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=-8.3 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_SANE_1 autolearn=unavailable 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 362C9C3A5A7 for ; Wed, 4 Sep 2019 00:46:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 033EE22CF8 for ; Wed, 4 Sep 2019 00:46:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="jrf17TSZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727536AbfIDAq3 (ORCPT ); Tue, 3 Sep 2019 20:46:29 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:40722 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727083AbfIDAq2 (ORCPT ); Tue, 3 Sep 2019 20:46:28 -0400 Received: by mail-pf1-f194.google.com with SMTP id w16so12052498pfn.7 for ; Tue, 03 Sep 2019 17:46:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=IRRqhH2tyZ7+XB/z8/zEf8laZnPNNt4IgLHMJO+UON0=; b=jrf17TSZAfr6GajhdyMbxXuqUcsdG3afXUIQ1hdQdp/TdEP7c1uP45aWwjmTzVTleq WDcNMrxctNwzJWsiYhX74ANd3D7dtvYq/IhDSp59cCbGoZobD84E2YRJMWYlH6Cgn45K muIg4ItTUidTQKKNWeqQbK/b8Ezygu+qWyNig= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=IRRqhH2tyZ7+XB/z8/zEf8laZnPNNt4IgLHMJO+UON0=; b=SkSNHz/6ZsDjnnHr/VkN07UqIVkkDQq5g6L4CEYYPYf5q1FnCn/ucVZ2tqQ0PPwEpC 0lXw3jam4xXjgxIR8p6F3gcExv771h4ff6yMIu8emqFmLIZnzjeiSL8cpBhPLgVW5LFy YzNTDQ+cNSI5sAESDsV1mNDQPjC8urstM8l5ujmkPwB7Oj5CPj3wX+1Jwq0iVuchzwEP +SpFdPA8pUtrqrxzldOVZu4Y3B++Fh7MmrPI2s79ttQ5O0JWZG3Dr5iYzpGiZAn3VRKn okkIygvl0anMyWRb6sst8txAQYZU1gp4SQSmXR2kHMqdjNaQOs+wl4QrMzAadrCXfzBt 0xaw== X-Gm-Message-State: APjAAAXNSv4fWZ6+/UFrWrEDjpgyeWSvQ+DhoaVh3KiHtXxyeauLJ2eK WBiXXekjH8hPQic/3d00YYS+lA== X-Google-Smtp-Source: APXvYqzCRYJf4WcESg8CeoZ2+KW8jWjiw0OZbT+HsvUrQgz11IU9JeweAy0YPnrOxhNNVpahRpJlBA== X-Received: by 2002:aa7:955d:: with SMTP id w29mr224378pfq.60.1567557987991; Tue, 03 Sep 2019 17:46:27 -0700 (PDT) Received: from localhost ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id w21sm696504pjh.19.2019.09.03.17.46.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Sep 2019 17:46:27 -0700 (PDT) Date: Tue, 3 Sep 2019 20:46:26 -0400 From: Joel Fernandes To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, Bjorn Helgaas , Ingo Molnar , Josh Triplett , Lai Jiangshan , Mathieu Desnoyers , Petr Mladek , "Rafael J. Wysocki" , rcu@vger.kernel.org, Steven Rostedt , Yafang Shao Subject: Re: [PATCH -rcu dev 2/2] rcu/dyntick-idle: Add better tracing Message-ID: <20190904004626.GB127034@google.com> References: <20190830162348.192303-1-joel@joelfernandes.org> <20190830162348.192303-2-joel@joelfernandes.org> <20190903200446.GE4125@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190903200446.GE4125@linux.ibm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 03, 2019 at 01:04:46PM -0700, Paul E. McKenney wrote: > On Fri, Aug 30, 2019 at 12:23:48PM -0400, Joel Fernandes (Google) wrote: > > The dyntick-idle traces are a bit confusing. This patch makes it simpler > > and adds some missing cases such as EQS-enter due to 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) > > This looks fine, but depends on the earlier patch. The earlier patch looks Ok? Did not see any review comments. That is just a revert of an old commit. thanks, - Joel > Thanx, Paul > > > --- > > include/trace/events/rcu.h | 13 ++++++++----- > > kernel/rcu/tree.c | 19 +++++++++++++------ > > 2 files changed, 21 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 417dd00b9e87..463407762b5a 100644 > > --- a/kernel/rcu/tree.c > > +++ b/kernel/rcu/tree.c > > @@ -533,7 +533,8 @@ 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); > > @@ -606,14 +607,17 @@ static __always_inline void rcu_nmi_exit_common(bool irq) > > * leave it in non-RCU-idle state. > > */ > > if (rdp->dynticks_nmi_nesting != 1) { > > - trace_rcu_dyntick(TPS("--="), rdp->dynticks_nmi_nesting, rdp->dynticks_nmi_nesting - 2, rdp->dynticks); > > + trace_rcu_dyntick(TPS("StillNonIdle"), TPS("IRQ"), > > + rdp->dynticks_nmi_nesting, > > + rdp->dynticks_nmi_nesting - 2, rdp->dynticks); > > WRITE_ONCE(rdp->dynticks_nmi_nesting, /* No store tearing. */ > > rdp->dynticks_nmi_nesting - 2); > > return; > > } > > > > /* This NMI interrupted an RCU-idle CPU, restore RCU-idleness. */ > > - trace_rcu_dyntick(TPS("Startirq"), rdp->dynticks_nmi_nesting, 0, rdp->dynticks); > > + trace_rcu_dyntick(TPS("Start"), TPS("IRQ"), rdp->dynticks_nmi_nesting, > > + 0, rdp->dynticks); > > WRITE_ONCE(rdp->dynticks_nmi_nesting, 0); /* Avoid store tearing. */ > > > > if (irq) > > @@ -700,7 +704,8 @@ 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); > > WARN_ON_ONCE(rdp->dynticks_nmi_nesting); > > @@ -787,9 +792,11 @@ static __always_inline void rcu_nmi_enter_common(bool irq) > > rdp->rcu_forced_tick = true; > > tick_dep_set_cpu(rdp->cpu, TICK_DEP_BIT_RCU); > > } > > - trace_rcu_dyntick(incby == 1 ? TPS("Endirq") : TPS("++="), > > - rdp->dynticks_nmi_nesting, > > + > > + trace_rcu_dyntick(incby == 1 ? TPS("End") : TPS("StillNonIdle"), > > + TPS("IRQ"), rdp->dynticks_nmi_nesting, > > rdp->dynticks_nmi_nesting + incby, rdp->dynticks); > > + > > WRITE_ONCE(rdp->dynticks_nmi_nesting, /* Prevent store tearing. */ > > rdp->dynticks_nmi_nesting + incby); > > barrier(); > > -- > > 2.23.0.187.g17f5b7556c-goog > >