version as such, but it should be getting closer
      to merge worthy ;)
      
      --
      After noticing some code in mm/filemap.c accidentally perform a __GFP_FS
      allocation when it should not have been, I thought it might be a good idea to
      try to catch this kind of thing with lockdep.
      
      I coded up a little idea that seems to work. Unfortunately the system has to
      actually be in __GFP_FS page reclaim, then take the lock, before it will mark
      it. But at least that might still be some orders of magnitude more common
      (and more debuggable) than an actual deadlock condition, so we have some
      improvement I hope (the concept is no less complete than discovery of a lock's
      interrupt contexts).
      
      I guess we could even do the same thing with __GFP_IO (normal reclaim), and
      even GFP_NOIO locks too... but filesystems will have the most locks and fiddly
      code paths, so let's start there and see how it goes.
      
      It *seems* to work. I did a quick test.
      
      =================================
      [ INFO: inconsistent lock state ]
      2.6.28-rc6-00007-ged313489-dirty #26
      ---------------------------------
      inconsistent {in-reclaim-W} -> {ov-reclaim-W} usage.
      modprobe/8526 [HC0[0]:SC0[0]:HE1:SE1] takes:
       (testlock){--..}, at: [<ffffffffa0020055>] brd_init+0x55/0x216 [brd]
      {in-reclaim-W} state was registered at:
        [<ffffffff80267bdb>] __lock_acquire+0x75b/0x1a60
        [<ffffffff80268f71>] lock_acquire+0x91/0xc0
        [<ffffffff8070f0e1>] mutex_lock_nested+0xb1/0x310
        [<ffffffffa002002b>] brd_init+0x2b/0x216 [brd]
        [<ffffffff8020903b>] _stext+0x3b/0x170
        [<ffffffff80272ebf>] sys_init_module+0xaf/0x1e0
        [<ffffffff8020c3fb>] system_call_fastpath+0x16/0x1b
        [<ffffffffffffffff>] 0xffffffffffffffff
      irq event stamp: 3929
      hardirqs last  enabled at (3929): [<ffffffff8070f2b5>] mutex_lock_nested+0x285/0x310
      hardirqs last disabled at (3928): [<ffffffff8070f089>] mutex_lock_nested+0x59/0x310
      softirqs last  enabled at (3732): [<ffffffff8061f623>] sk_filter+0x83/0xe0
      softirqs last disabled at (3730): [<ffffffff8061f5b6>] sk_filter+0x16/0xe0
      
      other info that might help us debug this:
      1 lock held by modprobe/8526:
       #0:  (testlock){--..}, at: [<ffffffffa0020055>] brd_init+0x55/0x216 [brd]
      
      stack backtrace:
      Pid: 8526, comm: modprobe Not tainted 2.6.28-rc6-00007-ged313489-dirty #26
      Call Trace:
       [<ffffffff80265483>] print_usage_bug+0x193/0x1d0
       [<ffffffff80266530>] mark_lock+0xaf0/0xca0
       [<ffffffff80266735>] mark_held_locks+0x55/0xc0
       [<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd]
       [<ffffffff802667ca>] trace_reclaim_fs+0x2a/0x60
       [<ffffffff80285005>] __alloc_pages_internal+0x475/0x580
       [<ffffffff8070f29e>] ? mutex_lock_nested+0x26e/0x310
       [<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd]
       [<ffffffffa002006a>] brd_init+0x6a/0x216 [brd]
       [<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd]
       [<ffffffff8020903b>] _stext+0x3b/0x170
       [<ffffffff8070f8b9>] ? mutex_unlock+0x9/0x10
       [<ffffffff8070f83d>] ? __mutex_unlock_slowpath+0x10d/0x180
       [<ffffffff802669ec>] ? trace_hardirqs_on_caller+0x12c/0x190
       [<ffffffff80272ebf>] sys_init_module+0xaf/0x1e0
       [<ffffffff8020c3fb>] system_call_fastpath+0x16/0x1b
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      cf40bd16
  2. 20 Oct, 2008 1 commit
  3. 23 Sep, 2008 1 commit
  4. 26 Aug, 2008 1 commit
    • Joe Korty's avatar
      lockstat: fix numerical output rounding error · 2189459d
      Joe Korty authored
      Fix rounding error in /proc/lock_stat numerical output.
      
      On occasion the two digit fractional part contains the three
      digit value '100'.  This is due to a bug in the rounding algorithm
      which pushes values in the range '95..99' to '100' rather than
      to '00' + an increment to the integer part.  For example,
      
      	- 123456.100      old display
      	+ 123457.00	  new display
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      2189459d
  5. 15 Aug, 2008 1 commit
  6. 11 Aug, 2008 1 commit
  7. 31 Jul, 2008 1 commit
    • David Miller's avatar
      lockdep: fix combinatorial explosion in lock subgraph traversal · 419ca3f1
      David Miller authored
      When we traverse the graph, either forwards or backwards, we
      are interested in whether a certain property exists somewhere
      in a node reachable in the graph.
      
      Therefore it is never necessary to traverse through a node more
      than once to get a correct answer to the given query.
      
      Take advantage of this property using a global ID counter so that we
      need not clear all the markers in all the lock_class entries before
      doing a traversal.  A new ID is choosen when we start to traverse, and
      we continue through a lock_class only if it's ID hasn't been marked
      with the new value yet.
      
      This short-circuiting is essential especially for high CPU count
      systems.  The scheduler has a runqueue per cpu, and needs to take
      two runqueue locks at a time, which leads to long chains of
      backwards and forwards subgraphs from these runqueue lock nodes.
      Without the short-circuit implemented here, a graph traversal on
      a runqueue lock can take up to (1 << (N - 1)) checks on a system
      with N cpus.
      
      For anything more than 16 cpus or so, lockdep will eventually bring
      the machine to a complete standstill.
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      419ca3f1
  8. 23 Jun, 2008 1 commit
  9. 20 Jun, 2008 1 commit
  10. 13 Jun, 2008 1 commit
  11. 29 Apr, 2008 1 commit
  12. 11 Oct, 2007 1 commit
    • Tim Pepper's avatar
      lockdep: Avoid /proc/lockdep & lock_stat infinite output · 94c61c0a
      Tim Pepper authored
      Both /proc/lockdep and /proc/lock_stat output may loop infinitely.
      
      When a read() requests an amount of data smaller than the amount of data
      that the seq_file's foo_show() outputs, the output starts looping and
      outputs the "stuck" element's data infinitely.  There may be multiple
      sequential calls to foo_start(), foo_next()/foo_show(), and foo_stop()
      for a single open with sequential read of the file.  The _start() does not
      have to start with the 0th element and _show() might be called multiple
      times in a row for the same element for a given open/read of the seq_file.
      
      Also header output should not be happening in _start().  All output should
      be in _show(), which SEQ_START_TOKEN is meant to help.  Having output in
      _start() may also negatively impact seq_file's seq_read() and traverse()
      accounting.
      Signed-off-by: default avatarTim Pepper <lnxninja@linux.vnet.ibm.com>
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Al Viro <viro@ftp.linux.org.uk>
      94c61c0a
  13. 31 Jul, 2007 1 commit
  14. 19 Jul, 2007 5 commits
    • Peter Zijlstra's avatar
      lockstat: better class name representation · d38e1d5a
      Peter Zijlstra authored
      optionally add class->name_version and class->subclass to the class name
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Ingo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d38e1d5a
    • Peter Zijlstra's avatar
      lockstat: measure lock bouncing · 96645678
      Peter Zijlstra authored
          __acquire
              |
             lock _____
              |        \
              |    __contended
              |         |
              |        wait
              | _______/
              |/
              |
         __acquired
              |
         __release
              |
           unlock
      
      We measure acquisition and contention bouncing.
      
      This is done by recording a cpu stamp in each lock instance.
      
      Contention bouncing requires the cpu stamp to be set on acquisition. Hence we
      move __acquired into the generic path.
      
      __acquired is then used to measure acquisition bouncing by comparing the
      current cpu with the old stamp before replacing it.
      
      __contended is used to measure contention bouncing (only useful for preemptable
      locks)
      
      [akpm@linux-foundation.org: cleanups]
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Acked-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      96645678
    • Peter Zijlstra's avatar
      lockdep: various fixes · 4b32d0a4
      Peter Zijlstra authored
       - update the copyright notices
       - use the default hash function
       - fix a thinko in a BUILD_BUG_ON
       - add a WARN_ON to spot inconsitent naming
       - fix a termination issue in /proc/lock_stat
      
      [akpm@linux-foundation.org: cleanups]
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Acked-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4b32d0a4
    • Peter Zijlstra's avatar
      lockstat: human readability tweaks · c46261de
      Peter Zijlstra authored
      Present all this fancy new lock statistics information:
      
      *warning, _wide_ output ahead*
      
      (output edited for purpose of brevity)
      
       # cat /proc/lock_stat
      lock_stat version 0.1
      -----------------------------------------------------------------------------------------------------------------------------------------------------------------
                                    class name    contentions   waittime-min   waittime-max waittime-total   acquisitions   holdtime-min   holdtime-max holdtime-total
      -----------------------------------------------------------------------------------------------------------------------------------------------------------------
      
                               &inode->i_mutex:         14458           6.57      398832.75     2469412.23        6768876           0.34    11398383.65   339410830.89
                               ---------------
                               &inode->i_mutex           4486          [<ffffffff802a08f9>] pipe_wait+0x86/0x8d
                               &inode->i_mutex              0          [<ffffffff802a01e8>] pipe_write_fasync+0x29/0x5d
                               &inode->i_mutex              0          [<ffffffff802a0e18>] pipe_read+0x74/0x3a5
                               &inode->i_mutex              0          [<ffffffff802a1a6a>] do_lookup+0x81/0x1ae
      
      .................................................................................................................................................................
      
                    &inode->i_data.tree_lock-W:           491           0.27          62.47         493.89        2477833           0.39         468.89     1146584.25
                    &inode->i_data.tree_lock-R:            65           0.44           4.27          48.78       26288792           0.36         184.62    10197458.24
                    --------------------------
                      &inode->i_data.tree_lock             46          [<ffffffff80277095>] __do_page_cache_readahead+0x69/0x24f
                      &inode->i_data.tree_lock             31          [<ffffffff8026f9fb>] add_to_page_cache+0x31/0xba
                      &inode->i_data.tree_lock              0          [<ffffffff802770ee>] __do_page_cache_readahead+0xc2/0x24f
                      &inode->i_data.tree_lock              0          [<ffffffff8026f6e4>] find_get_page+0x1a/0x58
      
      .................................................................................................................................................................
      
                            proc_inum_idr.lock:             0           0.00           0.00           0.00             36           0.00          65.60         148.26
                              proc_subdir_lock:             0           0.00           0.00           0.00        3049859           0.00         106.81     1563212.42
                              shrinker_rwsem-W:             0           0.00           0.00           0.00              5           0.00           1.73           3.68
                              shrinker_rwsem-R:             0           0.00           0.00           0.00            633           2.57         246.57       10909.76
      
      'contentions' and 'acquisitions' are the number of such events measured (since
      the last reset). The waittime- and holdtime- (min, max, total) numbers are
      presented in microseconds.
      
      If there are any contention points, the lock class is presented in the block
      format (as i_mutex and tree_lock above), otherwise a single line of output is
      presented.
      
      The output is sorted on absolute number of contentions (read + write), this
      should get the worst offenders presented first, so that:
      
       # grep : /proc/lock_stat | head
      
      will quickly show who's bad.
      
      The stats can be reset using:
      
       # echo 0 > /proc/lock_stat
      
      [bunk@stusta.de: make 2 functions static]
      [akpm@linux-foundation.org: fix printk warning]
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Acked-by: default avatarIngo Molnar <mingo@elte.hu>
      Acked-by: default avatarJason Baron <jbaron@redhat.com>
      Signed-off-by: default avatarAdrian Bunk <bunk@stusta.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c46261de
    • Peter Zijlstra's avatar
      lockdep: reduce the ifdeffery · 8e18257d
      Peter Zijlstra authored
      Move code around to get fewer but larger #ifdef sections.  Break some
      in-function #ifdefs out into their own functions.
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Acked-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8e18257d
  15. 14 Feb, 2007 1 commit
    • Tim Schmielau's avatar
      [PATCH] remove many unneeded #includes of sched.h · cd354f1a
      Tim Schmielau authored
      After Al Viro (finally) succeeded in removing the sched.h #include in module.h
      recently, it makes sense again to remove other superfluous sched.h includes.
      There are quite a lot of files which include it but don't actually need
      anything defined in there.  Presumably these includes were once needed for
      macros that used to live in sched.h, but moved to other header files in the
      course of cleaning it up.
      
      To ease the pain, this time I did not fiddle with any header files and only
      removed #includes from .c-files, which tend to cause less trouble.
      
      Compile tested against 2.6.20-rc2 and 2.6.20-rc2-mm2 (with offsets) on alpha,
      arm, i386, ia64, mips, powerpc, and x86_64 with allnoconfig, defconfig,
      allmodconfig, and allyesconfig as well as a few randconfigs on x86_64 and all
      configs in arch/arm/configs on arm.  I also checked that no new warnings were
      introduced by the patch (actually, some warnings are removed that were emitted
      by unnecessarily included header files).
      Signed-off-by: default avatarTim Schmielau <tim@physik3.uni-rostock.de>
      Acked-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      cd354f1a
  16. 11 Feb, 2007 2 commits
  17. 07 Dec, 2006 1 commit
  18. 03 Jul, 2006 1 commit