Jason Wang
2022-Dec-21 03:19 UTC
[PATCH v2 05/11] vduse: Introduce bound workqueue for irq injection
On Tue, Dec 20, 2022 at 6:02 PM Yongji Xie <xieyongji at bytedance.com> wrote:> > On Tue, Dec 20, 2022 at 2:28 PM Jason Wang <jasowang at redhat.com> wrote: > > > > On Mon, Dec 19, 2022 at 1:04 PM Yongji Xie <xieyongji at bytedance.com> wrote: > > > > > > On Fri, Dec 16, 2022 at 12:02 PM Jason Wang <jasowang at redhat.com> wrote: > > > > > > > > On Mon, Dec 5, 2022 at 4:44 PM Xie Yongji <xieyongji at bytedance.com> wrote: > > > > > > > > > > This introduces a bound workqueue to support running > > > > > irq callback in a specified cpu. > > > > > > > > > > Signed-off-by: Xie Yongji <xieyongji at bytedance.com> > > > > > --- > > > > > drivers/vdpa/vdpa_user/vduse_dev.c | 29 ++++++++++++++++++++++------- > > > > > 1 file changed, 22 insertions(+), 7 deletions(-) > > > > > > > > > > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c > > > > > index 37809bfcb7ef..d126f3e32a20 100644 > > > > > --- a/drivers/vdpa/vdpa_user/vduse_dev.c > > > > > +++ b/drivers/vdpa/vdpa_user/vduse_dev.c > > > > > @@ -57,6 +57,7 @@ struct vduse_virtqueue { > > > > > struct vdpa_callback cb; > > > > > struct work_struct inject; > > > > > struct work_struct kick; > > > > > + int irq_effective_cpu; > > > > > > > > I wonder why it's a cpu number instead of a cpumask. The latter seems > > > > more flexible, e.g when using NUMA. > > > > > > > > > > This variable represents the CPU that runs the interrupt callback > > > rather than CPU affinity. > > > > Ok, but for some reason it only gets updated when a new affinity is set? > > > > Yes, since we don't use round-robin now. And if affinity is not set, > we rollback to the default behavior (use un-bounded workqueue to run > irq callback). > > > (Btw, I don't see how the code deals with cpu hotplug, do we need > > cpuhot notifier?) > > > > Currently the queue_work_on() can handle the cpu hotplug case, so I > think we can simply check whether the CPU is online each time queuing > the kwork, then update the affinity if needed.Right. Thanks> > Thanks, > Yongji >