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=-16.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 7CD87C433DF for ; Fri, 7 Aug 2020 21:09:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5F98422C9F for ; Fri, 7 Aug 2020 21:09:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726536AbgHGVJz (ORCPT ); Fri, 7 Aug 2020 17:09:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:37248 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725934AbgHGVJx (ORCPT ); Fri, 7 Aug 2020 17:09:53 -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 8D14122C9F; Fri, 7 Aug 2020 21:09:52 +0000 (UTC) Date: Fri, 7 Aug 2020 17:09:50 -0400 From: Steven Rostedt To: LKML Cc: Ingo Molnar , Andrew Morton , Sean Paul Subject: [for-linus][PATCH] tracing: Add trace_array_init_printk() to initialize instance trace_printk() buffers Message-ID: <20200807170950.6e389d1e@oasis.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 Hopefully the last patch for this merge window pull request. -- Steve git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git for-next Head SHA1: 38ce2a9e33db61a3041840310077072d6210ead4 Steven Rostedt (VMware) (1): tracing: Add trace_array_init_printk() to initialize instance trace_printk() buffers ---- include/linux/trace.h | 1 + kernel/trace/trace.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 45 insertions(+) --------------------------- commit 38ce2a9e33db61a3041840310077072d6210ead4 Author: Steven Rostedt (VMware) Date: Thu Aug 6 12:46:49 2020 -0400 tracing: Add trace_array_init_printk() to initialize instance trace_printk() buffers As trace_array_printk() used with not global instances will not add noise to the main buffer, they are OK to have in the kernel (unlike trace_printk()). This require the subsystem to create their own tracing instance, and the trace_array_printk() only writes into those instances. Add trace_array_init_printk() to initialize the trace_printk() buffers without printing out the WARNING message. Reported-by: Sean Paul Reviewed-by: Sean Paul Signed-off-by: Steven Rostedt (VMware) diff --git a/include/linux/trace.h b/include/linux/trace.h index 7fd86d3c691f..36d255d66f88 100644 --- a/include/linux/trace.h +++ b/include/linux/trace.h @@ -29,6 +29,7 @@ struct trace_array; void trace_printk_init_buffers(void); int trace_array_printk(struct trace_array *tr, unsigned long ip, const char *fmt, ...); +int trace_array_init_printk(struct trace_array *tr); void trace_array_put(struct trace_array *tr); struct trace_array *trace_array_get_by_name(const char *name); int trace_array_destroy(struct trace_array *tr); diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 06c0feae5ff9..c5f822736261 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3129,6 +3129,9 @@ static int alloc_percpu_trace_buffer(void) { struct trace_buffer_struct *buffers; + if (trace_percpu_buffer) + return 0; + buffers = alloc_percpu(struct trace_buffer_struct); if (MEM_FAIL(!buffers, "Could not allocate percpu trace_printk buffer")) return -ENOMEM; @@ -3331,6 +3334,26 @@ int trace_array_vprintk(struct trace_array *tr, return __trace_array_vprintk(tr->array_buffer.buffer, ip, fmt, args); } +/** + * trace_array_printk - Print a message to a specific instance + * @tr: The instance trace_array descriptor + * @ip: The instruction pointer that this is called from. + * @fmt: The format to print (printf format) + * + * If a subsystem sets up its own instance, they have the right to + * printk strings into their tracing instance buffer using this + * function. Note, this function will not write into the top level + * buffer (use trace_printk() for that), as writing into the top level + * buffer should only have events that can be individually disabled. + * trace_printk() is only used for debugging a kernel, and should not + * be ever encorporated in normal use. + * + * trace_array_printk() can be used, as it will not add noise to the + * top level tracing buffer. + * + * Note, trace_array_init_printk() must be called on @tr before this + * can be used. + */ __printf(3, 0) int trace_array_printk(struct trace_array *tr, unsigned long ip, const char *fmt, ...) @@ -3355,6 +3378,27 @@ int trace_array_printk(struct trace_array *tr, } EXPORT_SYMBOL_GPL(trace_array_printk); +/** + * trace_array_init_printk - Initialize buffers for trace_array_printk() + * @tr: The trace array to initialize the buffers for + * + * As trace_array_printk() only writes into instances, they are OK to + * have in the kernel (unlike trace_printk()). This needs to be called + * before trace_array_printk() can be used on a trace_array. + */ +int trace_array_init_printk(struct trace_array *tr) +{ + if (!tr) + return -ENOENT; + + /* This is only allowed for created instances */ + if (tr == &global_trace) + return -EINVAL; + + return alloc_percpu_trace_buffer(); +} +EXPORT_SYMBOL_GPL(trace_array_init_printk); + __printf(3, 4) int trace_array_printk_buf(struct trace_buffer *buffer, unsigned long ip, const char *fmt, ...)