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=-6.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_GIT 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 C3B10C43219 for ; Thu, 2 May 2019 18:37:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 95F53204FD for ; Thu, 2 May 2019 18:37:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="NqZvTaSO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726299AbfEBShk (ORCPT ); Thu, 2 May 2019 14:37:40 -0400 Received: from mail-it1-f193.google.com ([209.85.166.193]:39620 "EHLO mail-it1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726144AbfEBShk (ORCPT ); Thu, 2 May 2019 14:37:40 -0400 Received: by mail-it1-f193.google.com with SMTP id t200so5158303itf.4 for ; Thu, 02 May 2019 11:37:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=3bTGTbTE8gGlzRl/POqzvQikyqE1rXFDWwJSoA19kt4=; b=NqZvTaSOo7uS4QqtoXCyXNDR4MTzOFCymDIYrBV/xH3OHScHgrHDqiUHPGj/nSPzFd K4GHaokfN+BPVUf6IYjKFwjoEPbEyrWttzYY1ZvjO/kzzZDRCyUuDmzE0n4HgIvBWSv7 GoFdgyAfNXliayepT0vgzm0HOpo9mTF87vHTZjfwe7LGne07W+kOrWJ9XnuLTO2fOEdb pNEpBljheyiqrUPD8qVWDu4WgXDL/2GhJm3/ZZA8JmiS8L1zHsggNGt6S8HgP2y03KA3 /mNcgAyQgwjtPf/tPRRcbV3RTztVYzExIX9xPZVn77ds5goQt+FUq6azcpDZYNOk2vKg ycvA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=3bTGTbTE8gGlzRl/POqzvQikyqE1rXFDWwJSoA19kt4=; b=WR+vEDgoCdCkotHVxtNw/sSmSYqIxA+AIEyqi9MjwcVirHkmIYXB8D4qBlrEoQo6Oq vD/NFRey8CEEA3QAPErqwE3nxbCLDuJgylBv8KVp9p+I7DvVaeCkLM2edK/rejO/Xsv+ 5dpBurR47l84zFoHTYVLAreKuZp5VprATAGAewEuV5+S+P6rpwMeYZL14eN1AEcRhlaT Em8sNUKPXtMB1uuYVTXYa91uiykCVKRMxIJCuB9Ozg67Y+nrycm+tlA5wF1MUoxB9DvJ sSFz6cfVZ6rA/ROOxcFgaeDDgUKAFjdbum/zd2/jdJZr/3FHSAvNoiKH9Dq5D542tiQi UFKA== X-Gm-Message-State: APjAAAXpUncf8qsvFUooA+HAmj6WcizrdLTQfhWNch3XYT033qwjGQXv pta5YSzod3GSHFUe20Kit+a/t59WEQ== X-Google-Smtp-Source: APXvYqwXZ9iW3ueXbFsrht124bBnKI982DqtgkNeLPEMOcNcbdz9Iaqu3cxF0+jajH0mXndUhFO+uw== X-Received: by 2002:a24:4614:: with SMTP id j20mr3344210itb.72.1556822259065; Thu, 02 May 2019 11:37:39 -0700 (PDT) Received: from localhost.localdomain ([92.117.168.44]) by smtp.gmail.com with ESMTPSA id y62sm4213ita.15.2019.05.02.11.37.36 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 02 May 2019 11:37:38 -0700 (PDT) From: Viktor Rosendahl To: Steven Rostedt Cc: Ingo Molnar , linux-kernel@vger.kernel.org, Joel Fernandes , Viktor Rosendahl Subject: Re: [PATCH v2 4/4] ftrace: Add an option for tracing console latencies Date: Thu, 2 May 2019 20:37:31 +0200 Message-Id: <20190502183731.9571-1-viktor.rosendahl@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190501213857.157e3741@oasis.local.home> References: <20190501213857.157e3741@oasis.local.home> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Instead of this being turned into a nop, don't have a kconfig option > but instead have this call into the trace_irqsoff.c code, and depending > on what the options are, it should stop it. Of course, this would need > to be smart enough to pair it. Perhaps return the result of > console_stop_critical_timings() and have that passed to > console_start_critical_timings(), and only have start do something if > stop did something. This way the option only needs to disable the stop > part. Something like this? I have only compile tested it so far. best regards, Viktor --- include/linux/irqflags.h | 17 +++++++++++++++++ kernel/printk/printk.c | 6 ++++-- kernel/trace/trace.h | 1 + kernel/trace/trace_irqsoff.c | 13 +++++++++++++ 4 files changed, 35 insertions(+), 2 deletions(-) diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h index 21619c92c377..e4f7ebc67a53 100644 --- a/include/linux/irqflags.h +++ b/include/linux/irqflags.h @@ -68,9 +68,26 @@ do { \ defined(CONFIG_PREEMPT_TRACER) extern void stop_critical_timings(void); extern void start_critical_timings(void); + extern bool console_tracing_disabled(void); + +#define console_stop_critical_timings(FLAG) \ + do { \ + FLAG = console_tracing_disabled(); \ + if (FLAG) \ + stop_critical_timings(); \ + } while(0) + +#define console_start_critical_timings(FLAG) \ + do { \ + if (FLAG) \ + start_critical_timings(); \ + } while(0) + #else # define stop_critical_timings() do { } while (0) # define start_critical_timings() do { } while (0) +# define console_stop_critical_timings(FLAG) do { } while (0) +# define console_start_critical_timings(FLAG) do { } while (0) #endif /* diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 02ca827b8fac..3a18b7208399 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2348,6 +2348,7 @@ void console_unlock(void) static char ext_text[CONSOLE_EXT_LOG_MAX]; static char text[LOG_LINE_MAX + PREFIX_MAX]; unsigned long flags; + bool cflag; bool do_cond_resched, retry; if (console_suspended) { @@ -2448,9 +2449,10 @@ void console_unlock(void) */ console_lock_spinning_enable(); - stop_critical_timings(); /* don't trace print latency */ + /* don't trace print latency if it's disabled */ + console_stop_critical_timings(cflag); call_console_drivers(ext_text, ext_len, text, len); - start_critical_timings(); + console_start_critical_timings(cflag); if (console_lock_spinning_disable_and_check()) { printk_safe_exit_irqrestore(flags); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 59dc01ac52fd..3eed4756dba3 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1253,6 +1253,7 @@ extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf, C(PRINTK_MSGONLY, "printk-msg-only"), \ C(CONTEXT_INFO, "context-info"), /* Print pid/cpu/time */ \ C(LATENCY_FMT, "latency-format"), \ + C(CONSOLE_LATENCY, "console-latency"), \ C(RECORD_CMD, "record-cmd"), \ C(RECORD_TGID, "record-tgid"), \ C(OVERWRITE, "overwrite"), \ diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index 07a391e845de..659a82209c1e 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -490,6 +490,19 @@ void stop_critical_timings(void) EXPORT_SYMBOL_GPL(stop_critical_timings); NOKPROBE_SYMBOL(stop_critical_timings); +bool console_tracing_disabled(void) +{ + struct trace_array *tr = irqsoff_trace; + int pc = preempt_count(); + + if (!preempt_trace(pc) && !irq_trace()) + return false; + + return !(tr->trace_flags & CONSOLE_LATENCY); +} + +EXPORT_SYMBOL_GPL(console_tracing_disabled); + #ifdef CONFIG_FUNCTION_TRACER static bool function_enabled; -- 2.17.1