From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:38766)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <alex.bennee@linaro.org>) id 1bhygh-0000BX-OQ
	for qemu-devel@nongnu.org; Thu, 08 Sep 2016 08:44:16 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <alex.bennee@linaro.org>) id 1bhygf-00046P-1d
	for qemu-devel@nongnu.org; Thu, 08 Sep 2016 08:44:15 -0400
Received: from mail-wm0-x234.google.com ([2a00:1450:400c:c09::234]:38822)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <alex.bennee@linaro.org>) id 1bhyge-00046L-Qy
	for qemu-devel@nongnu.org; Thu, 08 Sep 2016 08:44:12 -0400
Received: by mail-wm0-x234.google.com with SMTP id 1so86603213wmz.1
	for <qemu-devel@nongnu.org>; Thu, 08 Sep 2016 05:44:12 -0700 (PDT)
References: <1468917141-8155-1-git-send-email-pbonzini@redhat.com>
	<1468917141-8155-3-git-send-email-pbonzini@redhat.com>
From: Alex =?utf-8?Q?Benn=C3=A9e?= <alex.bennee@linaro.org>
In-reply-to: <1468917141-8155-3-git-send-email-pbonzini@redhat.com>
Date: Thu, 08 Sep 2016 13:44:10 +0100
Message-ID: <87wpimy31h.fsf@linaro.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit
Subject: Re: [Qemu-devel] [PATCH 02/10] tcg: Pass last_tb by value to
 tb_find_fast()
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel/>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-devel@nongnu.org, serge.fdrv@gmail.com, sergey.fedorov@linaro.org


Paolo Bonzini <pbonzini@redhat.com> writes:

> From: Sergey Fedorov <serge.fdrv@gmail.com>
>
> This is a small clean up. tb_find_fast() is a final consumer of this
> variable so no need to pass it by reference. 'last_tb' is always updated
> by subsequent cpu_loop_exec_tb() in cpu_exec().
>
<snip>
> @@ -621,7 +620,7 @@ int cpu_exec(CPUState *cpu)
>              cpu->tb_flushed = false; /* reset before first TB lookup */
>              for(;;) {
>                  cpu_handle_interrupt(cpu, &last_tb);
> -                tb = tb_find_fast(cpu, &last_tb, tb_exit);
> +                tb = tb_find_fast(cpu, last_tb, tb_exit);

Maybe a comment here for those that missed the subtly in the commit
message?

                   /* cpu_loop_exec_tb updates a to a new last_tb */

>                  cpu_loop_exec_tb(cpu, tb, &last_tb, &tb_exit, &sc);

You could even make it explicit and change cpu_loop_exec_tb to return
last_tb instead of passing by reference. Then it would be even clearer
when reading the code.

>                  /* Try to align the host and virtual clocks
>                     if the guest is in advance */



--
Alex Bennée