Re: [Qemu-devel] qemu 2.0, deadlock in block-commit

[Paolo Bonzini]

Il 22/05/2014 23:05, Marcin Gibuła ha scritto:
> Some more info.
> VM was doing lot of write IO during this test.

QEMU is waiting for librados to complete I/O.  Can you reproduce it with 
a different driver?

Paolo

> ppoll() is listening for these descriptors (from strace):
>
> ppoll([{fd=25, events=POLLIN|POLLERR|POLLHUP}, {fd=23,
> events=POLLIN|POLLERR|POLLHUP}, {fd=17, events=POLLIN|POLLERR|POLLHUP},
> {fd=4, events=POLLIN|POLLERR|POLLHUP}], 4, NULL, NULL, 8, ...)
>
> fd # ls -l 25 23 17 4
> lrwx------ 1 usr_5062 qemu 64 May 22 23:00 17 -> anon_inode:[eventfd]
> lrwx------ 1 usr_5062 qemu 64 May 22 23:00 23 -> anon_inode:[eventfd]
> lrwx------ 1 usr_5062 qemu 64 May 22 23:00 25 -> anon_inode:[eventfd]
> lrwx------ 1 usr_5062 qemu 64 May 22 23:00 4 -> anon_inode:[eventfd]
>
> VM is started via libvirt. No errors are reported in logs.
> Command line is:
>
> /usr/bin/qemu-system-x86_64 -machine accel=kvm -name
> 68189c3c-02f6-4aae-88a2-5f13c5e6f53a -S -machine
> pc-i440fx-2.0,accel=kvm,usb=off -cpu SandyBridge,-kvmclock -m 1536
> -realtime mlock=on -smp 2,sockets=2,cores=10,threads=1 -uuid
> 68189c3c-02f6-4aae-88a2-5f13c5e6f53a -smbios type=0,vendor=HAL 9000
> -smbios type=1,manufacturer=cloud -no-user-config -nodefaults -chardev
> socket,id=charmonitor,path=/var/lib/libvirt/qemu/68189c3c-02f6-4aae-88a2-5f13c5e6f53a.monitor,server,nowait
> -mon chardev=charmonitor,id=monitor,mode=control -rtc
> base=utc,clock=vm,driftfix=slew -global kvm-pit.lost_tick_policy=discard
> -no-shutdown -boot menu=off,strict=on -device
> piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -device
> virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x5 -drive
> file=/dev/cube2/5f751718-ff36-420f-b034-5f31230b5f23,if=none,id=drive-virtio-disk0,format=raw,cache=none,aio=native,bps_rd=57671680,bps_wr=57671680,iops_rd=275,iops_wr=275
> -device
> virtio-blk-pci,scsi=off,bus=pci.0,addr=0x6,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=2
> -drive
> file=/dev/cube1/c5b7a6e3-11f8-4b08-ac3e-5ea054028221,if=none,id=drive-virtio-disk1,format=raw,cache=none,aio=native,bps_rd=57671680,bps_wr=57671680,iops_rd=275,iops_wr=275
> -device
> virtio-blk-pci,scsi=off,bus=pci.0,addr=0x7,drive=drive-virtio-disk1,id=virtio-disk1
> -drive
> file=/mnt/nfs/volumes/66346c1b-add5-4412-89d9-b00a3bb13e75/72be1b50-982e-458a-9a84-c0fbd48b4b3c.qcow2,if=none,id=drive-virtio-disk2,format=qcow2,cache=none,aio=threads,bps_rd=57671680,bps_wr=57671680,iops_rd=275,iops_wr=275
> -device
> virtio-blk-pci,scsi=off,bus=pci.0,addr=0x8,drive=drive-virtio-disk2,id=virtio-disk2
> -drive
> file=/mnt/nfs/volumes/a20c3b29-6f21-4b3d-a3fb-8b80599e50df/b84716ea-2564-47cc-bbbf-dea6029132b4.qcow2,if=none,id=drive-virtio-disk3,format=qcow2,cache=none,aio=threads,bps_rd=57671680,bps_wr=57671680,iops_rd=275,iops_wr=275
> -device
> virtio-blk-pci,scsi=off,bus=pci.0,addr=0x9,drive=drive-virtio-disk3,id=virtio-disk3
> -drive
> file=/mnt/nfs/volumes/0c2996b5-abec-47ea-9e88-ebd7ebf0c79d/453cb20a-1705-45e2-9f9e-bc1ea096d52a.qcow2,if=none,id=drive-virtio-disk4,format=qcow2,cache=none,aio=threads,bps_rd=57671680,bps_wr=57671680,iops_rd=275,iops_wr=275
> -device
> virtio-blk-pci,scsi=off,bus=pci.0,addr=0xa,drive=drive-virtio-disk4,id=virtio-disk4
> -drive
> file=/mnt/nfs/volumes/7dcbd9ba-f0bc-4d3c-9b5c-b2ac824584d5/a8bb7e11-a9b5-4613-9b63-b9722fba2166.qcow2,if=none,id=drive-virtio-disk5,format=qcow2,cache=none,aio=threads,bps_rd=57671680,bps_wr=57671680,iops_rd=275,iops_wr=275
> -device
> virtio-blk-pci,scsi=off,bus=pci.0,addr=0xb,drive=drive-virtio-disk5,id=virtio-disk5
> -drive
> file=rbd:iso-images/rescue.iso:auth_supported=none,if=none,id=drive-ide0-0-0,readonly=on,format=raw
> -device
> ide-cd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1
> -netdev tap,fd=19,id=hostnet0,vhost=on,vhostfd=20 -device
> virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:82:41:c9,bus=pci.0,addr=0x3
> -netdev tap,fd=21,id=hostnet1,vhost=on,vhostfd=22 -device
> virtio-net-pci,netdev=hostnet1,id=net1,mac=52:54:00:70:10:35,bus=pci.0,addr=0x4
> -chardev pty,id=charserial0 -device
> isa-serial,chardev=charserial0,id=serial0 -chardev
> socket,id=charchannel0,path=/var/lib/libvirt/qemu/68189c3c-02f6-4aae-88a2-5f13c5e6f53a.agent,server,nowait
> -device
> virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=org.qemu.guest_agent.0
> -chardev
> socket,id=charchannel1,path=/var/lib/libvirt/qemu/68189c3c-02f6-4aae-88a2-5f13c5e6f53a.cloud.agent,server,nowait
> -device
> virtserialport,bus=virtio-serial0.0,nr=2,chardev=charchannel1,id=channel1,name=com.cloud.guest_agent.1
> -device usb-tablet,id=input0 -vnc 0.0.0.0:0,password -device
> cirrus-vga,id=video0,bus=pci.0,addr=0x2 -device
> virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0xc -sandbox on -device
> pvpanic