direct-io.hg

view extras/mini-os/README @ 7172:9c6b39746b78

Fix localhost live migration. We were overvigorously wiping out the store
entries when a domain closed and on save, which meant that the /vm entries
disappeared when a localhost migration occurred. XendCheckpoint has had extra
exception handling and logging added. It also now calls back through
XendDomain.restore_,which has the correct locking semantics to prevent race
conditions during migration.

Added assertions to XendCheckpoint to ensure that the channels are set after
XendDomainInfo.restore. I don't see why they would not be, and the old code
meant that in the case that they were not, IntroduceDomain would not be called
on the new domain, breaking Xend restart.

relocate calls through XendDomain.domain_restore_fd rather than directly to
XendCheckpoint to isolate XendCheckpoint from the rest of the world, and to
allow XendDomain to pass itself into XendCheckpoint for a callback.

Simplify the XendCheckpoint / XendDomainInfo interlock, giving only two
states, OK and TERMINATED. If XendCheckpoint asks for a suspend, but sees a
shutdown, it is valid for it to proceed -- either way the domain has stopped.
Higher level tools may wish to disallow this, but at the very least, there is
no sense in waiting for a suspend that will never come.

Signed-off-by: Ewan Mellor <ewan@xensource.com>
author emellor@ewan
date Tue Oct 04 11:14:50 2005 +0100 (2005-10-04)
parents 06d84bf87159
children 0839db0aa611
line source
1 Minimal OS
2 ----------
4 This shows some of the stuff that any guest OS will have to set up.
6 This includes:
8 * installing a virtual exception table
9 * handling virtual exceptions
10 * handling asynchronous events
11 * enabling/disabling async events
12 * parsing start_info struct at start-of-day
13 * registering virtual interrupt handlers (for timer interrupts)
14 * a simple page and memory allocator
15 * minimal libc support
17 Stuff it doesn't show:
19 * modifying page tables
20 * network code
21 * block-device code
24 - to build it just type make.
26 - to start it do the following in domain0 (assuming xend is running)
27 # xm create domain_config
29 this starts the kernel and prints out a bunch of stuff and then every
30 1000 timer interrupts the system time.