€•W[      Œsphinx.addnodes”Œdocument”“”)”}”(Œ	rawsource”Œ ”Œchildren”]”(Œtranslations”ŒLanguagesNode”“”)”}”(hhh]”(h Œpending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ
attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ	refdomain”Œstd”Œreftype”Œdoc”Œ	reftarget”Œ%/translations/zh_CN/trace/tracepoints”Œmodname”NŒ	classname”NŒrefexplicit”ˆuŒtagname”hhhubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ%/translations/zh_TW/trace/tracepoints”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ%/translations/it_IT/trace/tracepoints”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ%/translations/ja_JP/trace/tracepoints”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ%/translations/ko_KR/trace/tracepoints”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ%/translations/sp_SP/trace/tracepoints”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒ"Using the Linux Kernel Tracepoints”h]”hŒ"Using the Linux Kernel Tracepoints”…””}”(hh¨hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hh£hžhhŸŒ?/var/lib/git/docbuild/linux/Documentation/trace/tracepoints.rst”h KubhŒ
field_list”“”)”}”(hhh]”hŒfield”“”)”}”(hhh]”(hŒ
field_name”“”)”}”(hŒAuthor”h]”hŒAuthor”…””}”(hhÃhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÁhh¾hŸh¶h K ubhŒ
field_body”“”)”}”(hŒMathieu Desnoyers

”h]”hŒ	paragraph”“”)”}”(hŒMathieu Desnoyers”h]”hŒMathieu Desnoyers”…””}”(hhÙhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h KhhÓubah}”(h]”h ]”h"]”h$]”h&]”uh1hÑhh¾ubeh}”(h]”h ]”h"]”h$]”h&]”uh1h¼hŸh¶h Khh¹hžhubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hh£hžhhŸh¶h KubhØ)”}”(hŒÓThis document introduces Linux Kernel Tracepoints and their use. It
provides examples of how to insert tracepoints in the kernel and
connect probe functions to them and provides some examples of probe
functions.”h]”hŒÓThis document introduces Linux Kernel Tracepoints and their use. It
provides examples of how to insert tracepoints in the kernel and
connect probe functions to them and provides some examples of probe
functions.”…””}”(hhùhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h Khh£hžhubh¢)”}”(hhh]”(h§)”}”(hŒPurpose of tracepoints”h]”hŒPurpose of tracepoints”…””}”(hj
  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj  hžhhŸh¶h KubhØ)”}”(hXÇ  A tracepoint placed in code provides a hook to call a function (probe)
that you can provide at runtime. A tracepoint can be "on" (a probe is
connected to it) or "off" (no probe is attached). When a tracepoint is
"off" it has no effect, except for adding a tiny time penalty
(checking a condition for a branch) and space penalty (adding a few
bytes for the function call at the end of the instrumented function
and adds a data structure in a separate section).  When a tracepoint
is "on", the function you provide is called each time the tracepoint
is executed, in the execution context of the caller. When the function
provided ends its execution, it returns to the caller (continuing from
the tracepoint site).”h]”hX×  A tracepoint placed in code provides a hook to call a function (probe)
that you can provide at runtime. A tracepoint can be â€œonâ€ (a probe is
connected to it) or â€œoffâ€ (no probe is attached). When a tracepoint is
â€œoffâ€ it has no effect, except for adding a tiny time penalty
(checking a condition for a branch) and space penalty (adding a few
bytes for the function call at the end of the instrumented function
and adds a data structure in a separate section).  When a tracepoint
is â€œonâ€, the function you provide is called each time the tracepoint
is executed, in the execution context of the caller. When the function
provided ends its execution, it returns to the caller (continuing from
the tracepoint site).”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h Khj  hžhubhØ)”}”(hŒÛYou can put tracepoints at important locations in the code. They are
lightweight hooks that can pass an arbitrary number of parameters,
whose prototypes are described in a tracepoint declaration placed in a
header file.”h]”hŒÛYou can put tracepoints at important locations in the code. They are
lightweight hooks that can pass an arbitrary number of parameters,
whose prototypes are described in a tracepoint declaration placed in a
header file.”…””}”(hj&  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h Khj  hžhubhØ)”}”(hŒ8They can be used for tracing and performance accounting.”h]”hŒ8They can be used for tracing and performance accounting.”…””}”(hj4  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K!hj  hžhubeh}”(h]”Œpurpose-of-tracepoints”ah ]”h"]”Œpurpose of tracepoints”ah$]”h&]”uh1h¡hh£hžhhŸh¶h Kubh¢)”}”(hhh]”(h§)”}”(hŒUsage”h]”hŒUsage”…””}”(hjM  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjJ  hžhhŸh¶h K%ubhØ)”}”(hŒ+Two elements are required for tracepoints :”h]”hŒ+Two elements are required for tracepoints :”…””}”(hj[  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K&hjJ  hžhubhŒbullet_list”“”)”}”(hhh]”(hŒ	list_item”“”)”}”(hŒ1A tracepoint definition, placed in a header file.”h]”hØ)”}”(hjr  h]”hŒ1A tracepoint definition, placed in a header file.”…””}”(hjt  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K(hjp  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jn  hjk  hžhhŸh¶h Nubjo  )”}”(hŒ%The tracepoint statement, in C code.
”h]”hØ)”}”(hŒ$The tracepoint statement, in C code.”h]”hŒ$The tracepoint statement, in C code.”…””}”(hj‹  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K)hj‡  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jn  hjk  hžhhŸh¶h Nubeh}”(h]”h ]”h"]”h$]”h&]”Œbullet”Œ-”uh1ji  hŸh¶h K(hjJ  hžhubhØ)”}”(hŒCIn order to use tracepoints, you should include linux/tracepoint.h.”h]”hŒCIn order to use tracepoints, you should include linux/tracepoint.h.”…””}”(hj§  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K+hjJ  hžhubhØ)”}”(hŒ"In include/trace/events/subsys.h::”h]”hŒ!In include/trace/events/subsys.h:”…””}”(hjµ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K-hjJ  hžhubhŒliteral_block”“”)”}”(hXŠ  #undef TRACE_SYSTEM
#define TRACE_SYSTEM subsys

#if !defined(_TRACE_SUBSYS_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_SUBSYS_H

#include <linux/tracepoint.h>

DECLARE_TRACE(subsys_eventname,
        TP_PROTO(int firstarg, struct task_struct *p),
        TP_ARGS(firstarg, p));

#endif /* _TRACE_SUBSYS_H */

/* This part must be outside protection */
#include <trace/define_trace.h>”h]”hXŠ  #undef TRACE_SYSTEM
#define TRACE_SYSTEM subsys

#if !defined(_TRACE_SUBSYS_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_SUBSYS_H

#include <linux/tracepoint.h>

DECLARE_TRACE(subsys_eventname,
        TP_PROTO(int firstarg, struct task_struct *p),
        TP_ARGS(firstarg, p));

#endif /* _TRACE_SUBSYS_H */

/* This part must be outside protection */
#include <trace/define_trace.h>”…””}”hjÅ  sbah}”(h]”h ]”h"]”h$]”h&]”Œ	xml:space”Œpreserve”uh1jÃ  hŸh¶h K/hjJ  hžhubhØ)”}”(hŒ>In subsys/file.c (where the tracing statement must be added)::”h]”hŒ=In subsys/file.c (where the tracing statement must be added):”…””}”(hjÕ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K@hjJ  hžhubjÄ  )”}”(hŒ¸#include <trace/events/subsys.h>

#define CREATE_TRACE_POINTS
DEFINE_TRACE(subsys_eventname);

void somefct(void)
{
        ...
        trace_subsys_eventname(arg, task);
        ...
}”h]”hŒ¸#include <trace/events/subsys.h>

#define CREATE_TRACE_POINTS
DEFINE_TRACE(subsys_eventname);

void somefct(void)
{
        ...
        trace_subsys_eventname(arg, task);
        ...
}”…””}”hjã  sbah}”(h]”h ]”h"]”h$]”h&]”jÓ  jÔ  uh1jÃ  hŸh¶h KBhjJ  hžhubhŒdefinition_list”“”)”}”(hhh]”hŒdefinition_list_item”“”)”}”(hXÞ  Where :
- subsys_eventname is an identifier unique to your event

  - subsys is the name of your subsystem.
  - eventname is the name of the event to trace.

- `TP_PROTO(int firstarg, struct task_struct *p)` is the prototype of the
  function called by this tracepoint.

- `TP_ARGS(firstarg, p)` are the parameters names, same as found in the
  prototype.

- if you use the header in multiple source files, `#define CREATE_TRACE_POINTS`
  should appear only in one source file.
”h]”(hŒterm”“”)”}”(hŒWhere :”h]”hŒWhere :”…””}”(hjþ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jü  hŸh¶h K[hjø  ubhŒ
definition”“”)”}”(hhh]”jj  )”}”(hhh]”(jo  )”}”(hŒsubsys_eventname is an identifier unique to your event

- subsys is the name of your subsystem.
- eventname is the name of the event to trace.
”h]”(hØ)”}”(hŒ6subsys_eventname is an identifier unique to your event”h]”hŒ6subsys_eventname is an identifier unique to your event”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h KOhj  ubjj  )”}”(hhh]”(jo  )”}”(hŒ%subsys is the name of your subsystem.”h]”hØ)”}”(hj+  h]”hŒ%subsys is the name of your subsystem.”…””}”(hj-  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h KQhj)  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jn  hj&  ubjo  )”}”(hŒ-eventname is the name of the event to trace.
”h]”hØ)”}”(hŒ,eventname is the name of the event to trace.”h]”hŒ,eventname is the name of the event to trace.”…””}”(hjD  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h KRhj@  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jn  hj&  ubeh}”(h]”h ]”h"]”h$]”h&]”j¥  j¦  uh1ji  hŸh¶h KQhj  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jn  hj  ubjo  )”}”(hŒl`TP_PROTO(int firstarg, struct task_struct *p)` is the prototype of the
function called by this tracepoint.
”h]”hØ)”}”(hŒk`TP_PROTO(int firstarg, struct task_struct *p)` is the prototype of the
function called by this tracepoint.”h]”(hŒtitle_reference”“”)”}”(hŒ/`TP_PROTO(int firstarg, struct task_struct *p)`”h]”hŒ-TP_PROTO(int firstarg, struct task_struct *p)”…””}”(hjn  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jl  hjh  ubhŒ< is the prototype of the
function called by this tracepoint.”…””}”(hjh  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h KThjd  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jn  hj  ubjo  )”}”(hŒQ`TP_ARGS(firstarg, p)` are the parameters names, same as found in the
prototype.
”h]”hØ)”}”(hŒP`TP_ARGS(firstarg, p)` are the parameters names, same as found in the
prototype.”h]”(jm  )”}”(hŒ`TP_ARGS(firstarg, p)`”h]”hŒTP_ARGS(firstarg, p)”…””}”(hj”  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jl  hj  ubhŒ: are the parameters names, same as found in the
prototype.”…””}”(hj  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h KWhjŒ  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jn  hj  ubjo  )”}”(hŒuif you use the header in multiple source files, `#define CREATE_TRACE_POINTS`
should appear only in one source file.
”h]”hØ)”}”(hŒtif you use the header in multiple source files, `#define CREATE_TRACE_POINTS`
should appear only in one source file.”h]”(hŒ0if you use the header in multiple source files, ”…””}”(hj¶  hžhhŸNh Nubjm  )”}”(hŒ`#define CREATE_TRACE_POINTS`”h]”hŒ#define CREATE_TRACE_POINTS”…””}”(hj¾  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jl  hj¶  ubhŒ'
should appear only in one source file.”…””}”(hj¶  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h KZhj²  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jn  hj  ubeh}”(h]”h ]”h"]”h$]”h&]”j¥  j¦  uh1ji  hŸh¶h KOhj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hjø  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1jö  hŸh¶h K[hjó  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jñ  hjJ  hžhhŸNh NubhØ)”}”(hX  Connecting a function (probe) to a tracepoint is done by providing a
probe (function to call) for the specific tracepoint through
register_trace_subsys_eventname().  Removing a probe is done through
unregister_trace_subsys_eventname(); it will remove the probe.”h]”hX  Connecting a function (probe) to a tracepoint is done by providing a
probe (function to call) for the specific tracepoint through
register_trace_subsys_eventname().  Removing a probe is done through
unregister_trace_subsys_eventname(); it will remove the probe.”…””}”(hjô  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K]hjJ  hžhubhØ)”}”(hX  tracepoint_synchronize_unregister() must be called before the end of
the module exit function to make sure there is no caller left using
the probe. This, and the fact that preemption is disabled around the
probe call, make sure that probe removal and module unload are safe.”h]”hX  tracepoint_synchronize_unregister() must be called before the end of
the module exit function to make sure there is no caller left using
the probe. This, and the fact that preemption is disabled around the
probe call, make sure that probe removal and module unload are safe.”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h KbhjJ  hžhubhØ)”}”(hX  The tracepoint mechanism supports inserting multiple instances of the
same tracepoint, but a single definition must be made of a given
tracepoint name over all the kernel to make sure no type conflict will
occur. Name mangling of the tracepoints is done using the prototypes
to make sure typing is correct. Verification of probe type correctness
is done at the registration site by the compiler. Tracepoints can be
put in inline functions, inlined static functions, and unrolled loops
as well as regular functions.”h]”hX  The tracepoint mechanism supports inserting multiple instances of the
same tracepoint, but a single definition must be made of a given
tracepoint name over all the kernel to make sure no type conflict will
occur. Name mangling of the tracepoints is done using the prototypes
to make sure typing is correct. Verification of probe type correctness
is done at the registration site by the compiler. Tracepoints can be
put in inline functions, inlined static functions, and unrolled loops
as well as regular functions.”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h KghjJ  hžhubhØ)”}”(hŒêThe naming scheme "subsys_event" is suggested here as a convention
intended to limit collisions. Tracepoint names are global to the
kernel: they are considered as being the same whether they are in the
core kernel image or in modules.”h]”hŒîThe naming scheme â€œsubsys_eventâ€ is suggested here as a convention
intended to limit collisions. Tracepoint names are global to the
kernel: they are considered as being the same whether they are in the
core kernel image or in modules.”…””}”(hj  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h KphjJ  hžhubhØ)”}”(hŒ¢If the tracepoint has to be used in kernel modules, an
EXPORT_TRACEPOINT_SYMBOL_GPL() or EXPORT_TRACEPOINT_SYMBOL() can be
used to export the defined tracepoints.”h]”hŒ¢If the tracepoint has to be used in kernel modules, an
EXPORT_TRACEPOINT_SYMBOL_GPL() or EXPORT_TRACEPOINT_SYMBOL() can be
used to export the defined tracepoints.”…””}”(hj,  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h KuhjJ  hžhubhØ)”}”(hŒ´If you need to do a bit of work for a tracepoint parameter, and
that work is only used for the tracepoint, that work can be encapsulated
within an if statement with the following::”h]”hŒ³If you need to do a bit of work for a tracepoint parameter, and
that work is only used for the tracepoint, that work can be encapsulated
within an if statement with the following:”…””}”(hj:  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h KyhjJ  hžhubjÄ  )”}”(hŒ²if (trace_foo_bar_enabled()) {
        int i;
        int tot = 0;

        for (i = 0; i < count; i++)
                tot += calculate_nuggets();

        trace_foo_bar(tot);
}”h]”hŒ²if (trace_foo_bar_enabled()) {
        int i;
        int tot = 0;

        for (i = 0; i < count; i++)
                tot += calculate_nuggets();

        trace_foo_bar(tot);
}”…””}”hjH  sbah}”(h]”h ]”h"]”h$]”h&]”jÓ  jÔ  uh1jÃ  hŸh¶h K}hjJ  hžhubhØ)”}”(hXT  All trace_<tracepoint>() calls have a matching trace_<tracepoint>_enabled()
function defined that returns true if the tracepoint is enabled and
false otherwise. The trace_<tracepoint>() should always be within the
block of the if (trace_<tracepoint>_enabled()) to prevent races between
the tracepoint being enabled and the check being seen.”h]”hXT  All trace_<tracepoint>() calls have a matching trace_<tracepoint>_enabled()
function defined that returns true if the tracepoint is enabled and
false otherwise. The trace_<tracepoint>() should always be within the
block of the if (trace_<tracepoint>_enabled()) to prevent races between
the tracepoint being enabled and the check being seen.”…””}”(hjV  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K‡hjJ  hžhubhØ)”}”(hŒÅThe advantage of using the trace_<tracepoint>_enabled() is that it uses
the static_key of the tracepoint to allow the if statement to be implemented
with jump labels and avoid conditional branches.”h]”hŒÅThe advantage of using the trace_<tracepoint>_enabled() is that it uses
the static_key of the tracepoint to allow the if statement to be implemented
with jump labels and avoid conditional branches.”…””}”(hjd  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h KhjJ  hžhubhŒnote”“”)”}”(hŒèThe convenience macro TRACE_EVENT provides an alternative way to
define tracepoints. Check http://lwn.net/Articles/379903,
http://lwn.net/Articles/381064 and http://lwn.net/Articles/383362
for a series of articles with more details.”h]”hØ)”}”(hŒèThe convenience macro TRACE_EVENT provides an alternative way to
define tracepoints. Check http://lwn.net/Articles/379903,
http://lwn.net/Articles/381064 and http://lwn.net/Articles/383362
for a series of articles with more details.”h]”(hŒ[The convenience macro TRACE_EVENT provides an alternative way to
define tracepoints. Check ”…””}”(hjx  hžhhŸNh NubhŒ	reference”“”)”}”(hŒhttp://lwn.net/Articles/379903”h]”hŒhttp://lwn.net/Articles/379903”…””}”(hj‚  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”Œrefuri”j„  uh1j€  hjx  ubhŒ,
”…””}”(hjx  hžhhŸNh Nubj  )”}”(hŒhttp://lwn.net/Articles/381064”h]”hŒhttp://lwn.net/Articles/381064”…””}”(hj•  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”Œrefuri”j—  uh1j€  hjx  ubhŒ and ”…””}”(hjx  hžhhŸNh Nubj  )”}”(hŒhttp://lwn.net/Articles/383362”h]”hŒhttp://lwn.net/Articles/383362”…””}”(hj¨  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”Œrefuri”jª  uh1j€  hjx  ubhŒ,
for a series of articles with more details.”…””}”(hjx  hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K‘hjt  ubah}”(h]”h ]”h"]”h$]”h&]”uh1jr  hjJ  hžhhŸh¶h NubhØ)”}”(hXØ  If you require calling a tracepoint from a header file, it is not
recommended to call one directly or to use the trace_<tracepoint>_enabled()
function call, as tracepoints in header files can have side effects if a
header is included from a file that has CREATE_TRACE_POINTS set, as
well as the trace_<tracepoint>() is not that small of an inline
and can bloat the kernel if used by other inlined functions. Instead,
include tracepoint-defs.h and use tracepoint_enabled().”h]”hXØ  If you require calling a tracepoint from a header file, it is not
recommended to call one directly or to use the trace_<tracepoint>_enabled()
function call, as tracepoints in header files can have side effects if a
header is included from a file that has CREATE_TRACE_POINTS set, as
well as the trace_<tracepoint>() is not that small of an inline
and can bloat the kernel if used by other inlined functions. Instead,
include tracepoint-defs.h and use tracepoint_enabled().”…””}”(hjÇ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K–hjJ  hžhubhØ)”}”(hŒIn a C file::”h]”hŒIn a C file:”…””}”(hjÕ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h KžhjJ  hžhubjÄ  )”}”(hŒDvoid do_trace_foo_bar_wrapper(args)
{
        trace_foo_bar(args);
}”h]”hŒDvoid do_trace_foo_bar_wrapper(args)
{
        trace_foo_bar(args);
}”…””}”hjã  sbah}”(h]”h ]”h"]”h$]”h&]”jÓ  jÔ  uh1jÃ  hŸh¶h K hjJ  hžhubhØ)”}”(hŒIn the header file::”h]”hŒIn the header file:”…””}”(hjñ  hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h×hŸh¶h K¥hjJ  hžhubjÄ  )”}”(hŒ¾DECLARE_TRACEPOINT(foo_bar);

static inline void some_inline_function()
{
        [..]
        if (tracepoint_enabled(foo_bar))
                do_trace_foo_bar_wrapper(args);
        [..]
}”h]”hŒ¾DECLARE_TRACEPOINT(foo_bar);

static inline void some_inline_function()
{
        [..]
        if (tracepoint_enabled(foo_bar))
                do_trace_foo_bar_wrapper(args);
        [..]
}”…””}”hjÿ  sbah}”(h]”h ]”h"]”h$]”h&]”jÓ  jÔ  uh1jÃ  hŸh¶h K§hjJ  hžhubeh}”(h]”Œusage”ah ]”h"]”Œusage”ah$]”h&]”uh1h¡hh£hžhhŸh¶h K%ubeh}”(h]”Œ"using-the-linux-kernel-tracepoints”ah ]”h"]”Œ"using the linux kernel tracepoints”ah$]”h&]”uh1h¡hhhžhhŸh¶h Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”h¶uh1hŒcurrent_source”NŒcurrent_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(h¦NŒ	generator”NŒ	datestamp”NŒsource_link”NŒ
source_url”NŒtoc_backlinks”Œentry”Œfootnote_backlinks”KŒsectnum_xform”KŒstrip_comments”NŒstrip_elements_with_classes”NŒstrip_classes”NŒreport_level”KŒ
halt_level”KŒexit_status_level”KŒdebug”NŒwarning_stream”NŒ	traceback”ˆŒinput_encoding”Œ	utf-8-sig”Œinput_encoding_error_handler”Œstrict”Œoutput_encoding”Œutf-8”Œoutput_encoding_error_handler”j@  Œerror_encoding”Œutf-8”Œerror_encoding_error_handler”Œbackslashreplace”Œlanguage_code”Œen”Œrecord_dependencies”NŒconfig”NŒ	id_prefix”hŒauto_id_prefix”Œid”Œdump_settings”NŒdump_internals”NŒdump_transforms”NŒdump_pseudo_xml”NŒexpose_internals”NŒstrict_visitor”NŒ_disable_config”NŒ_source”h¶Œ_destination”NŒ_config_files”]”Œ7/var/lib/git/docbuild/linux/Documentation/docutils.conf”aŒfile_insertion_enabled”ˆŒraw_enabled”KŒline_length_limit”M'Œpep_references”NŒpep_base_url”Œhttps://peps.python.org/”Œpep_file_url_template”Œpep-%04d”Œrfc_references”NŒrfc_base_url”Œ&https://datatracker.ietf.org/doc/html/”Œ	tab_width”KŒtrim_footnote_reference_space”‰Œsyntax_highlight”Œlong”Œsmart_quotes”ˆŒsmartquotes_locales”]”Œcharacter_level_inline_markup”‰Œdoctitle_xform”‰Œdocinfo_xform”KŒsectsubtitle_xform”‰Œimage_loading”Œlink”Œembed_stylesheet”‰Œcloak_email_addresses”ˆŒsection_self_link”‰Œenv”NubŒreporter”NŒindirect_targets”]”Œsubstitution_defs”}”Œsubstitution_names”}”Œrefnames”}”Œrefids”}”Œnameids”}”(j  j  jG  jD  j  j  uŒ	nametypes”}”(j  ‰jG  ‰j  ‰uh}”(j  h£jD  j  j  jJ  uŒfootnote_refs”}”Œcitation_refs”}”Œautofootnotes”]”Œautofootnote_refs”]”Œsymbol_footnotes”]”Œsymbol_footnote_refs”]”Œ	footnotes”]”Œ	citations”]”Œautofootnote_start”KŒsymbol_footnote_start”K Œ
id_counter”Œcollections”ŒCounter”“”}”…”R”Œparse_messages”]”Œtransform_messages”]”Œtransformer”NŒinclude_log”]”Œ
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