Re: [Qemu-devel] QEMU live block-migration

[Yaodong Yang]

Hello Michael,

Thanks for your help! 

I read the function of tcp_wait_for_connect(), there is a statement; " qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL); " I guess this will disable this file-descriptor from the main loop and make the current execution parallel with the main loop. Is it correct? 

Also, I did not find any thread_create related function in the migrate_fd_connect() function.

I think my current goal is to find the exact start point of the migration thread. Thanks again.

Yaodong

On Mon, Jul 8, 2013 at 10:32 AM, Michael Roth <address@hidden> wrote:

Quoting Yaodong Yang (2013-07-07 09:55:06)

> Hello everyone,
>    I have a short question about the implementation of QEMU. When the qemu
>    perform the live block migration using "migrate -b tcp:...." command. Does
>    a new thread for migration created or not? I went through the code, only
>    find that this activity is triggered in the main loop (main_loop_wait(int

An outgoing non-blocking connection is triggered by
tcp_start_outgoing_migration, once the connection is completed the
tcp_wait_for_connect() callback is executed by the main loop.

>    nonblocking) function). I want to know is there a new dedicated thread
>    created for this migration task or not? If so, where in the code the new
>    thread created.

Within that callback there's a call to migrate_fd_connect(), which is where the
migration thread is created.

Incoming migration is still handled by the main loop's thread

>    Thanks!
>    Yaodong
>    --
>    Yaodong Yang
>    Computer Science and Engineering Department
>    University of Nebraska--Lincoln,
>    Lincoln, NE, U.S.A.

--
Yaodong Yang

Computer Science and Engineering Department

University of Nebraska--Lincoln, 

Lincoln, NE, U.S.A.