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@xxxxxxxxxx> 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@xxxxxxxxxx>
Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
---
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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