Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Mon, 10 Feb 2020 12:05:52 -0500
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        "Joel Fernandes, Google" <joel@joelfernandes.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Gustavo A. R. Silva" <gustavo@embeddedor.com>,
        Ingo Molnar <mingo@redhat.com>,
        Richard Fontana <rfontana@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        paulmck <paulmck@kernel.org>,
        Josh Triplett <josh@joshtriplett.org>,
        Lai Jiangshan <jiangshanlai@gmail.com>,
        Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Subject: Re: [RFC 0/3] Revert SRCU from tracepoint infrastructure
Message-ID: <20200210120552.1a06a7aa@gandalf.local.home>
In-Reply-To: <20200210094616.GC14879@hirez.programming.kicks-ass.net>
References: <20200207205656.61938-1-joel@joelfernandes.org>
        <1997032737.615438.1581179485507.JavaMail.zimbra@efficios.com>
        <20200210094616.GC14879@hirez.programming.kicks-ass.net>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, 10 Feb 2020 10:46:16 +0100
Peter Zijlstra <peterz@infradead.org> wrote:

> Furthermore, using srcu would be detrimental, because of how it has
> smp_mb() in the read side primitives.

I didn't realize that there was a full memory barrier in the srcu read
side. Seems to me that itself is rational for reverting it. And also a
big NAK for any suggestion to have any of the function tracing to use
it as well (which comes up here and there).

-- Steve