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=-11.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 5D5F9C4727E for ; Fri, 25 Sep 2020 20:19:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 13E3222211 for ; Fri, 25 Sep 2020 20:19:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728629AbgIYUTc (ORCPT ); Fri, 25 Sep 2020 16:19:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:43078 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727733AbgIYURc (ORCPT ); Fri, 25 Sep 2020 16:17:32 -0400 Received: from oasis.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 3CDF42086A; Fri, 25 Sep 2020 19:37:55 +0000 (UTC) Date: Fri, 25 Sep 2020 15:37:53 -0400 From: Steven Rostedt To: Masami Hiramatsu Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton Subject: Re: [PATCH] tracing/boot: Initialize per-instance event list in early boot Message-ID: <20200925153753.63c822ce@oasis.local.home> In-Reply-To: <160096560826.182763.17110991546046128881.stgit@devnote2> References: <20200924085214.f2e901534037bede0bb55447@kernel.org> <160096560826.182763.17110991546046128881.stgit@devnote2> 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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 25 Sep 2020 01:40:08 +0900 Masami Hiramatsu wrote: > Initialize per-instance event list in early boot time (before > initializing instance directory on tracefs). This fixes boot-time > tracing to correctly handle the boot-time per-instance settings. > I added: Fixes: 4114fbfd02f1 ("tracing: Enable creating new instance early boot") -- Steve > Signed-off-by: Masami Hiramatsu > --- > kernel/trace/trace.c | 3 ++- > kernel/trace/trace.h | 1 + > kernel/trace/trace_events.c | 30 ++++++++++++++++-------------- > 3 files changed, 19 insertions(+), 15 deletions(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index f7696db52e7d..400ed1ec3b64 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -8700,7 +8700,8 @@ static struct trace_array *trace_array_create(const char *name) > ret = trace_array_create_dir(tr); > if (ret) > goto out_free_tr; > - } > + } else > + __trace_early_add_events(tr); > > list_add(&tr->list, &ftrace_trace_arrays); > > diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h > index e1b3061ce06d..5b887cfbe5ec 100644 > --- a/kernel/trace/trace.h > +++ b/kernel/trace/trace.h > @@ -1658,6 +1658,7 @@ extern void trace_event_enable_tgid_record(bool enable); > extern int event_trace_init(void); > extern int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr); > extern int event_trace_del_tracer(struct trace_array *tr); > +extern void __trace_early_add_events(struct trace_array *tr); > > extern struct trace_event_file *__find_event_file(struct trace_array *tr, > const char *system, > diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c > index 720b0d72ea52..8ce334297bf3 100644 > --- a/kernel/trace/trace_events.c > +++ b/kernel/trace/trace_events.c > @@ -3131,14 +3131,13 @@ static inline int register_event_cmds(void) { return 0; } > #endif /* CONFIG_DYNAMIC_FTRACE */ > > /* > - * The top level array has already had its trace_event_file > - * descriptors created in order to allow for early events to > - * be recorded. This function is called after the tracefs has been > - * initialized, and we now have to create the files associated > - * to the events. > + * The top level array and trace arrays created by boot-time tracing > + * have already had its trace_event_file descriptors created in order > + * to allow for early events to be recorded. > + * This function is called after the tracefs has been initialized, > + * and we now have to create the files associated to the events. > */ > -static __init void > -__trace_early_add_event_dirs(struct trace_array *tr) > +static void __trace_early_add_event_dirs(struct trace_array *tr) > { > struct trace_event_file *file; > int ret; > @@ -3153,13 +3152,12 @@ __trace_early_add_event_dirs(struct trace_array *tr) > } > > /* > - * For early boot up, the top trace array requires to have > - * a list of events that can be enabled. This must be done before > - * the filesystem is set up in order to allow events to be traced > - * early. > + * For early boot up, the top trace array and the trace arrays created > + * by boot-time tracing require to have a list of events that can be > + * enabled. This must be done before the filesystem is set up in order > + * to allow events to be traced early. > */ > -static __init void > -__trace_early_add_events(struct trace_array *tr) > +void __trace_early_add_events(struct trace_array *tr) > { > struct trace_event_call *call; > int ret; > @@ -3290,7 +3288,11 @@ int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr) > goto out; > > down_write(&trace_event_sem); > - __trace_add_event_dirs(tr); > + /* If tr already has the event list, it is initialized in early boot. */ > + if (unlikely(!list_empty(&tr->events))) > + __trace_early_add_event_dirs(tr); > + else > + __trace_add_event_dirs(tr); > up_write(&trace_event_sem); > > out: