Some process can share one struct file-s, we may find them by "object IDs".
A file descriptor is opened in one process and send to other via unix socket.
The procedure of restoring files contains four stages.
* Collect data about all file's descriptors
On this stage we find process which will restore a file descriptor and
create a list of processes, who should get this descriptor.
* Create datagrams unix sockets
If a file descriptor should be received, a unix socket is created
instead of it.
* Open file descriptors
A process with the least pid opens a file and sends this file
descriptors to all one who wait it.
* Receive file descriptors.
When we were thinking up this algoritm, we wanted to minimize a number
of context switches. A number of context switches is proportional of a
number of processes.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
