From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:47920) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TBpGR-0007SZ-26 for qemu-devel@nongnu.org; Wed, 12 Sep 2012 11:54:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TBpGJ-0007ke-9X for qemu-devel@nongnu.org; Wed, 12 Sep 2012 11:54:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:20450) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TBpGJ-0007kT-2C for qemu-devel@nongnu.org; Wed, 12 Sep 2012 11:53:59 -0400 Message-ID: <5050B011.1000906@redhat.com> Date: Wed, 12 Sep 2012 18:53:53 +0300 From: Avi Kivity MIME-Version: 1.0 References: <1347451046-5513-1-git-send-email-lilei@linux.vnet.ibm.com> In-Reply-To: <1347451046-5513-1-git-send-email-lilei@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC v3 ATCH 0/5] char: expose CirMemCharDriver and provide QMP interface List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Lei Li Cc: aliguori@us.ibm.com, lcapitulino@redhat.com, eblake@redhat.com, qemu-devel@nongnu.org, armbru@redhat.com On 09/12/2012 02:57 PM, Lei Li wrote: > This RFC series attempts to convert the MemCharDriver to use a circular > buffer for input and output, expose it to users by introducing QMP commands > memchar_write and memchar_read and via the command line like the other > CharDriverStates. > > Serial ports in qemu always use CharDriverStates as there backends, > Right now, all of our backends always try to write the data from the > guest to a socket or file. The concern from OpenStack is that this could > lead to unbounded disk space usage since they log the serial output. > For more detail of the background info: > https://bugs.launchpad.net/nova/+bug/832507 > > So we want to use a circular buffer in QEMU instead, and then OpenStack > can periodically read the buffer in QEMU and log it. Can't they do it themselves? Have qemu write to a pipe, and on the other side, do whatever rate limiting is needed. -- error compiling committee.c: too many arguments to function