From ad42febe51ae0a2e875f507a37a6329277f75fdd Mon Sep 17 00:00:00 2001 From: Tom Zanussi Date: Mon, 15 Jan 2018 20:51:45 -0600 Subject: [PATCH] tracing: Add hist trigger timestamp support Add support for a timestamp event field. This is actually a 'pseudo-' event field in that it behaves like it's part of the event record, but is really part of the corresponding ring buffer event. To make use of the timestamp field, users can specify "common_timestamp" as a field name for any histogram. Note that this doesn't make much sense on its own either as either a key or value, but needs to be supported even so, since follow-on patches will add support for making use of this field in time deltas. The common_timestamp 'field' is not a bona fide event field - so you won't find it in the event description - but rather it's a synthetic field that can be used like a real field. Note that the use of this field requires the ring buffer be put into 'absolute timestamp' mode, which saves the complete timestamp for each event rather than an offset. This mode will be enabled if and only if a histogram makes use of the "common_timestamp" field. Link: http://lkml.kernel.org/r/97afbd646ed146e26271f3458b4b33e16d7817c2.1516069914.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi Signed-off-by: Baohong Liu [kasan use-after-free fix] Signed-off-by: Vedang Patel Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_events_hist.c | 94 ++++++++++++++++++++++++-------- 1 file changed, 71 insertions(+), 23 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index e4368bb7ba30..a793f8c04830 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -89,6 +89,12 @@ static u64 hist_field_log2(struct hist_field *hist_field, void *event, return (u64) ilog2(roundup_pow_of_two(val)); } +static u64 hist_field_timestamp(struct hist_field *hist_field, void *event, + struct ring_buffer_event *rbe) +{ + return ring_buffer_event_time_stamp(rbe); +} + #define DEFINE_HIST_FIELD_FN(type) \ static u64 hist_field_##type(struct hist_field *hist_field, \ void *event, \ @@ -135,6 +141,7 @@ enum hist_field_flags { HIST_FIELD_FL_SYSCALL = 1 << 7, HIST_FIELD_FL_STACKTRACE = 1 << 8, HIST_FIELD_FL_LOG2 = 1 << 9, + HIST_FIELD_FL_TIMESTAMP = 1 << 10, }; struct hist_trigger_attrs { @@ -159,6 +166,7 @@ struct hist_trigger_data { struct trace_event_file *event_file; struct hist_trigger_attrs *attrs; struct tracing_map *map; + bool enable_timestamps; }; static const char *hist_field_name(struct hist_field *field, @@ -173,6 +181,8 @@ static const char *hist_field_name(struct hist_field *field, field_name = field->field->name; else if (field->flags & HIST_FIELD_FL_LOG2) field_name = hist_field_name(field->operands[0], ++level); + else if (field->flags & HIST_FIELD_FL_TIMESTAMP) + field_name = "common_timestamp"; if (field_name == NULL) field_name = ""; @@ -440,6 +450,12 @@ static struct hist_field *create_hist_field(struct ftrace_event_field *field, goto out; } + if (flags & HIST_FIELD_FL_TIMESTAMP) { + hist_field->fn = hist_field_timestamp; + hist_field->size = sizeof(u64); + goto out; + } + if (WARN_ON_ONCE(!field)) goto out; @@ -517,10 +533,15 @@ static int create_val_field(struct hist_trigger_data *hist_data, } } - field = trace_find_event_field(file->event_call, field_name); - if (!field || !field->size) { - ret = -EINVAL; - goto out; + if (strcmp(field_name, "common_timestamp") == 0) { + flags |= HIST_FIELD_FL_TIMESTAMP; + hist_data->enable_timestamps = true; + } else { + field = trace_find_event_field(file->event_call, field_name); + if (!field || !field->size) { + ret = -EINVAL; + goto out; + } } hist_data->fields[val_idx] = create_hist_field(field, flags); @@ -615,16 +636,22 @@ static int create_key_field(struct hist_trigger_data *hist_data, } } - field = trace_find_event_field(file->event_call, field_name); - if (!field || !field->size) { - ret = -EINVAL; - goto out; - } + if (strcmp(field_name, "common_timestamp") == 0) { + flags |= HIST_FIELD_FL_TIMESTAMP; + hist_data->enable_timestamps = true; + key_size = sizeof(u64); + } else { + field = trace_find_event_field(file->event_call, field_name); + if (!field || !field->size) { + ret = -EINVAL; + goto out; + } - if (is_string_field(field)) - key_size = MAX_FILTER_STR_VAL; - else - key_size = field->size; + if (is_string_field(field)) + key_size = MAX_FILTER_STR_VAL; + else + key_size = field->size; + } } hist_data->fields[key_idx] = create_hist_field(field, flags); @@ -820,6 +847,9 @@ static int create_tracing_map_fields(struct hist_trigger_data *hist_data) if (hist_field->flags & HIST_FIELD_FL_STACKTRACE) cmp_fn = tracing_map_cmp_none; + else if (!field) + cmp_fn = tracing_map_cmp_num(hist_field->size, + hist_field->is_signed); else if (is_string_field(field)) cmp_fn = tracing_map_cmp_string; else @@ -1215,7 +1245,11 @@ static void hist_field_print(struct seq_file *m, struct hist_field *hist_field) { const char *field_name = hist_field_name(hist_field, 0); - seq_printf(m, "%s", field_name); + if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP) + seq_puts(m, "common_timestamp"); + else if (field_name) + seq_printf(m, "%s", field_name); + if (hist_field->flags) { const char *flags_str = get_hist_field_flags(hist_field); @@ -1266,27 +1300,25 @@ static int event_hist_trigger_print(struct seq_file *m, for (i = 0; i < hist_data->n_sort_keys; i++) { struct tracing_map_sort_key *sort_key; + unsigned int idx; sort_key = &hist_data->sort_keys[i]; + idx = sort_key->field_idx; + + if (WARN_ON(idx >= TRACING_MAP_FIELDS_MAX)) + return -EINVAL; if (i > 0) seq_puts(m, ","); - if (sort_key->field_idx == HITCOUNT_IDX) + if (idx == HITCOUNT_IDX) seq_puts(m, "hitcount"); - else { - unsigned int idx = sort_key->field_idx; - - if (WARN_ON(idx >= TRACING_MAP_FIELDS_MAX)) - return -EINVAL; - + else hist_field_print(m, hist_data->fields[idx]); - } if (sort_key->descending) seq_puts(m, ".descending"); } - seq_printf(m, ":size=%u", (1 << hist_data->map->map_bits)); if (data->filter_str) @@ -1454,6 +1486,10 @@ static bool hist_trigger_match(struct event_trigger_data *data, return false; if (key_field->offset != key_field_test->offset) return false; + if (key_field->size != key_field_test->size) + return false; + if (key_field->is_signed != key_field_test->is_signed) + return false; } for (i = 0; i < hist_data->n_sort_keys; i++) { @@ -1536,6 +1572,9 @@ static int hist_register_trigger(char *glob, struct event_trigger_ops *ops, update_cond_flag(file); + if (hist_data->enable_timestamps) + tracing_set_time_stamp_abs(file->tr, true); + if (trace_event_trigger_enable_disable(file, 1) < 0) { list_del_rcu(&data->list); update_cond_flag(file); @@ -1570,17 +1609,26 @@ static void hist_unregister_trigger(char *glob, struct event_trigger_ops *ops, if (unregistered && test->ops->free) test->ops->free(test->ops, test); + + if (hist_data->enable_timestamps) { + if (unregistered) + tracing_set_time_stamp_abs(file->tr, false); + } } static void hist_unreg_all(struct trace_event_file *file) { struct event_trigger_data *test, *n; + struct hist_trigger_data *hist_data; list_for_each_entry_safe(test, n, &file->triggers, list) { if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) { + hist_data = test->private_data; list_del_rcu(&test->list); trace_event_trigger_enable_disable(file, 0); update_cond_flag(file); + if (hist_data->enable_timestamps) + tracing_set_time_stamp_abs(file->tr, false); if (test->ops->free) test->ops->free(test->ops, test); } -- 2.30.2