[Qemu-devel] [PATCH RFC 0/2] Fix migration issues

[Fei Li <fli@suse.com>]

Hi,
these two patches are to fix live migration issues. The first is
about multifd, and the second is to fix some error handling.

But I have a question about using multifd migration.
In our current code, when multifd is used during migration, if there
is an error before the destination receives all new channels (I mean
multifd_recv_new_channel(ioc)), the destination does not exit but
keeps waiting (Hang in recvmsg() in qio_channel_socket_readv) until
the source exits.

My question is about the state of the destination host if fails during
this period. I did a test, after applying [1/2] patch, if
multifd_new_send_channel_async() fails, the destination host hangs for
a while then later pops up a window saying
    "'QEMU (...) [stopped]' is not responding.
    You may choose to wait a short while for it to continue or force
    the application to quit entirely."
But after closing the window by clicking, the qemu on the dest still
hangs there until I exclusively kill the qemu on the source.

The source host keeps running as expected, but I guess the hang
phenonmenon in the dest is not right.
Would someone kindly give some suggestions on this? Thanks a lot.


Fei Li (2):
  migration: fix the multifd code
  migration: fix some error handling

 migration/migration.c    |  5 +----
 migration/postcopy-ram.c |  3 +++
 migration/ram.c          | 33 +++++++++++++++++++++++----------
 migration/ram.h          |  2 +-
 4 files changed, 28 insertions(+), 15 deletions(-)

-- 
2.13.7