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From: Tom Zanussi <zanussi@kernel.org>
To: rostedt@goodmis.org
Cc: tglx@linutronix.de, mhiramat@kernel.org, namhyung@kernel.org,
	vedang.patel@intel.com, bigeasy@linutronix.de,
	joel@joelfernandes.org, mathieu.desnoyers@efficios.com,
	julia@ni.com, linux-kernel@vger.kernel.org,
	linux-rt-users@vger.kernel.org
Subject: [PATCH v14 08/15] tracing: Add hist trigger onchange() handler
Date: Tue,  5 Feb 2019 16:41:54 -0600	[thread overview]
Message-ID: <8947a0399b175406e51b0ffbee111e91c982e494.1549403369.git.tom.zanussi@linux.intel.com> (raw)
In-Reply-To: <cover.1549403369.git.tom.zanussi@linux.intel.com>
In-Reply-To: <cover.1549403369.git.tom.zanussi@linux.intel.com>

From: Tom Zanussi <tom.zanussi@linux.intel.com>

Add support for a hist:onchange($var) handler, similar to the onmax()
handler but triggering whenever there's any change in $var, not just a
max.

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
---
 kernel/trace/trace.c             |  3 ++-
 kernel/trace/trace_events_hist.c | 58 ++++++++++++++++++++++++++++++++++------
 2 files changed, 52 insertions(+), 9 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 1449a5201c87..3f9868b26f19 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4909,7 +4909,8 @@ static const char readme_msg[] =
 	"\t        <handler>.<action>\n\n"
 	"\t    The available handlers are:\n\n"
 	"\t        onmatch(matching.event)  - invoke on addition or update\n"
-	"\t        onmax(var)               - invoke if var exceeds current max\n\n"
+	"\t        onmax(var)               - invoke if var exceeds current max\n"
+	"\t        onchange(var)            - invoke action if var changes\n\n"
 	"\t    The available actions are:\n\n"
 	"\t        <synthetic_event>(param list)        - generate synthetic event\n"
 	"\t        save(field,...)                      - save current event fields\n"
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 9cc28cc82e3c..5b3643f39a86 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -391,6 +391,7 @@ typedef bool (*check_track_val_fn_t) (u64 track_val, u64 var_val);
 enum handler_id {
 	HANDLER_ONMATCH = 1,
 	HANDLER_ONMAX,
+	HANDLER_ONCHANGE,
 };
 
 enum action_id {
@@ -1990,7 +1991,8 @@ static int parse_action(char *str, struct hist_trigger_attrs *attrs)
 		return ret;
 
 	if ((str_has_prefix(str, "onmatch(")) ||
-	    (str_has_prefix(str, "onmax("))) {
+	    (str_has_prefix(str, "onmax(")) ||
+	    (str_has_prefix(str, "onchange("))) {
 		attrs->action_str[attrs->n_actions] = kstrdup(str, GFP_KERNEL);
 		if (!attrs->action_str[attrs->n_actions]) {
 			ret = -ENOMEM;
@@ -3482,6 +3484,14 @@ static bool check_track_val_max(u64 track_val, u64 var_val)
 	return true;
 }
 
+static bool check_track_val_changed(u64 track_val, u64 var_val)
+{
+	if (var_val == track_val)
+		return false;
+
+	return true;
+}
+
 static u64 get_track_val(struct hist_trigger_data *hist_data,
 			 struct tracing_map_elt *elt,
 			 struct action_data *data)
@@ -3641,6 +3651,8 @@ static void track_data_print(struct seq_file *m,
 
 	if (data->handler == HANDLER_ONMAX)
 		seq_printf(m, "\n\tmax: %10llu", track_val);
+	else if (data->handler == HANDLER_ONCHANGE)
+		seq_printf(m, "\n\tchanged: %10llu", track_val);
 
 	if (data->action == ACTION_SNAPSHOT)
 		return;
@@ -3728,14 +3740,14 @@ static int track_data_create(struct hist_trigger_data *hist_data,
 
 	track_data_var_str = data->track_data.var_str;
 	if (track_data_var_str[0] != '$') {
-		hist_err("For onmax(x), x must be a variable: ", track_data_var_str);
+		hist_err("For onmax(x) or onchange(x), x must be a variable: ", track_data_var_str);
 		return -EINVAL;
 	}
 	track_data_var_str++;
 
 	var_field = find_target_event_var(hist_data, NULL, NULL, track_data_var_str);
 	if (!var_field) {
-		hist_err("Couldn't find onmax variable: ", track_data_var_str);
+		hist_err("Couldn't find onmax or onchange variable: ", track_data_var_str);
 		return -EINVAL;
 	}
 
@@ -3752,6 +3764,14 @@ static int track_data_create(struct hist_trigger_data *hist_data,
 		ret = PTR_ERR(track_var);
 		goto out;
 	}
+
+	if (data->handler == HANDLER_ONCHANGE)
+		track_var = create_var(hist_data, file, "__change", sizeof(u64), "u64");
+	if (IS_ERR(track_var)) {
+		hist_err("Couldn't create onchange variable: ", "__change");
+		ret = PTR_ERR(track_var);
+		goto out;
+	}
 	data->track_data.track_var = track_var;
 
 	ret = action_create(hist_data, data);
@@ -3831,6 +3851,8 @@ static int action_parse(char *str, struct action_data *data,
 
 		if (handler == HANDLER_ONMAX)
 			data->track_data.check_val = check_track_val_max;
+		else if (handler == HANDLER_ONCHANGE)
+			data->track_data.check_val = check_track_val_changed;
 		else {
 			hist_err("action parsing: Handler doesn't support action: ", action_name);
 			ret = -EINVAL;
@@ -3851,6 +3873,8 @@ static int action_parse(char *str, struct action_data *data,
 
 		if (handler == HANDLER_ONMAX)
 			data->track_data.check_val = check_track_val_max;
+		else if (handler == HANDLER_ONCHANGE)
+			data->track_data.check_val = check_track_val_changed;
 		else {
 			hist_err("action parsing: Handler doesn't support action: ", action_name);
 			ret = -EINVAL;
@@ -3871,6 +3895,8 @@ static int action_parse(char *str, struct action_data *data,
 
 		if (handler == HANDLER_ONMAX)
 			data->track_data.check_val = check_track_val_max;
+		else if (handler == HANDLER_ONCHANGE)
+			data->track_data.check_val = check_track_val_changed;
 
 		if (handler != HANDLER_ONMATCH) {
 			data->track_data.save_data = action_trace;
@@ -4701,7 +4727,8 @@ static void destroy_actions(struct hist_trigger_data *hist_data)
 
 		if (data->handler == HANDLER_ONMATCH)
 			onmatch_destroy(data);
-		else if (data->handler == HANDLER_ONMAX)
+		else if (data->handler == HANDLER_ONMAX ||
+			 data->handler == HANDLER_ONCHANGE)
 			track_data_destroy(hist_data, data);
 		else
 			kfree(data);
@@ -4737,6 +4764,15 @@ static int parse_actions(struct hist_trigger_data *hist_data)
 				ret = PTR_ERR(data);
 				break;
 			}
+		} else if ((len = str_has_prefix(str, "onchange("))) {
+			char *action_str = str + len;
+
+			data = track_data_parse(hist_data, action_str,
+						HANDLER_ONCHANGE);
+			if (IS_ERR(data)) {
+				ret = PTR_ERR(data);
+				break;
+			}
 		} else {
 			ret = -EINVAL;
 			break;
@@ -4761,7 +4797,8 @@ static int create_actions(struct hist_trigger_data *hist_data)
 			ret = onmatch_create(hist_data, data);
 			if (ret)
 				break;
-		} else if (data->handler == HANDLER_ONMAX) {
+		} else if (data->handler == HANDLER_ONMAX ||
+			   data->handler == HANDLER_ONCHANGE) {
 			ret = track_data_create(hist_data, data);
 			if (ret)
 				break;
@@ -4786,7 +4823,8 @@ static void print_actions(struct seq_file *m,
 		if (data->action == ACTION_SNAPSHOT)
 			continue;
 
-		if (data->handler == HANDLER_ONMAX)
+		if (data->handler == HANDLER_ONMAX ||
+		    data->handler == HANDLER_ONCHANGE)
 			track_data_print(m, hist_data, elt, data);
 	}
 }
@@ -4818,6 +4856,8 @@ static void print_track_data_spec(struct seq_file *m,
 {
 	if (data->handler == HANDLER_ONMAX)
 		seq_puts(m, ":onmax(");
+	else if (data->handler == HANDLER_ONCHANGE)
+		seq_puts(m, ":onchange(");
 	seq_printf(m, "%s", data->track_data.var_str);
 	seq_printf(m, ").%s(", data->action_name);
 
@@ -4875,7 +4915,8 @@ static bool actions_match(struct hist_trigger_data *hist_data,
 			if (strcmp(data->match_data.event,
 				   data_test->match_data.event) != 0)
 				return false;
-		} else if (data->handler == HANDLER_ONMAX) {
+		} else if (data->handler == HANDLER_ONMAX ||
+			   data->handler == HANDLER_ONCHANGE) {
 			if (strcmp(data->track_data.var_str,
 				   data_test->track_data.var_str) != 0)
 				return false;
@@ -4896,7 +4937,8 @@ static void print_actions_spec(struct seq_file *m,
 
 		if (data->handler == HANDLER_ONMATCH)
 			print_onmatch_spec(m, hist_data, data);
-		else if (data->handler == HANDLER_ONMAX)
+		else if (data->handler == HANDLER_ONMAX ||
+			 data->handler == HANDLER_ONCHANGE)
 			print_track_data_spec(m, hist_data, data);
 	}
 }
-- 
2.14.1


  parent reply	other threads:[~2019-02-05 22:43 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-05 22:41 [PATCH v14 00/15] tracing: Hist trigger snapshot and onchange additions Tom Zanussi
2019-02-05 22:41 ` [PATCH v14 01/15] tracing: Refactor hist trigger action code Tom Zanussi
2019-02-05 22:41 ` [PATCH v14 02/15] tracing: Make hist trigger Documentation better reflect actions/handlers Tom Zanussi
2019-02-05 22:41 ` [PATCH v14 03/15] tracing: Split up onmatch action data Tom Zanussi
2019-02-05 22:41 ` [PATCH v14 04/15] tracing: Generalize hist trigger onmax and save action Tom Zanussi
2019-02-05 22:41 ` [PATCH v14 05/15] tracing: Add conditional snapshot Tom Zanussi
2019-02-13 19:18   ` Steven Rostedt
2019-02-05 22:41 ` [PATCH v14 06/15] tracing: Add hist trigger snapshot() action Tom Zanussi
2019-02-13 19:25   ` Steven Rostedt
2019-02-13 19:35     ` Steven Rostedt
2019-02-13 19:47       ` Tom Zanussi
2019-02-05 22:41 ` [PATCH v14 07/15] tracing: Add hist trigger snapshot() action Documentation Tom Zanussi
2019-02-05 22:41 ` Tom Zanussi [this message]
2019-02-05 22:41 ` [PATCH v14 09/15] tracing: Add hist trigger onchange() handler Documentation Tom Zanussi
2019-02-05 22:41 ` [PATCH v14 10/15] tracing: Add alternative synthetic event trace action syntax Tom Zanussi
2019-02-05 22:41 ` [PATCH v14 11/15] tracing: Add SPDX license GPL-2.0 license identifier to inter-event testcases Tom Zanussi
2019-02-05 22:41 ` [PATCH v14 12/15] tracing: Add hist trigger snapshot() action test case Tom Zanussi
2019-02-05 22:41 ` [PATCH v14 13/15] tracing: Add hist trigger onchange() handler " Tom Zanussi
2019-02-05 22:42 ` [PATCH v14 14/15] tracing: Add alternative synthetic event trace action " Tom Zanussi
2019-02-05 22:42 ` [PATCH v14 15/15] tracing: Add hist trigger action 'expected fail' " Tom Zanussi

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