On Tue, Dec 6, 2022 at 5:28 PM Yongji Xie <xieyongji@xxxxxxxxxxxxx> wrote: > > On Tue, Dec 6, 2022 at 4:47 PM Christoph Hellwig <hch@xxxxxx> wrote: > > > > On Tue, Dec 06, 2022 at 04:40:37PM +0800, Yongji Xie wrote: > > > With the vDPA framework, some drivers (vduse, vdpa-sim) can create > > > software-defined virtio devices and attach them to the virtio bus. > > > This kind of virtio device is not a pci device or a platform device. > > > So it would be needed to export this function if we want to implement > > > the automatic affinity management for the virtio device driver which > > > is binded to this device. > > > > Why are these devices even using interrupts? > > They don't use interrupt. But they use a bound workqueue to run the > interrupt callback. So the driver needs an algorithm to choose which > cpu to run the interrupt callback. Then we found the existing > interrupt affinity spreading mechanism is very suitable for this > scenario, so we try to export this function to reuse it. > > > The whjole vdpa thing > > is a mess, I also still need to fix up the horrible abuse of the DMA > > API for something that isn't even DMA, and this just seems to spread > > that same mistake even further. I think it's mostly an issue of some vDPA parents, not the vDPA itself. I had patches to get rid of the DMA API for vDPA simulators. Will post. > > We just want to reuse this algorithm. And it is completely independent > of the IRQ subsystem. I guess it would not mess things up. I think so, it's about which CPU do we want to run the callback and the callback is not necessarily triggered by an IRQ. Thanks > > Thanks, > Yongji > _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
