From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33024) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZwoQ8-0004G4-Dx for qemu-devel@nongnu.org; Thu, 12 Nov 2015 04:43:57 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZwoQ7-0002ra-9g for qemu-devel@nongnu.org; Thu, 12 Nov 2015 04:43:56 -0500 Message-ID: <56445EDE.5050607@cn.fujitsu.com> Date: Thu, 12 Nov 2015 17:41:50 +0800 From: Zhu Guihua MIME-Version: 1.0 References: <1438838837-28504-1-git-send-email-bharata@linux.vnet.ibm.com> <1438838837-28504-2-git-send-email-bharata@linux.vnet.ibm.com> <20150904053124.GV6537@voom.redhat.com> <20150909055246.GD17433@in.ibm.com> <55EFE2AA.7060500@cn.fujitsu.com> <20150909075600.GI17433@in.ibm.com> <564457A6.9020800@cn.fujitsu.com> <20151112093038.GA17747@in.ibm.com> In-Reply-To: <20151112093038.GA17747@in.ibm.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH v4 01/11] exec: Remove cpu from cpus list during cpu_exec_exit() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: bharata@linux.vnet.ibm.com Cc: mdroth@linux.vnet.ibm.com, aik@ozlabs.ru, guijianfeng@cn.fujitsu.com, izumi.taku@jp.fujitsu.com, agraf@suse.de, qemu-devel@nongnu.org, qemu-ppc@nongnu.org, tyreld@linux.vnet.ibm.com, imammedo@redhat.com, nfont@linux.vnet.ibm.com, afaerber@suse.de, kamezawa.hiroyu@jp.fujitsu.com, David Gibson On 11/12/2015 05:30 PM, Bharata B Rao wrote: > On Thu, Nov 12, 2015 at 05:11:02PM +0800, Zhu Guihua wrote: >> Hi Bharata, >> >> On 09/09/2015 03:56 PM, Bharata B Rao wrote: >>> On Wed, Sep 09, 2015 at 03:41:30PM +0800, Zhu Guihua wrote: >>>> On 09/09/2015 01:52 PM, Bharata B Rao wrote: >>>>> On Fri, Sep 04, 2015 at 03:31:24PM +1000, David Gibson wrote: >>>>>> On Thu, Aug 06, 2015 at 10:57:07AM +0530, Bharata B Rao wrote: >>>>>>> CPUState *cpu gets added to the cpus list during cpu_exec_init(). It >>>>>>> should be removed from cpu_exec_exit(). >>>>>>> >>>>>>> cpu_exec_init() is called from generic CPU::instance_finalize and some >>>>>>> archs like PowerPC call it from CPU unrealizefn. So ensure that we >>>>>>> dequeue the cpu only once. >>>>>>> >>>>>>> Instead of introducing a new field CPUState.queued, I could have used >>>>>>> CPUState.cpu_index to check if the cpu is already dequeued from the list. >>>>>>> Since that doesn't work for CONFIG_USER_ONLY, I had to add a new field. >>>>>>> >>>>>>> Signed-off-by: Bharata B Rao >>>>>> This seems reasonable to me, but I'm wondering how x86 cpu hotplug / >>>>>> unplug is working without it. >>>>> x86 hotplug/unplug code currently resides in Zhu's git tree >>>>> (git://github.com/zhugh/qemu). They are removing the CPU from the list >>>>> explicitly in x86 CPU's instance_finalize routine. >>>> Sorry, my git tree is git://github.com/zhuguihua/qemu >>>> >>>> Now there was no progress about topology, so we don't know what will happen >>>> in x86. I am not sure whether we will take this method finally. >>> Andreas had a presentation on this topic in KVM forum recently. >>> >>> Andreas - do you have any updates on the topology and other aspects >>> of CPU hotplug so that we can align the CPU hotplug work in different >>> archs accordingly and hope to get it merged in 2.5 time frame ? >> Do you update the patchset? >> >> My work in x86 has stopped for a while, Maybe I can get some ideas from >> another >> arch's worker. > My last version is here: > https://lists.gnu.org/archive/html/qemu-devel/2015-08/msg00650.html > > I initally started with core level CPU hotplug, moved to socket level hotplug > based on Andreas' patchset and then moved back again to core level hotplug. > > I was a bit confused about how the generic semantics would evovle and hence > the work got delayed. I wil be posting the next version of my patchset > based on core level semantics soon. > > I am hoping that I should be able to get CPU hotplug/unplug included > in QEMU-2.6 timeframe. > Thanks for your reply. Look forward to your next version. Regards, Zhu