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Groups > linux.kernel > #1186100

[PATCH v9 16/22] tracing: Add hist trigger 'execname' modifier

From Tom Zanussi <tom.zanussi@linux.intel.com>
Newsgroups linux.kernel
Subject [PATCH v9 16/22] tracing: Add hist trigger 'execname' modifier
Date 2015-07-16 19:30 +0200
Message-ID <pMV8T-4VI-49@gated-at.bofh.it> (permalink)
References <pMV8R-4VI-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Allow users to have pid fields displayed as program names in the output
by appending '.execname' to field names:

   # echo hist:keys=aaa.execname ... \
              [ if filter] > event/trigger

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
---
 kernel/trace/trace.c             |  1 +
 kernel/trace/trace_events_hist.c | 86 +++++++++++++++++++++++++++++++++++++++-
 2 files changed, 86 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8cdc7b3..a16ab69 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3816,6 +3816,7 @@ static const char readme_msg[] =
 	"\t            .hex        display a number as a hex value\n\n"
 	"\t            .sym        display an address as a symbol\n"
 	"\t            .sym-offset display an address as a symbol and offset\n"
+	"\t            .execname   display a common_pid as a program name\n\n"
 	"\t    By default, the size of the hash table is 2048 entries.  The\n"
 	"\t    'size' param can be used to specify more or fewer than that.\n"
 	"\t    The units are in terms of hashtable entries - if a run uses\n"
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 106d557..af1b846 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -75,6 +75,7 @@ enum hist_field_flags {
 	HIST_FIELD_HEX		= 8,
 	HIST_FIELD_SYM		= 16,
 	HIST_FIELD_SYM_OFFSET	= 32,
+	HIST_FIELD_EXECNAME	= 64,
 };
 
 struct hist_trigger_attrs {
@@ -218,6 +219,78 @@ static struct hist_trigger_attrs *parse_hist_trigger_attrs(char *trigger_str)
 	return ERR_PTR(ret);
 }
 
+static inline void save_comm(char *comm, struct task_struct *task)
+{
+	if (!task->pid) {
+		strcpy(comm, "<idle>");
+		return;
+	}
+
+	if (WARN_ON_ONCE(task->pid < 0)) {
+		strcpy(comm, "<XXX>");
+		return;
+	}
+
+	if (task->pid > PID_MAX_DEFAULT) {
+		strcpy(comm, "<...>");
+		return;
+	}
+
+	memcpy(comm, task->comm, TASK_COMM_LEN);
+}
+
+static void hist_trigger_elt_free(struct tracing_map_elt *elt)
+{
+	kfree((char *)elt->private_data);
+}
+
+static int hist_trigger_elt_alloc(struct tracing_map_elt *elt)
+{
+	struct hist_trigger_data *hist_data = elt->map->private_data;
+	struct hist_field *key_field;
+	unsigned int i;
+
+	for (i = hist_data->n_vals; i < hist_data->n_fields; i++) {
+		key_field = hist_data->fields[i];
+
+		if (key_field->flags & HIST_FIELD_EXECNAME) {
+			unsigned int size = TASK_COMM_LEN + 1;
+
+			elt->private_data = kzalloc(size, GFP_KERNEL);
+			if (!elt->private_data)
+				return -ENOMEM;
+			break;
+		}
+	}
+
+	return 0;
+}
+
+static void hist_trigger_elt_copy(struct tracing_map_elt *to,
+				  struct tracing_map_elt *from)
+{
+	char *comm_from = from->private_data;
+	char *comm_to = to->private_data;
+
+	if (comm_from)
+		memcpy(comm_to, comm_from, TASK_COMM_LEN + 1);
+}
+
+static void hist_trigger_elt_init(struct tracing_map_elt *elt)
+{
+	char *comm = elt->private_data;
+
+	if (comm)
+		save_comm(comm, current);
+}
+
+static struct tracing_map_ops hist_trigger_ops = {
+	.elt_alloc	= hist_trigger_elt_alloc,
+	.elt_copy	= hist_trigger_elt_copy,
+	.elt_free	= hist_trigger_elt_free,
+	.elt_init	= hist_trigger_elt_init,
+};
+
 static void destroy_hist_field(struct hist_field *hist_field)
 {
 	kfree(hist_field);
@@ -376,6 +449,9 @@ static int create_key_field(struct hist_trigger_data *hist_data,
 			flags |= HIST_FIELD_SYM;
 		else if (!strcmp(field_str, "sym-offset"))
 			flags |= HIST_FIELD_SYM_OFFSET;
+		else if (!strcmp(field_str, "execname") &&
+			 !strcmp(field_name, "common_pid"))
+			flags |= HIST_FIELD_EXECNAME;
 		else {
 			ret = -EINVAL;
 			goto out;
@@ -612,7 +688,7 @@ create_hist_data(unsigned int map_bits,
 		goto free;
 
 	hist_data->map = tracing_map_create(map_bits, hist_data->key_size,
-					    NULL, hist_data);
+					    &hist_trigger_ops, hist_data);
 	if (IS_ERR(hist_data->map)) {
 		ret = PTR_ERR(hist_data->map);
 		hist_data->map = NULL;
@@ -732,6 +808,12 @@ hist_trigger_entry_print(struct seq_file *m,
 			sprint_symbol(str, uval);
 			seq_printf(m, "%s: [%llx] %-55s",
 				   key_field->field->name, uval, str);
+		} else if (key_field->flags & HIST_FIELD_EXECNAME) {
+			char *comm = elt->private_data;
+
+			uval = *(u64 *)(key + key_field->offset);
+			seq_printf(m, "%s: %-16s[%10llu]",
+				   key_field->field->name, comm, uval);
 		} else if (key_field->flags & HIST_FIELD_STRING) {
 			seq_printf(m, "%s: %-35s", key_field->field->name,
 				   (char *)(key + key_field->offset));
@@ -845,6 +927,8 @@ static const char *get_hist_field_flags(struct hist_field *hist_field)
 		flags_str = "sym";
 	else if (hist_field->flags & HIST_FIELD_SYM_OFFSET)
 		flags_str = "sym-offset";
+	else if (hist_field->flags & HIST_FIELD_EXECNAME)
+		flags_str = "execname";
 
 	return flags_str;
 }
-- 
1.9.3

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Thread

[PATCH v9 00/22] tracing: 'hist' triggers Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-07-16 19:30 +0200
  [PATCH v9 09/22] tracing: Add hist trigger support for multiple values ('vals=' param) Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-07-16 19:30 +0200
  [PATCH v9 01/22] tracing: Update cond flag when enabling or disabling a trigger Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-07-16 19:30 +0200
  [PATCH v9 15/22] tracing: Add hist trigger 'sym' and 'sym-offset' modifiers Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-07-16 19:30 +0200
  [PATCH v9 16/22] tracing: Add hist trigger 'execname' modifier Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-07-16 19:30 +0200
  [PATCH v9 11/22] tracing: Add hist trigger support for user-defined sorting ('sort=' param) Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-07-16 19:30 +0200
  [PATCH v9 12/22] tracing: Add hist trigger support for pausing and continuing a trace Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-07-16 19:30 +0200
    Re: [PATCH v9 12/22] tracing: Add hist trigger support for pausing  and continuing a trace Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> - 2015-07-22 10:30 +0200
  [PATCH v9 08/22] tracing: Add 'hist' event trigger command Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-07-16 19:30 +0200
    Re: [PATCH v9 08/22] tracing: Add 'hist' event trigger command Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> - 2015-07-20 15:40 +0200
  [PATCH v9 14/22] tracing: Add hist trigger 'hex' modifier for displaying numeric fields Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-07-16 19:30 +0200
  [PATCH v9 17/22] tracing: Add hist trigger 'syscall' modifier Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-07-16 19:30 +0200
  [PATCH v9 04/22] tracing: Add event record param to trigger_ops.func() Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-07-16 19:30 +0200
  [PATCH v9 05/22] tracing: Add get_syscall_name() Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-07-16 19:30 +0200
  Re: [PATCH v9 07/22] tracing: Add lock-free tracing_map Peter Zijlstra <peterz@infradead.org> - 2015-07-16 20:00 +0200
    Re: [PATCH v9 07/22] tracing: Add lock-free tracing_map Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-07-16 23:50 +0200
      Re: [PATCH v9 07/22] tracing: Add lock-free tracing_map Peter Zijlstra <peterz@infradead.org> - 2015-07-17 00:40 +0200
        Re: [PATCH v9 07/22] tracing: Add lock-free tracing_map Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-07-17 04:00 +0200
  Re: [PATCH v9 07/22] tracing: Add lock-free tracing_map Peter Zijlstra <peterz@infradead.org> - 2015-07-16 20:10 +0200
    Re: [PATCH v9 07/22] tracing: Add lock-free tracing_map Tom Zanussi <tom.zanussi@linux.intel.com> - 2015-07-16 23:40 +0200

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