[tip:perf/probes] tracing/kprobes: Rename Kprobe-tracer to kprobe-event

tip-bot for Masami Hiramatsu
2009-11-04T15:26:59Z

Commit-ID: 77b44d1b7c28360910cdbd427fb62d485c08674c
Gitweb: http://git.kernel.org/tip/77b44d1b7c28360910cdbd427fb62d485c08674c
Author: Masami Hiramatsu <mhiramat@redhat.com>
AuthorDate: Tue, 3 Nov 2009 19:12:47 -0500
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Wed, 4 Nov 2009 13:02:48 +0100

tracing/kprobes: Rename Kprobe-tracer to kprobe-event

Rename Kprobes-based event tracer to kprobes-based tracing event
(kprobe-event), since it is not a tracer but an extensible
tracing event interface.

This also changes CONFIG_KPROBE_TRACER to CONFIG_KPROBE_EVENT
and sets it y by default.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
LKML-Reference: <20091104001247.3454.14131.stgit@harusame>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
Documentation/trace/kprobetrace.txt | 34 ++++++++++++++++------------------
kernel/trace/Kconfig | 19 ++++++++++++-------
kernel/trace/Makefile | 2 +-
kernel/trace/trace_kprobe.c | 6 ++----
4 files changed, 31 insertions(+), 30 deletions(-)

diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt
index 1541524..47aabee 100644
--- a/Documentation/trace/kprobetrace.txt
+++ b/Documentation/trace/kprobetrace.txt
@@ -1,26 +1,23 @@
- Kprobe-based Event Tracer
- =========================
+ Kprobe-based Event Tracing
+ ==========================

Documentation is written by Masami Hiramatsu

Overview
--------
-This tracer is similar to the events tracer which is based on Tracepoint
-infrastructure. Instead of Tracepoint, this tracer is based on kprobes(kprobe
-and kretprobe). It probes anywhere where kprobes can probe(this means, all
-functions body except for __kprobes functions).
+These events are similar to tracepoint based events. Instead of Tracepoint,
+this is based on kprobes (kprobe and kretprobe). So it can probe wherever
+kprobes can probe (this means, all functions body except for __kprobes
+functions). Unlike the Tracepoint based event, this can be added and removed
+dynamically, on the fly.

-Unlike the function tracer, this tracer can probe instructions inside of
-kernel functions. It allows you to check which instruction has been executed.
+To enable this feature, build your kernel with CONFIG_KPROBE_TRACING=y.

-Unlike the Tracepoint based events tracer, this tracer can add and remove
-probe points on the fly.
-
-Similar to the events tracer, this tracer doesn't need to be activated via
-current_tracer, instead of that, just set probe points via
-/sys/kernel/debug/tracing/kprobe_events. And you can set filters on each
-probe events via /sys/kernel/debug/tracing/events/kprobes/<EVENT>/filter.
+Similar to the events tracer, this doesn't need to be activated via
+current_tracer. Instead of that, add probe points via
+/sys/kernel/debug/tracing/kprobe_events, and enable it via
+/sys/kernel/debug/tracing/events/kprobes/<EVENT>/enabled.

Synopsis of kprobe_events
@@ -55,9 +52,9 @@ Per-Probe Event Filtering
-------------------------
Per-probe event filtering feature allows you to set different filter on each
probe and gives you what arguments will be shown in trace buffer. If an event
-name is specified right after 'p:' or 'r:' in kprobe_events, the tracer adds
-an event under tracing/events/kprobes/<EVENT>, at the directory you can see
-'id', 'enabled', 'format' and 'filter'.
+name is specified right after 'p:' or 'r:' in kprobe_events, it adds an event
+under tracing/events/kprobes/<EVENT>, at the directory you can see 'id',
+'enabled', 'format' and 'filter'.

enabled:
You can enable/disable the probe by writing 1 or 0 on it.
@@ -71,6 +68,7 @@ filter:
id:
This shows the id of this probe event.

+
Event Profiling
---------------
You can check the total number of probe hits and probe miss-hits via
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 15372a9..f056716 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -428,17 +428,22 @@ config BLK_DEV_IO_TRACE

If unsure, say N.

-config KPROBE_TRACER
+config KPROBE_EVENT
depends on KPROBES
depends on X86
- bool "Trace kprobes"
+ bool "Enable kprobes-based dynamic events"
select TRACING
- select GENERIC_TRACER
+ default y
help
- This tracer probes everywhere where kprobes can probe it, and
- records various registers and memories specified by user.
- This also allows you to trace kprobe probe points as a dynamic
- defined events. It provides per-probe event filtering interface.
+ This allows the user to add tracing events (similar to tracepoints) on the fly
+ via the ftrace interface. See Documentation/trace/kprobetrace.txt
+ for more details.
+
+ Those events can be inserted wherever kprobes can probe, and record
+ various register and memory values.
+
+ This option is also required by perf-probe subcommand of perf tools. If
+ you want to use perf tools, this option is strongly recommended.

config DYNAMIC_FTRACE
bool "enable/disable ftrace tracepoints dynamically"
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index c8cb75d..edc3a3c 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -53,7 +53,7 @@ obj-$(CONFIG_EVENT_TRACING) += trace_export.o
obj-$(CONFIG_FTRACE_SYSCALLS) += trace_syscalls.o
obj-$(CONFIG_EVENT_PROFILE) += trace_event_profile.o
obj-$(CONFIG_EVENT_TRACING) += trace_events_filter.o
-obj-$(CONFIG_KPROBE_TRACER) += trace_kprobe.o
+obj-$(CONFIG_KPROBE_EVENT) += trace_kprobe.o
obj-$(CONFIG_EVENT_TRACING) += power-traces.o

libftrace-y := ftrace.o
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index a86c3ac..cf17a66 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1,5 +1,5 @@
/*
- * kprobe based kernel tracer
+ * Kprobes-based tracing events
*
* Created by Masami Hiramatsu <mhiramat@redhat.com>
*
@@ -57,8 +57,6 @@ const char *reserved_field_names[] = {
FIELD_STRING_FUNC,
};

-/* currently, trace_kprobe only supports X86. */
-
struct fetch_func {
unsigned long (*func)(struct pt_regs *, void *);
void *data;
@@ -191,7 +189,7 @@ static __kprobes void free_indirect_fetch_data(struct indirect_fetch_data *data)
}

/**
- * Kprobe tracer core functions
+ * Kprobe event core functions
*/

struct probe_arg {