From: Jason Wang <jasowang@redhat.com> To: Stefano Garzarella <sgarzare@redhat.com> Cc: "Eugenio Pérez" <eperezma@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, linux-kernel <linux-kernel@vger.kernel.org>, virtualization <virtualization@lists.linux-foundation.org> Subject: Re: [PATCH 2/3] vdpa_sim_blk: limit the number of request handled per batch Date: Thu, 23 Jun 2022 11:50:22 +0800 [thread overview] Message-ID: <CACGkMEsk-O=dVwKoEHRY-nL3XEQktPWiBot2NfOUYNdkoL-s=Q@mail.gmail.com> (raw) In-Reply-To: <20220621160859.196646-3-sgarzare@redhat.com> 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? Thanks > /* Make sure used is visible before rasing the interrupt. */ > smp_wmb(); > > @@ -218,10 +223,18 @@ static void vdpasim_blk_work(struct work_struct *work) > if (vringh_need_notify_iotlb(&vq->vring) > 0) > vringh_notify(&vq->vring); > local_bh_enable(); > + > + if (++reqs > 4) { > + vq_work = false; > + reschedule = true; > + } > } > } > out: > spin_unlock(&vdpasim->lock); > + > + if (reschedule) > + schedule_work(&vdpasim->work); > } > > static void vdpasim_blk_get_config(struct vdpasim *vdpasim, void *config) > -- > 2.36.1 > _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
WARNING: multiple messages have this Message-ID (diff)
From: Jason Wang <jasowang@redhat.com> To: Stefano Garzarella <sgarzare@redhat.com> Cc: virtualization <virtualization@lists.linux-foundation.org>, "Eugenio Pérez" <eperezma@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, linux-kernel <linux-kernel@vger.kernel.org> Subject: Re: [PATCH 2/3] vdpa_sim_blk: limit the number of request handled per batch Date: Thu, 23 Jun 2022 11:50:22 +0800 [thread overview] Message-ID: <CACGkMEsk-O=dVwKoEHRY-nL3XEQktPWiBot2NfOUYNdkoL-s=Q@mail.gmail.com> (raw) In-Reply-To: <20220621160859.196646-3-sgarzare@redhat.com> 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? Thanks > /* Make sure used is visible before rasing the interrupt. */ > smp_wmb(); > > @@ -218,10 +223,18 @@ static void vdpasim_blk_work(struct work_struct *work) > if (vringh_need_notify_iotlb(&vq->vring) > 0) > vringh_notify(&vq->vring); > local_bh_enable(); > + > + if (++reqs > 4) { > + vq_work = false; > + reschedule = true; > + } > } > } > out: > spin_unlock(&vdpasim->lock); > + > + if (reschedule) > + schedule_work(&vdpasim->work); > } > > static void vdpasim_blk_get_config(struct vdpasim *vdpasim, void *config) > -- > 2.36.1 >
next prev parent reply other threads:[~2022-06-23 3:50 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-06-21 16:08 [PATCH 0/3] vdpa_sim_blk: several fixes for the vDPA block simulator Stefano Garzarella 2022-06-21 16:08 ` Stefano Garzarella 2022-06-21 16:08 ` [PATCH 1/3] vdpa_sim_blk: use dev_dbg() to print errors Stefano Garzarella 2022-06-21 16:08 ` Stefano Garzarella 2022-06-23 3:40 ` Jason Wang 2022-06-23 3:40 ` Jason Wang 2022-06-21 16:08 ` [PATCH 2/3] vdpa_sim_blk: limit the number of request handled per batch Stefano Garzarella 2022-06-21 16:08 ` Stefano Garzarella 2022-06-23 3:50 ` Jason Wang [this message] 2022-06-23 3:50 ` Jason Wang 2022-06-23 8:58 ` Stefano Garzarella 2022-06-23 8:58 ` Stefano Garzarella 2022-06-28 4:01 ` Jason Wang 2022-06-28 4:01 ` Jason Wang 2022-06-28 7:55 ` Stefano Garzarella 2022-06-28 7:55 ` Stefano Garzarella 2022-06-21 16:12 ` [PATCH 3/3] vdpa_sim_blk: call vringh_complete_iotlb() also in the error path Stefano Garzarella 2022-06-21 16:12 ` Stefano Garzarella 2022-06-23 3:52 ` Jason Wang 2022-06-23 3:52 ` Jason Wang
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