Re: [Qemu-devel] virtio-serial-pci very expensive during live migration

[Chris Friesen]

On 05/08/2014 07:44 PM, ChenLiang wrote:

> Hi,
> I have test the patch at the qemu.git, qemu crashed when vm is booting.
> 
> the backtrace is:
> 
> Program received signal SIGABRT, Aborted.
> [Switching to Thread 0x7f6bf67f9700 (LWP 9740)]
> 0x00007f6bfacb2b55 in raise () from /lib64/libc.so.6
> (gdb) bt
> #0  0x00007f6bfacb2b55 in raise () from /lib64/libc.so.6
> #1  0x00007f6bfacb4131 in abort () from /lib64/libc.so.6
> #2  0x00007f6bfd51047c in kvm_io_ioeventfd_del (listener=
>      0x7f6bfd9ffee0 <kvm_io_listener>, section=0x7f6bf67f87c0, 
> match_data=true, data=
>      0, e=0x7f6970000930) at /tmp/qemu/kvm-all.c:879
> #3  0x00007f6bfd5163b5 in address_space_add_del_ioeventfds (as=
>      0x7f6bfde3d6e0 <address_space_io>, fds_new=0x0, fds_new_nb=0, fds_old=
>      0x7f6bfdfd8ce0, fds_old_nb=1) at /tmp/qemu/memory.c:628
> #4  0x00007f6bfd51698e in address_space_update_ioeventfds (as=
>      0x7f6bfde3d6e0 <address_space_io>) at /tmp/qemu/memory.c:687
> #5  0x00007f6bfd517949 in address_space_update_topology (as=
>      0x7f6bfde3d6e0 <address_space_io>) at /tmp/qemu/memory.c:780
> #6  0x00007f6bfd517a68 in memory_region_transaction_commit ()
>      at /tmp/qemu/memory.c:800
> #7  0x00007f6bfd3e2942 in virtio_pci_stop_ioeventfd (proxy=0x7f6bfdfde080)
>      at hw/virtio/virtio-pci.c:270


Hah...I attached gdb to the source qemu this time and got basically the same 
thing.
This is with the stable-1.4 branch plus the patch, using "-machine accel=kvm".

#0  0x00007f4e08e1e9e9 in raise () from /lib64/libc.so.6
#1  0x00007f4e08e200f8 in abort () from /lib64/libc.so.6
#2  0x00007f4e0b30e8a4 in kvm_io_ioeventfd_del (listener=<optimized out>, 
section=0x7f4e080f2c00, match_data=<optimized out>, data=0, e=<optimized out>) 
at /home/cfriesen/devel/qemu/kvm-all.c:804
#3  0x00007f4e0b311f60 in address_space_add_del_ioeventfds (fds_old_nb=64, 
fds_old=0x7f4df8004b40, fds_new_nb=0, fds_new=0x0, as=0x7f4e0bfb9fe0 
<address_space_io>) at /home/cfriesen/devel/qemu/memory.c:603
#4  address_space_update_ioeventfds (as=0x7f4e0bfb9fe0 <address_space_io>) at 
/home/cfriesen/devel/qemu/memory.c:649
#5  address_space_update_topology (as=0x7f4e0bfb9fe0 <address_space_io>) at 
/home/cfriesen/devel/qemu/memory.c:730
#6  memory_region_transaction_commit () at 
/home/cfriesen/devel/qemu/memory.c:750
#7  0x00007f4e0b255cb5 in virtio_pci_stop_ioeventfd (proxy=0x7f4e0d3266a0) at 
hw/virtio-pci.c:259
#8  0x00007f4e0b3086d0 in virtio_vmstate_change (opaque=0x7f4e0d31c370, 
running=<optimized out>, state=<optimized out>) at 
/home/cfriesen/devel/qemu/hw/virtio.c:914
#9  0x00007f4e0b2bdf5b in vm_state_notify (address@hidden, address@hidden) at 
vl.c:1674
#10 0x00007f4e0b2c3f62 in do_vm_stop (state=RUN_STATE_FINISH_MIGRATE) at 
/home/cfriesen/devel/qemu/cpus.c:446
#11 vm_stop (address@hidden) at /home/cfriesen/devel/qemu/cpus.c:1080
#12 0x00007f4e0b25e5c5 in buffered_file_thread (opaque=0x7f4e0b79a640 
<current_migration.19392>) at migration.c:707
#13 0x00007f4e09cacc53 in start_thread () from /lib64/libpthread.so.0
#14 0x00007f4e08ededbd in clone () from /lib64/libc.so.6

Chris