From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34D4FC33CAF for ; Thu, 16 Jan 2020 21:57:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0342F20728 for ; Thu, 16 Jan 2020 21:57:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387429AbgAPV5B (ORCPT ); Thu, 16 Jan 2020 16:57:01 -0500 Received: from mail.kernel.org ([198.145.29.99]:54002 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729153AbgAPV5B (ORCPT ); Thu, 16 Jan 2020 16:57:01 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5121920728; Thu, 16 Jan 2020 21:57:00 +0000 (UTC) Date: Thu, 16 Jan 2020 16:56:58 -0500 From: Steven Rostedt To: Tom Zanussi Cc: LKML Subject: Re: Unresolved reference for histogram variable Message-ID: <20200116165658.4e8d15fb@gandalf.local.home> In-Reply-To: <20200116154216.58ca08eb@gandalf.local.home> References: <20200116154216.58ca08eb@gandalf.local.home> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 16 Jan 2020 15:42:16 -0500 Steven Rostedt wrote: > in parse_expr(): > > operand1->read_once = true; > operand2->read_once = true; > > Why is that? > > This means that any variable used in an expression can not be use later > on. > > Or should the variable be detected that it is used multiple times in > the expression, and have the parser detect this, and just reuse the > same variable multiple times? This patch seems to fix the problem, and lets us reuse the same variable multiple times. -- Steve diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 117a1202a6b9..b7f944735a4a 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -116,6 +116,7 @@ struct hist_field { struct ftrace_event_field *field; unsigned long flags; hist_field_fn_t fn; + unsigned int ref; unsigned int size; unsigned int offset; unsigned int is_signed; @@ -2432,8 +2433,16 @@ static int contains_operator(char *str) return field_op; } +static void get_hist_field(struct hist_field *hist_field) +{ + hist_field->ref++; +} + static void __destroy_hist_field(struct hist_field *hist_field) { + if (--hist_field->ref > 1) + return; + kfree(hist_field->var.name); kfree(hist_field->name); kfree(hist_field->type); @@ -2475,6 +2484,8 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data, if (!hist_field) return NULL; + hist_field->ref = 1; + hist_field->hist_data = hist_data; if (flags & HIST_FIELD_FL_EXPR || flags & HIST_FIELD_FL_ALIAS) @@ -2670,6 +2681,19 @@ static struct hist_field *create_var_ref(struct hist_trigger_data *hist_data, { unsigned long flags = HIST_FIELD_FL_VAR_REF; struct hist_field *ref_field; + int i; + + for (i = 0; i < hist_data->n_var_refs; i++) { + ref_field = hist_data->var_refs[i]; + /* Maybe this is overkill? */ + if (ref_field->var.idx == var_field->var.idx && + ref_field->var.hist_data == var_field->hist_data && + ref_field->size == var_field->size && + ref_field->is_signed == var_field->is_signed) { + get_hist_field(ref_field); + return ref_field; + } + } ref_field = create_hist_field(var_field->hist_data, NULL, flags, NULL); if (ref_field) {