From: Jean-Mickael Guerin <jean-mickael.guerin@6wind.com>
To: Sasha Levin <levinsasha928@gmail.com>
Cc: mst@redhat.com, asias@redhat.com, stefanha@gmail.com,
kvm@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: Re: [RFC 2/2] virtio-ring: Allocate indirect buffers from cache when possible
Date: Tue, 19 Jun 2012 07:51:17 +0200 [thread overview]
Message-ID: <4FE01355.6070909@6wind.com> (raw)
In-Reply-To: <1340028598-10142-2-git-send-email-levinsasha928@gmail.com>
On 18/06/2012 16:09, 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>
> ---
> 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 a2c8d97..3c6d1bd 100644
> --- a/drivers/block/virtio_blk.c
> +++ b/drivers/block/virtio_blk.c
> @@ -22,6 +22,9 @@ struct workqueue_struct *virtblk_wq;
> static unsigned int indirect_thresh = 0;
> module_param(indirect_thresh, uint, S_IRUGO);
>
> +static unsigned int indirect_alloc_thresh = 0;
> +module_param(indirect_alloc_thresh, uint, S_IRUGO);
> +
> struct virtio_blk
> {
> spinlock_t lock;
> @@ -442,6 +445,7 @@ 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 bcaddb9..6a32f76 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 = 0;
> module_param(indirect_thresh, uint, S_IRUGO);
>
> +static unsigned int indirect_alloc_thresh = 0;
> +module_param(indirect_alloc_thresh, uint, S_IRUGO);
> +
> static struct virtqueue *vq;
> static unsigned int data_avail;
> static DECLARE_COMPLETION(have_data);
> @@ -94,6 +97,7 @@ static int virtrng_probe(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 60397a4..7c33714 100644
> --- a/drivers/char/virtio_console.c
> +++ b/drivers/char/virtio_console.c
> @@ -40,6 +40,9 @@
> static unsigned int indirect_thresh = 0;
> module_param(indirect_thresh, uint, S_IRUGO);
>
> +static unsigned int indirect_alloc_thresh = 0;
> +module_param(indirect_alloc_thresh, uint, S_IRUGO);
> +
> /*
> * This is a global struct for storing common data for all the devices
> * this driver handles.
> @@ -1733,6 +1736,7 @@ 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 5c1be92..441bd2f 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 = 0;
> module_param(indirect_thresh, uint, S_IRUGO);
>
> +static unsigned int indirect_alloc_thresh = 0;
> +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 4fc11ba..6e6313b 100644
> --- a/drivers/virtio/virtio_balloon.c
> +++ b/drivers/virtio/virtio_balloon.c
> @@ -38,6 +38,9 @@
> static unsigned int indirect_thresh = 0;
> module_param(indirect_thresh, uint, S_IRUGO);
>
> +static unsigned int indirect_alloc_thresh = 0;
> +module_param(indirect_alloc_thresh, uint, S_IRUGO);
> +
> struct virtio_balloon
> {
> struct virtio_device *vdev;
> @@ -364,6 +367,7 @@ 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..f0b0ce3 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)
This should be > instead of <, no?
>
> + 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 36019ec..f3f0d3f 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 357bfba..8424b36 100644
> --- a/net/9p/trans_virtio.c
> +++ b/net/9p/trans_virtio.c
> @@ -55,6 +55,9 @@
> static unsigned int indirect_thresh = 0;
> module_param(indirect_thresh, uint, S_IRUGO);
>
> +static unsigned int indirect_alloc_thresh = 0;
> +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);
Jean-Mickael
next prev parent reply other threads:[~2012-06-19 5:51 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-18 14:09 [RFC 1/2] virtio-ring: Use threshold for switching to indirect descriptors Sasha Levin
2012-06-18 14:09 ` [RFC 2/2] virtio-ring: Allocate indirect buffers from cache when possible Sasha Levin
2012-06-19 5:51 ` Jean-Mickael Guerin [this message]
2012-08-28 12:54 ` Sasha Levin
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