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From: Sasha Levin <levinsasha928@gmail.com>
To: mst@redhat.com, asias@redhat.com, stefanha@gmail.com
Cc: virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
	Sasha Levin <levinsasha928@gmail.com>
Subject: [RFC 2/2] virtio-ring: Allocate indirect buffers from cache when possible
Date: Mon, 18 Jun 2012 16:09:58 +0200	[thread overview]
Message-ID: <1340028598-10142-2-git-send-email-levinsasha928@gmail.com> (raw)
In-Reply-To: <1340028598-10142-1-git-send-email-levinsasha928@gmail.com>

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)
+			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);
-- 
1.7.8.6


  reply	other threads:[~2012-06-18 14:09 UTC|newest]

Thread overview: 6+ 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 ` Sasha Levin [this message]
2012-06-19  5:51   ` [RFC 2/2] virtio-ring: Allocate indirect buffers from cache when possible Jean-Mickael Guerin
2012-06-19  5:51   ` Jean-Mickael Guerin
2012-08-28 12:54     ` Sasha Levin
2012-06-18 14:09 ` Sasha Levin

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