1. 01 Jun, 2009 9 commits
    • Li Zefan's avatar
      tracing/stat: do some cleanups · dbd3fbdf
      Li Zefan authored
      
      
      - remove duplicate code in stat_seq_init()
      - update comments to reflect the change from stat list to stat rbtree
      
      [ Impact: clean up ]
      Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      dbd3fbdf
    • Li Zefan's avatar
      tracing/stat: remember to free root node · e1622806
      Li Zefan authored
      
      
      When closing a trace_stat file, we destroy the rbtree constructed during
      file open, but there is memory leak that the root node is not freed.
      
      [ Impact: fix memory leak when closing a trace_stat file ]
      Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      e1622806
    • Li Zefan's avatar
      tracing/stat: change dummpy_cmp() to return -1 · b3dd7ba7
      Li Zefan authored
      
      
      Currently the output of trace_stat/workqueues is totally reversed:
      
       # cat /debug/tracing/trace_stat/workqueues
          ...
          1       17       17      210       37   `-blk_unplug_work+0x0/0x57
          1     3779     3779      181       11   |-cfq_kick_queue+0x0/0x2f
          1     3796     3796                     kblockd/1:120
          ...
      
      The correct output should be:
      
          1     3796     3796                     kblockd/1:120
          1     3779     3779      181       11   |-cfq_kick_queue+0x0/0x2f
          1       17       17      210       37   `-blk_unplug_work+0x0/0x57
      
      It's caused by "tracing/stat: replace linked list by an rbtree for
      sorting"
      (53059c9b67a62a3dc8c80204d3da42b9267ea5a0).
      
      dummpy_cmp() should return -1, so rb_node will always be inserted as
      right-most node in the rbtree, thus we sort the output in ascending
      order.
      
      [ Impact: fix the output of trace_stat/workqueues ]
      Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      b3dd7ba7
    • Frederic Weisbecker's avatar
      tracing/stat: replace linked list by an rbtree for sorting · 8f184f27
      Frederic Weisbecker authored
      
      
      When the stat tracing framework prepares the entries from a tracer
      to output them to the user, it starts by computing a linear sort
      through a linked list to give the entries ordered by relevance
      to the user.
      
      This is quite ugly and causes a small latency when we begin to
      read the file.
      
      This patch changes that by turning the linked list into a red-black
      tree. Athough the whole iteration using the start and next tracer
      callbacks while opening the file remain the same, it is now much
      more fast and scalable.
      
      The rbtree guarantees O(log(n)) insertions whereas a linked
      list with linear sorting brought us a O(n) despair. Now the
      (visible) latency has disapeared.
      
      [ Impact: kill the latency while starting to read a stat tracer file ]
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      8f184f27
    • Frederic Weisbecker's avatar
      tracing/stat: replace trace_stat_session by stat_session · 0d64f834
      Frederic Weisbecker authored
      
      
      The "trace" prefix in struct trace_stat_session type is annoying while
      reading the trace_stat.c file. It makes the lines longer, and
      is not that much useful to explain the sense of this type.
      
      Just keep "struct stat_session" for this type.
      
      [ Impact: make the code a bit more readable ]
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      0d64f834
    • Zhaolei's avatar
      trace_workqueue: remove blank line between each cpu · f3c4ae26
      Zhaolei authored
      
      
      The blankline between each cpu's workqueue stat is not necessary, because
      the cpu number is enough to part them by eye.
      Old style also caused a blankline below headline, and made code complex
      by using lock, disableirq and get cpu var.
      
      Old style:
       # CPU  INSERTED  EXECUTED   NAME
       # |      |         |          |
      
         0   8644       8644       events/0
         0      0          0       cpuset
         ...
         0      1          1       kdmflush
      
         1  35365      35365       events/1
         ...
      
      New style:
       # CPU  INSERTED  EXECUTED   NAME
       # |      |         |          |
      
         0   8644       8644       events/0
         0      0          0       cpuset
         ...
         0      1          1       kdmflush
         1  35365      35365       events/1
         ...
      
      [ Impact: provide more readable code ]
      Signed-off-by: default avatarZhao Lei <zhaolei@cn.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Tom Zanussi <tzanussi@gmail.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      f3c4ae26
    • Zhaolei's avatar
      trace_workqueue: remove cpu_workqueue_stats->first_entry · b8867164
      Zhaolei authored
      
      
      cpu_workqueue_stats->first_entry is useless because we can retrieve the
      header of a cpu workqueue using:
      if (&cpu_workqueue_stats->list == workqueue_cpu_stat(cpu)->list.next)
      
      [ Impact: cleanup ]
      Signed-off-by: default avatarZhao Lei <zhaolei@cn.fujitsu.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Tom Zanussi <tzanussi@gmail.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      b8867164
    • Zhaolei's avatar
      trace_workqueue: use list_for_each_entry() instead of list_for_each_entry_safe() · 1fdfca9c
      Zhaolei authored
      
      
      No need to use list_for_each_entry_safe() in iteration without deleting
      any node, we can use list_for_each_entry() instead.
      
      [ Impact: cleanup ]
      Signed-off-by: default avatarZhao Lei <zhaolei@cn.fujitsu.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Tom Zanussi <tzanussi@gmail.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      1fdfca9c
    • Zhaolei's avatar
      ftrace, workqueuetrace: make workqueue tracepoints use TRACE_EVENT macro · fb39125f
      Zhaolei authored
      
      
      v3: zhaolei@cn.fujitsu.com: Change TRACE_EVENT definition to new format
          introduced by Steven Rostedt: consolidate trace and trace_event headers
      v2: kosaki@jp.fujitsu.com: print the function names instead of addr, and zap
          the work addr
      v1: zhaolei@cn.fujitsu.com: Make workqueue tracepoints use TRACE_EVENT macro
      
      TRACE_EVENT is a more generic way to define tracepoints.
      Doing so adds these new capabilities to the tracepoints:
      
        - zero-copy and per-cpu splice() tracing
        - binary tracing without printf overhead
        - structured logging records exposed under /debug/tracing/events
        - trace events embedded in function tracer output and other plugins
        - user-defined, per tracepoint filter expressions
      
      Then, this patch converts DEFINE_TRACE to TRACE_EVENT in workqueue related
      tracepoints.
      
      [ Impact: expand workqueue tracer to events tracing ]
      Signed-off-by: default avatarZhao Lei <zhaolei@cn.fujitsu.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Tom Zanussi <tzanussi@gmail.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      fb39125f
  2. 27 May, 2009 2 commits
    • Zhaolei's avatar
      ftrace: don't convert function's local variable name in macro · f2aebaee
      Zhaolei authored
      
      
      "call" is an argument of macro, but it is also used as a local
      variable name of function in macro.
      We should keep this local variable name distinct from any
      CPP macro parameter name if both are in the same macro scope,
      although it hasn't caused any problem yet.
      
      [ Impact: robustify macro ]
      Signed-off-by: default avatarZhao Lei <zhaolei@cn.fujitsu.com>
      Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      f2aebaee
    • Heiko Carstens's avatar
      trace: disable preemption before taking raw spinlocks · 5b6045a9
      Heiko Carstens authored
      
      
      s390 code uses smp_processor_id() in __raw_spin_lock() code which
      reveals that a (raw) spinlock is taken without preemption disabled.
      This can potentially deadlock.
      
      To fix this explicitly disable and enable preemption.
      
      BUG: using smp_processor_id() in preemptible [00000000] code: cat/2278
      caller is trace_find_cmdline+0x40/0xfc
      CPU: 0 Not tainted 2.6.30-rc7-dirty #39
      Process cat (pid: 2278, task: 000000003faedb68, ksp: 000000003b33b988)
      000000003b33b988 000000003b33bae0 0000000000000002 0000000000000000
             000000003b33bb80 000000003b33baf8 000000003b33baf8 00000000000175d6
             0000000000000001 000000003b33b988 000000003f9b0000 000000000000000b
             000000000000000c 000000003b33bb40 000000003b33bae0 0000000000000000
             0000000000000000 00000000000175d6 000000003b33bae0 000000003b33bb28
      Call Trace:
      ([<00000000000174b2>] show_trace+0x112/0x170)
       [<0000000000017582>] show_stack+0x72/0x100
       [<0000000000441538>] dump_stack+0xc8/0xd8
       [<000000000025c350>] debug_smp_processor_id+0x114/0x130
       [<00000000000bf0e4>] trace_find_cmdline+0x40/0xfc
       [<00000000000c35d4>] trace_print_context+0x58/0xac
       [<00000000000bb676>] print_trace_line+0x416/0x470
       [<00000000000bc8fe>] s_show+0x4e/0x428
       [<000000000013834e>] seq_read+0x36a/0x5d4
       [<0000000000112a78>] vfs_read+0xc8/0x174
       [<0000000000112c58>] SyS_read+0x74/0xc4
       [<000000000002c7ae>] sysc_noemu+0x10/0x16
       [<000002000012436c>] 0x2000012436c
      1 lock held by cat/2278:
       #0:  (&p->lock){+.+.+.}, at: [<0000000000138056>] seq_read+0x72/0x5d4
      
      [ Impact: fix preempt-unsafe raw spinlock ]
      Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
      Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      5b6045a9
  3. 26 May, 2009 8 commits
    • Steven Rostedt's avatar
      tracing: convert irq events to use __print_symbolic · c2adae09
      Steven Rostedt authored
      
      
      The recording of the names at trace time is inefficient. This patch
      implements the softirq event recording to only record the vector
      and then use the __print_symbolic interface to print out the names.
      
      [ Impact: faster recording of softirq events ]
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      c2adae09
    • Steven Rostedt's avatar
      tracing: add __print_symbolic to trace events · 0f4fc29d
      Steven Rostedt authored
      
      
      This patch adds __print_symbolic which is similar to __print_flags but
      works for an enumeration type instead. That is, there is only a one to one
      mapping between the values and the symbols. When a match is made, then
      it is printed, otherwise the hex value is outputed.
      
      [ Impact: add interface for showing symbol names in events ]
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      0f4fc29d
    • Steven Rostedt's avatar
      tracing: add flag output for kmem events · 62ba180e
      Steven Rostedt authored
      
      
      This patch changes the output for gfp_flags from being a simple hex value
      to the actual names.
      
        gfp_flags=GFP_ATOMIC  instead of gfp_flags=00000020
      
      And even
      
        gfp_flags=GFP_KERNEL instead of gfp_flags=000000d0
      
      (Thanks to Frederic Weisbecker for pointing out that the first version
       had a bad order of GFP masks)
      
      [ Impact: more human readable output from tracer ]
      Acked-by: default avatarEduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      62ba180e
    • Steven Rostedt's avatar
      tracing: add previous task state info to sched switch event · 937cdb9d
      Steven Rostedt authored
      
      
      It is useful to see the state of a task that is being switched out.
      This patch adds the output of the state of the previous task in
      the context switch event.
      
      [ Impact: see state of switched out task in context switch ]
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      937cdb9d
    • Steven Rostedt's avatar
      tracing: add __print_flags for events · be74b73a
      Steven Rostedt authored
      
      
      Developers have been asking for the ability in the ftrace event tracer
      to display names of bits in a flags variable.
      
      Instead of printing out c2, it would be easier to read FOO|BAR|GOO,
      assuming that FOO is bit 1, BAR is bit 6 and GOO is bit 7.
      
      Some examples where this would be useful are the state flags in a context
      switch, kmalloc flags, and even permision flags in accessing files.
      
      [
        v2 changes include:
      
        Frederic Weisbecker's idea of using a mask instead of bits,
        thus we can output GFP_KERNEL instead of GPF_WAIT|GFP_IO|GFP_FS.
      
        Li Zefan's idea of allowing the caller of __print_flags to add their
        own delimiter (or no delimiter) where we can get for file permissions
        rwx instead of r|w|x.
      ]
      
      [
        v3 changes:
      
         Christoph Hellwig's idea of using an array instead of va_args.
      ]
      
      [ Impact: better displaying of flags in trace output ]
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      be74b73a
    • Zhaolei's avatar
      ftrace: clean up of using ftrace_event_enable_disable() · 0e907c99
      Zhaolei authored
      
      
      Always use ftrace_event_enable_disable() to enable/disable an event
      so that we can factorize out the event toggling code.
      
      [ Impact: factorize and cleanup event tracing code ]
      Signed-off-by: default avatarZhao Lei <zhaolei@cn.fujitsu.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Tom Zanussi <tzanussi@gmail.com>
      LKML-Reference: <4A14FDFE.2080402@cn.fujitsu.com>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      0e907c99
    • Zhaolei's avatar
      ftrace: Add task_comm support for trace_event · b11c53e1
      Zhaolei authored
      
      
      If we enable a trace event alone without any tracer running (such as
      function tracer, sched switch tracer, etc...) it can't output enough
      task command information.
      
      We need to use the tracing_{start/stop}_cmdline_record() helpers
      which are designed to keep track of cmdlines for any tasks that
      were scheduled during the tracing.
      
      Before this patch:
       # echo 1 > debugfs/tracing/events/sched/sched_switch/enable
       # cat debugfs/tracing/trace
       # tracer: nop
       #
       #           TASK-PID    CPU#    TIMESTAMP  FUNCTION
       #              | |       |          |         |
                  <...>-2289  [000] 526276.724790: sched_switch: task bash:2289 [120] ==> sshd:2287 [120]
                  <...>-2287  [000] 526276.725231: sched_switch: task sshd:2287 [120] ==> bash:2289 [120]
                  <...>-2289  [000] 526276.725452: sched_switch: task bash:2289 [120] ==> sshd:2287 [120]
                  <...>-2287  [000] 526276.727181: sched_switch: task sshd:2287 [120] ==> swapper:0 [140]
                 <idle>-0     [000] 526277.032734: sched_switch: task swapper:0 [140] ==> events/0:5 [115]
                  <...>-5     [000] 526277.032782: sched_switch: task events/0:5 [115] ==> swapper:0 [140]
       ...
      
      After this patch:
       # tracer: nop
       #
       #           TASK-PID    CPU#    TIMESTAMP  FUNCTION
       #              | |       |          |         |
                   bash-2269  [000] 527347.989229: sched_switch: task bash:2269 [120] ==> sshd:2267 [120]
                   sshd-2267  [000] 527347.990960: sched_switch: task sshd:2267 [120] ==> bash:2269 [120]
                   bash-2269  [000] 527347.991143: sched_switch: task bash:2269 [120] ==> sshd:2267 [120]
                   sshd-2267  [000] 527347.992959: sched_switch: task sshd:2267 [120] ==> swapper:0 [140]
                 <idle>-0     [000] 527348.531989: sched_switch: task swapper:0 [140] ==> events/0:5 [115]
               events/0-5     [000] 527348.532115: sched_switch: task events/0:5 [115] ==> swapper:0 [140]
       ...
      
      Changelog:
      v1->v2: Update Kconfig to select CONTEXT_SWITCH_TRACER in
              ENABLE_EVENT_TRACING
      v2->v3: v2 can solve problem that was caused by config EVENT_TRACING
              alone, but when CONFIG_FTRACE is off and CONFIG_TRACING is
              selected by other config, compile fail happened again.
              This version solves it.
      
      [ Impact: fix incomplete output of event tracing ]
      Signed-off-by: default avatarZhao Lei <zhaolei@cn.fujitsu.com>
      Cc: Tom Zanussi <tzanussi@gmail.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      LKML-Reference: <4A14FDFE.2080402@cn.fujitsu.com>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      b11c53e1
    • Pekka Enberg's avatar
      kmemtrace: fix kernel parameter documentation · 29fcefba
      Pekka Enberg authored
      
      
      The kmemtrace.enable kernel parameter no longer works. To enable
      kmemtrace at boot-time, you must pass "ftrace=kmemtrace" instead.
      
      [ Impact: remove obsolete kernel parameter documentation ]
      
      Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
      Signed-off-by: default avatarPekka Enberg <penberg@cs.helsinki.fi>
      LKML-Reference: <alpine.DEB.2.00.0905241112190.10296@rocky>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      29fcefba
  4. 25 May, 2009 2 commits
    • Li Zefan's avatar
      tracing/events: change the type of __str_loc_item to unsigned short · b0aae68c
      Li Zefan authored
      
      
      When defining a dynamic size string, we add __str_loc_##item to the
      trace entry, and it stores the location of the actual string in
      entry->_str_data[]
      
      'unsigned short' should be sufficient to store this information, thus
      we save 2 bytes per dyn-size string in the ring buffer.
      
      [ Impact: reduce memory occupied by dyn-size strings in ring buffer ]
      Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      LKML-Reference: <4A14EDB6.2050507@cn.fujitsu.com>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      b0aae68c
    • Lai Jiangshan's avatar
      tracing: add trace_event_read_lock() · 4f535968
      Lai Jiangshan authored
      
      
      I found that there is nothing to protect event_hash in
      ftrace_find_event(). Rcu protects the event hashlist
      but not the event itself while we use it after its extraction
      through ftrace_find_event().
      
      This lack of a proper locking in this spot opens a race
      window between any event dereferencing and module removal.
      
      Eg:
      
      --Task A--
      
      print_trace_line(trace) {
        event = find_ftrace_event(trace)
      
      --Task B--
      
      trace_module_remove_events(mod) {
        list_trace_events_module(ev, mod) {
          unregister_ftrace_event(ev->event) {
            hlist_del(ev->event->node)
              list_del(....)
          }
        }
      }
      |--> module removed, the event has been dropped
      
      --Task A--
      
        event->print(trace); // Dereferencing freed memory
      
      If the event retrieved belongs to a module and this module
      is concurrently removed, we may end up dereferencing a data
      from a freed module.
      
      RCU could solve this, but it would add latency to the kernel and
      forbid tracers output callbacks to call any sleepable code.
      So this fix converts 'trace_event_mutex' to a read/write semaphore,
      and adds trace_event_read_lock() to protect ftrace_find_event().
      
      [ Impact: fix possible freed memory dereference in ftrace ]
      Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
      Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      LKML-Reference: <4A114806.7090302@cn.fujitsu.com>
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      4f535968
  5. 20 May, 2009 1 commit
  6. 19 May, 2009 2 commits
    • Stefan Raspl's avatar
      blktrace: remove debugfs entries on bad path · fd51d251
      Stefan Raspl authored
      
      
      debugfs directory entries for devices are not removed on some
      of the failure pathes in do_blk_trace_setup().
      One way to reproduce is to start blktrace on multiple devices
      with insufficient Vmalloc space: Devices will fail with
      a message like this:
      
      	BLKTRACESETUP(2) /dev/sdu failed: 5/Input/output error
      
      If so, the respective entries in debugfs
      (e.g. /sys/kernel/debug/block/sdu) will remain and subsequent
      attempts to start blktrace on the respective devices will not
      succeed due to existing directories.
      
      [ Impact: fix /debug/tracing file cleanup corner case ]
      Signed-off-by: default avatarStefan Raspl <stefan.raspl@linux.vnet.ibm.com>
      Acked-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
      Cc: Li Zefan <lizf@cn.fujitsu.com>
      Cc: schwidefsky@de.ibm.com
      Cc: heiko.carstens@de.ibm.com
      LKML-Reference: <4A1266CC.5040801@linux.vnet.ibm.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      fd51d251
    • Li Zefan's avatar
      tracing/events: Documentation updates · 143c145e
      Li Zefan authored
      
      
      - fix some typos
      - document the difference between '>' and '>>'
      - document the 'enable' toggle
      - remove section "Defining an event-enabled tracepoint", since it's
        out-dated and sample/trace_events/ already serves this purpose.
      
      v2: add "Updated by Li Zefan"
      
      [ Impact: make documentation up-to-date ]
      Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: "Theodore Ts'o" <tytso@mit.edu>
      LKML-Reference: <4A125503.5060406@cn.fujitsu.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      143c145e
  7. 18 May, 2009 2 commits
  8. 16 May, 2009 1 commit
  9. 15 May, 2009 13 commits