On Thu, Nov 03, 2011 at 11:03:13AM +0100, Jiri Denemark wrote:
When a client wants to send a keepalive message it needs to do so in a non-blocking way to avoid blocking its event loop. This patch adds dontBlock flag which says that the call should be processed without blocking. Such calls do not have a thread waiting for the result associated with them. This means, that sending such call fails if no thread is dispatching and writing to the socket would block. In case there is a thread waiting for its (normal) call to finish, sending non-blocking call just pushes it into the queue and lets the dispatching thread send it. The thread which has the buck tries to send all non-blocking calls in the queue in a best effort way---if sending them would block or there's an error on the socket, non-blocking calls are simply removed from the queue and discarded. In case a non-blocking call is partially sent but sending the rest of it would block, it is moved into client's unfinishedCall and left for future delivery. Every sending attempt first sends the rest of unfinishedCall and than continues with other queued calls. --- Notes: Version 5: - partially sent non-blocking calls now work even for SASL (or other transports that cache data internally) - fixed several other bugs in that area
Version 4: - correctly handle partially sent non-blocking calls that would block
Version 3: - no changes
Version 2: - no changes
src/rpc/virnetclient.c | 285 ++++++++++++++++++++++++++++++++++++++---------- 1 files changed, 229 insertions(+), 56 deletions(-)
I started reviewing this patch, but I'm finding the changes somewhat confusing. I think there might be a different way to go about it, so I'm hacking up a proof of concept counter-proposal for non-blocking I/O. We sort of needed this already for the streams code, but we rather ignored it because it was rarely important in practice. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|