On Thu, Jun 30, 2022 at 10:51 AM Jakub Kicinski <[email protected]> wrote: > > On Thu, 30 Jun 2022 10:08:04 +0800 Jason Wang wrote: > > +static void enable_refill_work(struct virtnet_info *vi) > > +{ > > + spin_lock(&vi->refill_lock); > > + vi->refill_work_enabled = true; > > + spin_unlock(&vi->refill_lock); > > +} > > + > > +static void disable_refill_work(struct virtnet_info *vi) > > +{ > > + spin_lock(&vi->refill_lock); > > + vi->refill_work_enabled = false; > > + spin_unlock(&vi->refill_lock); > > +} > > + > > static void virtqueue_napi_schedule(struct napi_struct *napi, > > struct virtqueue *vq) > > { > > @@ -1527,8 +1547,12 @@ static int virtnet_receive(struct receive_queue *rq, > > int budget, > > } > > > > if (rq->vq->num_free > min((unsigned int)budget, > > virtqueue_get_vring_size(rq->vq)) / 2) { > > - if (!try_fill_recv(vi, rq, GFP_ATOMIC)) > > - schedule_delayed_work(&vi->refill, 0); > > + if (!try_fill_recv(vi, rq, GFP_ATOMIC)) { > > + spin_lock(&vi->refill_lock); > > + if (vi->refill_work_enabled) > > + schedule_delayed_work(&vi->refill, 0); > > + spin_unlock(&vi->refill_lock); > > Are you sure you can use the basic spin_lock() flavor in all cases? > Isn't the disable/enable called from a different context than this > thing here?
This function will only be called in bh so it's safe. > > The entire delayed work construct seems a little risky because the work > may go to sleep after disabling napi, causing large latency spikes. Yes, but it only happens on OOM. > I guess you must have a good reason no to simply reschedule the NAPI > and keep retrying with GFP_ATOMIC... Less pressure on the memory allocator on OOM probably, but it looks like an independent issue that might be optimized in the future. > > Please add the target tree name to the subject. Ok Thanks > _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
