On Wed, Jan 06, 2010 at 12:43:07PM -0800, Davide Libenzi wrote: > On Wed, 6 Jan 2010, Michael S. Tsirkin wrote: > > > On Tue, Sep 01, 2009 at 07:24:24AM -0700, Davide Libenzi wrote: > > > On Tue, 1 Sep 2009, Avi Kivity wrote: > > > > > > > On 09/01/2009 02:45 AM, Davide Libenzi wrote: > > > > > On Thu, 27 Aug 2009, Davide Libenzi wrote: > > > > > > > > > > > > > > > > On Thu, 27 Aug 2009, Michael S. Tsirkin wrote: > > > > > > > > > > > > > > > > > > > Oh, I stopped pushing EFD_STATE since we have a solution. > > > > > > > > > > > > > Do you guys need the kernel-side eventfd_ctx_read() I posted or not? > > > > > > Because if nobody uses it, I'm not going to push it. > > > > > > > > > > > Guys, I did not get a reply on this. Do you need me to push it, or you're > > > > > not going to use it at the end? > > > > > > > > > > > > > We'll use it eventually, but we're still some ways from it. > > > > > > OK, then bug me when you're going to need it. I won't push it before that. > > > > > > > > > - Davide > > > > So, it turns out that we need this: be thought we don't because > > currently kvm does not zero eventfd counter when it polls eventfd. But > > this causes spurious interrupts when we disconnect irqfd from kvm and > > re-connect it back. > > > > However, since kvm does its own thing with the wait queue, and might > > read the counter from wait queue callback (which might be from > > interrupt context), a simpler, lower-level interface would be better for > > us. Does the following (build tested only) look palatable? > > What is wrong with you? :/ I was trying to be helpful. > There was a patch attached with this email, and yet you did your own, I tried to explain, no? That patch was taking wait queue spinlock and was assuming that eventfd_read_ctx is called from a task that can block. KVM attaches its own poller so this is not a good fit for us. Hope this clarifies. > and yet again you managed to add an underscore at the beginning of the > API name, in an API set where there are no leading underscores. Even > if KVM does that for its own reasons, you should be able to fit your > naming "style" to the interface you're adding your droplets into. I > will post an eventfd_read_ctx() to Andrew ASAP. > > > > - Davide Sorry about the underscore - it's easy to fix but I won't bore you with more patch revisions before I understand what makes you unhappy. Before KVM starts creating workqueues and doing schedule_work calls just to work around the API, can we discuss this please? I am not hung on my patch, but could we have it work so that we can call eventfd_read_ctx from wait queue callback directly? Thanks! -- MST -- 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
