On Mon, 2015-01-26 at 12:27 +0100, Alexandre DERUMIER wrote: > >>About this, I can do it successfully on my qemu. > >>So can you tell us more information about your operation? > simply start with > > -smp 2,sockets=2,cores=2,maxcpus=4 -device kvm64-x86_64-cpu,apic-id=2,id=cpu2 > > then > > #device_del cpu2 > > Guest return > [ 324.195024] Unregister pv shared memory for cpu 2 > [ 324.250579] smpboot: CPU 2 is now offline > > but cpu is not remove in qemu. > > I had also try to eject manualy from guest > echo 1 > /sys/bus/acpi/devices/LNXCPU\:02/eject > > But I have this error message > ACPI: \_SB_.CP02: Eject incomplete - status 0xf > > (maybe is it normal ? or maybe is it a guest bug (kernel 3.16 from debian > wheezy backports) ?) >
According to your description, the guest has invoked _EJ0 method, but the method was executed unsuccessfully. Thus, only hot-unplug request was invoked in qemu, but hot-unplug was not so that cpu was still in qemu. Did you test any other kernel version? I will try kernel 3.16 to investigate this problem later. Regards, Zhu > > >>And I found the patchset you applied is the last version in your last > >>email. I think you'd better apply the latest version. > > I have applied on top of git theses patches series > > https://www.mail-archive.com/qemu-devel%40nongnu.org/msg272745.html > [Qemu-devel] [RESEND PATCH v1 0/5] Common unplug and unplug request cb for > memory and CPU hot-unplug. > https://lists.nongnu.org/archive/html/qemu-devel/2015-01/msg01552.html > [Qemu-devel] [PATCH v3 0/7] cpu: add device_add foo-x86_64-cpu support > https://www.mail-archive.com/qemu-devel@nongnu.org/msg273870.html > [Qemu-devel] [PATCH v2 00/11] cpu: add i386 cpu hot remove support > > ----- Mail original ----- > De: "Zhu Guihua" <zhugh.f...@cn.fujitsu.com> > À: "aderumier" <aderum...@odiso.com> > Cc: "qemu-devel" <qemu-devel@nongnu.org>, tangc...@cn.fujitsu.com, "guz fnst" > <guz.f...@cn.fujitsu.com>, "isimatu yasuaki" > <isimatu.yasu...@jp.fujitsu.com>, "Anshul Makkar" > <anshul.mak...@profitbricks.com>, "chen fan fnst" > <chen.fan.f...@cn.fujitsu.com>, "Igor Mammedov" <imamm...@redhat.com>, > "afaerber" <afaer...@suse.de> > Envoyé: Lundi 26 Janvier 2015 04:47:13 > Objet: Re: [Qemu-devel] [PATCH v2 00/11] cpu: add i386 cpu hot remove support > > On Mon, 2015-01-26 at 04:19 +0100, Alexandre DERUMIER wrote: > > Thanks for your reply. > > > > 2 others things: > > > > 1) > > on cpu unplug, I see that the cpu is correctly removed from my linux guest > > but not from qemu > > > > About this, I can do it successfully on my qemu. > So can you tell us more information about your operation? > > And I found the patchset you applied is the last version in your last > email. I think you'd better apply the latest version. > > Regards, > Zhu > > > starting with a guest with 3cpus: > > > > guest: #ls -lah /sys/devices/system/ |grep cpu > > drwxr-xr-x 6 root root 0 Jan 25 22:16 cpu0 > > drwxr-xr-x 6 root root 0 Jan 25 22:16 cpu1 > > drwxr-xr-x 6 root root 0 Jan 25 22:16 cpu2 > > > > hmp: # info cpus > > * CPU #0: pc=0xffffffff81057022 (halted) thread_id=24972 > > CPU #1: pc=0xffffffff81057022 (halted) thread_id=24973 > > CPU #2: pc=0xffffffff81048bc1 (halted) thread_id=25102 > > > > > > then unplug cpu2 > > hmp : device_del cpu2 > > > > guest: > > > > dmesg: > > [ 176.219754] Unregister pv shared memory for cpu 2 > > [ 176.278881] smpboot: CPU 2 is now offline > > > > #ls -lah /sys/devices/system/ |grep cpu > > drwxr-xr-x 6 root root 0 Jan 25 22:16 cpu0 > > drwxr-xr-x 6 root root 0 Jan 25 22:16 cpu1 > > > > hmp: # info cpus > > * CPU #0: pc=0xffffffff81057022 (halted) thread_id=24972 > > CPU #1: pc=0xffffffff81057022 (halted) thread_id=24973 > > CPU #2: pc=0xffffffff81048bc1 (halted) thread_id=25102 > > > > > > > > > > 2)when numa is used, the hotplugged cpu is always on numa node 0 > > (cpu_add or device_add cpu) > > > > > > starting a guest, with 2 sockets,1 cores > > > > -smp 2,sockets=2,cores=1,maxcpus=2 > > -object memory-backend-ram,size=256M,id=ram-node0 -numa > > node,nodeid=0,cpus=0,memdev=ram-node0 > > -object memory-backend-ram,size=256M,id=ram-node1 -numa > > node,nodeid=1,cpus=1,memdev=ram-node1 > > > > hmp: > > # info numa > > 2 nodes > > node 0 cpus: 0 > > node 0 size: 256 MB > > node 1 cpus: 1 > > node 1 size: 256 MB > > > > ok > > > > now > > > > starting with same topology, but with 1cpu at start > > -smp 2,sockets=2,cores=1,maxcpus=2 > > -object memory-backend-ram,size=256M,id=ram-node0 -numa > > node,nodeid=0,cpus=0,memdev=ram-node0 > > -object memory-backend-ram,size=256M,id=ram-node1 -numa > > node,nodeid=1,cpus=1,memdev=ram-node1 > > > > # info numa > > 2 nodes > > node 0 cpus: 0 > > node 0 size: 256 MB > > node 1 cpus: > > node 1 size: 256 MB > > > > hotpluging a cpu > > # device_add kvm64-x86_64-cpu,apic-id=1,id=cpu1 > > > > # info numa > > 2 nodes > > node 0 cpus: 0 1 > > node 0 size: 256 MB > > node 1 cpus: > > node 1 size: 256 MB > > > > cpu1 should be on node1, not node0. > > > > > > Regards, > > > > Alexandre > > > > ----- Mail original ----- > > De: "Zhu Guihua" <zhugh.f...@cn.fujitsu.com> > > À: "aderumier" <aderum...@odiso.com> > > Cc: "qemu-devel" <qemu-devel@nongnu.org>, tangc...@cn.fujitsu.com, "guz > > fnst" <guz.f...@cn.fujitsu.com>, "isimatu yasuaki" > > <isimatu.yasu...@jp.fujitsu.com>, "Anshul Makkar" > > <anshul.mak...@profitbricks.com>, "chen fan fnst" > > <chen.fan.f...@cn.fujitsu.com>, "Igor Mammedov" <imamm...@redhat.com>, > > "afaerber" <afaer...@suse.de> > > Envoyé: Lundi 26 Janvier 2015 03:01:48 > > Objet: Re: [Qemu-devel] [PATCH v2 00/11] cpu: add i386 cpu hot remove > > support > > > > On Fri, 2015-01-23 at 11:24 +0100, Alexandre DERUMIER wrote: > > > Hello, > > > > > > I'm currently testing the new cpu unplug features, > > > Works fine here with debian guests and kernel 3.14. > > > > > > > Thanks for your test. > > > > > But I have notice some small potential bugs, but I'm not sure I'm doing > > > it right. > > > > > > 1)first, to unplug cpu, we need an id for cpu > > > > > > > Yes, if you want to unplug cpu, you must have an id for cpu. > > > > > The problem is that the current qemu command line > > > -smp 1,sockets=2,cores=1,maxcpus=2 > > > > > > for example, will create 1 cpu on apic-id 0 without any id, so we can't > > > unplug it. > > > > > > > > > So, I have tried with > > > > > > -smp 1,sockets=2,cores=1,maxcpus=2 -device > > > kvm64-x86_64-cpu,apic-id=0,id=cpu0 > > > > > > But this give me an error: > > > "-device kvm64-x86_64-cpu,apic-id=0,id=cpu0: CPU with APIC ID 0 exists" > > > > > > > APIC ID 0 was used by the cpu of '-smp 1'. > > So you should use apic-id=1 > > > > > (also try to set -smp 0, but it's not working). > > > > > > > > > > > > 2) second problem, if I start with > > > -smp 1,sockets=2,cores=1,maxcpus=2 > > > > > > then hmp: > > > device_add kvm64-x86_64-cpu,apic-id=1,id=cpu1 > > > > > > then hmp : device_del cpu1 > > > > > > Got an error:" > > > This is the last cpu, should not be removed!" > > > > > > > > > > Oh, it's our problem, thanks for your pointing out. > > I will fix it in next version. > > > > Regards, > > Zhu > > > > > > > > This is coming from > > > [PATCH 06/12] pc: add cpu hot unplug request callback support > > > + if (smp_cpus == 1) { > > > + error_setg(&local_err, > > > + "This is the last cpu, should not be removed!"); > > > + goto out; > > > + } > > > > > > > > > > > > So, the only way unplug is working for me, is to start with -smp 2 > > > minimum > > > -smp 2,sockets=2,cores=1,maxcpus=4 > > > > > > Then I can hotplug|unplug cpuid >= 2 > > > > > > > > > > > > Regards, > > > > > > Alexandre Derumier > > [...]
