tracing: Remove markers

Now that the last users of markers have migrated to the event
tracer we can kill off the (now orphan) support code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20090917173527.GA1699@lst.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Documentation/markers.txt

- 	             Using the Linux Kernel Markers
-
-			    Mathieu Desnoyers
-
-
-This document introduces Linux Kernel Markers and their use. It provides
-examples of how to insert markers in the kernel and connect probe functions to
-them and provides some examples of probe functions.
-
-
-* Purpose of markers
-
-A marker placed in code provides a hook to call a function (probe) that you can
-provide at runtime. A marker can be "on" (a probe is connected to it) or "off"
-(no probe is attached). When a marker 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
-marker is "on", the function you provide is called each time the marker is
-executed, in the execution context of the caller. When the function provided
-ends its execution, it returns to the caller (continuing from the marker site).
-
-You can put markers at important locations in the code. Markers are
-lightweight hooks that can pass an arbitrary number of parameters,
-described in a printk-like format string, to the attached probe function.
-
-They can be used for tracing and performance accounting.
-
-
-* Usage
-
-In order to use the macro trace_mark, you should include linux/marker.h.
-
-#include <linux/marker.h>
-
-And,
-
-trace_mark(subsystem_event, "myint %d mystring %s", someint, somestring);
-Where :
-- subsystem_event is an identifier unique to your event
-    - subsystem is the name of your subsystem.
-    - event is the name of the event to mark.
-- "myint %d mystring %s" is the formatted string for the serializer. "myint" and
-  "mystring" are repectively the field names associated with the first and
-  second parameter.
-- someint is an integer.
-- somestring is a char pointer.
-
-Connecting a function (probe) to a marker is done by providing a probe (function
-to call) for the specific marker through marker_probe_register() and can be
-activated by calling marker_arm(). Marker deactivation can be done by calling
-marker_disarm() as many times as marker_arm() has been called. Removing a probe
-is done through marker_probe_unregister(); it will disarm the probe.
-
-marker_synchronize_unregister() must be called between probe unregistration and
-the first occurrence of
-- the end of module exit function,
-  to make sure there is no caller left using the probe;
-- the free of any resource used by the probes,
-  to make sure the probes wont be accessing invalid data.
-This, and the fact that preemption is disabled around the probe call, make sure
-that probe removal and module unload are safe. See the "Probe example" section
-below for a sample probe module.
-
-The marker mechanism supports inserting multiple instances of the same marker.
-Markers can be put in inline functions, inlined static functions, and
-unrolled loops as well as regular functions.
-
-The naming scheme "subsystem_event" is suggested here as a convention intended
-to limit collisions. Marker names are global to the kernel: they are considered
-as being the same whether they are in the core kernel image or in modules.
-Conflicting format strings for markers with the same name will cause the markers
-to be detected to have a different format string not to be armed and will output
-a printk warning which identifies the inconsistency:
-
-"Format mismatch for probe probe_name (format), marker (format)"
-
-Another way to use markers is to simply define the marker without generating any
-function call to actually call into the marker. This is useful in combination
-with tracepoint probes in a scheme like this :
-
-void probe_tracepoint_name(unsigned int arg1, struct task_struct *tsk);
-
-DEFINE_MARKER_TP(marker_eventname, tracepoint_name, probe_tracepoint_name,
-	"arg1 %u pid %d");
-
-notrace void probe_tracepoint_name(unsigned int arg1, struct task_struct *tsk)
-{
-	struct marker *marker = &GET_MARKER(kernel_irq_entry);
-	/* write data to trace buffers ... */
-}
-
-* Probe / marker example
-
-See the example provided in samples/markers/src
-
-Compile them with your kernel.
-
-Run, as root :
-modprobe marker-example (insmod order is not important)
-modprobe probe-example
-cat /proc/marker-example (returns an expected error)
-rmmod marker-example probe-example
-dmesg

arch/powerpc/platforms/cell/spufs/file.c

@@ -29,7 +29,6 @@
 #include <linux/poll.h>
 #include <linux/ptrace.h>
 #include <linux/seq_file.h>
-#include <linux/marker.h>
 
 #include <asm/io.h>
 #include <asm/time.h>

arch/powerpc/platforms/cell/spufs/sched.c

@@ -39,7 +39,6 @@
 #include <linux/pid_namespace.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
-#include <linux/marker.h>
 
 #include <asm/io.h>
 #include <asm/mmu_context.h>

include/linux/kvm_host.h

@@ -15,7 +15,6 @@
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/preempt.h>
-#include <linux/marker.h>
 #include <linux/msi.h>
 #include <asm/signal.h>
 

include/linux/marker.h

-#ifndef _LINUX_MARKER_H
-#define _LINUX_MARKER_H
-
-/*
- * Code markup for dynamic and static tracing.
- *
- * See Documentation/marker.txt.
- *
- * (C) Copyright 2006 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
- *
- * This file is released under the GPLv2.
- * See the file COPYING for more details.
- */
-
-#include <stdarg.h>
-#include <linux/types.h>
-
-struct module;
-struct marker;
-
-/**
- * marker_probe_func - Type of a marker probe function
- * @probe_private: probe private data
- * @call_private: call site private data
- * @fmt: format string
- * @args: variable argument list pointer. Use a pointer to overcome C's
- *        inability to pass this around as a pointer in a portable manner in
- *        the callee otherwise.
- *
- * Type of marker probe functions. They receive the mdata and need to parse the
- * format string to recover the variable argument list.
- */
-typedef void marker_probe_func(void *probe_private, void *call_private,
-		const char *fmt, va_list *args);
-
-struct marker_probe_closure {
-	marker_probe_func *func;	/* Callback */
-	void *probe_private;		/* Private probe data */
-};
-
-struct marker {
-	const char *name;	/* Marker name */
-	const char *format;	/* Marker format string, describing the
-				 * variable argument list.
-				 */
-	char state;		/* Marker state. */
-	char ptype;		/* probe type : 0 : single, 1 : multi */
-				/* Probe wrapper */
-	void (*call)(const struct marker *mdata, void *call_private, ...);
-	struct marker_probe_closure single;
-	struct marker_probe_closure *multi;
-	const char *tp_name;	/* Optional tracepoint name */
-	void *tp_cb;		/* Optional tracepoint callback */
-} __attribute__((aligned(8)));
-
-#ifdef CONFIG_MARKERS
-
-#define _DEFINE_MARKER(name, tp_name_str, tp_cb, format)		\
-		static const char __mstrtab_##name[]			\
-		__attribute__((section("__markers_strings")))		\
-		= #name "\0" format;					\
-		static struct marker __mark_##name			\
-		__attribute__((section("__markers"), aligned(8))) =	\
-		{ __mstrtab_##name, &__mstrtab_##name[sizeof(#name)],	\
-		  0, 0, marker_probe_cb, { __mark_empty_function, NULL},\
-		  NULL, tp_name_str, tp_cb }
-
-#define DEFINE_MARKER(name, format)					\
-		_DEFINE_MARKER(name, NULL, NULL, format)
-
-#define DEFINE_MARKER_TP(name, tp_name, tp_cb, format)			\
-		_DEFINE_MARKER(name, #tp_name, tp_cb, format)
-
-/*
- * Note : the empty asm volatile with read constraint is used here instead of a
- * "used" attribute to fix a gcc 4.1.x bug.
- * Make sure the alignment of the structure in the __markers section will
- * not add unwanted padding between the beginning of the section and the
- * structure. Force alignment to the same alignment as the section start.
- *
- * The "generic" argument controls which marker enabling mechanism must be used.
- * If generic is true, a variable read is used.
- * If generic is false, immediate values are used.
- */
-#define __trace_mark(generic, name, call_private, format, args...)	\
-	do {								\
-		DEFINE_MARKER(name, format);				\
-		__mark_check_format(format, ## args);			\
-		if (unlikely(__mark_##name.state)) {			\
-			(*__mark_##name.call)				\
-				(&__mark_##name, call_private, ## args);\
-		}							\
-	} while (0)
-
-#define __trace_mark_tp(name, call_private, tp_name, tp_cb, format, args...) \
-	do {								\
-		void __check_tp_type(void)				\
-		{							\
-			register_trace_##tp_name(tp_cb);		\
-		}							\
-		DEFINE_MARKER_TP(name, tp_name, tp_cb, format);		\
-		__mark_check_format(format, ## args);			\
-		(*__mark_##name.call)(&__mark_##name, call_private,	\
-					## args);			\
-	} while (0)
-
-extern void marker_update_probe_range(struct marker *begin,
-	struct marker *end);
-
-#define GET_MARKER(name)	(__mark_##name)
-
-#else /* !CONFIG_MARKERS */
-#define DEFINE_MARKER(name, tp_name, tp_cb, format)
-#define __trace_mark(generic, name, call_private, format, args...) \
-		__mark_check_format(format, ## args)
-#define __trace_mark_tp(name, call_private, tp_name, tp_cb, format, args...) \
-	do {								\
-		void __check_tp_type(void)				\
-		{							\
-			register_trace_##tp_name(tp_cb);		\
-		}							\
-		__mark_check_format(format, ## args);			\
-	} while (0)
-static inline void marker_update_probe_range(struct marker *begin,
-	struct marker *end)
-{ }
-#define GET_MARKER(name)
-#endif /* CONFIG_MARKERS */
-
-/**
- * trace_mark - Marker using code patching
- * @name: marker name, not quoted.
- * @format: format string
- * @args...: variable argument list
- *
- * Places a marker using optimized code patching technique (imv_read())
- * to be enabled when immediate values are present.
- */
-#define trace_mark(name, format, args...) \
-	__trace_mark(0, name, NULL, format, ## args)
-
-/**
- * _trace_mark - Marker using variable read
- * @name: marker name, not quoted.
- * @format: format string
- * @args...: variable argument list
- *
- * Places a marker using a standard memory read (_imv_read()) to be
- * enabled. Should be used for markers in code paths where instruction
- * modification based enabling is not welcome. (__init and __exit functions,
- * lockdep, some traps, printk).
- */
-#define _trace_mark(name, format, args...) \
-	__trace_mark(1, name, NULL, format, ## args)
-
-/**
- * trace_mark_tp - Marker in a tracepoint callback
- * @name: marker name, not quoted.
- * @tp_name: tracepoint name, not quoted.
- * @tp_cb: tracepoint callback. Should have an associated global symbol so it
- *         is not optimized away by the compiler (should not be static).
- * @format: format string
- * @args...: variable argument list
- *
- * Places a marker in a tracepoint callback.
- */
-#define trace_mark_tp(name, tp_name, tp_cb, format, args...)	\
-	__trace_mark_tp(name, NULL, tp_name, tp_cb, format, ## args)
-
-/**
- * MARK_NOARGS - Format string for a marker with no argument.
- */
-#define MARK_NOARGS " "
-
-/* To be used for string format validity checking with gcc */
-static inline void __printf(1, 2) ___mark_check_format(const char *fmt, ...)
-{
-}
-
-#define __mark_check_format(format, args...)				\
-	do {								\
-		if (0)							\
-			___mark_check_format(format, ## args);		\
-	} while (0)
-
-extern marker_probe_func __mark_empty_function;
-
-extern void marker_probe_cb(const struct marker *mdata,
-	void *call_private, ...);
-
-/*
- * Connect a probe to a marker.
- * private data pointer must be a valid allocated memory address, or NULL.
- */
-extern int marker_probe_register(const char *name, const char *format,
-				marker_probe_func *probe, void *probe_private);
-
-/*
- * Returns the private data given to marker_probe_register.
- */
-extern int marker_probe_unregister(const char *name,
-	marker_probe_func *probe, void *probe_private);
-/*
- * Unregister a marker by providing the registered private data.
- */
-extern int marker_probe_unregister_private_data(marker_probe_func *probe,
-	void *probe_private);
-
-extern void *marker_get_private_data(const char *name, marker_probe_func *probe,
-	int num);
-
-/*
- * marker_synchronize_unregister must be called between the last marker probe
- * unregistration and the first one of
- * - the end of module exit function
- * - the free of any resource used by the probes
- * to ensure the code and data are valid for any possibly running probes.
- */
-#define marker_synchronize_unregister() synchronize_sched()
-
-#endif

include/linux/module.h

@@ -15,7 +15,6 @@
 #include <linux/stringify.h>
 #include <linux/kobject.h>
 #include <linux/moduleparam.h>
-#include <linux/marker.h>
 #include <linux/tracepoint.h>
 
 #include <asm/local.h>
@@ -327,10 +326,6 @@ struct module
 	/* The command line arguments (may be mangled).  People like
 	   keeping pointers to this stuff */
 	char *args;
-#ifdef CONFIG_MARKERS
-	struct marker *markers;
-	unsigned int num_markers;
-#endif
 #ifdef CONFIG_TRACEPOINTS
 	struct tracepoint *tracepoints;
 	unsigned int num_tracepoints;
@@ -535,8 +530,6 @@ int unregister_module_notifier(struct notifier_block * nb);
 
 extern void print_modules(void);
 
-extern void module_update_markers(void);
-
 extern void module_update_tracepoints(void);
 extern int module_get_iter_tracepoints(struct tracepoint_iter *iter);
 
@@ -651,10 +644,6 @@ static inline void print_modules(void)
 {
 }
 
-static inline void module_update_markers(void)
-{
-}
-
 static inline void module_update_tracepoints(void)
 {
 }

init/Kconfig

@@ -1054,13 +1054,6 @@ config PROFILING
 config TRACEPOINTS
 	bool
 
-config MARKERS
-	bool "Activate markers"
-	select TRACEPOINTS
-	help
-	  Place an empty function call at each marker site. Can be
-	  dynamically changed for a probe function.
-
 source "arch/Kconfig"
 
 config SLOW_WORK

kernel/Makefile

@@ -87,7 +87,6 @@ obj-$(CONFIG_RELAY) += relay.o
 obj-$(CONFIG_SYSCTL) += utsname_sysctl.o
 obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o
 obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o
-obj-$(CONFIG_MARKERS) += marker.o
 obj-$(CONFIG_TRACEPOINTS) += tracepoint.o
 obj-$(CONFIG_LATENCYTOP) += latencytop.o
 obj-$(CONFIG_FUNCTION_TRACER) += trace/

kernel/module.c

@@ -2237,10 +2237,6 @@ static noinline struct module *load_module(void __user *umod,
 				  sizeof(*mod->ctors), &mod->num_ctors);
 #endif
 
-#ifdef CONFIG_MARKERS
-	mod->markers = section_objs(hdr, sechdrs, secstrings, "__markers",
-				    sizeof(*mod->markers), &mod->num_markers);
-#endif
 #ifdef CONFIG_TRACEPOINTS
 	mod->tracepoints = section_objs(hdr, sechdrs, secstrings,
 					"__tracepoints",
@@ -2958,20 +2954,6 @@ void module_layout(struct module *mod,
 EXPORT_SYMBOL(module_layout);
 #endif
 
-#ifdef CONFIG_MARKERS
-void module_update_markers(void)
-{
-	struct module *mod;
-
-	mutex_lock(&module_mutex);
-	list_for_each_entry(mod, &modules, list)
-		if (!mod->taints)
-			marker_update_probe_range(mod->markers,
-				mod->markers + mod->num_markers);
-	mutex_unlock(&module_mutex);
-}
-#endif
-
 #ifdef CONFIG_TRACEPOINTS
 void module_update_tracepoints(void)
 {

kernel/trace/trace_printk.c

@@ -11,7 +11,6 @@
 #include <linux/ftrace.h>
 #include <linux/string.h>
 #include <linux/module.h>
-#include <linux/marker.h>
 #include <linux/mutex.h>
 #include <linux/ctype.h>
 #include <linux/list.h>

samples/Kconfig

@@ -7,12 +7,6 @@ menuconfig SAMPLES
 
 if SAMPLES
 
-config SAMPLE_MARKERS
-	tristate "Build markers examples -- loadable modules only"
-	depends on MARKERS && m
-	help
-	  This build markers example modules.
-
 config SAMPLE_TRACEPOINTS
 	tristate "Build tracepoints examples -- loadable modules only"
 	depends on TRACEPOINTS && m

samples/Makefile

 # Makefile for Linux samples code
 
-obj-$(CONFIG_SAMPLES)	+= markers/ kobject/ kprobes/ tracepoints/ trace_events/
+obj-$(CONFIG_SAMPLES)	+= kobject/ kprobes/ tracepoints/ trace_events/

samples/markers/Makefile

-# builds the kprobes example kernel modules;
-# then to use one (as root):  insmod <module_name.ko>
-
-obj-$(CONFIG_SAMPLE_MARKERS) += probe-example.o marker-example.o

samples/markers/marker-example.c

-/* marker-example.c
- *
- * Executes a marker when /proc/marker-example is opened.
- *
- * (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
- *
- * This file is released under the GPLv2.
- * See the file COPYING for more details.
- */
-
-#include <linux/module.h>
-#include <linux/marker.h>
-#include <linux/sched.h>
-#include <linux/proc_fs.h>
-
-struct proc_dir_entry *pentry_example;
-
-static int my_open(struct inode *inode, struct file *file)
-{
-	int i;
-
-	trace_mark(subsystem_event, "integer %d string %s", 123,
-		"example string");
-	for (i = 0; i < 10; i++)
-		trace_mark(subsystem_eventb, MARK_NOARGS);
-	return -EPERM;
-}
-
-static struct file_operations mark_ops = {
-	.open = my_open,
-};
-
-static int __init example_init(void)
-{
-	printk(KERN_ALERT "example init\n");
-	pentry_example = proc_create("marker-example", 0444, NULL, &mark_ops);
-	if (!pentry_example)
-		return -EPERM;
-	return 0;
-}
-
-static void __exit example_exit(void)
-{
-	printk(KERN_ALERT "example exit\n");
-	remove_proc_entry("marker-example", NULL);
-}
-
-module_init(example_init)
-module_exit(example_exit)
-
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Mathieu Desnoyers");
-MODULE_DESCRIPTION("Marker example");

samples/markers/probe-example.c

-/* probe-example.c
- *
- * Connects two functions to marker call sites.
- *
- * (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
- *
- * This file is released under the GPLv2.
- * See the file COPYING for more details.
- */
-
-#include <linux/sched.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/marker.h>
-#include <asm/atomic.h>
-
-struct probe_data {
-	const char *name;
-	const char *format;
-	marker_probe_func *probe_func;
-};
-
-void probe_subsystem_event(void *probe_data, void *call_data,
-	const char *format, va_list *args)
-{
-	/* Declare args */
-	unsigned int value;
-	const char *mystr;
-
-	/* Assign args */
-	value = va_arg(*args, typeof(value));
-	mystr = va_arg(*args, typeof(mystr));
-
-	/* Call printk */
-	printk(KERN_INFO "Value %u, string %s\n", value, mystr);
-
-	/* or count, check rights, serialize data in a buffer */
-}
-
-atomic_t eventb_count = ATOMIC_INIT(0);
-
-void probe_subsystem_eventb(void *probe_data, void *call_data,
-	const char *format, va_list *args)
-{
-	/* Increment counter */
-	atomic_inc(&eventb_count);
-}
-
-static struct probe_data probe_array[] =
-{
-	{	.name = "subsystem_event",
-		.format = "integer %d string %s",
-		.probe_func = probe_subsystem_event },
-	{	.name = "subsystem_eventb",
-		.format = MARK_NOARGS,
-		.probe_func = probe_subsystem_eventb },
-};
-
-static int __init probe_init(void)
-{
-	int result;
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(probe_array); i++) {
-		result = marker_probe_register(probe_array[i].name,
-				probe_array[i].format,
-				probe_array[i].probe_func, &probe_array[i]);
-		if (result)
-			printk(KERN_INFO "Unable to register probe %s\n",
-				probe_array[i].name);
-	}
-	return 0;
-}
-
-static void __exit probe_fini(void)
-{
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(probe_array); i++)
-		marker_probe_unregister(probe_array[i].name,
-			probe_array[i].probe_func, &probe_array[i]);
-	printk(KERN_INFO "Number of event b : %u\n",
-			atomic_read(&eventb_count));
-	marker_synchronize_unregister();
-}
-
-module_init(probe_init);
-module_exit(probe_fini);
-
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Mathieu Desnoyers");
-MODULE_DESCRIPTION("SUBSYSTEM Probe");

scripts/Makefile.modpost

@@ -13,7 +13,6 @@
 # 2) modpost is then used to
 # 3)  create one <module>.mod.c file pr. module
 # 4)  create one Module.symvers file with CRC for all exported symbols
-# 4a) [CONFIG_MARKERS] create one Module.markers file listing defined markers
 # 5) compile all <module>.mod.c files
 # 6) final link of the module to a <module.ko> file
 
@@ -59,10 +58,6 @@ include scripts/Makefile.lib
 
 kernelsymfile := $(objtree)/Module.symvers
 modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers
-kernelmarkersfile := $(objtree)/Module.markers
-modulemarkersfile := $(firstword $(KBUILD_EXTMOD))/Module.markers
-
-markersfile = $(if $(KBUILD_EXTMOD),$(modulemarkersfile),$(kernelmarkersfile))
 
 # Step 1), find all modules listed in $(MODVERDIR)/
 __modules := $(sort $(shell grep -h '\.ko' /dev/null $(wildcard $(MODVERDIR)/*.mod)))
@@ -85,8 +80,6 @@ modpost = scripts/mod/modpost                    \
  $(if $(KBUILD_EXTRA_SYMBOLS), $(patsubst %, -e %,$(KBUILD_EXTRA_SYMBOLS))) \
  $(if $(KBUILD_EXTMOD),-o $(modulesymfile))      \
  $(if $(CONFIG_DEBUG_SECTION_MISMATCH),,-S)      \
- $(if $(CONFIG_MARKERS),-K $(kernelmarkersfile)) \
- $(if $(CONFIG_MARKERS),-M $(markersfile))	 \
  $(if $(KBUILD_EXTMOD)$(KBUILD_MODPOST_WARN),-w) \
  $(if $(cross_build),-c)
 
@@ -101,17 +94,12 @@ quiet_cmd_kernel-mod = MODPOST $@
       cmd_kernel-mod = $(modpost) $@
 
 vmlinux.o: FORCE
-	@rm -fr $(kernelmarkersfile)
 	$(call cmd,kernel-mod)
 
 # Declare generated files as targets for modpost
 $(symverfile):         __modpost ;
 $(modules:.ko=.mod.c): __modpost ;
 
-ifdef CONFIG_MARKERS
-$(markersfile):	       __modpost ;
-endif
-
 
 # Step 5), compile all *.mod.c files