[Qemu-devel] [RFC PATCH 0/6] Run incoming migration in a coroutine

[Paolo Bonzini]

Howdy,

this series moves incoming migration to a coroutine, so that the monitor
remains usable.  I did this is as a step towards implementing an NBD
server inside QEMU (which needs to configured and/or to serve requests
during migration), but I think it is useful in general.

Coroutines work very simply by making the file descriptor non-blocking.
On EAGAIN you call qemu_coroutine_yield(); when the file descriptor
becomes readable, you call qemu_coroutine_enter().

This is mostly an RFC on the approach.  Still, it mostly consists of
cleanups and the first 3 patches could be applied right away.  What
needs some refinement is the hideous passing of file descriptors in
patch 4 and especially the last patch.

Paolo Bonzini (6):
  migration: clean up server sockets and handlers before invoking 
process_incoming_migration
  migration: close socket QEMUFile from socket_close
  migration: move qemu_fclose to process_incoming_migration
  migration: remove iohandlers before closing the file
  migration: handle EAGAIN while reading QEMUFile
  migration: move process_incoming_migration to a coroutine

 migration-exec.c |  3 +--
 migration-fd.c   |  3 +--
 migration-tcp.c  | 12 ++++++------
 migration-unix.c | 12 ++++++------
 migration.c      | 23 +++++++++++++++++++++--
 migration.h      |  2 +-
 savevm.c         | 34 ++++++++++++++++++++++++++++------
 7 file modificati, 64 inserzioni(+), 25 rimozioni(-)

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1.7.11.2