From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:57450)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <paolo.bonzini@gmail.com>) id 1bpfu8-00066e-U8
	for qemu-devel@nongnu.org; Thu, 29 Sep 2016 14:17:57 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <paolo.bonzini@gmail.com>) id 1bpfu7-0004QM-D7
	for qemu-devel@nongnu.org; Thu, 29 Sep 2016 14:17:56 -0400
Sender: Paolo Bonzini <paolo.bonzini@gmail.com>
References: <1474984441-28516-1-git-send-email-kwolf@redhat.com>
	<CAFEAcA8YtMEPb5Xt7axASm0aaJ8_rt_71hbwdfwn8io5FVzyoA@mail.gmail.com>
	<20160928093744.GH5236@noname.redhat.com>
	<CAFEAcA__cOs3ey3Dgzc1zcY=diF3EDyOwmbyLemWynksvajatw@mail.gmail.com>
	<20160929102507.GD5742@noname.redhat.com>
	<8a79dd86-4fbc-0a59-254a-0e537dd8b6e7@redhat.com>
From: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <8c6a5e31-7bfb-1947-f4a8-8667edfd17e8@redhat.com>
Date: Thu, 29 Sep 2016 20:17:44 +0200
MIME-Version: 1.0
In-Reply-To: <8a79dd86-4fbc-0a59-254a-0e537dd8b6e7@redhat.com>
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 8bit
Subject: Re: [Qemu-devel] [PULL 00/18] Block layer patches
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: John Snow <jsnow@redhat.com>, Kevin Wolf <kwolf@redhat.com>, Peter Maydell <peter.maydell@linaro.org>
Cc: pl@kamp.de, QEMU Developers <qemu-devel@nongnu.org>, Qemu-block <qemu-block@nongnu.org>



On 29/09/2016 19:02, John Snow wrote:
> 
> 
> On 09/29/2016 06:25 AM, Kevin Wolf wrote:
>> John, can you have a look at the IDE code and check whether we can get
>> rid of the deep recursion? It seems that the test issues a large request
>> that is then split into many small requests. But it should be possible
>> to do this iteratively rather than recursively.
> 
> http://wiki.qemu.org/Features/IDE
> 
> "Rewrite ide_atapi_cmd_reply_end to be fully non-recursive; and ideally
> less confusing."
> 
> Guess I have to float this one to the top.

Would it be enough to hide the call to s->bus->dma->ops->start_transfer
behind a bottom half?

Paolo