On Thu, 2015-07-02 at 08:58 +0000, Wu, Feng wrote: > > -----Original Message----- > > From: Dario Faggioli [mailto:dario.faggi...@citrix.com] > > > > This is the third time that I ask: > > (1) whether it is possible to have more vcpus queued on one pcpu PI > > blocked list with desc.on (I really believe it is); > > I think it is, please see the following scenario: > > When cpu masks the interrupts, and an external interrupt occurs for the > assigned device while the target vCPU2 is blocked, the wakeup notification > event handler has no chance to run, after a while, another wakeup > notification event for vCPU4 blocking on the same pCPU occurs, > after cpu unmakes the interrupts, wakeup notification handler > gets called. Then we get: > vCPU2, desc.on = 1 and vCPU4, desc.on = 1 > Then in the handler we need to kick both of them. > Ok, first of all, thanks for answering! :-)
And yes, this makes sense. > > (2) if yes, whether it is TheRightThing(TM) to kick all of them, as > > soon as any notification arrives, instead that putting together a > > mechanism for kicking only a specific one. > > > Why can't we kick all of them, 'desc.on = 1' means there is a pending > interrupt, when we meet this condition, kicking the related vCPU should > be the right thing to do. > Right, I see it now. I felt like I was missing something, and that's why I was asking to you to elaborate a bit more. Thanks again for having done this. I was missing/forgetting half of the way desc.on is actually handled, sorry for this. BTW, I'm finding it hard reading this series from the archives; there appears to be some threading issues and some missing messages. I also don't have it in my inbox, because my filters failed to spot and flag it properly. If you send a new version, please, Cc me, so it will be easier for me to look at all the patches, and provide a more helpful review. Thanks and Regards, Dario -- <<This happens because I choose it to happen!>> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://about.me/dario.faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)
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