| Message ID | 1346159043-16446-2-git-send-email-levinsasha928@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Aug 28, 2012 at 03:04:03PM +0200, Sasha Levin wrote: > Currently if VIRTIO_RING_F_INDIRECT_DESC is enabled we will > use indirect descriptors and allocate them using a simple > kmalloc(). > > This patch adds a cache which will allow indirect buffers under > a configurable size to be allocated from that cache instead. > > Signed-off-by: Sasha Levin <levinsasha928@gmail.com> I imagine this helps performance? Any numbers? > --- > > Changes in v2: > > - Free correctly indirect buffers. > > drivers/block/virtio_blk.c | 4 ++++ > drivers/char/hw_random/virtio-rng.c | 4 ++++ > drivers/char/virtio_console.c | 4 ++++ > drivers/net/virtio_net.c | 4 ++++ > drivers/virtio/virtio_balloon.c | 4 ++++ > drivers/virtio/virtio_ring.c | 28 ++++++++++++++++++++++++---- > include/linux/virtio.h | 1 + > net/9p/trans_virtio.c | 5 +++++ > 8 files changed, 50 insertions(+), 4 deletions(-) > > diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c > index 13b8ae9..7f670af 100644 > --- a/drivers/block/virtio_blk.c > +++ b/drivers/block/virtio_blk.c > @@ -25,6 +25,9 @@ struct workqueue_struct *virtblk_wq; > static unsigned int indirect_thresh; > module_param(indirect_thresh, uint, S_IRUGO); > > +static unsigned int indirect_alloc_thresh; > +module_param(indirect_alloc_thresh, uint, S_IRUGO); > + > struct virtio_blk > { > struct virtio_device *vdev; > @@ -739,6 +742,7 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) > INIT_WORK(&vblk->config_work, virtblk_config_changed_work); > vblk->config_enable = true; > vdev->indirect_thresh = indirect_thresh; > + vdev->indirect_alloc_thresh = indirect_alloc_thresh; > > err = init_vq(vblk); > if (err) > diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c > index 02d8421..8475ece 100644 > --- a/drivers/char/hw_random/virtio-rng.c > +++ b/drivers/char/hw_random/virtio-rng.c > @@ -28,6 +28,9 @@ > static unsigned int indirect_thresh; > module_param(indirect_thresh, uint, S_IRUGO); > > +static unsigned int indirect_alloc_thresh; > +module_param(indirect_alloc_thresh, uint, S_IRUGO); > + > static struct virtqueue *vq; > static unsigned int data_avail; > static DECLARE_COMPLETION(have_data); > @@ -97,6 +100,7 @@ static int probe_common(struct virtio_device *vdev) > > /* We expect a single virtqueue. */ > vdev->indirect_thresh = indirect_thresh; > + vdev->indirect_alloc_thresh = indirect_alloc_thresh; > vq = virtio_find_single_vq(vdev, random_recv_done, "input"); > if (IS_ERR(vq)) > return PTR_ERR(vq); > diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c > index fc14e7f..c6f24a7 100644 > --- a/drivers/char/virtio_console.c > +++ b/drivers/char/virtio_console.c > @@ -42,6 +42,9 @@ > static unsigned int indirect_thresh; > module_param(indirect_thresh, uint, S_IRUGO); > > +static unsigned int indirect_alloc_thresh; > +module_param(indirect_alloc_thresh, uint, S_IRUGO); > + > /* > * This is a global struct for storing common data for all the devices > * this driver handles. > @@ -1891,6 +1894,7 @@ static int __devinit virtcons_probe(struct virtio_device *vdev) > &portdev->config.max_nr_ports) == 0) > multiport = true; > vdev->indirect_thresh = indirect_thresh; > + vdev->indirect_alloc_thresh = indirect_alloc_thresh; > > err = init_vqs(portdev); > if (err < 0) { > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 64a8321..c091efd 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -37,6 +37,9 @@ module_param(gso, bool, 0444); > static unsigned int indirect_thresh; > module_param(indirect_thresh, uint, S_IRUGO); > > +static unsigned int indirect_alloc_thresh; > +module_param(indirect_alloc_thresh, uint, S_IRUGO); > + > /* FIXME: MTU in config. */ > #define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN) > #define GOOD_COPY_LEN 128 > @@ -1132,6 +1135,7 @@ static int virtnet_probe(struct virtio_device *vdev) > if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF)) > vi->mergeable_rx_bufs = true; > vdev->indirect_thresh = indirect_thresh; > + vdev->indirect_alloc_thresh = indirect_alloc_thresh; > > err = init_vqs(vi); > if (err) > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index fce7347..ccf87db 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -38,6 +38,9 @@ > static unsigned int indirect_thresh; > module_param(indirect_thresh, uint, S_IRUGO); > > +static unsigned int indirect_alloc_thresh; > +module_param(indirect_alloc_thresh, uint, S_IRUGO); > + > struct virtio_balloon > { > struct virtio_device *vdev; > @@ -360,6 +363,7 @@ static int virtballoon_probe(struct virtio_device *vdev) > vb->vdev = vdev; > vb->need_stats_update = 0; > vdev->indirect_thresh = indirect_thresh; > + vdev->indirect_alloc_thresh = indirect_alloc_thresh; > > err = init_vqs(vb); > if (err) > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index 99a64a7..e8b9c54 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -93,6 +93,10 @@ struct vring_virtqueue > */ > unsigned int indirect_thresh; > > + /* Buffers below this size will be allocated from cache */ > + unsigned int indirect_alloc_thresh; > + struct kmem_cache *indirect_cache; > + > /* Host publishes avail event idx */ > bool event; > > @@ -135,7 +139,10 @@ static int vring_add_indirect(struct vring_virtqueue *vq, > unsigned head; > int i; > > - desc = kmalloc((out + in) * sizeof(struct vring_desc), gfp); > + if ((out + in) <= vq->indirect_alloc_thresh) > + desc = kmem_cache_alloc(vq->indirect_cache, gfp); > + else > + desc = kmalloc((out + in) * sizeof(struct vring_desc), gfp); > if (!desc) > return -ENOMEM; > > @@ -384,8 +391,13 @@ static void detach_buf(struct vring_virtqueue *vq, unsigned int head) > i = head; > > /* Free the indirect table */ > - if (vq->vring.desc[i].flags & VRING_DESC_F_INDIRECT) > - kfree(phys_to_virt(vq->vring.desc[i].addr)); > + if (vq->vring.desc[i].flags & VRING_DESC_F_INDIRECT) { > + if (vq->vring.desc[i].len > vq->indirect_alloc_thresh) > + kfree(phys_to_virt(vq->vring.desc[i].addr)); > + else > + kmem_cache_free(vq->indirect_cache, > + phys_to_virt(vq->vring.desc[i].addr)); > + } > > while (vq->vring.desc[i].flags & VRING_DESC_F_NEXT) { > i = vq->vring.desc[i].next; > @@ -654,14 +666,20 @@ struct virtqueue *vring_new_virtqueue(unsigned int num, > vq->last_used_idx = 0; > vq->num_added = 0; > vq->indirect_thresh = 0; > + vq->indirect_alloc_thresh = 0; > + vq->indirect_cache = NULL; > list_add_tail(&vq->vq.list, &vdev->vqs); > #ifdef DEBUG > vq->in_use = false; > vq->last_add_time_valid = false; > #endif > > - if (virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) > + if (virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) { > vq->indirect_thresh = vdev->indirect_thresh; > + vq->indirect_alloc_thresh = vdev->indirect_alloc_thresh; > + if (vq->indirect_alloc_thresh) > + vq->indirect_cache = KMEM_CACHE(vring_desc[vq->indirect_alloc_thresh], 0); > + } > > vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); > > @@ -685,6 +703,8 @@ EXPORT_SYMBOL_GPL(vring_new_virtqueue); > void vring_del_virtqueue(struct virtqueue *vq) > { > list_del(&vq->list); > + if (to_vvq(vq)->indirect_cache) > + kmem_cache_destroy(to_vvq(vq)->indirect_cache); > kfree(to_vvq(vq)); > } > EXPORT_SYMBOL_GPL(vring_del_virtqueue); > diff --git a/include/linux/virtio.h b/include/linux/virtio.h > index 48bc457..3261c02 100644 > --- a/include/linux/virtio.h > +++ b/include/linux/virtio.h > @@ -70,6 +70,7 @@ struct virtio_device { > unsigned long features[1]; > void *priv; > unsigned int indirect_thresh; > + unsigned int indirect_alloc_thresh; > }; > > #define dev_to_virtio(dev) container_of(dev, struct virtio_device, dev) > diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c > index fc93962..3044c86 100644 > --- a/net/9p/trans_virtio.c > +++ b/net/9p/trans_virtio.c > @@ -55,6 +55,9 @@ > static unsigned int indirect_thresh; > module_param(indirect_thresh, uint, S_IRUGO); > > +static unsigned int indirect_alloc_thresh; > +module_param(indirect_alloc_thresh, uint, S_IRUGO); > + > /* a single mutex to manage channel initialization and attachment */ > static DEFINE_MUTEX(virtio_9p_lock); > static DECLARE_WAIT_QUEUE_HEAD(vp_wq); > @@ -505,6 +508,8 @@ static int p9_virtio_probe(struct virtio_device *vdev) > > /* We expect one virtqueue, for requests. */ > vdev->indirect_thresh = indirect_thresh; > + vdev->indirect_alloc_thresh = indirect_alloc_thresh; > + > chan->vq = virtio_find_single_vq(vdev, req_done, "requests"); > if (IS_ERR(chan->vq)) { > err = PTR_ERR(chan->vq); > -- > 1.7.12 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 08/28/2012 03:20 PM, Michael S. Tsirkin wrote: > On Tue, Aug 28, 2012 at 03:04:03PM +0200, Sasha Levin wrote: >> Currently if VIRTIO_RING_F_INDIRECT_DESC is enabled we will >> use indirect descriptors and allocate them using a simple >> kmalloc(). >> >> This patch adds a cache which will allow indirect buffers under >> a configurable size to be allocated from that cache instead. >> >> Signed-off-by: Sasha Levin <levinsasha928@gmail.com> > > I imagine this helps performance? Any numbers? I ran benchmarks on the original RFC, I've re-tested it now and got similar numbers to the original ones (virtio-net using vhost-net, thresh=16): Before: Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 4512.12 After: Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 5399.18 Thanks, Sasha -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Aug 28, 2012 at 03:35:00PM +0200, Sasha Levin wrote: > On 08/28/2012 03:20 PM, Michael S. Tsirkin wrote: > > On Tue, Aug 28, 2012 at 03:04:03PM +0200, Sasha Levin wrote: > >> Currently if VIRTIO_RING_F_INDIRECT_DESC is enabled we will > >> use indirect descriptors and allocate them using a simple > >> kmalloc(). > >> > >> This patch adds a cache which will allow indirect buffers under > >> a configurable size to be allocated from that cache instead. > >> > >> Signed-off-by: Sasha Levin <levinsasha928@gmail.com> > > > > I imagine this helps performance? Any numbers? > > I ran benchmarks on the original RFC, I've re-tested it now and got similar > numbers to the original ones (virtio-net using vhost-net, thresh=16): > > Before: > Recv Send Send > Socket Socket Message Elapsed > Size Size Size Time Throughput > bytes bytes bytes secs. 10^6bits/sec > > 87380 16384 16384 10.00 4512.12 > > After: > Recv Send Send > Socket Socket Message Elapsed > Size Size Size Time Throughput > bytes bytes bytes secs. 10^6bits/sec > > 87380 16384 16384 10.00 5399.18 > > > Thanks, > Sasha This is with both patches 1 + 2? Sorry could you please also test what happens if you apply - just patch 1 - just patch 2 Thanks! -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 08/29/2012 01:07 PM, Michael S. Tsirkin wrote: > On Tue, Aug 28, 2012 at 03:35:00PM +0200, Sasha Levin wrote: >> On 08/28/2012 03:20 PM, Michael S. Tsirkin wrote: >>> On Tue, Aug 28, 2012 at 03:04:03PM +0200, Sasha Levin wrote: >>>> Currently if VIRTIO_RING_F_INDIRECT_DESC is enabled we will >>>> use indirect descriptors and allocate them using a simple >>>> kmalloc(). >>>> >>>> This patch adds a cache which will allow indirect buffers under >>>> a configurable size to be allocated from that cache instead. >>>> >>>> Signed-off-by: Sasha Levin <levinsasha928@gmail.com> >>> >>> I imagine this helps performance? Any numbers? >> >> I ran benchmarks on the original RFC, I've re-tested it now and got similar >> numbers to the original ones (virtio-net using vhost-net, thresh=16): >> >> Before: >> Recv Send Send >> Socket Socket Message Elapsed >> Size Size Size Time Throughput >> bytes bytes bytes secs. 10^6bits/sec >> >> 87380 16384 16384 10.00 4512.12 >> >> After: >> Recv Send Send >> Socket Socket Message Elapsed >> Size Size Size Time Throughput >> bytes bytes bytes secs. 10^6bits/sec >> >> 87380 16384 16384 10.00 5399.18 >> >> >> Thanks, >> Sasha > > This is with both patches 1 + 2? > Sorry could you please also test what happens if you apply > - just patch 1 > - just patch 2 > > Thanks! Sure thing! I've also re-ran it on a IBM server type host instead of my laptop. Here are the results: Vanilla kernel: MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.1 () port 0 AF_INET enable_enobufs failed: getprotobyname Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 7922.72 Patch 1, with threshold=16: MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.1 () port 0 AF_INET enable_enobufs failed: getprotobyname Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 8415.07 Patch 2: MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.1 () port 0 AF_INET enable_enobufs failed: getprotobyname Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 8931.05 Note that these are simple tests with netperf listening on one end and a simple 'netperf -H [host]' within the guest. If there are other tests which may be interesting please let me know. Thanks, Sasha -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Aug 29, 2012 at 05:03:03PM +0200, Sasha Levin wrote: > On 08/29/2012 01:07 PM, Michael S. Tsirkin wrote: > > On Tue, Aug 28, 2012 at 03:35:00PM +0200, Sasha Levin wrote: > >> On 08/28/2012 03:20 PM, Michael S. Tsirkin wrote: > >>> On Tue, Aug 28, 2012 at 03:04:03PM +0200, Sasha Levin wrote: > >>>> Currently if VIRTIO_RING_F_INDIRECT_DESC is enabled we will > >>>> use indirect descriptors and allocate them using a simple > >>>> kmalloc(). > >>>> > >>>> This patch adds a cache which will allow indirect buffers under > >>>> a configurable size to be allocated from that cache instead. > >>>> > >>>> Signed-off-by: Sasha Levin <levinsasha928@gmail.com> > >>> > >>> I imagine this helps performance? Any numbers? > >> > >> I ran benchmarks on the original RFC, I've re-tested it now and got similar > >> numbers to the original ones (virtio-net using vhost-net, thresh=16): > >> > >> Before: > >> Recv Send Send > >> Socket Socket Message Elapsed > >> Size Size Size Time Throughput > >> bytes bytes bytes secs. 10^6bits/sec > >> > >> 87380 16384 16384 10.00 4512.12 > >> > >> After: > >> Recv Send Send > >> Socket Socket Message Elapsed > >> Size Size Size Time Throughput > >> bytes bytes bytes secs. 10^6bits/sec > >> > >> 87380 16384 16384 10.00 5399.18 > >> > >> > >> Thanks, > >> Sasha > > > > This is with both patches 1 + 2? > > Sorry could you please also test what happens if you apply > > - just patch 1 > > - just patch 2 > > > > Thanks! > > Sure thing! > > I've also re-ran it on a IBM server type host instead of my laptop. Here are the > results: > > Vanilla kernel: > > MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.1 > () port 0 AF_INET > enable_enobufs failed: getprotobyname > Recv Send Send > Socket Socket Message Elapsed > Size Size Size Time Throughput > bytes bytes bytes secs. 10^6bits/sec > > 87380 16384 16384 10.00 7922.72 > > Patch 1, with threshold=16: OK so let us set it to 16 for virtio-net by default then? > MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.1 > () port 0 AF_INET > enable_enobufs failed: getprotobyname > Recv Send Send > Socket Socket Message Elapsed > Size Size Size Time Throughput > bytes bytes bytes secs. 10^6bits/sec > > 87380 16384 16384 10.00 8415.07 > > Patch 2: > > MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.1 > () port 0 AF_INET > enable_enobufs failed: getprotobyname > Recv Send Send > Socket Socket Message Elapsed > Size Size Size Time Throughput > bytes bytes bytes secs. 10^6bits/sec > > 87380 16384 16384 10.00 8931.05 > > > Note that these are simple tests with netperf listening on one end and a simple > 'netperf -H [host]' within the guest. If there are other tests which may be > interesting please let me know. > > > Thanks, > Sasha Checking that host CPU utilization did not jump would be nice. E.g. measure BW/host CPU.
On Tue, Aug 28, 2012 at 03:04:03PM +0200, Sasha Levin wrote: > Currently if VIRTIO_RING_F_INDIRECT_DESC is enabled we will > use indirect descriptors and allocate them using a simple > kmalloc(). > > This patch adds a cache which will allow indirect buffers under > a configurable size to be allocated from that cache instead. > > Signed-off-by: Sasha Levin <levinsasha928@gmail.com> The API is ugly - how does driver know what to set? Is this a typical request size? Then let's call it that. Also this is really per VQ, right? What is a good default for net? I guess max sg? > --- > > Changes in v2: > > - Free correctly indirect buffers. > > drivers/block/virtio_blk.c | 4 ++++ > drivers/char/hw_random/virtio-rng.c | 4 ++++ > drivers/char/virtio_console.c | 4 ++++ > drivers/net/virtio_net.c | 4 ++++ > drivers/virtio/virtio_balloon.c | 4 ++++ > drivers/virtio/virtio_ring.c | 28 ++++++++++++++++++++++++---- > include/linux/virtio.h | 1 + > net/9p/trans_virtio.c | 5 +++++ > 8 files changed, 50 insertions(+), 4 deletions(-) > > diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c > index 13b8ae9..7f670af 100644 > --- a/drivers/block/virtio_blk.c > +++ b/drivers/block/virtio_blk.c > @@ -25,6 +25,9 @@ struct workqueue_struct *virtblk_wq; > static unsigned int indirect_thresh; > module_param(indirect_thresh, uint, S_IRUGO); > > +static unsigned int indirect_alloc_thresh; > +module_param(indirect_alloc_thresh, uint, S_IRUGO); > + > struct virtio_blk > { > struct virtio_device *vdev; > @@ -739,6 +742,7 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) > INIT_WORK(&vblk->config_work, virtblk_config_changed_work); > vblk->config_enable = true; > vdev->indirect_thresh = indirect_thresh; > + vdev->indirect_alloc_thresh = indirect_alloc_thresh; > > err = init_vq(vblk); > if (err) > diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c > index 02d8421..8475ece 100644 > --- a/drivers/char/hw_random/virtio-rng.c > +++ b/drivers/char/hw_random/virtio-rng.c > @@ -28,6 +28,9 @@ > static unsigned int indirect_thresh; > module_param(indirect_thresh, uint, S_IRUGO); > > +static unsigned int indirect_alloc_thresh; > +module_param(indirect_alloc_thresh, uint, S_IRUGO); > + > static struct virtqueue *vq; > static unsigned int data_avail; > static DECLARE_COMPLETION(have_data); > @@ -97,6 +100,7 @@ static int probe_common(struct virtio_device *vdev) > > /* We expect a single virtqueue. */ > vdev->indirect_thresh = indirect_thresh; > + vdev->indirect_alloc_thresh = indirect_alloc_thresh; > vq = virtio_find_single_vq(vdev, random_recv_done, "input"); > if (IS_ERR(vq)) > return PTR_ERR(vq); > diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c > index fc14e7f..c6f24a7 100644 > --- a/drivers/char/virtio_console.c > +++ b/drivers/char/virtio_console.c > @@ -42,6 +42,9 @@ > static unsigned int indirect_thresh; > module_param(indirect_thresh, uint, S_IRUGO); > > +static unsigned int indirect_alloc_thresh; > +module_param(indirect_alloc_thresh, uint, S_IRUGO); > + > /* > * This is a global struct for storing common data for all the devices > * this driver handles. > @@ -1891,6 +1894,7 @@ static int __devinit virtcons_probe(struct virtio_device *vdev) > &portdev->config.max_nr_ports) == 0) > multiport = true; > vdev->indirect_thresh = indirect_thresh; > + vdev->indirect_alloc_thresh = indirect_alloc_thresh; > > err = init_vqs(portdev); > if (err < 0) { > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 64a8321..c091efd 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -37,6 +37,9 @@ module_param(gso, bool, 0444); > static unsigned int indirect_thresh; > module_param(indirect_thresh, uint, S_IRUGO); > > +static unsigned int indirect_alloc_thresh; > +module_param(indirect_alloc_thresh, uint, S_IRUGO); > + > /* FIXME: MTU in config. */ > #define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN) > #define GOOD_COPY_LEN 128 > @@ -1132,6 +1135,7 @@ static int virtnet_probe(struct virtio_device *vdev) > if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF)) > vi->mergeable_rx_bufs = true; > vdev->indirect_thresh = indirect_thresh; > + vdev->indirect_alloc_thresh = indirect_alloc_thresh; > > err = init_vqs(vi); > if (err) > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index fce7347..ccf87db 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -38,6 +38,9 @@ > static unsigned int indirect_thresh; > module_param(indirect_thresh, uint, S_IRUGO); > > +static unsigned int indirect_alloc_thresh; > +module_param(indirect_alloc_thresh, uint, S_IRUGO); > + > struct virtio_balloon > { > struct virtio_device *vdev; > @@ -360,6 +363,7 @@ static int virtballoon_probe(struct virtio_device *vdev) > vb->vdev = vdev; > vb->need_stats_update = 0; > vdev->indirect_thresh = indirect_thresh; > + vdev->indirect_alloc_thresh = indirect_alloc_thresh; > > err = init_vqs(vb); > if (err) > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index 99a64a7..e8b9c54 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -93,6 +93,10 @@ struct vring_virtqueue > */ > unsigned int indirect_thresh; > > + /* Buffers below this size will be allocated from cache */ > + unsigned int indirect_alloc_thresh; > + struct kmem_cache *indirect_cache; > + > /* Host publishes avail event idx */ > bool event; > > @@ -135,7 +139,10 @@ static int vring_add_indirect(struct vring_virtqueue *vq, > unsigned head; > int i; > > - desc = kmalloc((out + in) * sizeof(struct vring_desc), gfp); > + if ((out + in) <= vq->indirect_alloc_thresh) > + desc = kmem_cache_alloc(vq->indirect_cache, gfp); > + else > + desc = kmalloc((out + in) * sizeof(struct vring_desc), gfp); > if (!desc) > return -ENOMEM; So this means that drivers need to know how large each descriptor is to avoid trying to allocate 32Mbyte chunks :) > > @@ -384,8 +391,13 @@ static void detach_buf(struct vring_virtqueue *vq, unsigned int head) > i = head; > > /* Free the indirect table */ > - if (vq->vring.desc[i].flags & VRING_DESC_F_INDIRECT) > - kfree(phys_to_virt(vq->vring.desc[i].addr)); > + if (vq->vring.desc[i].flags & VRING_DESC_F_INDIRECT) { > + if (vq->vring.desc[i].len > vq->indirect_alloc_thresh) This looks wrong. indirect_alloc_thresh is in entries but len is in bytes, isn't it? > + kfree(phys_to_virt(vq->vring.desc[i].addr)); > + else > + kmem_cache_free(vq->indirect_cache, > + phys_to_virt(vq->vring.desc[i].addr)); > + } > > while (vq->vring.desc[i].flags & VRING_DESC_F_NEXT) { > i = vq->vring.desc[i].next; > @@ -654,14 +666,20 @@ struct virtqueue *vring_new_virtqueue(unsigned int num, > vq->last_used_idx = 0; > vq->num_added = 0; > vq->indirect_thresh = 0; > + vq->indirect_alloc_thresh = 0; > + vq->indirect_cache = NULL; > list_add_tail(&vq->vq.list, &vdev->vqs); > #ifdef DEBUG > vq->in_use = false; > vq->last_add_time_valid = false; > #endif > > - if (virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) > + if (virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) { > vq->indirect_thresh = vdev->indirect_thresh; > + vq->indirect_alloc_thresh = vdev->indirect_alloc_thresh; > + if (vq->indirect_alloc_thresh) > + vq->indirect_cache = KMEM_CACHE(vring_desc[vq->indirect_alloc_thresh], > 0); I am not a purist but this line looks way too long. Also - no need to check cache creation succeeded? On failure - disable caching? Also - let's check that values are sane before passing them on? They come from user after all. Also - should not threshold be per VQ? E.g. for -net we do not need the cache for RX unless in legacy big packet mode. > + } > > vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); > > @@ -685,6 +703,8 @@ EXPORT_SYMBOL_GPL(vring_new_virtqueue); > void vring_del_virtqueue(struct virtqueue *vq) > { > list_del(&vq->list); > + if (to_vvq(vq)->indirect_cache) > + kmem_cache_destroy(to_vvq(vq)->indirect_cache); > kfree(to_vvq(vq)); > } > EXPORT_SYMBOL_GPL(vring_del_virtqueue); > diff --git a/include/linux/virtio.h b/include/linux/virtio.h > index 48bc457..3261c02 100644 > --- a/include/linux/virtio.h > +++ b/include/linux/virtio.h > @@ -70,6 +70,7 @@ struct virtio_device { > unsigned long features[1]; > void *priv; > unsigned int indirect_thresh; > + unsigned int indirect_alloc_thresh; > }; > > #define dev_to_virtio(dev) container_of(dev, struct virtio_device, dev) > diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c > index fc93962..3044c86 100644 > --- a/net/9p/trans_virtio.c > +++ b/net/9p/trans_virtio.c > @@ -55,6 +55,9 @@ > static unsigned int indirect_thresh; > module_param(indirect_thresh, uint, S_IRUGO); > > +static unsigned int indirect_alloc_thresh; > +module_param(indirect_alloc_thresh, uint, S_IRUGO); > + > /* a single mutex to manage channel initialization and attachment */ > static DEFINE_MUTEX(virtio_9p_lock); > static DECLARE_WAIT_QUEUE_HEAD(vp_wq); > @@ -505,6 +508,8 @@ static int p9_virtio_probe(struct virtio_device *vdev) > > /* We expect one virtqueue, for requests. */ > vdev->indirect_thresh = indirect_thresh; > + vdev->indirect_alloc_thresh = indirect_alloc_thresh; > + > chan->vq = virtio_find_single_vq(vdev, req_done, "requests"); > if (IS_ERR(chan->vq)) { > err = PTR_ERR(chan->vq); > -- > 1.7.12 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Aug 29, 2012 at 05:03:03PM +0200, Sasha Levin wrote: > On 08/29/2012 01:07 PM, Michael S. Tsirkin wrote: > > On Tue, Aug 28, 2012 at 03:35:00PM +0200, Sasha Levin wrote: > >> On 08/28/2012 03:20 PM, Michael S. Tsirkin wrote: > >>> On Tue, Aug 28, 2012 at 03:04:03PM +0200, Sasha Levin wrote: > >>>> Currently if VIRTIO_RING_F_INDIRECT_DESC is enabled we will > >>>> use indirect descriptors and allocate them using a simple > >>>> kmalloc(). > >>>> > >>>> This patch adds a cache which will allow indirect buffers under > >>>> a configurable size to be allocated from that cache instead. > >>>> > >>>> Signed-off-by: Sasha Levin <levinsasha928@gmail.com> > >>> > >>> I imagine this helps performance? Any numbers? > >> > >> I ran benchmarks on the original RFC, I've re-tested it now and got similar > >> numbers to the original ones (virtio-net using vhost-net, thresh=16): > >> > >> Before: > >> Recv Send Send > >> Socket Socket Message Elapsed > >> Size Size Size Time Throughput > >> bytes bytes bytes secs. 10^6bits/sec > >> > >> 87380 16384 16384 10.00 4512.12 > >> > >> After: > >> Recv Send Send > >> Socket Socket Message Elapsed > >> Size Size Size Time Throughput > >> bytes bytes bytes secs. 10^6bits/sec > >> > >> 87380 16384 16384 10.00 5399.18 > >> > >> > >> Thanks, > >> Sasha > > > > This is with both patches 1 + 2? > > Sorry could you please also test what happens if you apply > > - just patch 1 > > - just patch 2 > > > > Thanks! > > Sure thing! > > I've also re-ran it on a IBM server type host instead of my laptop. Here are the > results: > > Vanilla kernel: > > MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.1 > () port 0 AF_INET > enable_enobufs failed: getprotobyname > Recv Send Send > Socket Socket Message Elapsed > Size Size Size Time Throughput > bytes bytes bytes secs. 10^6bits/sec > > 87380 16384 16384 10.00 7922.72 > > Patch 1, with threshold=16: > > MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.1 > () port 0 AF_INET > enable_enobufs failed: getprotobyname > Recv Send Send > Socket Socket Message Elapsed > Size Size Size Time Throughput > bytes bytes bytes secs. 10^6bits/sec > > 87380 16384 16384 10.00 8415.07 > > Patch 2: > > MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.1 > () port 0 AF_INET > enable_enobufs failed: getprotobyname > Recv Send Send > Socket Socket Message Elapsed > Size Size Size Time Throughput > bytes bytes bytes secs. 10^6bits/sec > > 87380 16384 16384 10.00 8931.05 > > > Note that these are simple tests with netperf listening on one end and a simple > 'netperf -H [host]' within the guest. If there are other tests which may be > interesting please let me know. > > > Thanks, > Sasha And which parameter did you use for patch 2? -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 08/29/2012 05:38 PM, Michael S. Tsirkin wrote: > On Wed, Aug 29, 2012 at 05:03:03PM +0200, Sasha Levin wrote: >> On 08/29/2012 01:07 PM, Michael S. Tsirkin wrote: >>> On Tue, Aug 28, 2012 at 03:35:00PM +0200, Sasha Levin wrote: >>>> On 08/28/2012 03:20 PM, Michael S. Tsirkin wrote: >>>>> On Tue, Aug 28, 2012 at 03:04:03PM +0200, Sasha Levin wrote: >>>>>> Currently if VIRTIO_RING_F_INDIRECT_DESC is enabled we will >>>>>> use indirect descriptors and allocate them using a simple >>>>>> kmalloc(). >>>>>> >>>>>> This patch adds a cache which will allow indirect buffers under >>>>>> a configurable size to be allocated from that cache instead. >>>>>> >>>>>> Signed-off-by: Sasha Levin <levinsasha928@gmail.com> >>>>> >>>>> I imagine this helps performance? Any numbers? >>>> >>>> I ran benchmarks on the original RFC, I've re-tested it now and got similar >>>> numbers to the original ones (virtio-net using vhost-net, thresh=16): >>>> >>>> Before: >>>> Recv Send Send >>>> Socket Socket Message Elapsed >>>> Size Size Size Time Throughput >>>> bytes bytes bytes secs. 10^6bits/sec >>>> >>>> 87380 16384 16384 10.00 4512.12 >>>> >>>> After: >>>> Recv Send Send >>>> Socket Socket Message Elapsed >>>> Size Size Size Time Throughput >>>> bytes bytes bytes secs. 10^6bits/sec >>>> >>>> 87380 16384 16384 10.00 5399.18 >>>> >>>> >>>> Thanks, >>>> Sasha >>> >>> This is with both patches 1 + 2? >>> Sorry could you please also test what happens if you apply >>> - just patch 1 >>> - just patch 2 >>> >>> Thanks! >> >> Sure thing! >> >> I've also re-ran it on a IBM server type host instead of my laptop. Here are the >> results: >> >> Vanilla kernel: >> >> MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.1 >> () port 0 AF_INET >> enable_enobufs failed: getprotobyname >> Recv Send Send >> Socket Socket Message Elapsed >> Size Size Size Time Throughput >> bytes bytes bytes secs. 10^6bits/sec >> >> 87380 16384 16384 10.00 7922.72 >> >> Patch 1, with threshold=16: >> >> MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.1 >> () port 0 AF_INET >> enable_enobufs failed: getprotobyname >> Recv Send Send >> Socket Socket Message Elapsed >> Size Size Size Time Throughput >> bytes bytes bytes secs. 10^6bits/sec >> >> 87380 16384 16384 10.00 8415.07 >> >> Patch 2: >> >> MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.33.1 >> () port 0 AF_INET >> enable_enobufs failed: getprotobyname >> Recv Send Send >> Socket Socket Message Elapsed >> Size Size Size Time Throughput >> bytes bytes bytes secs. 10^6bits/sec >> >> 87380 16384 16384 10.00 8931.05 >> >> >> Note that these are simple tests with netperf listening on one end and a simple >> 'netperf -H [host]' within the guest. If there are other tests which may be >> interesting please let me know. >> >> >> Thanks, >> Sasha > > > And which parameter did you use for patch 2? > Same as in the first one, 16, the only difference in patch 2 is that we use a kmemcache, so there's no point in changing the threshold vs patch 1. Thanks, Sasha -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 08/29/2012 05:38 PM, Michael S. Tsirkin wrote: > On Tue, Aug 28, 2012 at 03:04:03PM +0200, Sasha Levin wrote: >> Currently if VIRTIO_RING_F_INDIRECT_DESC is enabled we will >> use indirect descriptors and allocate them using a simple >> kmalloc(). >> >> This patch adds a cache which will allow indirect buffers under >> a configurable size to be allocated from that cache instead. >> >> Signed-off-by: Sasha Levin <levinsasha928@gmail.com> > > The API is ugly - how does driver know what to set? > Is this a typical request size? Then let's call it that. We've discussed it during the RFC phase, the idea is that we don't know what would be a good number to use as threshold - which is why I'd like to keep it disabled as default until it gets more serious tests. The driver doesn't know what to set, the plan was to make it a dynamic algorithms which would change it based on current load. Since I can't really do testing which will provide the correct values for that, the decision was to do it this way as the first stage and modify it later. > Also this is really per VQ, right? Right, we keep it per-device at this stage to keep it simple. > What is a good default for net? I guess max sg? I think that it depends on the workload. I'd say we should keep the default to 0 (disabled) unless we can have a good way to adjust it to the load. >> --- >> >> Changes in v2: >> >> - Free correctly indirect buffers. >> >> drivers/block/virtio_blk.c | 4 ++++ >> drivers/char/hw_random/virtio-rng.c | 4 ++++ >> drivers/char/virtio_console.c | 4 ++++ >> drivers/net/virtio_net.c | 4 ++++ >> drivers/virtio/virtio_balloon.c | 4 ++++ >> drivers/virtio/virtio_ring.c | 28 ++++++++++++++++++++++++---- >> include/linux/virtio.h | 1 + >> net/9p/trans_virtio.c | 5 +++++ >> 8 files changed, 50 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c >> index 13b8ae9..7f670af 100644 >> --- a/drivers/block/virtio_blk.c >> +++ b/drivers/block/virtio_blk.c >> @@ -25,6 +25,9 @@ struct workqueue_struct *virtblk_wq; >> static unsigned int indirect_thresh; >> module_param(indirect_thresh, uint, S_IRUGO); >> >> +static unsigned int indirect_alloc_thresh; >> +module_param(indirect_alloc_thresh, uint, S_IRUGO); >> + >> struct virtio_blk >> { >> struct virtio_device *vdev; >> @@ -739,6 +742,7 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) >> INIT_WORK(&vblk->config_work, virtblk_config_changed_work); >> vblk->config_enable = true; >> vdev->indirect_thresh = indirect_thresh; >> + vdev->indirect_alloc_thresh = indirect_alloc_thresh; >> >> err = init_vq(vblk); >> if (err) >> diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c >> index 02d8421..8475ece 100644 >> --- a/drivers/char/hw_random/virtio-rng.c >> +++ b/drivers/char/hw_random/virtio-rng.c >> @@ -28,6 +28,9 @@ >> static unsigned int indirect_thresh; >> module_param(indirect_thresh, uint, S_IRUGO); >> >> +static unsigned int indirect_alloc_thresh; >> +module_param(indirect_alloc_thresh, uint, S_IRUGO); >> + >> static struct virtqueue *vq; >> static unsigned int data_avail; >> static DECLARE_COMPLETION(have_data); >> @@ -97,6 +100,7 @@ static int probe_common(struct virtio_device *vdev) >> >> /* We expect a single virtqueue. */ >> vdev->indirect_thresh = indirect_thresh; >> + vdev->indirect_alloc_thresh = indirect_alloc_thresh; >> vq = virtio_find_single_vq(vdev, random_recv_done, "input"); >> if (IS_ERR(vq)) >> return PTR_ERR(vq); >> diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c >> index fc14e7f..c6f24a7 100644 >> --- a/drivers/char/virtio_console.c >> +++ b/drivers/char/virtio_console.c >> @@ -42,6 +42,9 @@ >> static unsigned int indirect_thresh; >> module_param(indirect_thresh, uint, S_IRUGO); >> >> +static unsigned int indirect_alloc_thresh; >> +module_param(indirect_alloc_thresh, uint, S_IRUGO); >> + >> /* >> * This is a global struct for storing common data for all the devices >> * this driver handles. >> @@ -1891,6 +1894,7 @@ static int __devinit virtcons_probe(struct virtio_device *vdev) >> &portdev->config.max_nr_ports) == 0) >> multiport = true; >> vdev->indirect_thresh = indirect_thresh; >> + vdev->indirect_alloc_thresh = indirect_alloc_thresh; >> >> err = init_vqs(portdev); >> if (err < 0) { >> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c >> index 64a8321..c091efd 100644 >> --- a/drivers/net/virtio_net.c >> +++ b/drivers/net/virtio_net.c >> @@ -37,6 +37,9 @@ module_param(gso, bool, 0444); >> static unsigned int indirect_thresh; >> module_param(indirect_thresh, uint, S_IRUGO); >> >> +static unsigned int indirect_alloc_thresh; >> +module_param(indirect_alloc_thresh, uint, S_IRUGO); >> + >> /* FIXME: MTU in config. */ >> #define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN) >> #define GOOD_COPY_LEN 128 >> @@ -1132,6 +1135,7 @@ static int virtnet_probe(struct virtio_device *vdev) >> if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF)) >> vi->mergeable_rx_bufs = true; >> vdev->indirect_thresh = indirect_thresh; >> + vdev->indirect_alloc_thresh = indirect_alloc_thresh; >> >> err = init_vqs(vi); >> if (err) >> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c >> index fce7347..ccf87db 100644 >> --- a/drivers/virtio/virtio_balloon.c >> +++ b/drivers/virtio/virtio_balloon.c >> @@ -38,6 +38,9 @@ >> static unsigned int indirect_thresh; >> module_param(indirect_thresh, uint, S_IRUGO); >> >> +static unsigned int indirect_alloc_thresh; >> +module_param(indirect_alloc_thresh, uint, S_IRUGO); >> + >> struct virtio_balloon >> { >> struct virtio_device *vdev; >> @@ -360,6 +363,7 @@ static int virtballoon_probe(struct virtio_device *vdev) >> vb->vdev = vdev; >> vb->need_stats_update = 0; >> vdev->indirect_thresh = indirect_thresh; >> + vdev->indirect_alloc_thresh = indirect_alloc_thresh; >> >> err = init_vqs(vb); >> if (err) >> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c >> index 99a64a7..e8b9c54 100644 >> --- a/drivers/virtio/virtio_ring.c >> +++ b/drivers/virtio/virtio_ring.c >> @@ -93,6 +93,10 @@ struct vring_virtqueue >> */ >> unsigned int indirect_thresh; >> >> + /* Buffers below this size will be allocated from cache */ >> + unsigned int indirect_alloc_thresh; >> + struct kmem_cache *indirect_cache; >> + >> /* Host publishes avail event idx */ >> bool event; >> >> @@ -135,7 +139,10 @@ static int vring_add_indirect(struct vring_virtqueue *vq, >> unsigned head; >> int i; >> >> - desc = kmalloc((out + in) * sizeof(struct vring_desc), gfp); >> + if ((out + in) <= vq->indirect_alloc_thresh) >> + desc = kmem_cache_alloc(vq->indirect_cache, gfp); >> + else >> + desc = kmalloc((out + in) * sizeof(struct vring_desc), gfp); >> if (!desc) >> return -ENOMEM; > > So this means that drivers need to know how large each > descriptor is to avoid trying to allocate 32Mbyte chunks :) Right, this interface isn't perfect and would hopefully be removed in favour of a dynamic algorithm in the driver. >> >> @@ -384,8 +391,13 @@ static void detach_buf(struct vring_virtqueue *vq, unsigned int head) >> i = head; >> >> /* Free the indirect table */ >> - if (vq->vring.desc[i].flags & VRING_DESC_F_INDIRECT) >> - kfree(phys_to_virt(vq->vring.desc[i].addr)); >> + if (vq->vring.desc[i].flags & VRING_DESC_F_INDIRECT) { >> + if (vq->vring.desc[i].len > vq->indirect_alloc_thresh) > > This looks wrong. indirect_alloc_thresh is in entries but len is in > bytes, isn't it? Uh, yes. It's supposed to be '.len/sizeof(struct vring_desc)'. >> + kfree(phys_to_virt(vq->vring.desc[i].addr)); >> + else >> + kmem_cache_free(vq->indirect_cache, >> + phys_to_virt(vq->vring.desc[i].addr)); >> + } >> >> while (vq->vring.desc[i].flags & VRING_DESC_F_NEXT) { >> i = vq->vring.desc[i].next; >> @@ -654,14 +666,20 @@ struct virtqueue *vring_new_virtqueue(unsigned int num, >> vq->last_used_idx = 0; >> vq->num_added = 0; >> vq->indirect_thresh = 0; >> + vq->indirect_alloc_thresh = 0; >> + vq->indirect_cache = NULL; >> list_add_tail(&vq->vq.list, &vdev->vqs); >> #ifdef DEBUG >> vq->in_use = false; >> vq->last_add_time_valid = false; >> #endif >> >> - if (virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) >> + if (virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) { >> vq->indirect_thresh = vdev->indirect_thresh; >> + vq->indirect_alloc_thresh = vdev->indirect_alloc_thresh; >> + if (vq->indirect_alloc_thresh) >> + vq->indirect_cache = KMEM_CACHE(vring_desc[vq->indirect_alloc_thresh], >> 0); > > I am not a purist but this line looks way too long. > Also - no need to check cache creation succeeded? > On failure - disable caching? > > Also - let's check that values are sane before passing them on? > They come from user after all. will fix these two. > Also - should not threshold be per VQ? E.g. for -net we do not > need the cache for RX unless in legacy big packet mode. We've discussed it two months ago over IRC (at least thats what I have in my notes) - the plan was to keep it simple per-device until something more advanced to deal with the threshold shows up. Thanks, Sasha > >> + } >> >> vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); >> >> @@ -685,6 +703,8 @@ EXPORT_SYMBOL_GPL(vring_new_virtqueue); >> void vring_del_virtqueue(struct virtqueue *vq) >> { >> list_del(&vq->list); >> + if (to_vvq(vq)->indirect_cache) >> + kmem_cache_destroy(to_vvq(vq)->indirect_cache); >> kfree(to_vvq(vq)); >> } >> EXPORT_SYMBOL_GPL(vring_del_virtqueue); >> diff --git a/include/linux/virtio.h b/include/linux/virtio.h >> index 48bc457..3261c02 100644 >> --- a/include/linux/virtio.h >> +++ b/include/linux/virtio.h >> @@ -70,6 +70,7 @@ struct virtio_device { >> unsigned long features[1]; >> void *priv; >> unsigned int indirect_thresh; >> + unsigned int indirect_alloc_thresh; >> }; >> >> #define dev_to_virtio(dev) container_of(dev, struct virtio_device, dev) >> diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c >> index fc93962..3044c86 100644 >> --- a/net/9p/trans_virtio.c >> +++ b/net/9p/trans_virtio.c >> @@ -55,6 +55,9 @@ >> static unsigned int indirect_thresh; >> module_param(indirect_thresh, uint, S_IRUGO); >> >> +static unsigned int indirect_alloc_thresh; >> +module_param(indirect_alloc_thresh, uint, S_IRUGO); >> + >> /* a single mutex to manage channel initialization and attachment */ >> static DEFINE_MUTEX(virtio_9p_lock); >> static DECLARE_WAIT_QUEUE_HEAD(vp_wq); >> @@ -505,6 +508,8 @@ static int p9_virtio_probe(struct virtio_device *vdev) >> >> /* We expect one virtqueue, for requests. */ >> vdev->indirect_thresh = indirect_thresh; >> + vdev->indirect_alloc_thresh = indirect_alloc_thresh; >> + >> chan->vq = virtio_find_single_vq(vdev, req_done, "requests"); >> if (IS_ERR(chan->vq)) { >> err = PTR_ERR(chan->vq); >> -- >> 1.7.12 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Aug 29, 2012 at 07:14:01PM +0200, Sasha Levin wrote: > On 08/29/2012 05:38 PM, Michael S. Tsirkin wrote: > > On Tue, Aug 28, 2012 at 03:04:03PM +0200, Sasha Levin wrote: > >> Currently if VIRTIO_RING_F_INDIRECT_DESC is enabled we will > >> use indirect descriptors and allocate them using a simple > >> kmalloc(). > >> > >> This patch adds a cache which will allow indirect buffers under > >> a configurable size to be allocated from that cache instead. > >> > >> Signed-off-by: Sasha Levin <levinsasha928@gmail.com> > > > > The API is ugly - how does driver know what to set? > > Is this a typical request size? Then let's call it that. > > We've discussed it during the RFC phase, the idea is that we don't know what > would be a good number to use as threshold - which is why I'd like to keep it > disabled as default until it gets more serious tests. > > The driver doesn't know what to set, the plan was to make it a dynamic > algorithms which would change it based on current load. Since I can't really do > testing which will provide the correct values for that, the decision was to do > it this way as the first stage and modify it later. > > > Also this is really per VQ, right? > > Right, we keep it per-device at this stage to keep it simple. > > > What is a good default for net? I guess max sg? > > I think that it depends on the workload. I'd say we should keep the default to 0 > (disabled) unless we can have a good way to adjust it to the load. For *all* drivers? Then it is mostly useless. No one has the time to tweak module parameters in real life. For virtio-net, 16+1 is not too much and ensures we always use the cache. If that works better than 0 I would say run with 17. > >> --- > >> > >> Changes in v2: > >> > >> - Free correctly indirect buffers. > >> > >> drivers/block/virtio_blk.c | 4 ++++ > >> drivers/char/hw_random/virtio-rng.c | 4 ++++ > >> drivers/char/virtio_console.c | 4 ++++ > >> drivers/net/virtio_net.c | 4 ++++ > >> drivers/virtio/virtio_balloon.c | 4 ++++ > >> drivers/virtio/virtio_ring.c | 28 ++++++++++++++++++++++++---- > >> include/linux/virtio.h | 1 + > >> net/9p/trans_virtio.c | 5 +++++ > >> 8 files changed, 50 insertions(+), 4 deletions(-) > >> > >> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c > >> index 13b8ae9..7f670af 100644 > >> --- a/drivers/block/virtio_blk.c > >> +++ b/drivers/block/virtio_blk.c > >> @@ -25,6 +25,9 @@ struct workqueue_struct *virtblk_wq; > >> static unsigned int indirect_thresh; > >> module_param(indirect_thresh, uint, S_IRUGO); > >> > >> +static unsigned int indirect_alloc_thresh; > >> +module_param(indirect_alloc_thresh, uint, S_IRUGO); > >> + > >> struct virtio_blk > >> { > >> struct virtio_device *vdev; > >> @@ -739,6 +742,7 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) > >> INIT_WORK(&vblk->config_work, virtblk_config_changed_work); > >> vblk->config_enable = true; > >> vdev->indirect_thresh = indirect_thresh; > >> + vdev->indirect_alloc_thresh = indirect_alloc_thresh; > >> > >> err = init_vq(vblk); > >> if (err) > >> diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c > >> index 02d8421..8475ece 100644 > >> --- a/drivers/char/hw_random/virtio-rng.c > >> +++ b/drivers/char/hw_random/virtio-rng.c > >> @@ -28,6 +28,9 @@ > >> static unsigned int indirect_thresh; > >> module_param(indirect_thresh, uint, S_IRUGO); > >> > >> +static unsigned int indirect_alloc_thresh; > >> +module_param(indirect_alloc_thresh, uint, S_IRUGO); > >> + > >> static struct virtqueue *vq; > >> static unsigned int data_avail; > >> static DECLARE_COMPLETION(have_data); > >> @@ -97,6 +100,7 @@ static int probe_common(struct virtio_device *vdev) > >> > >> /* We expect a single virtqueue. */ > >> vdev->indirect_thresh = indirect_thresh; > >> + vdev->indirect_alloc_thresh = indirect_alloc_thresh; > >> vq = virtio_find_single_vq(vdev, random_recv_done, "input"); > >> if (IS_ERR(vq)) > >> return PTR_ERR(vq); > >> diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c > >> index fc14e7f..c6f24a7 100644 > >> --- a/drivers/char/virtio_console.c > >> +++ b/drivers/char/virtio_console.c > >> @@ -42,6 +42,9 @@ > >> static unsigned int indirect_thresh; > >> module_param(indirect_thresh, uint, S_IRUGO); > >> > >> +static unsigned int indirect_alloc_thresh; > >> +module_param(indirect_alloc_thresh, uint, S_IRUGO); > >> + > >> /* > >> * This is a global struct for storing common data for all the devices > >> * this driver handles. > >> @@ -1891,6 +1894,7 @@ static int __devinit virtcons_probe(struct virtio_device *vdev) > >> &portdev->config.max_nr_ports) == 0) > >> multiport = true; > >> vdev->indirect_thresh = indirect_thresh; > >> + vdev->indirect_alloc_thresh = indirect_alloc_thresh; > >> > >> err = init_vqs(portdev); > >> if (err < 0) { > >> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > >> index 64a8321..c091efd 100644 > >> --- a/drivers/net/virtio_net.c > >> +++ b/drivers/net/virtio_net.c > >> @@ -37,6 +37,9 @@ module_param(gso, bool, 0444); > >> static unsigned int indirect_thresh; > >> module_param(indirect_thresh, uint, S_IRUGO); > >> > >> +static unsigned int indirect_alloc_thresh; > >> +module_param(indirect_alloc_thresh, uint, S_IRUGO); > >> + > >> /* FIXME: MTU in config. */ > >> #define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN) > >> #define GOOD_COPY_LEN 128 > >> @@ -1132,6 +1135,7 @@ static int virtnet_probe(struct virtio_device *vdev) > >> if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF)) > >> vi->mergeable_rx_bufs = true; > >> vdev->indirect_thresh = indirect_thresh; > >> + vdev->indirect_alloc_thresh = indirect_alloc_thresh; > >> > >> err = init_vqs(vi); > >> if (err) > >> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > >> index fce7347..ccf87db 100644 > >> --- a/drivers/virtio/virtio_balloon.c > >> +++ b/drivers/virtio/virtio_balloon.c > >> @@ -38,6 +38,9 @@ > >> static unsigned int indirect_thresh; > >> module_param(indirect_thresh, uint, S_IRUGO); > >> > >> +static unsigned int indirect_alloc_thresh; > >> +module_param(indirect_alloc_thresh, uint, S_IRUGO); > >> + > >> struct virtio_balloon > >> { > >> struct virtio_device *vdev; > >> @@ -360,6 +363,7 @@ static int virtballoon_probe(struct virtio_device *vdev) > >> vb->vdev = vdev; > >> vb->need_stats_update = 0; > >> vdev->indirect_thresh = indirect_thresh; > >> + vdev->indirect_alloc_thresh = indirect_alloc_thresh; > >> > >> err = init_vqs(vb); > >> if (err) > >> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > >> index 99a64a7..e8b9c54 100644 > >> --- a/drivers/virtio/virtio_ring.c > >> +++ b/drivers/virtio/virtio_ring.c > >> @@ -93,6 +93,10 @@ struct vring_virtqueue > >> */ > >> unsigned int indirect_thresh; > >> > >> + /* Buffers below this size will be allocated from cache */ > >> + unsigned int indirect_alloc_thresh; > >> + struct kmem_cache *indirect_cache; > >> + > >> /* Host publishes avail event idx */ > >> bool event; > >> > >> @@ -135,7 +139,10 @@ static int vring_add_indirect(struct vring_virtqueue *vq, > >> unsigned head; > >> int i; > >> > >> - desc = kmalloc((out + in) * sizeof(struct vring_desc), gfp); > >> + if ((out + in) <= vq->indirect_alloc_thresh) > >> + desc = kmem_cache_alloc(vq->indirect_cache, gfp); > >> + else > >> + desc = kmalloc((out + in) * sizeof(struct vring_desc), gfp); > >> if (!desc) > >> return -ENOMEM; > > > > So this means that drivers need to know how large each > > descriptor is to avoid trying to allocate 32Mbyte chunks :) > > Right, this interface isn't perfect and would hopefully be removed in favour of > a dynamic algorithm in the driver. > > >> > >> @@ -384,8 +391,13 @@ static void detach_buf(struct vring_virtqueue *vq, unsigned int head) > >> i = head; > >> > >> /* Free the indirect table */ > >> - if (vq->vring.desc[i].flags & VRING_DESC_F_INDIRECT) > >> - kfree(phys_to_virt(vq->vring.desc[i].addr)); > >> + if (vq->vring.desc[i].flags & VRING_DESC_F_INDIRECT) { > >> + if (vq->vring.desc[i].len > vq->indirect_alloc_thresh) > > > > This looks wrong. indirect_alloc_thresh is in entries but len is in > > bytes, isn't it? > > Uh, yes. It's supposed to be '.len/sizeof(struct vring_desc)'. > > >> + kfree(phys_to_virt(vq->vring.desc[i].addr)); > >> + else > >> + kmem_cache_free(vq->indirect_cache, > >> + phys_to_virt(vq->vring.desc[i].addr)); > >> + } > >> > >> while (vq->vring.desc[i].flags & VRING_DESC_F_NEXT) { > >> i = vq->vring.desc[i].next; > >> @@ -654,14 +666,20 @@ struct virtqueue *vring_new_virtqueue(unsigned int num, > >> vq->last_used_idx = 0; > >> vq->num_added = 0; > >> vq->indirect_thresh = 0; > >> + vq->indirect_alloc_thresh = 0; > >> + vq->indirect_cache = NULL; > >> list_add_tail(&vq->vq.list, &vdev->vqs); > >> #ifdef DEBUG > >> vq->in_use = false; > >> vq->last_add_time_valid = false; > >> #endif > >> > >> - if (virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) > >> + if (virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) { > >> vq->indirect_thresh = vdev->indirect_thresh; > >> + vq->indirect_alloc_thresh = vdev->indirect_alloc_thresh; > >> + if (vq->indirect_alloc_thresh) > >> + vq->indirect_cache = KMEM_CACHE(vring_desc[vq->indirect_alloc_thresh], > >> 0); > > > > I am not a purist but this line looks way too long. > > Also - no need to check cache creation succeeded? > > On failure - disable caching? > > > > Also - let's check that values are sane before passing them on? > > They come from user after all. > > will fix these two. > > > Also - should not threshold be per VQ? E.g. for -net we do not > > need the cache for RX unless in legacy big packet mode. > > We've discussed it two months ago over IRC (at least thats what I have in my > notes) - the plan was to keep it simple per-device until something more advanced > to deal with the threshold shows up. > > > Thanks, > Sasha > > > > >> + } > >> > >> vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); > >> > >> @@ -685,6 +703,8 @@ EXPORT_SYMBOL_GPL(vring_new_virtqueue); > >> void vring_del_virtqueue(struct virtqueue *vq) > >> { > >> list_del(&vq->list); > >> + if (to_vvq(vq)->indirect_cache) > >> + kmem_cache_destroy(to_vvq(vq)->indirect_cache); > >> kfree(to_vvq(vq)); > >> } > >> EXPORT_SYMBOL_GPL(vring_del_virtqueue); > >> diff --git a/include/linux/virtio.h b/include/linux/virtio.h > >> index 48bc457..3261c02 100644 > >> --- a/include/linux/virtio.h > >> +++ b/include/linux/virtio.h > >> @@ -70,6 +70,7 @@ struct virtio_device { > >> unsigned long features[1]; > >> void *priv; > >> unsigned int indirect_thresh; > >> + unsigned int indirect_alloc_thresh; > >> }; > >> > >> #define dev_to_virtio(dev) container_of(dev, struct virtio_device, dev) > >> diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c > >> index fc93962..3044c86 100644 > >> --- a/net/9p/trans_virtio.c > >> +++ b/net/9p/trans_virtio.c > >> @@ -55,6 +55,9 @@ > >> static unsigned int indirect_thresh; > >> module_param(indirect_thresh, uint, S_IRUGO); > >> > >> +static unsigned int indirect_alloc_thresh; > >> +module_param(indirect_alloc_thresh, uint, S_IRUGO); > >> + > >> /* a single mutex to manage channel initialization and attachment */ > >> static DEFINE_MUTEX(virtio_9p_lock); > >> static DECLARE_WAIT_QUEUE_HEAD(vp_wq); > >> @@ -505,6 +508,8 @@ static int p9_virtio_probe(struct virtio_device *vdev) > >> > >> /* We expect one virtqueue, for requests. */ > >> vdev->indirect_thresh = indirect_thresh; > >> + vdev->indirect_alloc_thresh = indirect_alloc_thresh; > >> + > >> chan->vq = virtio_find_single_vq(vdev, req_done, "requests"); > >> if (IS_ERR(chan->vq)) { > >> err = PTR_ERR(chan->vq); > >> -- > >> 1.7.12 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 08/29/2012 08:12 PM, Michael S. Tsirkin wrote: >>> > > What is a good default for net? I guess max sg? >> > >> > I think that it depends on the workload. I'd say we should keep the default to 0 >> > (disabled) unless we can have a good way to adjust it to the load. > For *all* drivers? > > Then it is mostly useless. No one has the time to tweak module > parameters in real life. > > For virtio-net, 16+1 is not too much and ensures we always > use the cache. > > If that works better than 0 I would say run with 17. I was being extra-cautious with leaving it disabled until specifically enabled because I assumed that this would be one of the first comments I'll get if it was enabled by default :) If you're comfortable with setting it to a sane default like 17, I'm perfectly fine with that as well. Thanks, Sasha -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Aug 29, 2012 at 10:46:19PM +0200, Sasha Levin wrote: > On 08/29/2012 08:12 PM, Michael S. Tsirkin wrote: > >>> > > What is a good default for net? I guess max sg? > >> > > >> > I think that it depends on the workload. I'd say we should keep the default to 0 > >> > (disabled) unless we can have a good way to adjust it to the load. > > For *all* drivers? > > > > Then it is mostly useless. No one has the time to tweak module > > parameters in real life. > > > > For virtio-net, 16+1 is not too much and ensures we always > > use the cache. > > > > If that works better than 0 I would say run with 17. > > I was being extra-cautious with leaving it disabled until specifically enabled > because I assumed that this would be one of the first comments I'll get if it > was enabled by default :) > > If you're comfortable with setting it to a sane default like 17, I'm perfectly > fine with that as well. > > > Thanks, > Sasha If our testing shows it helps and does not trigger regressions, then why not? module params are mostly there for developers. They are not all that helpful to users. > _______________________________________________ > Virtualization mailing list > Virtualization@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/virtualization -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 08/29/2012 05:14 PM, Michael S. Tsirkin wrote: >> > Note that these are simple tests with netperf listening on one end and a simple >> > 'netperf -H [host]' within the guest. If there are other tests which may be >> > interesting please let me know. > Checking that host CPU utilization did not jump would be nice. > E.g. measure BW/host CPU. Tested it now, no change in CPU between the original, patch 1 and patch 2. Thanks, Sasha -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 13b8ae9..7f670af 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -25,6 +25,9 @@ struct workqueue_struct *virtblk_wq; static unsigned int indirect_thresh; module_param(indirect_thresh, uint, S_IRUGO); +static unsigned int indirect_alloc_thresh; +module_param(indirect_alloc_thresh, uint, S_IRUGO); + struct virtio_blk { struct virtio_device *vdev; @@ -739,6 +742,7 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) INIT_WORK(&vblk->config_work, virtblk_config_changed_work); vblk->config_enable = true; vdev->indirect_thresh = indirect_thresh; + vdev->indirect_alloc_thresh = indirect_alloc_thresh; err = init_vq(vblk); if (err) diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c index 02d8421..8475ece 100644 --- a/drivers/char/hw_random/virtio-rng.c +++ b/drivers/char/hw_random/virtio-rng.c @@ -28,6 +28,9 @@ static unsigned int indirect_thresh; module_param(indirect_thresh, uint, S_IRUGO); +static unsigned int indirect_alloc_thresh; +module_param(indirect_alloc_thresh, uint, S_IRUGO); + static struct virtqueue *vq; static unsigned int data_avail; static DECLARE_COMPLETION(have_data); @@ -97,6 +100,7 @@ static int probe_common(struct virtio_device *vdev) /* We expect a single virtqueue. */ vdev->indirect_thresh = indirect_thresh; + vdev->indirect_alloc_thresh = indirect_alloc_thresh; vq = virtio_find_single_vq(vdev, random_recv_done, "input"); if (IS_ERR(vq)) return PTR_ERR(vq); diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index fc14e7f..c6f24a7 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -42,6 +42,9 @@ static unsigned int indirect_thresh; module_param(indirect_thresh, uint, S_IRUGO); +static unsigned int indirect_alloc_thresh; +module_param(indirect_alloc_thresh, uint, S_IRUGO); + /* * This is a global struct for storing common data for all the devices * this driver handles. @@ -1891,6 +1894,7 @@ static int __devinit virtcons_probe(struct virtio_device *vdev) &portdev->config.max_nr_ports) == 0) multiport = true; vdev->indirect_thresh = indirect_thresh; + vdev->indirect_alloc_thresh = indirect_alloc_thresh; err = init_vqs(portdev); if (err < 0) { diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 64a8321..c091efd 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -37,6 +37,9 @@ module_param(gso, bool, 0444); static unsigned int indirect_thresh; module_param(indirect_thresh, uint, S_IRUGO); +static unsigned int indirect_alloc_thresh; +module_param(indirect_alloc_thresh, uint, S_IRUGO); + /* FIXME: MTU in config. */ #define MAX_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN) #define GOOD_COPY_LEN 128 @@ -1132,6 +1135,7 @@ static int virtnet_probe(struct virtio_device *vdev) if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF)) vi->mergeable_rx_bufs = true; vdev->indirect_thresh = indirect_thresh; + vdev->indirect_alloc_thresh = indirect_alloc_thresh; err = init_vqs(vi); if (err) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index fce7347..ccf87db 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -38,6 +38,9 @@ static unsigned int indirect_thresh; module_param(indirect_thresh, uint, S_IRUGO); +static unsigned int indirect_alloc_thresh; +module_param(indirect_alloc_thresh, uint, S_IRUGO); + struct virtio_balloon { struct virtio_device *vdev; @@ -360,6 +363,7 @@ static int virtballoon_probe(struct virtio_device *vdev) vb->vdev = vdev; vb->need_stats_update = 0; vdev->indirect_thresh = indirect_thresh; + vdev->indirect_alloc_thresh = indirect_alloc_thresh; err = init_vqs(vb); if (err) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 99a64a7..e8b9c54 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -93,6 +93,10 @@ struct vring_virtqueue */ unsigned int indirect_thresh; + /* Buffers below this size will be allocated from cache */ + unsigned int indirect_alloc_thresh; + struct kmem_cache *indirect_cache; + /* Host publishes avail event idx */ bool event; @@ -135,7 +139,10 @@ static int vring_add_indirect(struct vring_virtqueue *vq, unsigned head; int i; - desc = kmalloc((out + in) * sizeof(struct vring_desc), gfp); + if ((out + in) <= vq->indirect_alloc_thresh) + desc = kmem_cache_alloc(vq->indirect_cache, gfp); + else + desc = kmalloc((out + in) * sizeof(struct vring_desc), gfp); if (!desc) return -ENOMEM; @@ -384,8 +391,13 @@ static void detach_buf(struct vring_virtqueue *vq, unsigned int head) i = head; /* Free the indirect table */ - if (vq->vring.desc[i].flags & VRING_DESC_F_INDIRECT) - kfree(phys_to_virt(vq->vring.desc[i].addr)); + if (vq->vring.desc[i].flags & VRING_DESC_F_INDIRECT) { + if (vq->vring.desc[i].len > vq->indirect_alloc_thresh) + kfree(phys_to_virt(vq->vring.desc[i].addr)); + else + kmem_cache_free(vq->indirect_cache, + phys_to_virt(vq->vring.desc[i].addr)); + } while (vq->vring.desc[i].flags & VRING_DESC_F_NEXT) { i = vq->vring.desc[i].next; @@ -654,14 +666,20 @@ struct virtqueue *vring_new_virtqueue(unsigned int num, vq->last_used_idx = 0; vq->num_added = 0; vq->indirect_thresh = 0; + vq->indirect_alloc_thresh = 0; + vq->indirect_cache = NULL; list_add_tail(&vq->vq.list, &vdev->vqs); #ifdef DEBUG vq->in_use = false; vq->last_add_time_valid = false; #endif - if (virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) + if (virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) { vq->indirect_thresh = vdev->indirect_thresh; + vq->indirect_alloc_thresh = vdev->indirect_alloc_thresh; + if (vq->indirect_alloc_thresh) + vq->indirect_cache = KMEM_CACHE(vring_desc[vq->indirect_alloc_thresh], 0); + } vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); @@ -685,6 +703,8 @@ EXPORT_SYMBOL_GPL(vring_new_virtqueue); void vring_del_virtqueue(struct virtqueue *vq) { list_del(&vq->list); + if (to_vvq(vq)->indirect_cache) + kmem_cache_destroy(to_vvq(vq)->indirect_cache); kfree(to_vvq(vq)); } EXPORT_SYMBOL_GPL(vring_del_virtqueue); diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 48bc457..3261c02 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -70,6 +70,7 @@ struct virtio_device { unsigned long features[1]; void *priv; unsigned int indirect_thresh; + unsigned int indirect_alloc_thresh; }; #define dev_to_virtio(dev) container_of(dev, struct virtio_device, dev) diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c index fc93962..3044c86 100644 --- a/net/9p/trans_virtio.c +++ b/net/9p/trans_virtio.c @@ -55,6 +55,9 @@ static unsigned int indirect_thresh; module_param(indirect_thresh, uint, S_IRUGO); +static unsigned int indirect_alloc_thresh; +module_param(indirect_alloc_thresh, uint, S_IRUGO); + /* a single mutex to manage channel initialization and attachment */ static DEFINE_MUTEX(virtio_9p_lock); static DECLARE_WAIT_QUEUE_HEAD(vp_wq); @@ -505,6 +508,8 @@ static int p9_virtio_probe(struct virtio_device *vdev) /* We expect one virtqueue, for requests. */ vdev->indirect_thresh = indirect_thresh; + vdev->indirect_alloc_thresh = indirect_alloc_thresh; + chan->vq = virtio_find_single_vq(vdev, req_done, "requests"); if (IS_ERR(chan->vq)) { err = PTR_ERR(chan->vq);
Currently if VIRTIO_RING_F_INDIRECT_DESC is enabled we will use indirect descriptors and allocate them using a simple kmalloc(). This patch adds a cache which will allow indirect buffers under a configurable size to be allocated from that cache instead. Signed-off-by: Sasha Levin <levinsasha928@gmail.com> --- Changes in v2: - Free correctly indirect buffers. drivers/block/virtio_blk.c | 4 ++++ drivers/char/hw_random/virtio-rng.c | 4 ++++ drivers/char/virtio_console.c | 4 ++++ drivers/net/virtio_net.c | 4 ++++ drivers/virtio/virtio_balloon.c | 4 ++++ drivers/virtio/virtio_ring.c | 28 ++++++++++++++++++++++++---- include/linux/virtio.h | 1 + net/9p/trans_virtio.c | 5 +++++ 8 files changed, 50 insertions(+), 4 deletions(-)