tracing: Use dyn_event framework for synthetic events (7bbab38d) · Commits · 戴 / test

kernel/trace/Kconfig

+1 −0

Original line number	Diff line number	Diff line
		@@ -635,6 +635,7 @@ config HIST_TRIGGERS
		depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
		select TRACING_MAP
		select TRACING
		select DYNAMIC_EVENTS
		default n
		help
		Hist triggers allow one or more arbitrary trace event fields

kernel/trace/trace.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -4620,6 +4620,9 @@ static const char readme_msg[] =
		"\t accepts: event-definitions (one definition per line)\n"
		"\t Format: p[:[<group>/]<event>] <place> [<args>]\n"
		"\t r[maxactive][:[<group>/]<event>] <place> [<args>]\n"
		#ifdef CONFIG_HIST_TRIGGERS
		"\t s:[synthetic/]<event> <field> [<field>]\n"
		#endif
		"\t -:[<group>/]<event>\n"
		#ifdef CONFIG_KPROBE_EVENTS
		"\t place: [<module>:]<symbol>[+<offset>]\|<memaddr>\n"
		@@ -4638,6 +4641,11 @@ static const char readme_msg[] =
		"\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string, symbol,\n"
		"\t b<bit-width>@<bit-offset>/<container-size>,\n"
		"\t <type>\\[<array-size>\\]\n"
		#ifdef CONFIG_HIST_TRIGGERS
		"\t field: <stype> <name>;\n"
		"\t stype: u8/u16/u32/u64, s8/s16/s32/s64, pid_t,\n"
		"\t [unsigned] char/int/long\n"
		#endif
		#endif
		" events/\t\t- Directory containing all trace event subsystems:\n"
		" enable\t\t- Write 0/1 to enable/disable tracing of all events\n"

kernel/trace/trace_events_hist.c

+167 −98

Original line number	Diff line number	Diff line
		@@ -15,6 +15,7 @@

		#include "tracing_map.h"
		#include "trace.h"
		#include "trace_dynevent.h"

		#define SYNTH_SYSTEM "synthetic"
		#define SYNTH_FIELDS_MAX 16
		@@ -292,6 +293,21 @@ struct hist_trigger_data {
		unsigned int n_max_var_str;
		};

		static int synth_event_create(int argc, const char **argv);
		static int synth_event_show(struct seq_file m, struct dyn_event ev);
		static int synth_event_release(struct dyn_event *ev);
		static bool synth_event_is_busy(struct dyn_event *ev);
		static bool synth_event_match(const char system, const char event,
		struct dyn_event *ev);

		static struct dyn_event_operations synth_event_ops = {
		.create = synth_event_create,
		.show = synth_event_show,
		.is_busy = synth_event_is_busy,
		.free = synth_event_release,
		.match = synth_event_match,
		};

		struct synth_field {
		char *type;
		char *name;
		@@ -301,7 +317,7 @@ struct synth_field {
		};

		struct synth_event {
		struct list_head list;
		struct dyn_event devent;
		int ref;
		char *name;
		struct synth_field **fields;
		@@ -312,6 +328,32 @@ struct synth_event {
		struct tracepoint *tp;
		};

		static bool is_synth_event(struct dyn_event *ev)
		{
		return ev->ops == &synth_event_ops;
		}

		static struct synth_event to_synth_event(struct dyn_event ev)
		{
		return container_of(ev, struct synth_event, devent);
		}

		static bool synth_event_is_busy(struct dyn_event *ev)
		{
		struct synth_event *event = to_synth_event(ev);

		return event->ref != 0;
		}

		static bool synth_event_match(const char system, const char event,
		struct dyn_event *ev)
		{
		struct synth_event *sev = to_synth_event(ev);

		return strcmp(sev->name, event) == 0 &&
		(!system \|\| strcmp(system, SYNTH_SYSTEM) == 0);
		}

		struct action_data;

		typedef void (action_fn_t) (struct hist_trigger_data hist_data,
		@@ -402,7 +444,6 @@ static bool have_hist_err(void)
		return false;
		}

		static LIST_HEAD(synth_event_list);
		static DEFINE_MUTEX(synth_event_mutex);

		struct synth_trace_event {
		@@ -738,14 +779,12 @@ static void free_synth_field(struct synth_field *field)
		kfree(field);
		}

		static struct synth_field parse_synth_field(int argc, char *argv,
		static struct synth_field parse_synth_field(int argc, const char *argv,
		int *consumed)
		{
		struct synth_field *field;
		const char *prefix = NULL;
		char field_type = argv[0], field_name;
		const char prefix = NULL, field_type = argv[0], field_name, array;
		int len, ret = 0;
		char *array;

		if (field_type[0] == ';')
		field_type++;
		@@ -762,20 +801,31 @@ static struct synth_field parse_synth_field(int argc, char *argv,
		*consumed = 2;
		}

		len = strlen(field_name);
		if (field_name[len - 1] == ';')
		field_name[len - 1] = '\0';

		field = kzalloc(sizeof(*field), GFP_KERNEL);
		if (!field)
		return ERR_PTR(-ENOMEM);

		len = strlen(field_type) + 1;
		len = strlen(field_name);
		array = strchr(field_name, '[');
		if (array)
		len -= strlen(array);
		else if (field_name[len - 1] == ';')
		len--;

		field->name = kmemdup_nul(field_name, len, GFP_KERNEL);
		if (!field->name) {
		ret = -ENOMEM;
		goto free;
		}

		if (field_type[0] == ';')
		field_type++;
		len = strlen(field_type) + 1;
		if (array)
		len += strlen(array);
		if (prefix)
		len += strlen(prefix);

		field->type = kzalloc(len, GFP_KERNEL);
		if (!field->type) {
		ret = -ENOMEM;
		@@ -786,7 +836,8 @@ static struct synth_field parse_synth_field(int argc, char *argv,
		strcat(field->type, field_type);
		if (array) {
		strcat(field->type, array);
		*array = '\0';
		if (field->type[len - 1] == ';')
		field->type[len - 1] = '\0';
		}

		field->size = synth_field_size(field->type);
		@@ -800,11 +851,6 @@ static struct synth_field parse_synth_field(int argc, char *argv,

		field->is_signed = synth_field_signed(field->type);

		field->name = kstrdup(field_name, GFP_KERNEL);
		if (!field->name) {
		ret = -ENOMEM;
		goto free;
		}
		out:
		return field;
		free:
		@@ -868,9 +914,13 @@ static inline void trace_synth(struct synth_event event, u64 var_ref_vals,

		static struct synth_event find_synth_event(const char name)
		{
		struct dyn_event *pos;
		struct synth_event *event;

		list_for_each_entry(event, &synth_event_list, list) {
		for_each_dyn_event(pos) {
		if (!is_synth_event(pos))
		continue;
		event = to_synth_event(pos);
		if (strcmp(event->name, name) == 0)
		return event;
		}
		@@ -921,7 +971,7 @@ static int register_synth_event(struct synth_event *event)

		ret = set_synth_event_print_fmt(call);
		if (ret < 0) {
		trace_remove_event_call(call);
		trace_remove_event_call_nolock(call);
		goto err;
		}
		out:
		@@ -959,7 +1009,7 @@ static void free_synth_event(struct synth_event *event)
		kfree(event);
		}

		static struct synth_event alloc_synth_event(char event_name, int n_fields,
		static struct synth_event alloc_synth_event(const char name, int n_fields,
		struct synth_field **fields)
		{
		struct synth_event *event;
		@@ -971,7 +1021,7 @@ static struct synth_event alloc_synth_event(char event_name, int n_fields,
		goto out;
		}

		event->name = kstrdup(event_name, GFP_KERNEL);
		event->name = kstrdup(name, GFP_KERNEL);
		if (!event->name) {
		kfree(event);
		event = ERR_PTR(-ENOMEM);
		@@ -985,6 +1035,8 @@ static struct synth_event alloc_synth_event(char event_name, int n_fields,
		goto out;
		}

		dyn_event_init(&event->devent, &synth_event_ops);

		for (i = 0; i < n_fields; i++)
		event->fields[i] = fields[i];

		@@ -1008,16 +1060,11 @@ struct hist_var_data {
		struct hist_trigger_data *hist_data;
		};

		static int create_synth_event(int argc, char **argv)
		static int __create_synth_event(int argc, const char name, const char *argv)
		{
		struct synth_field field, fields[SYNTH_FIELDS_MAX];
		struct synth_event *event = NULL;
		bool delete_event = false;
		int i, consumed = 0, n_fields = 0, ret = 0;
		char *name;

		mutex_lock(&event_mutex);
		mutex_lock(&synth_event_mutex);

		/*
		* Argument syntax:
		@@ -1025,43 +1072,20 @@ static int create_synth_event(int argc, char **argv)
		* - Remove synthetic event: !<event_name> field[;field] ...
		* where 'field' = type field_name
		*/
		if (argc < 1) {
		ret = -EINVAL;
		goto out;
		}

		name = argv[0];
		if (name[0] == '!') {
		delete_event = true;
		name++;
		}
		if (name[0] == '\0' \|\| argc < 1)
		return -EINVAL;

		mutex_lock(&event_mutex);
		mutex_lock(&synth_event_mutex);

		event = find_synth_event(name);
		if (event) {
		if (delete_event) {
		if (event->ref) {
		ret = -EBUSY;
		goto out;
		}
		ret = unregister_synth_event(event);
		if (!ret) {
		list_del(&event->list);
		free_synth_event(event);
		}
		} else
		ret = -EEXIST;
		goto out;
		} else if (delete_event) {
		ret = -ENOENT;
		goto out;
		}

		if (argc < 2) {
		ret = -EINVAL;
		goto out;
		}

		for (i = 1; i < argc - 1; i++) {
		for (i = 0; i < argc - 1; i++) {
		if (strcmp(argv[i], ";") == 0)
		continue;
		if (n_fields == SYNTH_FIELDS_MAX) {
		@@ -1091,7 +1115,7 @@ static int create_synth_event(int argc, char **argv)
		}
		ret = register_synth_event(event);
		if (!ret)
		list_add(&event->list, &synth_event_list);
		dyn_event_add(&event->devent);
		else
		free_synth_event(event);
		out:
		@@ -1106,57 +1130,77 @@ static int create_synth_event(int argc, char **argv)
		goto out;
		}

		static int release_all_synth_events(void)
		static int create_or_delete_synth_event(int argc, char **argv)
		{
		struct synth_event event, e;
		int ret = 0;
		const char *name = argv[0];
		struct synth_event *event = NULL;
		int ret;

		/* trace_run_command() ensures argc != 0 */
		if (name[0] == '!') {
		mutex_lock(&event_mutex);
		mutex_lock(&synth_event_mutex);

		list_for_each_entry(event, &synth_event_list, list) {
		if (event->ref) {
		mutex_unlock(&synth_event_mutex);
		return -EBUSY;
		}
		}

		list_for_each_entry_safe(event, e, &synth_event_list, list) {
		event = find_synth_event(name + 1);
		if (event) {
		if (event->ref)
		ret = -EBUSY;
		else {
		ret = unregister_synth_event(event);
		if (!ret) {
		list_del(&event->list);
		dyn_event_remove(&event->devent);
		free_synth_event(event);
		} else
		break;
		}
		}
		} else
		ret = -ENOENT;
		mutex_unlock(&synth_event_mutex);
		mutex_unlock(&event_mutex);

		return ret;
		}

		ret = __create_synth_event(argc - 1, name, (const char **)argv + 1);
		return ret == -ECANCELED ? -EINVAL : ret;
		}

		static void synth_events_seq_start(struct seq_file m, loff_t *pos)
		static int synth_event_create(int argc, const char **argv)
		{
		mutex_lock(&synth_event_mutex);
		const char *name = argv[0];
		int len;

		return seq_list_start(&synth_event_list, *pos);
		}
		if (name[0] != 's' \|\| name[1] != ':')
		return -ECANCELED;
		name += 2;

		static void synth_events_seq_next(struct seq_file m, void v, loff_t pos)
		{
		return seq_list_next(v, &synth_event_list, pos);
		/* This interface accepts group name prefix */
		if (strchr(name, '/')) {
		len = sizeof(SYNTH_SYSTEM "/") - 1;
		if (strncmp(name, SYNTH_SYSTEM "/", len))
		return -EINVAL;
		name += len;
		}
		return __create_synth_event(argc - 1, name, argv + 1);
		}

		static void synth_events_seq_stop(struct seq_file m, void v)
		static int synth_event_release(struct dyn_event *ev)
		{
		mutex_unlock(&synth_event_mutex);
		struct synth_event *event = to_synth_event(ev);
		int ret;

		if (event->ref)
		return -EBUSY;

		ret = unregister_synth_event(event);
		if (ret)
		return ret;

		dyn_event_remove(ev);
		free_synth_event(event);
		return 0;
		}

		static int synth_events_seq_show(struct seq_file m, void v)
		static int __synth_event_show(struct seq_file m, struct synth_event event)
		{
		struct synth_field *field;
		struct synth_event *event = v;
		unsigned int i;

		seq_printf(m, "%s\t", event->name);
		@@ -1174,11 +1218,30 @@ static int synth_events_seq_show(struct seq_file m, void v)
		return 0;
		}

		static int synth_event_show(struct seq_file m, struct dyn_event ev)
		{
		struct synth_event *event = to_synth_event(ev);

		seq_printf(m, "s:%s/", event->class.system);

		return __synth_event_show(m, event);
		}

		static int synth_events_seq_show(struct seq_file m, void v)
		{
		struct dyn_event *ev = v;

		if (!is_synth_event(ev))
		return 0;

		return __synth_event_show(m, to_synth_event(ev));
		}

		static const struct seq_operations synth_events_seq_op = {
		.start = synth_events_seq_start,
		.next = synth_events_seq_next,
		.stop = synth_events_seq_stop,
		.show = synth_events_seq_show
		.start = dyn_event_seq_start,
		.next = dyn_event_seq_next,
		.stop = dyn_event_seq_stop,
		.show = synth_events_seq_show,
		};

		static int synth_events_open(struct inode inode, struct file file)
		@@ -1186,7 +1249,7 @@ static int synth_events_open(struct inode inode, struct file file)
		int ret;

		if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
		ret = release_all_synth_events();
		ret = dyn_events_release_all(&synth_event_ops);
		if (ret < 0)
		return ret;
		}
		@@ -1199,7 +1262,7 @@ static ssize_t synth_events_write(struct file *file,
		size_t count, loff_t *ppos)
		{
		return trace_parse_run_command(file, buffer, count, ppos,
		create_synth_event);
		create_or_delete_synth_event);
		}

		static const struct file_operations synth_events_fops = {
		@@ -5791,6 +5854,12 @@ static __init int trace_events_hist_init(void)
		struct dentry *d_tracer;
		int err = 0;

		err = dyn_event_register(&synth_event_ops);
		if (err) {
		pr_warn("Could not register synth_event_ops\n");
		return err;
		}

		d_tracer = tracing_init_dentry();
		if (IS_ERR(d_tracer)) {
		err = PTR_ERR(d_tracer);

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