On 10/03/2013 09:34 PM, Paolo Bonzini wrote:
Il 03/10/2013 15:29, Lei Li ha scritto:
On 10/03/2013 06:34 PM, Paolo Bonzini wrote:
Il 03/10/2013 12:28, Lei Li ha scritto:
The load_hook callback is only be called if the RAM_SAVE_FLAG_HOOK is
received.
To check this flags, it means there would be a check action first in
unix_accept_incoming_migration(), like:
f = qemu_fopen_pipe(c, "rb");
flags = qemu_get_be64(f);
if (flags == RAM_SAVE_FLAG_HOOK) {
load_hook();
...
}
Otherwise, the incoming side has no idea whether the special 8-bytes
record
(RAM_SAVE_FLAG_HOOK) is sent.
No, ram_load is taking care of checking for RAM_SAVE_FLAG_HOOK. If
before_iterate writes the 8 bytes (followed by passing the fd for the
pipe's read-side via SCM_RIGHTS), ram_load will call load_hook before it
loads any page and load_hook will fetch the fd.
If let ram_load take care of checking for RAM_SAVE_FLAG_HOOK, then in
unix_accept_incoming_migration(), how to decide which QEMUFile should
be opened? Since there would be two types of QEMUFile, one is the original
QEMUFile opened by qemu_fopen_socket() for normal Unix migration, the
other is opened by qemu_fopen_pipe() for unix-page-flipping migration.
Or, were you suggesting replace this qemu_fopen_socket() with the
qemu_fopen_pipe(), which also contain the copy of the QEMUFile code for
Unix sockets?
Yes (though I'd call it qemu_fopen_socket_local() or something like that).
On the incoming side, if non-page-flipping was enabled you will use the
normal RAM loading code, if page-flipping was enabled you will get
load_hook calls.
Ah, I see. :)
qemu_fopen_socket_local() sounds good, thanks!
Paolo
Subsequent calls to load_hook will match data written by the sender's
save_page hook (so they contain a RAM address, with the 4k page data
sent on the pipe).
Paolo
--
Lei
