Messages in this thread | | | Date | Thu, 23 Jun 2022 10:58:30 +0200 | From | Stefano Garzarella <> | Subject | Re: [PATCH 2/3] vdpa_sim_blk: limit the number of request handled per batch |
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On Thu, Jun 23, 2022 at 11:50:22AM +0800, Jason Wang wrote: >On Wed, Jun 22, 2022 at 12:09 AM Stefano Garzarella <sgarzare@redhat.com> wrote: >> >> Limit the number of requests (4 per queue as for vdpa_sim_net) handled >> in a batch to prevent the worker from using the CPU for too long. >> >> Suggested-by: Eugenio Pérez <eperezma@redhat.com> >> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> >> --- >> drivers/vdpa/vdpa_sim/vdpa_sim_blk.c | 15 ++++++++++++++- >> 1 file changed, 14 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c >> index a83a5c76f620..ac86478845b6 100644 >> --- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c >> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c >> @@ -197,6 +197,7 @@ static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim, >> static void vdpasim_blk_work(struct work_struct *work) >> { >> struct vdpasim *vdpasim = container_of(work, struct vdpasim, work); >> + bool reschedule = false; >> int i; >> >> spin_lock(&vdpasim->lock); >> @@ -206,11 +207,15 @@ static void vdpasim_blk_work(struct work_struct *work) >> >> for (i = 0; i < VDPASIM_BLK_VQ_NUM; i++) { >> struct vdpasim_virtqueue *vq = &vdpasim->vqs[i]; >> + bool vq_work = true; >> + int reqs = 0; >> >> if (!vq->ready) >> continue; >> >> - while (vdpasim_blk_handle_req(vdpasim, vq)) { >> + while (vq_work) { >> + vq_work = vdpasim_blk_handle_req(vdpasim, vq); >> + > >Is it better to check and exit the loop early here?
Maybe, but I'm not sure.
In vdpa_sim_net we call vringh_complete_iotlb() and send notification also in the error path, so I thought was better to send notification also when vdpasim_blk_handle_req() return false, since we will update the used.idx.
However, I don't think it's a common path, so if you think it's better to exit the loop early, I can do it.
Thanks, Stefano
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