From patchwork Tue Feb 7 17:28:50 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 13131938 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 73F70C636D4 for ; Tue, 7 Feb 2023 17:30:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231777AbjBGRau (ORCPT ); Tue, 7 Feb 2023 12:30:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36264 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231645AbjBGRak (ORCPT ); Tue, 7 Feb 2023 12:30:40 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D499F21A25; Tue, 7 Feb 2023 09:30:30 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 0279BCE1E47; Tue, 7 Feb 2023 17:30:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F72FC4339B; Tue, 7 Feb 2023 17:30:27 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.96) (envelope-from ) id 1pPRnW-006Rwl-1B; Tue, 07 Feb 2023 12:30:26 -0500 Message-ID: <20230207173026.186210158@goodmis.org> User-Agent: quilt/0.66 Date: Tue, 07 Feb 2023 12:28:50 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: Masami Hiramatsu , Andrew Morton , Ross Zwisler , Randy Dunlap Subject: [PATCH v2 1/4] tracing: Add creation of instances at boot command line References: <20230207172849.461894073@goodmis.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org From: "Steven Rostedt (Google)" Add kernel command line to add tracing instances. This only creates instances at boot but still does not enable any events to them. Later changes will extend this command line to add enabling of events, filters, and triggers. As well as possibly redirecting trace_printk()! Cc: Randy Dunlap Reviewed-by: Ross Zwisler Signed-off-by: Steven Rostedt (Google) --- Changes since v1: https://lkml.kernel.org/r/20230111145842.376427803@goodmis.org - Fixed document grammar (Randy Dunlap) - Removed extra workqueue.h include (Ross Zwisler) - Use sizeof(boot_instance_info) than using COMMAND_LINE_SIZE) .../admin-guide/kernel-parameters.txt | 6 +++ kernel/trace/trace.c | 50 +++++++++++++++++++ 2 files changed, 56 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 6cfa6e3996cf..9545da5ed849 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -6272,6 +6272,12 @@ comma-separated list of trace events to enable. See also Documentation/trace/events.rst + trace_instance=[instance-info] + [FTRACE] Create a ring buffer instance early in boot up. + This will be listed in: + + /sys/kernel/tracing/instances + trace_options=[option-list] [FTRACE] Enable or disable tracer options at boot. The option-list is a comma delimited list of options diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index b90eecd27dfc..863716fcca49 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -49,6 +49,8 @@ #include #include +#include /* COMMAND_LINE_SIZE */ + #include "trace.h" #include "trace_output.h" @@ -186,6 +188,9 @@ static char *default_bootup_tracer; static bool allocate_snapshot; static bool snapshot_at_boot; +static char boot_instance_info[COMMAND_LINE_SIZE] __initdata; +static int boot_instance_index; + static int __init set_cmdline_ftrace(char *str) { strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE); @@ -239,6 +244,23 @@ static int __init boot_snapshot(char *str) __setup("ftrace_boot_snapshot", boot_snapshot); +static int __init boot_instance(char *str) +{ + char *slot = boot_instance_info + boot_instance_index; + int left = sizeof(boot_instance_info) - boot_instance_index; + int ret; + + if (strlen(str) >= left) + return -1; + + ret = snprintf(slot, left, "%s\t", str); + boot_instance_index += ret; + + return 1; +} +__setup("trace_instance=", boot_instance); + + static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata; static int __init set_trace_boot_options(char *str) @@ -10144,6 +10166,31 @@ ssize_t trace_parse_run_command(struct file *file, const char __user *buffer, return ret; } +__init static void enable_instances(void) +{ + struct trace_array *tr; + char *curr_str; + char *str; + char *tok; + + /* A tab is always appended */ + boot_instance_info[boot_instance_index - 1] = '\0'; + str = boot_instance_info; + + while ((curr_str = strsep(&str, "\t"))) { + + tok = strsep(&curr_str, ","); + + tr = trace_array_get_by_name(tok); + if (!tr) { + pr_warn("Failed to create instance buffer %s\n", curr_str); + continue; + } + /* Allow user space to delete it */ + trace_array_put(tr); + } +} + __init static int tracer_alloc_buffers(void) { int ring_buf_size; @@ -10302,6 +10349,9 @@ void __init early_trace_init(void) void __init trace_init(void) { trace_event_init(); + + if (boot_instance_index) + enable_instances(); } __init static void clear_boot_tracer(void)