From 85745f4b7c22cb614abaf97352ad62581600ad89 Mon Sep 17 00:00:00 2001 From: Tom Zanussi Date: Wed, 13 Feb 2019 17:42:48 -0600 Subject: [PATCH] tracing: Add hist trigger onchange() handler 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. Link: http://lkml.kernel.org/r/dfbc7e4ada242603e9ec3f049b5ad076a07dfd03.1550100284.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt (VMware) --- 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 dd60c14a0fb0d..be6779f963c6c 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4915,7 +4915,8 @@ static const char readme_msg[] = "\t .\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 (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 571937a268a33..2f3323ca9d24e 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 { @@ -1989,7 +1990,8 @@ 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; @@ -3481,6 +3483,14 @@ 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) @@ -3640,6 +3650,8 @@ 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; @@ -3727,14 +3739,14 @@ 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; } @@ -3751,6 +3763,14 @@ 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); @@ -3830,6 +3850,8 @@ 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; @@ -3850,6 +3872,8 @@ 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; @@ -3870,6 +3894,8 @@ 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; @@ -4700,7 +4726,8 @@ 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); @@ -4736,6 +4763,15 @@ 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; @@ -4760,7 +4796,8 @@ 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; @@ -4785,7 +4822,8 @@ 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); } } @@ -4817,6 +4855,8 @@ 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); @@ -4874,7 +4914,8 @@ 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; @@ -4895,7 +4936,8 @@ 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); } } -- 2.39.5