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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 407DAC3A5A1 for ; Wed, 28 Aug 2019 18:26:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0DB9920644 for ; Wed, 28 Aug 2019 18:26:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="IAgXANXy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726839AbfH1S0X (ORCPT ); Wed, 28 Aug 2019 14:26:23 -0400 Received: from mail-pg1-f193.google.com ([209.85.215.193]:35682 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726554AbfH1S0W (ORCPT ); Wed, 28 Aug 2019 14:26:22 -0400 Received: by mail-pg1-f193.google.com with SMTP id n4so180502pgv.2 for ; Wed, 28 Aug 2019 11:26:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=vZ3/HRnCHQe+XyNK1hE0wDq1hKDWRVGKFXrsRvw+dRA=; b=IAgXANXyGR5PVXWHS79Z4ccBFA5/ChlBzQI2tIFNaEFvyC+hqblWWmrGdXZd5oHoOy hH1e6dt0Bjs1jz6a1FdBbN5uKBj5BgFnBMr5AwB6y0oOCbm7Th6Iz23Qu6YWvQmh+5DB llZld8RlLB2s5PrWT9d6tVazOJrmxr4qmGX8M= 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:mime-version:content-transfer-encoding; bh=vZ3/HRnCHQe+XyNK1hE0wDq1hKDWRVGKFXrsRvw+dRA=; b=TBHf3NPsmbps9wHo29ajVdXOKCYXVod7B8AfZ5wsFKOnkWe5VXUb/AKsj/VqFwMm6W 401TDvxvWkjiJyl8GyMJ13eSFOMB3K3sJiuhc1ONtdT162CrUb60qhCh1XNyS3mFGVrk rnoo19BjSxI6Jujsc4sWxeyXldTtZBlBjmtrlX8PyGtym7rRvFEMY9OFNd5vVq8f1Wp0 KhIJd72Krvs3ZmES8g+nFRHp4oisYWiLN0A3zO2WI65V3pwxUOpydlKLae0Nh9HsxsVi D6Pn66G12Dw7vqnwLVOIXGwbyGBd3x89FgvhOBBYSaoHEadBs87dbd6GZlGkDdBIFHOh q4Rg== X-Gm-Message-State: APjAAAU1uGEHJQ16E/9jn/zoOnW40C3TfbrjslyTGWhBpIzVrCzH+t5Z XEGeIz1RNtcZYTKADG8i/XHJ1g== X-Google-Smtp-Source: APXvYqw9hPh56bJPohT8x3/1DCryoAZyRxSsLjKVc6arKocRvaCgWTedb8ZQfqfVEKRAqxtItHbRdA== X-Received: by 2002:a63:b20f:: with SMTP id x15mr4779141pge.453.1567016781250; Wed, 28 Aug 2019 11:26:21 -0700 (PDT) Received: from joelaf.cam.corp.google.com ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id b30sm7082pfr.117.2019.08.28.11.26.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Aug 2019 11:26:20 -0700 (PDT) From: "Joel Fernandes (Google)" To: linux-kernel@vger.kernel.org, paulmck@kernel.org Cc: "Joel Fernandes (Google)" , Frederic Weisbecker , Jonathan Corbet , Josh Triplett , kernel-team@android.com, Lai Jiangshan , linux-doc@vger.kernel.org, Mathieu Desnoyers , Mauro Carvalho Chehab , rcu@vger.kernel.org, Steven Rostedt Subject: [PATCH] rcu/dyntick-idle: Add better tracing Date: Wed, 28 Aug 2019 14:26:13 -0400 Message-Id: <20190828182613.37715-1-joel@joelfernandes.org> X-Mailer: git-send-email 2.23.0.187.g17f5b7556c-goog In-Reply-To: <20190828001146.GM26530@linux.ibm.com> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org The dyntick-idle traces are a bit confusing. This patch makes it simpler and adds some missing cases such as EQS-enter because user vs idle mode. Following are the changes: (1) Add a new context field to trace_rcu_dyntick tracepoint. This context field can be "USER", "IDLE" or "IRQ". (2) Remove the "++=" and "--=" strings and replace them with "StillNonIdle". This is much easier on the eyes, and the -- and ++ are easily apparent in the dynticks_nesting counters we are printing anyway. This patch is based on the previous patches to simplify rcu_dyntick counters [1] and with these traces, I have verified the counters are working properly. [1] Link: https://lore.kernel.org/patchwork/patch/1120021/ Link: https://lore.kernel.org/patchwork/patch/1120022/ Signed-off-by: Joel Fernandes (Google) --- include/trace/events/rcu.h | 13 ++++++++----- kernel/rcu/tree.c | 17 +++++++++++------ 2 files changed, 19 insertions(+), 11 deletions(-) diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index 66122602bd08..474c1f7e7104 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -449,12 +449,14 @@ TRACE_EVENT_RCU(rcu_fqs, */ TRACE_EVENT_RCU(rcu_dyntick, - TP_PROTO(const char *polarity, long oldnesting, long newnesting, atomic_t dynticks), + TP_PROTO(const char *polarity, const char *context, long oldnesting, + long newnesting, atomic_t dynticks), - TP_ARGS(polarity, oldnesting, newnesting, dynticks), + TP_ARGS(polarity, context, oldnesting, newnesting, dynticks), TP_STRUCT__entry( __field(const char *, polarity) + __field(const char *, context) __field(long, oldnesting) __field(long, newnesting) __field(int, dynticks) @@ -462,14 +464,15 @@ TRACE_EVENT_RCU(rcu_dyntick, TP_fast_assign( __entry->polarity = polarity; + __entry->context = context; __entry->oldnesting = oldnesting; __entry->newnesting = newnesting; __entry->dynticks = atomic_read(&dynticks); ), - TP_printk("%s %lx %lx %#3x", __entry->polarity, - __entry->oldnesting, __entry->newnesting, - __entry->dynticks & 0xfff) + TP_printk("%s %s %lx %lx %#3x", __entry->polarity, + __entry->context, __entry->oldnesting, __entry->newnesting, + __entry->dynticks & 0xfff) ); /* diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 1465a3e406f8..1a65919ec800 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -570,7 +570,8 @@ static void rcu_eqs_enter(bool user) } lockdep_assert_irqs_disabled(); - trace_rcu_dyntick(TPS("Start"), rdp->dynticks_nesting, 0, rdp->dynticks); + trace_rcu_dyntick(TPS("Start"), (user ? TPS("USER") : TPS("IDLE")), + rdp->dynticks_nesting, 0, rdp->dynticks); WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !user && !is_idle_task(current)); rdp = this_cpu_ptr(&rcu_data); do_nocb_deferred_wakeup(rdp); @@ -642,15 +643,17 @@ static __always_inline void rcu_nmi_exit_common(bool irq) * leave it in non-RCU-idle state. */ if (rdp->dynticks_nesting != 1) { - trace_rcu_dyntick(TPS("--="), rdp->dynticks_nesting, - rdp->dynticks_nesting - 2, rdp->dynticks); + trace_rcu_dyntick(TPS("StillNonIdle"), TPS("IRQ"), + rdp->dynticks_nesting, rdp->dynticks_nesting - 2, + rdp->dynticks); WRITE_ONCE(rdp->dynticks_nesting, /* No store tearing. */ rdp->dynticks_nesting - 2); return; } /* This NMI interrupted an RCU-idle CPU, restore RCU-idleness. */ - trace_rcu_dyntick(TPS("Startirq"), rdp->dynticks_nesting, 0, rdp->dynticks); + trace_rcu_dyntick(TPS("Start"), TPS("IRQ"), rdp->dynticks_nesting, 0, + rdp->dynticks); WRITE_ONCE(rdp->dynticks_nesting, 0); /* Avoid store tearing. */ if (irq) @@ -733,7 +736,8 @@ static void rcu_eqs_exit(bool user) rcu_dynticks_task_exit(); rcu_dynticks_eqs_exit(); rcu_cleanup_after_idle(); - trace_rcu_dyntick(TPS("End"), rdp->dynticks_nesting, 1, rdp->dynticks); + trace_rcu_dyntick(TPS("End"), (user ? TPS("USER") : TPS("IDLE")), + rdp->dynticks_nesting, 1, rdp->dynticks); WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !user && !is_idle_task(current)); WRITE_ONCE(rdp->dynticks_nesting, 1); @@ -825,7 +829,8 @@ static __always_inline void rcu_nmi_enter_common(bool irq) tick_dep_set_cpu(rdp->cpu, TICK_DEP_BIT_RCU); } - trace_rcu_dyntick(incby == 1 ? TPS("Endirq") : TPS("++="), + trace_rcu_dyntick(incby == 1 ? TPS("End") : TPS("StillNonIdle"), + TPS("IRQ"), rdp->dynticks_nesting, rdp->dynticks_nesting + incby, rdp->dynticks); -- 2.23.0.187.g17f5b7556c-goog