src/patches/suse-2.6.27.25/patches.trace/lttng-instrumentation-kernel.patch

   1 From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
   2 Subject: LTTng instrumentation - kernel
   3
   4 Original patch header:
   5   LTTng instrumentation - kernel
   6
   7   Instrument the core kernel : module load/free and printk events. It helps the
   8   tracer to keep track of module related events and to export valuable printk
   9   information into the traces.
  10
  11   Those tracepoints are used by LTTng.
  12
  13   About the performance impact of tracepoints (which is comparable to markers),
  14   even without immediate values optimizations, tests done by Hideo Aoki on ia64
  15   show no regression. His test case was using hackbench on a kernel where
  16   scheduler instrumentation (about 5 events in code scheduler code) was added.
  17   See the "Tracepoints" patch header for performance result detail.
  18
  19   Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
  20   CC: Andrew Morton <akpm@linux-foundation.org>
  21   CC: Masami Hiramatsu <mhiramat@redhat.com>
  22   CC: 'Peter Zijlstra' <peterz@infradead.org>
  23   CC: "Frank Ch. Eigler" <fche@redhat.com>
  24   CC: 'Ingo Molnar' <mingo@elte.hu>
  25   CC: 'Hideo AOKI' <haoki@redhat.com>
  26   CC: Takashi Nishiie <t-nishiie@np.css.fujitsu.com>
  27   CC: 'Steven Rostedt' <rostedt@goodmis.org>
  28   CC: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
  29
  30 Acked-by: Jan Blunck <jblunck@suse.de>
  31 ---
  32 ---
  33  include/trace/kernel.h |   13 +++++++++++++
  34  kernel/module.c        |    5 +++++
  35  2 files changed, 18 insertions(+)
  36
  37 --- /dev/null
  38 +++ b/include/trace/kernel.h
  39 @@ -0,0 +1,13 @@
  40 +#ifndef _TRACE_KERNEL_H
  41 +#define _TRACE_KERNEL_H
  42 +
  43 +#include <linux/tracepoint.h>
  44 +
  45 +DEFINE_TRACE(kernel_module_free,
  46 +       TPPROTO(struct module *mod),
  47 +       TPARGS(mod));
  48 +DEFINE_TRACE(kernel_module_load,
  49 +       TPPROTO(struct module *mod),
  50 +       TPARGS(mod));
  51 +
  52 +#endif
  53 --- a/kernel/module.c
  54 +++ b/kernel/module.c
  55 @@ -47,6 +47,7 @@
  56  #include <linux/license.h>
  57  #include <asm/sections.h>
  58  #include <linux/tracepoint.h>
  59 +#include <trace/kernel.h>
  60
  61  #if 0
  62  #define DEBUGP printk
  63 @@ -1473,6 +1474,8 @@ static int __unlink_module(void *_mod)
  64  /* Free a module, remove from lists, etc (must hold module_mutex). */
  65  static void free_module(struct module *mod)
  66  {
  67 +       trace_kernel_module_free(mod);
  68 +
  69         /* Delete from various lists */
  70         stop_machine(__unlink_module, mod, NULL);
  71         remove_notes_attrs(mod);
  72 @@ -2354,6 +2357,8 @@ static noinline struct module *load_modu
  73         /* Get rid of temporary copy */
  74         vfree(hdr);
  75
  76 +       trace_kernel_module_load(mod);
  77 +
  78         /* Done! */
  79         return mod;
  80