Mark McLoughlin
2007-Jun-18 15:36 UTC
[Xen-devel] [PATCH][RESEND] Add fallback code to blktap for missing poll-on-aio support
Hey, As Stephen explains in this mail: http://lists.xensource.com/archives/html/xen-devel/2006-10/msg00331.html blktap requires a xen specific kernel AIO ABI which has been vetoed by upstream in favour of another approach. Rather than include this ABI, Fedora has been carrying a patch which makes tap:aio use a thread to poll for aio events and notify the main thread via a pipe. The upstream approach of allowing io_getevents() poll normal file descriptors via epoll is still progressing: http://lkml.org/lkml/2007/1/3/16 but when that does make it upstream, blktap will require significant re-working to use that approach. In the meantime, here''s a patch which uses the poll-in-a-thread approach only if AIO poll support isn''t available. It also hides the details behind a simple abstraction and makes both tap:aio and tap:qcow use it. Built and tested with latest xen-unstable. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Cheers, Mark. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel