On Thu, Jan 21, 2010 at 07:13:13PM +0200, Avi Kivity wrote: > On 01/21/2010 06:58 PM, Davide Libenzi wrote: >> On Thu, 21 Jan 2010, Michael S. Tsirkin wrote: >> >> >>> This is a backport of commit: 03db343a6320f780937078433fa7d8da955e6fce >>> modified in a way that introduces some code duplication on the one hand, >>> but reduces the risk of regressing existing eventfd users on the other >>> hand. >>> >>> KVM needs a wait to atomically remove themselves from the eventfd >>> ->poll() wait queue head, in order to handle correctly their IRQfd >>> deassign operation. >>> >>> This patch introduces such API, plus a way to read an eventfd from its >>> context. >>> >>> Signed-off-by: Michael S. Tsirkin<mst@xxxxxxxxxx> >>> --- >>> >>> Avi, Davidel, how about only including the following part for -stable >>> then? Reason is, I still would like to be able to use irqfd there, and >>> getting spurious interrupts 100% of times unmask is done isn't a very >>> good idea IMO ... >>> >> It's the same thing. Unless there are *real* problems in KVM due to the >> spurious ints, I still think this is .33 material. >> > > I agree. > > But I think we can solve this in another way in .32: we can clear the > eventfd from irqfd->inject work, which is in process context. The new > stuff is only needed for lockless clearing, no? No, AFAIK there's no way to clear the counter from kernel without this patch. > -- > Do not meddle in the internals of kernels, for they are subtle and quick to panic. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
