Kevin Wolf writes ("Re: [Xen-devel] [RFC][PATCH] Use ioemu block drivers through
blktap"):
I needed a shutdown handler to properly close the blktap connection and
delete the named pipes associated with the qemu-dm instance. When a
domain is destroyed, qemu-dm receives a SIGHUP. However, with the
default SIGHUP handler no atexit functions are called, so I had to add
this handler which performs a clean exit.
Sadly in that case using a signal hanlder is no good, because qemu-dm
might die for some other reason than SIGHUP, skipping the cleanup.
(For example, it might have a bug and segfault, or the kernel's OOM
killer might send it a SIGKILL, or ...)
If this cleanup is really necessary, then that will cause problems for
future runs. If not then the cleanup isn't really necessary :-).
Leftover named pipes, for example, aren't really a big problem and can
just be garbage collected at some point (provided their names are
sufficiently unique).
I haven't eyeballed all of the new qemu blktap arrangements in detail.
What processes are there and why can't the process at the other end of
the pipe do the cleanup ?
Ian.
13 messages in com.xensource.lists.xen-develRe: [Xen-devel] [RFC][PATCH] Use ioem...
.patch