Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753025AbdLFWki (ORCPT ); Wed, 6 Dec 2017 17:40:38 -0500 Received: from mga01.intel.com ([192.55.52.88]:42971 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752772AbdLFWkg (ORCPT ); Wed, 6 Dec 2017 17:40:36 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.45,369,1508828400"; d="scan'208";a="11205543" From: Tom Zanussi To: rostedt@goodmis.org Cc: tglx@linutronix.de, mhiramat@kernel.org, namhyung@kernel.org, vedang.patel@intel.com, bigeasy@linutronix.de, joel.opensrc@gmail.com, joelaf@google.com, mathieu.desnoyers@efficios.com, baohong.liu@intel.com, rajvi.jingar@intel.com, julia@ni.com, fengguang.wu@intel.com, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, Tom Zanussi Subject: [PATCH v7 30/37] tracing: Add hist trigger support for variable reference aliases Date: Wed, 6 Dec 2017 16:38:11 -0600 Message-Id: <5911e0dde2b7a6bc76971fd866a0e3e15a4f77a5.1512593081.git.tom.zanussi@linux.intel.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4618 Lines: 135 Add support for alias=$somevar where alias can be used as onmatch.xxx($alias). Aliases are a way of creating a new name for an existing variable, for flexibly in making naming more clear in certain cases. For example in the below the user perhaps feels that using $new_lat in the synthetic event invocation is opaque or doesn't fit well stylistically with previous triggers, so creates an alias of $new_lat named $latency and uses that in the call instead: # echo 'hist:keys=next_pid:new_lat=common_timestamp.usecs' > /sys/kernel/debug/tracing/events/sched/sched_switch/trigger # echo 'hist:keys=pid:latency=$new_lat: onmatch(sched.sched_switch).wake2($latency,pid)' > /sys/kernel/debug/tracing/events/synthetic/wake1/trigger Signed-off-by: Tom Zanussi --- kernel/trace/trace_events_hist.c | 58 +++++++++++++++++++++++++++++++++++++--- 1 file changed, 55 insertions(+), 3 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 6f3e985..1e79f79 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -228,6 +228,7 @@ enum hist_field_flags { HIST_FIELD_FL_EXPR = 1 << 13, HIST_FIELD_FL_VAR_REF = 1 << 14, HIST_FIELD_FL_CPU = 1 << 15, + HIST_FIELD_FL_ALIAS = 1 << 16, }; struct var_defs { @@ -1626,7 +1627,8 @@ static const char *hist_field_name(struct hist_field *field, if (field->field) field_name = field->field->name; - else if (field->flags & HIST_FIELD_FL_LOG2) + else if (field->flags & HIST_FIELD_FL_LOG2 || + field->flags & HIST_FIELD_FL_ALIAS) field_name = hist_field_name(field->operands[0], ++level); else if (field->flags & HIST_FIELD_FL_TIMESTAMP) field_name = "common_timestamp"; @@ -2095,7 +2097,7 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data, hist_field->hist_data = hist_data; - if (flags & HIST_FIELD_FL_EXPR) + if (flags & HIST_FIELD_FL_EXPR || flags & HIST_FIELD_FL_ALIAS) goto out; /* caller will populate */ if (flags & HIST_FIELD_FL_VAR_REF) { @@ -2395,6 +2397,28 @@ static struct hist_field *parse_var_ref(struct hist_trigger_data *hist_data, return field; } +static struct hist_field *create_alias(struct hist_trigger_data *hist_data, + struct hist_field *var_ref, + char *var_name) +{ + struct hist_field *alias = NULL; + unsigned long flags = HIST_FIELD_FL_ALIAS | HIST_FIELD_FL_VAR; + + alias = create_hist_field(hist_data, NULL, flags, var_name); + if (!alias) + return NULL; + + alias->fn = var_ref->fn; + alias->operands[0] = var_ref; + + if (init_var_ref(alias, var_ref, var_ref->system, var_ref->event_name)) { + destroy_hist_field(alias, 0); + return NULL; + } + + return alias; +} + struct hist_field *parse_atom(struct hist_trigger_data *hist_data, struct trace_event_file *file, char *str, unsigned long *flags, char *var_name) @@ -2428,6 +2452,13 @@ struct hist_field *parse_atom(struct hist_trigger_data *hist_data, if (hist_field) { hist_data->var_refs[hist_data->n_var_refs] = hist_field; hist_field->var_ref_idx = hist_data->n_var_refs++; + if (var_name) { + hist_field = create_alias(hist_data, hist_field, var_name); + if (!hist_field) { + ret = -ENOMEM; + goto out; + } + } return hist_field; } } else @@ -2532,6 +2563,26 @@ static int check_expr_operands(struct hist_field *operand1, unsigned long operand1_flags = operand1->flags; unsigned long operand2_flags = operand2->flags; + if ((operand1_flags & HIST_FIELD_FL_VAR_REF) || + (operand1_flags & HIST_FIELD_FL_ALIAS)) { + struct hist_field *var; + + var = find_var_field(operand1->var.hist_data, operand1->name); + if (!var) + return -EINVAL; + operand1_flags = var->flags; + } + + if ((operand2_flags & HIST_FIELD_FL_VAR_REF) || + (operand2_flags & HIST_FIELD_FL_ALIAS)) { + struct hist_field *var; + + var = find_var_field(operand2->var.hist_data, operand2->name); + if (!var) + return -EINVAL; + operand2_flags = var->flags; + } + if ((operand1_flags & HIST_FIELD_FL_TIMESTAMP_USECS) != (operand2_flags & HIST_FIELD_FL_TIMESTAMP_USECS)) return -EINVAL; @@ -4659,7 +4710,8 @@ static void hist_field_print(struct seq_file *m, struct hist_field *hist_field) else if (hist_field->flags & HIST_FIELD_FL_CPU) seq_puts(m, "cpu"); else if (field_name) { - if (hist_field->flags & HIST_FIELD_FL_VAR_REF) + if (hist_field->flags & HIST_FIELD_FL_VAR_REF || + hist_field->flags & HIST_FIELD_FL_ALIAS) seq_putc(m, '$'); seq_printf(m, "%s", field_name); } -- 1.9.3