1. 09 5月, 2010 1 次提交
    • F
      tracing: Drop lock_acquired waittime field · 883a2a31
      Frederic Weisbecker 提交于
      Drop the waittime field from the lock_acquired event, we can
      calculate it by substracting the lock_acquired event timestamp
      with the matching lock_acquire one.
      
      It is not needed and takes useless space in the traces.
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      883a2a31
  2. 30 3月, 2010 1 次提交
    • T
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking... · 5a0e3ad6
      Tejun Heo 提交于
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
      
      percpu.h is included by sched.h and module.h and thus ends up being
      included when building most .c files.  percpu.h includes slab.h which
      in turn includes gfp.h making everything defined by the two files
      universally available and complicating inclusion dependencies.
      
      percpu.h -> slab.h dependency is about to be removed.  Prepare for
      this change by updating users of gfp and slab facilities include those
      headers directly instead of assuming availability.  As this conversion
      needs to touch large number of source files, the following script is
      used as the basis of conversion.
      
        http://userweb.kernel.org/~tj/misc/slabh-sweep.py
      
      The script does the followings.
      
      * Scan files for gfp and slab usages and update includes such that
        only the necessary includes are there.  ie. if only gfp is used,
        gfp.h, if slab is used, slab.h.
      
      * When the script inserts a new include, it looks at the include
        blocks and try to put the new include such that its order conforms
        to its surrounding.  It's put in the include block which contains
        core kernel includes, in the same order that the rest are ordered -
        alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
        doesn't seem to be any matching order.
      
      * If the script can't find a place to put a new include (mostly
        because the file doesn't have fitting include block), it prints out
        an error message indicating which .h file needs to be added to the
        file.
      
      The conversion was done in the following steps.
      
      1. The initial automatic conversion of all .c files updated slightly
         over 4000 files, deleting around 700 includes and adding ~480 gfp.h
         and ~3000 slab.h inclusions.  The script emitted errors for ~400
         files.
      
      2. Each error was manually checked.  Some didn't need the inclusion,
         some needed manual addition while adding it to implementation .h or
         embedding .c file was more appropriate for others.  This step added
         inclusions to around 150 files.
      
      3. The script was run again and the output was compared to the edits
         from #2 to make sure no file was left behind.
      
      4. Several build tests were done and a couple of problems were fixed.
         e.g. lib/decompress_*.c used malloc/free() wrappers around slab
         APIs requiring slab.h to be added manually.
      
      5. The script was run on all .h files but without automatically
         editing them as sprinkling gfp.h and slab.h inclusions around .h
         files could easily lead to inclusion dependency hell.  Most gfp.h
         inclusion directives were ignored as stuff from gfp.h was usually
         wildly available and often used in preprocessor macros.  Each
         slab.h inclusion directive was examined and added manually as
         necessary.
      
      6. percpu.h was updated not to include slab.h.
      
      7. Build test were done on the following configurations and failures
         were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
         distributed build env didn't work with gcov compiles) and a few
         more options had to be turned off depending on archs to make things
         build (like ipr on powerpc/64 which failed due to missing writeq).
      
         * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
         * powerpc and powerpc64 SMP allmodconfig
         * sparc and sparc64 SMP allmodconfig
         * ia64 SMP allmodconfig
         * s390 SMP allmodconfig
         * alpha SMP allmodconfig
         * um on x86_64 SMP allmodconfig
      
      8. percpu.h modifications were reverted so that it could be applied as
         a separate patch and serve as bisection point.
      
      Given the fact that I had only a couple of failures from tests on step
      6, I'm fairly confident about the coverage of this conversion patch.
      If there is a breakage, it's likely to be something in one of the arch
      headers which should be easily discoverable easily on most builds of
      the specific arch.
      Signed-off-by: NTejun Heo <tj@kernel.org>
      Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
      5a0e3ad6
  3. 29 3月, 2010 1 次提交
  4. 10 3月, 2010 1 次提交
    • F
      lockdep: Move lock events under lockdep recursion protection · db2c4c77
      Frederic Weisbecker 提交于
      There are rcu locked read side areas in the path where we submit
      a trace event. And these rcu_read_(un)lock() trigger lock events,
      which create recursive events.
      
      One pair in do_perf_sw_event:
      
      __lock_acquire
            |
            |--96.11%-- lock_acquire
            |          |
            |          |--27.21%-- do_perf_sw_event
            |          |          perf_tp_event
            |          |          |
            |          |          |--49.62%-- ftrace_profile_lock_release
            |          |          |          lock_release
            |          |          |          |
            |          |          |          |--33.85%-- _raw_spin_unlock
      
      Another pair in perf_output_begin/end:
      
      __lock_acquire
            |--23.40%-- perf_output_begin
            |          |          __perf_event_overflow
            |          |          perf_swevent_overflow
            |          |          perf_swevent_add
            |          |          perf_swevent_ctx_event
            |          |          do_perf_sw_event
            |          |          perf_tp_event
            |          |          |
            |          |          |--55.37%-- ftrace_profile_lock_acquire
            |          |          |          lock_acquire
            |          |          |          |
            |          |          |          |--37.31%-- _raw_spin_lock
      
      The problem is not that much the trace recursion itself, as we have a
      recursion protection already (though it's always wasteful to recurse).
      But the trace events are outside the lockdep recursion protection, then
      each lockdep event triggers a lock trace, which will trigger two
      other lockdep events. Here the recursive lock trace event won't
      be taken because of the trace recursion, so the recursion stops there
      but lockdep will still analyse these new events:
      
      To sum up, for each lockdep events we have:
      
      	lock_*()
      	     |
                   trace lock_acquire
                        |
                        ----- rcu_read_lock()
                        |          |
                        |          lock_acquire()
                        |          |
                        |          trace_lock_acquire() (stopped)
                        |          |
      		  |          lockdep analyze
                        |
                        ----- rcu_read_unlock()
                                   |
                                   lock_release
                                   |
                                   trace_lock_release() (stopped)
                                   |
                                   lockdep analyze
      
      And you can repeat the above two times as we have two rcu read side
      sections when we submit an event.
      
      This is fixed in this patch by moving the lock trace event under
      the lockdep recursion protection.
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
      Cc: Li Zefan <lizf@cn.fujitsu.com>
      Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
      Cc: Masami Hiramatsu <mhiramat@redhat.com>
      Cc: Jens Axboe <jens.axboe@oracle.com>
      db2c4c77
  5. 04 3月, 2010 1 次提交
  6. 26 2月, 2010 1 次提交
  7. 25 2月, 2010 1 次提交
  8. 27 1月, 2010 1 次提交
    • O
      lockdep: Fix check_usage_backwards() error message · 48d50674
      Oleg Nesterov 提交于
      Lockdep has found the real bug, but the output doesn't look right to me:
      
      > =========================================================
      > [ INFO: possible irq lock inversion dependency detected ]
      > 2.6.33-rc5 #77
      > ---------------------------------------------------------
      > emacs/1609 just changed the state of lock:
      >  (&(&tty->ctrl_lock)->rlock){+.....}, at: [<ffffffff8127c648>] tty_fasync+0xe8/0x190
      > but this lock took another, HARDIRQ-unsafe lock in the past:
      >  (&(&sighand->siglock)->rlock){-.....}
      
      "HARDIRQ-unsafe" and "this lock took another" looks wrong, afaics.
      
      >   ... key      at: [<ffffffff81c054a4>] __key.46539+0x0/0x8
      >   ... acquired at:
      >    [<ffffffff81089af6>] __lock_acquire+0x1056/0x15a0
      >    [<ffffffff8108a0df>] lock_acquire+0x9f/0x120
      >    [<ffffffff81423012>] _raw_spin_lock_irqsave+0x52/0x90
      >    [<ffffffff8127c1be>] __proc_set_tty+0x3e/0x150
      >    [<ffffffff8127e01d>] tty_open+0x51d/0x5e0
      
      The stack-trace shows that this lock (ctrl_lock) was taken under
      ->siglock (which is hopefully irq-safe).
      
      This is a clear typo in check_usage_backwards() where we tell the print a
      fancy routine we're forwards.
      Signed-off-by: NOleg Nesterov <oleg@redhat.com>
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      LKML-Reference: <20100126181641.GA10460@redhat.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      48d50674
  9. 15 12月, 2009 3 次提交
  10. 10 12月, 2009 1 次提交
  11. 06 12月, 2009 1 次提交
  12. 13 11月, 2009 1 次提交
  13. 29 10月, 2009 1 次提交
    • T
      percpu: make percpu symbols under kernel/ and mm/ unique · 1871e52c
      Tejun Heo 提交于
      This patch updates percpu related symbols under kernel/ and mm/ such
      that percpu symbols are unique and don't clash with local symbols.
      This serves two purposes of decreasing the possibility of global
      percpu symbol collision and allowing dropping per_cpu__ prefix from
      percpu symbols.
      
      * kernel/lockdep.c: s/lock_stats/cpu_lock_stats/
      
      * kernel/sched.c: s/init_rq_rt/init_rt_rq_var/	(any better idea?)
        		  s/sched_group_cpus/sched_groups/
      
      * kernel/softirq.c: s/ksoftirqd/run_ksoftirqd/a
      
      * kernel/softlockup.c: s/(*)_timestamp/softlockup_\1_ts/
        		       s/watchdog_task/softlockup_watchdog/
      		       s/timestamp/ts/ for local variables
      
      * kernel/time/timer_stats: s/lookup_lock/tstats_lookup_lock/
      
      * mm/slab.c: s/reap_work/slab_reap_work/
        	     s/reap_node/slab_reap_node/
      
      * mm/vmstat.c: local variable changed to avoid collision with vmstat_work
      
      Partly based on Rusty Russell's "alloc_percpu: rename percpu vars
      which cause name clashes" patch.
      Signed-off-by: NTejun Heo <tj@kernel.org>
      Acked-by: N(slab/vmstat) Christoph Lameter <cl@linux-foundation.org>
      Reviewed-by: NChristoph Lameter <cl@linux-foundation.org>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Nick Piggin <npiggin@suse.de>
      1871e52c
  14. 09 10月, 2009 1 次提交
  15. 23 9月, 2009 1 次提交
  16. 29 8月, 2009 1 次提交
  17. 02 8月, 2009 6 次提交
    • M
      lockdep: Fix memory usage info of BFS · 90629209
      Ming Lei 提交于
      The unit is KB, so sizeof(struct circular_queue) should be
      divided by 1024.
      Signed-off-by: NMing Lei <tom.leiming@gmail.com>
      Cc: akpm@linux-foundation.org
      Cc: torvalds@linux-foundation.org
      Cc: davem@davemloft.net
      Cc: Ming Lei <tom.leiming@gmail.com>
      Cc: a.p.zijlstra@chello.nl
      LKML-Reference: <1249220616-7190-1-git-send-email-tom.leiming@gmail.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      90629209
    • M
      lockdep: Reintroduce generation count to make BFS faster · e351b660
      Ming Lei 提交于
      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: NMing Lei <tom.leiming@gmail.com>
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: "David S. Miller" <davem@davemloft.net>
      LKML-Reference: <1248274089-6358-1-git-send-email-tom.leiming@gmail.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      e351b660
    • P
      lockdep: Deal with many similar locks · bb97a91e
      Peter Zijlstra 提交于
      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: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Marcelo Tosatti <mtosatti@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      bb97a91e
    • P
      lockdep: Introduce lockdep_assert_held() · f607c668
      Peter Zijlstra 提交于
      Add a lockdep helper to validate that we indeed are the owner
      of a lock.
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      f607c668
    • P
      lockdep: Fix style nits · 98c33edd
      Peter Zijlstra 提交于
      fixes a few comments and whitespaces that annoyed me.
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      98c33edd
    • P
      lockdep: Fix backtraces · 4f84f433
      Peter Zijlstra 提交于
      Truncate stupid -1 entries in backtraces.
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      LKML-Reference: <1248096665.15751.8816.camel@twins>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      4f84f433
  18. 24 7月, 2009 10 次提交
  19. 18 4月, 2009 1 次提交
    • P
      lockdep: more robust lockdep_map init sequence · c8a25005
      Peter Zijlstra 提交于
      Steven Rostedt reported:
      
      > OK, I think I figured this bug out. This is a lockdep issue with respect
      > to tracepoints.
      >
      > The trace points in lockdep are called all the time. Outside the lockdep
      > logic. But if lockdep were to trigger an error / warning (which this run
      > did) we might be in trouble. For new locks, like the dentry->d_lock, that
      > are created, they will not get a name:
      >
      > void lockdep_init_map(struct lockdep_map *lock, const char *name,
      >                       struct lock_class_key *key, int subclass)
      > {
      >         if (unlikely(!debug_locks))
      >                 return;
      >
      > When a problem is found by lockdep, debug_locks becomes false. Thus we
      > stop allocating names for locks. This dentry->d_lock I had, now has no
      > name. Worse yet, I have CONFIG_DEBUG_VM set, that scrambles non
      > initialized memory. Thus, when the trace point was hit, it had junk for
      > the lock->name, and the machine crashed.
      
      Ah, nice catch. I think we should put at least the name in regardless.
      
      Ensure we at least initialize the trivial entries of the depmap so that
      they can be relied upon, even when lockdep itself decided to pack up and
      go home.
      
      [ Impact: fix lock tracing after lockdep warnings. ]
      Reported-by: NSteven Rostedt <rostedt@goodmis.org>
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Acked-by: NSteven Rostedt <rostedt@goodmis.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      LKML-Reference: <1239954049.23397.4156.camel@laptop>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      c8a25005
  20. 15 4月, 2009 2 次提交
    • S
      tracing/events: move trace point headers into include/trace/events · ad8d75ff
      Steven Rostedt 提交于
      Impact: clean up
      
      Create a sub directory in include/trace called events to keep the
      trace point headers in their own separate directory. Only headers that
      declare trace points should be defined in this directory.
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Neil Horman <nhorman@tuxdriver.com>
      Cc: Zhao Lei <zhaolei@cn.fujitsu.com>
      Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
      Cc: Pekka Enberg <penberg@cs.helsinki.fi>
      Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
      ad8d75ff
    • S
      tracing: create automated trace defines · a8d154b0
      Steven Rostedt 提交于
      This patch lowers the number of places a developer must modify to add
      new tracepoints. The current method to add a new tracepoint
      into an existing system is to write the trace point macro in the
      trace header with one of the macros TRACE_EVENT, TRACE_FORMAT or
      DECLARE_TRACE, then they must add the same named item into the C file
      with the macro DEFINE_TRACE(name) and then add the trace point.
      
      This change cuts out the needing to add the DEFINE_TRACE(name).
      Every file that uses the tracepoint must still include the trace/<type>.h
      file, but the one C file must also add a define before the including
      of that file.
      
       #define CREATE_TRACE_POINTS
       #include <trace/mytrace.h>
      
      This will cause the trace/mytrace.h file to also produce the C code
      necessary to implement the trace point.
      
      Note, if more than one trace/<type>.h is used to create the C code
      it is best to list them all together.
      
       #define CREATE_TRACE_POINTS
       #include <trace/foo.h>
       #include <trace/bar.h>
       #include <trace/fido.h>
      
      Thanks to Mathieu Desnoyers and Christoph Hellwig for coming up with
      the cleaner solution of the define above the includes over my first
      design to have the C code include a "special" header.
      
      This patch converts sched, irq and lockdep and skb to use this new
      method.
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Neil Horman <nhorman@tuxdriver.com>
      Cc: Zhao Lei <zhaolei@cn.fujitsu.com>
      Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
      Cc: Pekka Enberg <penberg@cs.helsinki.fi>
      Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
      a8d154b0
  21. 10 4月, 2009 1 次提交
    • F
      tracing/lockdep: report the time waited for a lock · 2062501a
      Frederic Weisbecker 提交于
      While trying to optimize the new lock on reiserfs to replace
      the bkl, I find the lock tracing very useful though it lacks
      something important for performance (and latency) instrumentation:
      the time a task waits for a lock.
      
      That's what this patch implements:
      
        bash-4816  [000]   202.652815: lock_contended: lock_contended: &sb->s_type->i_mutex_key
        bash-4816  [000]   202.652819: lock_acquired: &rq->lock (0.000 us)
       <...>-4787  [000]   202.652825: lock_acquired: &rq->lock (0.000 us)
       <...>-4787  [000]   202.652829: lock_acquired: &rq->lock (0.000 us)
        bash-4816  [000]   202.652833: lock_acquired: &sb->s_type->i_mutex_key (16.005 us)
      
      As shown above, the "lock acquired" field is followed by the time
      it has been waiting for the lock. Usually, a lock contended entry
      is followed by a near lock_acquired entry with a non-zero time waited.
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Acked-by: NPeter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      LKML-Reference: <1238975373-15739-1-git-send-email-fweisbec@gmail.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      2062501a
  22. 31 3月, 2009 2 次提交