On Thu, Apr 28, 2022 at 3:42 PM Cornelia Huck <cohuck@xxxxxxxxxx> wrote: > > On Thu, Apr 28 2022, Jason Wang <jasowang@xxxxxxxxxx> wrote: > > > On Thu, Apr 28, 2022 at 1:55 PM Michael S. Tsirkin <mst@xxxxxxxxxx> wrote: > >> > >> On Thu, Apr 28, 2022 at 01:51:59PM +0800, Jason Wang wrote: > >> > On Thu, Apr 28, 2022 at 1:24 PM Michael S. Tsirkin <mst@xxxxxxxxxx> wrote: > >> > > > >> > > On Thu, Apr 28, 2022 at 11:04:41AM +0800, Jason Wang wrote: > >> > > > > But my guess is that rwlock + some testing for the legacy indicator case > >> > > > > just to double check if there is a heavy regression despite of our > >> > > > > expectations to see none should do the trick. > >> > > > > >> > > > I suggest this, rwlock (for not airq) seems better than spinlock, but > >> > > > at worst case it will cause cache line bouncing. But I wonder if it's > >> > > > noticeable (anyhow it has been used for airq). > >> > > > > >> > > > Thanks > >> > > > >> > > Which existing rwlock does airq use right now? Can we take it to sync? > >> > > >> > It's the rwlock in airq_info, it has already been used in this patch. > >> > > >> > write_lock(&info->lock); > >> > write_unlock(&info->lock); > >> > > >> > But the problem is, it looks to me there could be a case that airq is > >> > not used, (virtio_ccw_int_hander()). That's why the patch use a > >> > spinlock, it could be optimized with using a rwlock as well. > >> > > >> > Thanks > >> > >> Ah, right. So let's take that on the legacy path too and Halil promises > >> to test to make sure performance isn't impacted too badly? > > > > I think what you meant is using a dedicated rwlock instead of trying > > to reuse one of the airq_info locks. > > > > If this is true, it should be fine. > > FWIW, that approach makes sense to me as well. > Good to know that. Let me post a new version. Thanks _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
