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authorNamhyung Kim <namhyung@kernel.org>2016-03-03 12:54:53 -0600
committerSteven Rostedt <rostedt@goodmis.org>2016-04-19 18:55:00 -0400
commit79e577cbce4c4c2bf0d64ec315adb04eda40736b (patch)
treed23113ca6d30c229e2d2c00f91c1eb65193ac23f /kernel/trace
parent69a0200c2e25d61c50091549d00cfeb426c258f5 (diff)
downloadlinux-sh-79e577cbce4c4c2bf0d64ec315adb04eda40736b.tar.gz
tracing: Support string type key properly
The string in a trace event is usually recorded as dynamic array which is variable length. But current hist code only support fixed length array so it cannot support most strings. This patch fixes it by checking filter_type of the field and get proper pointer with it. With this, it can get a histogram of exec() based on filenames like below: # cd /sys/kernel/tracing/events/sched/sched_process_exec # cat 'hist:key=filename' > trigger # ps PID TTY TIME CMD 1 ? 00:00:00 init 29 ? 00:00:00 sh 38 ? 00:00:00 ps # ls enable filter format hist id trigger # cat hist # trigger info: hist:keys=filename:vals=hitcount:sort=hitcount:size=2048 [active] { filename: /usr/bin/ps } hitcount: 1 { filename: /usr/bin/ls } hitcount: 1 { filename: /usr/bin/cat } hitcount: 1 Totals: Hits: 3 Entries: 3 Dropped: 0 Link: http://lkml.kernel.org/r/610180d6df0cfdf11ee205452f3b241dea657233.1457029949.git.tom.zanussi@linux.intel.com Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Namhyung Kim <namhyung@kernel.org> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> [ Added (unsigned long) typecast to fix compile warning ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace_events_hist.c49
1 files changed, 45 insertions, 4 deletions
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 21cae42b54da..418ff27cbbaf 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -52,12 +52,28 @@ static u64 hist_field_string(struct hist_field *hist_field, void *event)
return (u64)(unsigned long)addr;
}
+static u64 hist_field_dynstring(struct hist_field *hist_field, void *event)
+{
+ u32 str_item = *(u32 *)(event + hist_field->field->offset);
+ int str_loc = str_item & 0xffff;
+ char *addr = (char *)(event + str_loc);
+
+ return (u64)(unsigned long)addr;
+}
+
+static u64 hist_field_pstring(struct hist_field *hist_field, void *event)
+{
+ char **addr = (char **)(event + hist_field->field->offset);
+
+ return (u64)(unsigned long)*addr;
+}
+
#define DEFINE_HIST_FIELD_FN(type) \
static u64 hist_field_##type(struct hist_field *hist_field, void *event)\
{ \
type *addr = (type *)(event + hist_field->field->offset); \
\
- return (u64)*addr; \
+ return (u64)(unsigned long)*addr; \
}
DEFINE_HIST_FIELD_FN(s64);
@@ -340,7 +356,13 @@ static struct hist_field *create_hist_field(struct ftrace_event_field *field,
if (is_string_field(field)) {
flags |= HIST_FIELD_FL_STRING;
- hist_field->fn = hist_field_string;
+
+ if (field->filter_type == FILTER_STATIC_STRING)
+ hist_field->fn = hist_field_string;
+ else if (field->filter_type == FILTER_DYN_STRING)
+ hist_field->fn = hist_field_dynstring;
+ else
+ hist_field->fn = hist_field_pstring;
} else {
hist_field->fn = select_value_fn(field->size,
field->is_signed);
@@ -508,7 +530,10 @@ static int create_key_field(struct hist_trigger_data *hist_data,
goto out;
}
- key_size = field->size;
+ if (is_string_field(field)) /* should be last key field */
+ key_size = HIST_KEY_SIZE_MAX - key_offset;
+ else
+ key_size = field->size;
}
hist_data->fields[key_idx] = create_hist_field(field, flags);
@@ -841,8 +866,24 @@ static void event_hist_trigger(struct event_trigger_data *data, void *rec)
key = (void *)&field_contents;
if (hist_data->n_keys > 1) {
+ /* ensure NULL-termination */
+ size_t size = key_field->size - 1;
+
+ if (key_field->flags & HIST_FIELD_FL_STRING) {
+ struct ftrace_event_field *field;
+
+ field = key_field->field;
+ if (field->filter_type == FILTER_DYN_STRING)
+ size = *(u32 *)(rec + field->offset) >> 16;
+ else if (field->filter_type == FILTER_PTR_STRING)
+ size = strlen(key);
+
+ if (size > key_field->size - 1)
+ size = key_field->size - 1;
+ }
+
memcpy(compound_key + key_field->offset, key,
- key_field->size);
+ size);
}
}
}