1. 18 2月, 2014 4 次提交
  2. 10 2月, 2014 1 次提交
    • M
      perf probe: Do not add offset twice to uprobe address · 981a2379
      Masami Hiramatsu 提交于
      Fix perf-probe not to add offset value twice to uprobe probe address
      when post processing.
      
      The tevs[i].point.address struct member is the address of symbol+offset,
      but current perf-probe adjusts the point.address by adding the offset.
      
      As a result, the probe address becomes symbol+offset+offset. This may
      cause unexpected code corruption. Urgent fix is needed.
      
      Without this fix:
        ---
        # ./perf probe -x ./perf dso__load_vmlinux+4
        # ./perf probe -l
          probe_perf:dso__load_vmlinux (on 0x000000000006d2b8)
        # nm ./perf.orig | grep dso__load_vmlinux\$
        000000000046d0a0 T dso__load_vmlinux
        ---
      
      You can see the given offset is 3 but the actual probed address is
      dso__load_vmlinux+8.
      
      With this fix:
        ---
        # ./perf probe -x ./perf dso__load_vmlinux+4
        # ./perf probe -l
          probe_perf:dso__load_vmlinux (on 0x000000000006d2b4)
        ---
      
      Now the problem is fixed.
      
      Note: This bug is introduced by
      	commit fb7345bbSigned-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Cc: "David A. Long" <dave.long@linaro.org>
      Cc: David Ahern <dsahern@gmail.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: yrl.pp-manager.tt@hitachi.com
      Link: http://lkml.kernel.org/r/20140205051858.6519.27314.stgit@kbuild-fedora.yrl.intra.hitachi.co.jpSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      981a2379
  3. 17 1月, 2014 3 次提交
  4. 14 1月, 2014 1 次提交
    • A
      perf probe: Fix build when DWARF support libraries not present · 1d027ee9
      Arnaldo Carvalho de Melo 提交于
      On a freshly installed system, after libelf-dev is installed we get:
      
          CC       /tmp/build/perf/util/probe-event.o
        util/probe-event.c: In function ‘try_to_find_probe_trace_events’:
        util/probe-event.c:753:46: error: unused parameter ‘target’ [-Werror=unused-parameter]
             int max_tevs __maybe_unused, const char *target)
                                                      ^
          CC       /tmp/build/perf/util/cgroup.o
        util/probe-event.c: At top level:
        util/probe-event.c:193:12: error: ‘get_text_start_address’ defined but not used [-Werror=unused-function]
         static int get_text_start_address(const char *exec, unsigned long *address)
                  ^
        cc1: all warnings being treated as errors
        make[1]: *** [/tmp/build/perf/util/probe-event.o] Error 1
        make[1]: *** Waiting for unfinished jobs....
        make: *** [install] Error 2
      
      Fix it by enclosing functions only used when those libraries are installed
      under the suitable preprocessor define and using __maybe_unused to a function
      that is only built when DWARF support is disabled.
      
      Problem introduced in this changeset:
      
        commit fb7345bb
        Author: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
        Date:   Thu Dec 26 05:41:53 2013 +0000
      
            perf probe: Support basic dwarf-based operations on uprobe events
      
      Cc: Adrian Hunter <adrian.hunter@intel.com>
      Cc: David Ahern <dsahern@gmail.com>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Jiri Olsa <jolsa@redhat.com>
      Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Stephane Eranian <eranian@google.com>
      Link: http://lkml.kernel.org/n/tip-73kc2fopt81517hrdgdra18o@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      1d027ee9
  5. 28 12月, 2013 2 次提交
  6. 27 12月, 2013 1 次提交
  7. 26 12月, 2013 2 次提交
    • M
      perf probe: Support basic dwarf-based operations on uprobe events · fb7345bb
      Masami Hiramatsu 提交于
      Support basic dwarf(debuginfo) based operations for uprobe events.  With
      this change, perf probe can analyze debuginfo of user application binary
      to set up new uprobe event.
      
      This allows perf-probe --add(with local variables, line numbers) and
      --line works with -x option.  (Actually, --vars has already accepted -x
      option)
      
      For example, the following command shows the probe-able lines of a given
      user space function. Something that so far was only available in the
      'perf probe' tool for kernel space functions:
      
        # ./perf probe -x perf --line map__load
        <map__load@/home/fedora/ksrc/linux-2.6/tools/perf/util/map.c:0>
              0  int map__load(struct map *map, symbol_filter_t filter)
              1  {
              2         const char *name = map->dso->long_name;
                        int nr;
      
              5         if (dso__loaded(map->dso, map->type))
              6                 return 0;
      
              8         nr = dso__load(map->dso, map, filter);
              9         if (nr < 0) {
             10                 if (map->dso->has_build_id) {
      
      And this shows the available variables at the given line of the
      function.
      
        # ./perf probe -x perf --vars map__load:8
        Available variables at map__load:8
                @<map__load+96>
                        char*   name
                        struct map*     map
                        symbol_filter_t filter
                @<map__find_symbol+112>
                        char*   name
                        symbol_filter_t filter
                @<map__find_symbol_by_name+136>
                        char*   name
                        symbol_filter_t filter
                @<map_groups__find_symbol_by_name+176>
                        char*   name
                        struct map*     map
                        symbol_filter_t filter
      
      And lastly, we can now define probe(s) with all available
      variables on the given line:
      
        # ./perf probe -x perf --add 'map__load:8 $vars'
      
        Added new events:
          probe_perf:map__load (on map__load:8 with $vars)
          probe_perf:map__load_1 (on map__load:8 with $vars)
          probe_perf:map__load_2 (on map__load:8 with $vars)
          probe_perf:map__load_3 (on map__load:8 with $vars)
      
        You can now use it in all perf tools, such as:
      
                perf record -e probe_perf:map__load_3 -aR sleep 1
      
        Changes from previous version:
         - Add examples in the patch description.
         - Use .text section start address and dwarf symbol address
           for calculating the offset of given symbol, instead of
           searching the symbol in symtab again.
           With this change, we can safely handle multiple local
           function instances (e.g. scnprintf in perf).
      Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Cc: David Ahern <dsahern@gmail.com>
      Cc: David A. Long <dave.long@linaro.org>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: systemtap@sourceware.org
      Cc: yrl.pp-manager.tt@hitachi.com
      Link: http://lkml.kernel.org/r/20131226054152.22364.47021.stgit@kbuild-fedora.novalocalSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      fb7345bb
    • M
      perf probe: Expand given path to absolute path · 8a613d40
      Masami Hiramatsu 提交于
      Expand given path to absolute path in the option parser, except for a
      module name.
      
      Since realpath at later stage in processing several probe point, can be
      called several times (even if currently doesn't, it can happen when we
      expands the feature), it is waste of the performance.
      
      Processing it once at the early stage can avoid that.
      
      Changes from previous one:
       - Fix not to print null string.
       - Allocate memory for given path/module name everytime.
      Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Cc: "David A. Long" <dave.long@linaro.org>
      Cc: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
      Cc: David Ahern <dsahern@gmail.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
      Cc: systemtap@sourceware.org
      Cc: yrl.pp-manager.tt@hitachi.com
      Link: http://lkml.kernel.org/r/20131226054150.22364.12187.stgit@kbuild-fedora.novalocal
      [ Clarified the pr_warning message as per David Ahern's suggestion ]
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      8a613d40
  8. 17 12月, 2013 1 次提交
    • B
      tools/: Convert to new topic libraries · 553873e1
      Borislav Petkov 提交于
      Move debugfs.* to api/fs/. We have a common tools/lib/api/ place where
      the Makefile lives and then we place the headers in subdirs.
      
      For example, all the fs-related stuff goes to tools/lib/api/fs/ from
      which we get libapikfs.a (acme got almost the naming he wanted :-)) and
      we link it into the tools which need it - in this case perf and
      tools/vm/page-types.
      
      acme:
      
      "Looking at the implementation, I think some tools can even link
      directly to the .o files, avoiding the .a file altogether.
      
      But that is just an optimization/finer granularity tools/lib/
      cherrypicking that toolers can make use of."
      
      Fixup documentation cleaning target while at it.
      Signed-off-by: NBorislav Petkov <bp@suse.de>
      Acked-by: NIngo Molnar <mingo@kernel.org>
      Cc: Adrian Hunter <adrian.hunter@intel.com>
      Cc: Andi Kleen <ak@linux.intel.com>
      Cc: Arjan van de Ven <arjan@linux.intel.com>
      Cc: David Ahern <dsahern@gmail.com>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Jiri Olsa <jolsa@redhat.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Namhyung Kim <namhyung@gmail.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Robert Richter <rric@kernel.org>
      Cc: Stanislav Fomichev <stfomichev@yandex-team.ru>
      Cc: Stephane Eranian <eranian@google.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Link: http://lkml.kernel.org/r/1386605664-24041-2-git-send-email-bp@alien8.deSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      553873e1
  9. 11 12月, 2013 1 次提交
  10. 23 10月, 2013 1 次提交
  11. 09 10月, 2013 1 次提交
  12. 16 3月, 2013 1 次提交
  13. 24 9月, 2012 1 次提交
  14. 11 9月, 2012 1 次提交
    • I
      perf tools: Use __maybe_used for unused variables · 1d037ca1
      Irina Tirdea 提交于
      perf defines both __used and __unused variables to use for marking
      unused variables. The variable __used is defined to
      __attribute__((__unused__)), which contradicts the kernel definition to
      __attribute__((__used__)) for new gcc versions. On Android, __used is
      also defined in system headers and this leads to warnings like: warning:
      '__used__' attribute ignored
      
      __unused is not defined in the kernel and is not a standard definition.
      If __unused is included everywhere instead of __used, this leads to
      conflicts with glibc headers, since glibc has a variables with this name
      in its headers.
      
      The best approach is to use __maybe_unused, the definition used in the
      kernel for __attribute__((unused)). In this way there is only one
      definition in perf sources (instead of 2 definitions that point to the
      same thing: __used and __unused) and it works on both Linux and Android.
      This patch simply replaces all instances of __used and __unused with
      __maybe_unused.
      Signed-off-by: NIrina Tirdea <irina.tirdea@intel.com>
      Acked-by: NPekka Enberg <penberg@kernel.org>
      Cc: David Ahern <dsahern@gmail.com>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Namhyung Kim <namhyung.kim@lge.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Link: http://lkml.kernel.org/r/1347315303-29906-7-git-send-email-irina.tirdea@intel.com
      [ committer note: fixed up conflict with a116e05d in builtin-sched.c ]
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      1d037ca1
  15. 09 9月, 2012 1 次提交
  16. 31 5月, 2012 1 次提交
  17. 12 5月, 2012 1 次提交
    • S
      perf probe: Provide perf interface for uprobes · 225466f1
      Srikar Dronamraju 提交于
      - Enhances perf to probe user space executables and libraries.
      - Enhances -F/--funcs option of "perf probe" to list possible probe points in
        an executable file or library.
      - Documents userspace probing support in perf.
      
      [ Probing a function in the executable using function name  ]
      perf probe -x /bin/zsh zfree
      
      [ Probing a library function using function name ]
      perf probe -x /lib64/libc.so.6 malloc
      
      [ list probe-able functions in an executable ]
      perf probe -F -x /bin/zsh
      
      [ list probe-able functions in an library]
      perf probe -F -x /lib/libc.so.6
      Signed-off-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>
      Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Anton Arapov <anton@redhat.com>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Linux-mm <linux-mm@kvack.org>
      Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/20120416120909.30661.99781.sendpatchset@srdronam.in.ibm.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      225466f1
  18. 01 3月, 2012 1 次提交
  19. 18 2月, 2012 1 次提交
  20. 03 2月, 2012 1 次提交
  21. 31 1月, 2012 1 次提交
    • D
      perf tools: Fix broken build by defining _GNU_SOURCE in Makefile · 0a84f007
      David Daney 提交于
      When building on my Debian/mips system, util/util.c fails to build
      because commit 1aed2671 (perf kvm: Do
      guest-only counting by default) indirectly includes stdio.h before the
      feature selection in util.h is done.  This prevents _GNU_SOURCE in
      util.h from enabling the declaration of getline(), from now second
      inclusion of stdio.h, and the build is broken.
      
      There is another breakage in util/evsel.c caused by include ordering,
      but I didn't fully track down the commit that caused it.
      
      The root cause of all this is an inconsistent definition of _GNU_SOURCE,
      so I move the definition into the Makefile so that it is passed to all
      invocations of the compiler and used uniformly for all system header
      files.  All other #define and #undef of _GNU_SOURCE are removed as they
      cause conflicts with the definition passed to the compiler.
      
      All the features.h definitions (_LARGEFILE64_SOURCE _FILE_OFFSET_BITS=64
      and _GNU_SOURCE) are needed by the python glue code too, so they are
      moved to BASIC_CFLAGS, and the misleading comments about BASIC_CFLAGS
      are removed.
      
      This gives me a clean build on x86_64 (fc12) and mips (Debian).
      
      Cc: David Daney <david.daney@cavium.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Joerg Roedel <joerg.roedel@amd.com>
      Cc: Namhyung Kim <namhyung.kim@lge.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Link: http://lkml.kernel.org/r/1326836461-11952-1-git-send-email-ddaney.cavm@gmail.comSigned-off-by: NDavid Daney <david.daney@cavium.com>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      0a84f007
  22. 25 1月, 2012 2 次提交
    • S
      perf probe: Usability fixes · a844d1ef
      Srikar Dronamraju 提交于
      Ingo pointed out few perf probe usability related errors during his
      review of uprobes.
      
      Since these issues are independent of uprobes, fixing them in a separate
      patch.
      Suggested-by: NIngo Molnar <mingo@elte.hu>
      Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Link: http://lkml.kernel.org/r/20120120121354.GL15447@linux.vnet.ibm.comSigned-off-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      a844d1ef
    • D
      perf tools: Fix broken build by defining _GNU_SOURCE in Makefile · 2ef1ea38
      David Daney 提交于
      When building on my Debian/mips system, util/util.c fails to build
      because commit 1aed2671 (perf kvm: Do
      guest-only counting by default) indirectly includes stdio.h before the
      feature selection in util.h is done.  This prevents _GNU_SOURCE in
      util.h from enabling the declaration of getline(), from now second
      inclusion of stdio.h, and the build is broken.
      
      There is another breakage in util/evsel.c caused by include ordering,
      but I didn't fully track down the commit that caused it.
      
      The root cause of all this is an inconsistent definition of _GNU_SOURCE,
      so I move the definition into the Makefile so that it is passed to all
      invocations of the compiler and used uniformly for all system header
      files.  All other #define and #undef of _GNU_SOURCE are removed as they
      cause conflicts with the definition passed to the compiler.
      
      All the features.h definitions (_LARGEFILE64_SOURCE _FILE_OFFSET_BITS=64
      and _GNU_SOURCE) are needed by the python glue code too, so they are
      moved to BASIC_CFLAGS, and the misleading comments about BASIC_CFLAGS
      are removed.
      
      This gives me a clean build on x86_64 (fc12) and mips (Debian).
      
      Cc: David Daney <david.daney@cavium.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Joerg Roedel <joerg.roedel@amd.com>
      Cc: Namhyung Kim <namhyung.kim@lge.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Link: http://lkml.kernel.org/r/1326836461-11952-1-git-send-email-ddaney.cavm@gmail.comSigned-off-by: NDavid Daney <david.daney@cavium.com>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      2ef1ea38
  23. 11 10月, 2011 1 次提交
  24. 08 8月, 2011 1 次提交
  25. 16 7月, 2011 3 次提交
  26. 06 4月, 2011 2 次提交
  27. 22 2月, 2011 2 次提交
    • A
      perf probe: Remove redundant checks · 8635bf6e
      Arnaldo Carvalho de Melo 提交于
      While fixing an error propagating problem in f809b25 I added two
      redundant checks.
      
      I did that because I didn't expect the checks to be on the while and for
      loop condition expression, where they are tested before we run the loop,
      where the 'ret' variable is set.
      
      So remove it from there and leave it just after it is actually set,
      eliminating unneded tests.
      Reported-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Stephane Eranian <eranian@google.com>
      Cc: Tom Zanussi <tzanussi@gmail.com>
      LKML-Reference: <new-submission>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      8635bf6e
    • A
      perf probe: Fix error propagation leading to segfault · fbee632d
      Arnaldo Carvalho de Melo 提交于
      There are two hunks in this patch that stops probe processing as soon as one
      error is found, breaking out of loops, the other fix an error propagation that
      should return a negative error number but instead was returning the result of
      "ret < 0", which is 1 and thus made several error checks fail because they test
      agains < 0.
      
      The problem could be triggered by asking for a variable that was optimized out,
      fact that should stop the whole probe processing but instead was segfaulting
      while installing broken probes:
      
      [root@emilia ~]# probe perf_mmap:55 user_lock_limit
      Failed to find the location of user_lock_limit at this address.
       Perhaps, it has been optimized out.
      Failed to find 'user_lock_limit' in this function.
      Add new events:
        probe:perf_mmap      (on perf_mmap:55 with user_lock_limit)
        probe:perf_mmap_1    (on perf_mmap:55 with user_lock_limit)
      Segmentation fault (core dumped)
      [root@emilia ~]# perf probe -l
        probe:perf_mmap      (on perf_mmap:55@git/linux/kernel/perf_event.c with user_lock_limit)
        probe:perf_mmap_1    (on perf_mmap:55@git/linux/kernel/perf_event.c with user_lock_limit)
      [root@emilia ~]#
      
      After the fix:
      
      [root@emilia ~]# probe perf_mmap:55 user_lock_limit
      Failed to find the location of user_lock_limit at this address.
       Perhaps, it has been optimized out.
      Failed to find 'user_lock_limit' in this function.
        Error: Failed to add events. (-2)
      [root@emilia ~]#
      
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Stephane Eranian <eranian@google.com>
      Cc: Tom Zanussi <tzanussi@gmail.com>
      LKML-Reference: <new-submission>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      fbee632d
  28. 17 2月, 2011 1 次提交
    • M
      perf probe: Show filename which contains target function · 8737ebde
      Masami Hiramatsu 提交于
      Show filename which contains a target function with the function name on
      "--lines" mode, because perf-probe just shows the first function even if
      there are many same-name functions.
      
      Originally adopted by Franck Bui-Huu's patch which shows file name
      instead of function name. I've just modified it to show both of function
      name and file name, because of completeness of output.
      
       E.g.)
       $ perf probe -L t_show
       <t_show@/home/mhiramat/ksrc/linux-2.6-tip/kernel/trace/ftrace.c:0>
            0  static int t_show(struct seq_file *m, void *v)
            1  {
            2         struct ftrace_iterator *iter = m->private;
       ...
      
       $ perf probe -L t_show@trace/trace.c
       <t_show@/home/mhiramat/ksrc/linux-2.6-tip/kernel/trace/trace.c:0>
            0  static int t_show(struct seq_file *m, void *v)
            1  {
                      struct tracer *t = v;
       ...
      Original-patch-by: NFranck Bui-Huu <fbuihuu@gmail.com>
      Cc: 2nddept-manager@sdl.hitachi.co.jp
      Cc: Franck Bui-Huu <fbuihuu@gmail.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      LKML-Reference: <20110210090816.1809.43426.stgit@ltc236.sdl.hitachi.co.jp>
      Signed-off-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
      8737ebde