[PATCH v13 16/29] tracing: Add hist trigger 'sym' and 'sym-offset' modifiers

From: Tom Zanussi
Date: Thu Dec 10 2015 - 14:01:30 EST


Allow users to have address fields displayed as symbols in the output
by appending '.sym' or 'sym-offset' to field names:

# echo hist:keys=aaa.sym,bbb.sym-offset ... \
[ if filter] > event/trigger

Signed-off-by: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Reviewed-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
kernel/trace/trace.c | 4 +++-
kernel/trace/trace_events_hist.c | 21 +++++++++++++++++++++
2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 15eda83..b1525b8 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3846,7 +3846,9 @@ static const char readme_msg[] =
"\t table in its entirety to stdout. The default format used to\n"
"\t display a given field can be modified by appending any of the\n"
"\t following modifiers to the field name, as applicable:\n\n"
- "\t .hex display a number as a hex value\n\n"
+ "\t .hex display a number as a hex value\n"
+ "\t .sym display an address as a symbol\n"
+ "\t .sym-offset display an address as a symbol and offset\n\n"
"\t The 'pause' parameter can be used to pause an existing hist\n"
"\t trigger or to start a hist trigger but not log any events\n"
"\t until told to do so. 'continue' can be used to start or\n"
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 5ced452..a23aa5e 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -82,6 +82,8 @@ enum hist_field_flags {
HIST_FIELD_KEY = 2,
HIST_FIELD_STRING = 4,
HIST_FIELD_HEX = 8,
+ HIST_FIELD_SYM = 16,
+ HIST_FIELD_SYM_OFFSET = 32,
};

struct hist_trigger_attrs {
@@ -385,6 +387,10 @@ static int create_key_field(struct hist_trigger_data *hist_data,
if (field_str) {
if (!strcmp(field_str, "hex"))
flags |= HIST_FIELD_HEX;
+ else if (!strcmp(field_str, "sym"))
+ flags |= HIST_FIELD_SYM;
+ else if (!strcmp(field_str, "sym-offset"))
+ flags |= HIST_FIELD_SYM_OFFSET;
else {
ret = -EINVAL;
goto out;
@@ -710,6 +716,7 @@ hist_trigger_entry_print(struct seq_file *m,
struct tracing_map_elt *elt)
{
struct hist_field *key_field;
+ char str[KSYM_SYMBOL_LEN];
unsigned int i;
u64 uval;

@@ -725,6 +732,16 @@ hist_trigger_entry_print(struct seq_file *m,
uval = *(u64 *)(key + key_field->offset);
seq_printf(m, "%s: %llx",
key_field->field->name, uval);
+ } else if (key_field->flags & HIST_FIELD_SYM) {
+ uval = *(u64 *)(key + key_field->offset);
+ sprint_symbol_no_offset(str, uval);
+ seq_printf(m, "%s: [%llx] %-45s",
+ key_field->field->name, uval, str);
+ } else if (key_field->flags & HIST_FIELD_SYM_OFFSET) {
+ uval = *(u64 *)(key + key_field->offset);
+ sprint_symbol(str, uval);
+ seq_printf(m, "%s: [%llx] %-55s",
+ key_field->field->name, uval, str);
} else if (key_field->flags & HIST_FIELD_STRING) {
seq_printf(m, "%s: %-50s", key_field->field->name,
(char *)(key + key_field->offset));
@@ -840,6 +857,10 @@ static const char *get_hist_field_flags(struct hist_field *hist_field)

if (hist_field->flags & HIST_FIELD_HEX)
flags_str = "hex";
+ else if (hist_field->flags & HIST_FIELD_SYM)
+ flags_str = "sym";
+ else if (hist_field->flags & HIST_FIELD_SYM_OFFSET)
+ flags_str = "sym-offset";

return flags_str;
}
--
1.9.3

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