Hi, On 10/19/2010 09:32 AM, Amit Shah wrote: > On (Tue) Oct 19 2010 [09:23:00], Hans de Goede wrote: >>>> 3) This patch will cause processes filling the virtqueue fast enough to >>>> block >>>> to never wake up again, due to a missing waitqueue wakeup, see: >>>> https://bugzilla.redhat.com/show_bug.cgi?id=643750 >>> >>> Doesn't happen in my testcase, but this patch shouldn't cause that >>> problem if it exists -- it's a problem that exists even now for >>> nonblocking ports. So if such a bug exists, it needs to be fixed >>> independently. >> >> First of all lets agree that this is a real problem, > > Sure, got a testcase for the test-virtserial or kvm-autotest projects? > ;-) > > I did try it and POLLOUT gets set for me immediately when I read one > buffer from the host. >
Ok, weird but ok :) <snip> >> I agree it is an independent problem, and should be fixed in a separate >> patch, but that patch should be part of the same set and become *before* >> this one, as this patch now extends the problem to ports opened in blocking >> mode too. > > Strongly disagree. This patch fixes a problem wherein blocking-mode > writes to a port freeze the entire guest. That's a much uglier problem > to have than poll not indicating a port is writable again. Ack, you're right. Acked-by: Hans de Goede <[email protected]> Regards, Hans _______________________________________________ Virtualization mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/virtualization
