Re: [PATCH v2 01/11] genirq/affinity:: Export irq_create_affinity_masks()
On Mon, Feb 13 2023 at 22:50, Yongji Xie wrote: > On Mon, Feb 13, 2023 at 8:00 PM Michael S. Tsirkin wrote: > I can try to split irq_create_affinity_masks() into a common part and > an irq specific part, and move the common part to a common dir such as > /lib and export it. Then we can use the common part to build a new API > for usage. https://lore.kernel.org/all/20221227022905.352674-1-ming@redhat.com/ Thanks, tglx ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [PATCH v2 01/11] genirq/affinity:: Export irq_create_affinity_masks()
On Mon, Jan 30, 2023 at 07:53:55PM +0800, Yongji Xie wrote: > On Fri, Jan 27, 2023 at 4:22 PM Michael S. Tsirkin wrote: > > > > On Mon, Dec 19, 2022 at 05:36:02PM +0800, Yongji Xie wrote: > > > On Mon, Dec 19, 2022 at 3:33 PM Michael S. Tsirkin > > > wrote: > > > > > > > > On Mon, Dec 05, 2022 at 04:41:17PM +0800, Xie Yongji wrote: > > > > > Export irq_create_affinity_masks() so that some modules > > > > > can make use of it to implement interrupt affinity > > > > > spreading mechanism. > > > > > > > > > > Signed-off-by: Xie Yongji > > > > > > > > So this got nacked, what's the plan now? > > > > > > > > > > I‘d like to check with Christoph again first. > > > > > > Hi Christoph, > > > > > > Jason will post some patches to get rid of the DMA API for vDPA > > > simulators. And the irq affinity algorithm is independent of the IRQ > > > subsystem IIUC. So could you allow this patch so that we can reuse the > > > algorithm to select the best CPU (per-cpu affinity if possible, or at > > > least per-node) to run the virtqueue's irq callback. > > > > > > Thanks, > > > Yongji > > > > I think you need to explain why you are building low level > > affinity masks. > > In VDUSE case, we use workqueue to run the virtqueue's irq callback. > Now I want to queue the irq callback kwork to one specific CPU to get > per-cpu affinity if possible, or at least per-node. So I need to use > this function to build the low level affinity masks for each > virtqueue. > > > what's the plan now? > > > > If there is no objection, I'll post a new version. > > Thanks, > Yongji I doubt you made a convicing case here - I think Christoph was saying if it is not an irq it should not use an irq affinity API. So a new API possibly sharing implementation with irq affinity is called for then? Maybe. -- MST ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [PATCH v2 01/11] genirq/affinity:: Export irq_create_affinity_masks()
On Mon, Dec 19, 2022 at 05:36:02PM +0800, Yongji Xie wrote: > On Mon, Dec 19, 2022 at 3:33 PM Michael S. Tsirkin wrote: > > > > On Mon, Dec 05, 2022 at 04:41:17PM +0800, Xie Yongji wrote: > > > Export irq_create_affinity_masks() so that some modules > > > can make use of it to implement interrupt affinity > > > spreading mechanism. > > > > > > Signed-off-by: Xie Yongji > > > > So this got nacked, what's the plan now? > > > > I‘d like to check with Christoph again first. > > Hi Christoph, > > Jason will post some patches to get rid of the DMA API for vDPA > simulators. And the irq affinity algorithm is independent of the IRQ > subsystem IIUC. So could you allow this patch so that we can reuse the > algorithm to select the best CPU (per-cpu affinity if possible, or at > least per-node) to run the virtqueue's irq callback. > > Thanks, > Yongji I think you need to explain why you are building low level affinity masks. what's the plan now? > > > --- > > > kernel/irq/affinity.c | 1 + > > > 1 file changed, 1 insertion(+) > > > > > > diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c > > > index d9a5c1d65a79..f074a7707c6d 100644 > > > --- a/kernel/irq/affinity.c > > > +++ b/kernel/irq/affinity.c > > > @@ -487,6 +487,7 @@ irq_create_affinity_masks(unsigned int nvecs, struct > > > irq_affinity *affd) > > > > > > return masks; > > > } > > > +EXPORT_SYMBOL_GPL(irq_create_affinity_masks); > > > > > > /** > > > * irq_calc_affinity_vectors - Calculate the optimal number of vectors > > > -- > > > 2.20.1 > > ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [PATCH v2 01/11] genirq/affinity:: Export irq_create_affinity_masks()
On Mon, Dec 05, 2022 at 04:41:17PM +0800, Xie Yongji wrote: > Export irq_create_affinity_masks() so that some modules > can make use of it to implement interrupt affinity > spreading mechanism. > > Signed-off-by: Xie Yongji So this got nacked, what's the plan now? > --- > kernel/irq/affinity.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c > index d9a5c1d65a79..f074a7707c6d 100644 > --- a/kernel/irq/affinity.c > +++ b/kernel/irq/affinity.c > @@ -487,6 +487,7 @@ irq_create_affinity_masks(unsigned int nvecs, struct > irq_affinity *affd) > > return masks; > } > +EXPORT_SYMBOL_GPL(irq_create_affinity_masks); > > /** > * irq_calc_affinity_vectors - Calculate the optimal number of vectors > -- > 2.20.1 ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [PATCH v2 01/11] genirq/affinity:: Export irq_create_affinity_masks()
On Tue, Dec 6, 2022 at 5:28 PM Yongji Xie wrote: > > On Tue, Dec 6, 2022 at 4:47 PM Christoph Hellwig 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@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [PATCH v2 01/11] genirq/affinity:: Export irq_create_affinity_masks()
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? 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. ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [PATCH v2 01/11] genirq/affinity:: Export irq_create_affinity_masks()
On Mon, Dec 05, 2022 at 04:41:17PM +0800, Xie Yongji wrote: > Export irq_create_affinity_masks() so that some modules > can make use of it to implement interrupt affinity > spreading mechanism. I don't think driver should be building low-level affinity masks. ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
