| Message ID | 1346325718-11151-2-git-send-email-levinsasha928@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Aug 30, 2012 at 01:21:58PM +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 am not sure we need these module params. But assuming we keep them, we need to validate values - they come from user. > --- > 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 | 34 ++++++++++++++++++++++++++++++---- > include/linux/virtio.h | 1 + > net/9p/trans_virtio.c | 5 +++++ > 8 files changed, 56 insertions(+), 4 deletions(-) > > diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c > index 7c63065..e4c6c42 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 3a644f1..ed22db8 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 da2e44c..8f30732 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 949c89e..a00e19d 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 = 16; > module_param(indirect_thresh, uint, S_IRUGO); > > +static unsigned int indirect_alloc_thresh = 16; Why 16? Please make is MAX_SG + 1 this makes some sense. > +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 ca5ae7a..039c4a6 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 4063e03..dde867b 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 +391,14 @@ 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) { > + u32 descs = vq->vring.desc[i].len / sizeof(struct vring_desc); > + if (descs > 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)); > + } If logic in two chunks above does not match it all blows up. So let's add a helper is_cache(vq, buf) and call from both places. > > while (vq->vring.desc[i].flags & VRING_DESC_F_NEXT) { > i = vq->vring.desc[i].next; > @@ -654,14 +667,25 @@ 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; This means for virtio-net we still create a cache for both TX and RX, but it's later unused for RX unless big packet mode is set. Pls make this flag per vq not per device. > + if (vq->indirect_alloc_thresh) { > + vq->indirect_cache = > + KMEM_CACHE(vring_desc[vq->indirect_alloc_thresh], 0); > + > + if (vq->indirect_cache == NULL) > + vq->indirect_alloc_thresh = 0; > + } > + } > > vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); > > @@ -685,6 +709,8 @@ 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) So what is a reasonable value? It would be such that most bufs have # of s/g below it. So I think 'expected_sg' would be a better name, add documentation explaining what it is. > diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c > index 418f933..058b6dd 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 08/30/2012 03:38 PM, Michael S. Tsirkin wrote: >> +static unsigned int indirect_alloc_thresh = 16; > Why 16? Please make is MAX_SG + 1 this makes some sense. Wouldn't MAX_SG mean we always allocate from the cache? Isn't the memory waste too big in this case? -- 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 Fri, Aug 31, 2012 at 11:36:07AM +0200, Sasha Levin wrote: > On 08/30/2012 03:38 PM, Michael S. Tsirkin wrote: > >> +static unsigned int indirect_alloc_thresh = 16; > > Why 16? Please make is MAX_SG + 1 this makes some sense. > > Wouldn't MAX_SG mean we always allocate from the cache? Isn't the memory waste > too big in this case? Sorry. I really meant MAX_SKB_FRAGS + 1. MAX_SKB_FRAGS is 17 so gets us threshold of 18. It is less than the size of an skb+shinfo itself so - does it look too big to you? Also why do you think 16 is not too big but 18 is? If there's a reason then I am fine with 16 too but then please put it in code comment near where the value is set. Yes this means virtio net always allocates from cache but this is a good thing, isn't it? Gets us more consistent performance.
On 08/31/2012 12:56 PM, Michael S. Tsirkin wrote: > On Fri, Aug 31, 2012 at 11:36:07AM +0200, Sasha Levin wrote: >> On 08/30/2012 03:38 PM, Michael S. Tsirkin wrote: >> >> +static unsigned int indirect_alloc_thresh = 16; >> > Why 16? Please make is MAX_SG + 1 this makes some sense. >> >> Wouldn't MAX_SG mean we always allocate from the cache? Isn't the memory waste >> too big in this case? > > Sorry. I really meant MAX_SKB_FRAGS + 1. MAX_SKB_FRAGS is 17 so gets us > threshold of 18. It is less than the size of an skb+shinfo itself so - > does it look too big to you? Also why do you think 16 is not too big but > 18 is? If there's a reason then I am fine with 16 too but then please > put it in code comment near where the value is set. > > Yes this means virtio net always allocates from cache > but this is a good thing, isn't it? Gets us more consistent > performance. kmalloc() also goes to a cache. Is there a measurable difference? Ugh, there's an ugly loop in __find_general_cachep(), which really wants to be replaced with fls().
On 09/04/2012 07:34 PM, Avi Kivity wrote: > On 08/31/2012 12:56 PM, Michael S. Tsirkin wrote: >> On Fri, Aug 31, 2012 at 11:36:07AM +0200, Sasha Levin wrote: >>> On 08/30/2012 03:38 PM, Michael S. Tsirkin wrote: >>> >> +static unsigned int indirect_alloc_thresh = 16; >>> > Why 16? Please make is MAX_SG + 1 this makes some sense. >>> >>> Wouldn't MAX_SG mean we always allocate from the cache? Isn't the memory waste >>> too big in this case? >> >> Sorry. I really meant MAX_SKB_FRAGS + 1. MAX_SKB_FRAGS is 17 so gets us >> threshold of 18. It is less than the size of an skb+shinfo itself so - >> does it look too big to you? Also why do you think 16 is not too big but >> 18 is? If there's a reason then I am fine with 16 too but then please >> put it in code comment near where the value is set. >> >> Yes this means virtio net always allocates from cache >> but this is a good thing, isn't it? Gets us more consistent >> performance. > > kmalloc() also goes to a cache. Is there a measurable difference? > > Ugh, there's an ugly loop in __find_general_cachep(), which really wants > to be replaced with fls(). > Actually, not, as the loop will be very short for small sizes.
On Tue, Sep 04, 2012 at 07:34:19PM +0300, Avi Kivity wrote: > On 08/31/2012 12:56 PM, Michael S. Tsirkin wrote: > > On Fri, Aug 31, 2012 at 11:36:07AM +0200, Sasha Levin wrote: > >> On 08/30/2012 03:38 PM, Michael S. Tsirkin wrote: > >> >> +static unsigned int indirect_alloc_thresh = 16; > >> > Why 16? Please make is MAX_SG + 1 this makes some sense. > >> > >> Wouldn't MAX_SG mean we always allocate from the cache? Isn't the memory waste > >> too big in this case? > > > > Sorry. I really meant MAX_SKB_FRAGS + 1. MAX_SKB_FRAGS is 17 so gets us > > threshold of 18. It is less than the size of an skb+shinfo itself so - > > does it look too big to you? Also why do you think 16 is not too big but > > 18 is? If there's a reason then I am fine with 16 too but then please > > put it in code comment near where the value is set. > > > > Yes this means virtio net always allocates from cache > > but this is a good thing, isn't it? Gets us more consistent > > performance. > > kmalloc() also goes to a cache. Is there a measurable difference? Yes see 0/2 and followup discussion. > Ugh, there's an ugly loop in __find_general_cachep(), which really wants > to be replaced with fls(). > > -- > error compiling committee.c: too many arguments to function -- 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 09/04/2012 09:41 PM, Michael S. Tsirkin wrote: > On Tue, Sep 04, 2012 at 07:34:19PM +0300, Avi Kivity wrote: >> On 08/31/2012 12:56 PM, Michael S. Tsirkin wrote: >> > On Fri, Aug 31, 2012 at 11:36:07AM +0200, Sasha Levin wrote: >> >> On 08/30/2012 03:38 PM, Michael S. Tsirkin wrote: >> >> >> +static unsigned int indirect_alloc_thresh = 16; >> >> > Why 16? Please make is MAX_SG + 1 this makes some sense. >> >> >> >> Wouldn't MAX_SG mean we always allocate from the cache? Isn't the memory waste >> >> too big in this case? >> > >> > Sorry. I really meant MAX_SKB_FRAGS + 1. MAX_SKB_FRAGS is 17 so gets us >> > threshold of 18. It is less than the size of an skb+shinfo itself so - >> > does it look too big to you? Also why do you think 16 is not too big but >> > 18 is? If there's a reason then I am fine with 16 too but then please >> > put it in code comment near where the value is set. >> > >> > Yes this means virtio net always allocates from cache >> > but this is a good thing, isn't it? Gets us more consistent >> > performance. >> >> kmalloc() also goes to a cache. Is there a measurable difference? > > Yes see 0/2 and followup discussion. I don't see 0/2, looks like this was not threaded properly. What was the subject line?
On Wed, Sep 05, 2012 at 05:21:12PM +0300, Avi Kivity wrote: > On 09/04/2012 09:41 PM, Michael S. Tsirkin wrote: > > On Tue, Sep 04, 2012 at 07:34:19PM +0300, Avi Kivity wrote: > >> On 08/31/2012 12:56 PM, Michael S. Tsirkin wrote: > >> > On Fri, Aug 31, 2012 at 11:36:07AM +0200, Sasha Levin wrote: > >> >> On 08/30/2012 03:38 PM, Michael S. Tsirkin wrote: > >> >> >> +static unsigned int indirect_alloc_thresh = 16; > >> >> > Why 16? Please make is MAX_SG + 1 this makes some sense. > >> >> > >> >> Wouldn't MAX_SG mean we always allocate from the cache? Isn't the memory waste > >> >> too big in this case? > >> > > >> > Sorry. I really meant MAX_SKB_FRAGS + 1. MAX_SKB_FRAGS is 17 so gets us > >> > threshold of 18. It is less than the size of an skb+shinfo itself so - > >> > does it look too big to you? Also why do you think 16 is not too big but > >> > 18 is? If there's a reason then I am fine with 16 too but then please > >> > put it in code comment near where the value is set. > >> > > >> > Yes this means virtio net always allocates from cache > >> > but this is a good thing, isn't it? Gets us more consistent > >> > performance. > >> > >> kmalloc() also goes to a cache. Is there a measurable difference? > > > > Yes see 0/2 and followup discussion. > > I don't see 0/2, looks like this was not threaded properly. What was > the subject line? My mistake, there is no 0/2, the resolts where in the followup thread of the previous version: [PATCH v2 2/2] virtio-ring: Allocate indirect buffers from cache when possible Sasha, could you please accompany the next version with a cover letter 0/2) including performance results? > > -- > error compiling committee.c: too many arguments to function -- 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 7c63065..e4c6c42 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 3a644f1..ed22db8 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 da2e44c..8f30732 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 949c89e..a00e19d 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 = 16; module_param(indirect_thresh, uint, S_IRUGO); +static unsigned int indirect_alloc_thresh = 16; +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 ca5ae7a..039c4a6 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 4063e03..dde867b 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 +391,14 @@ 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) { + u32 descs = vq->vring.desc[i].len / sizeof(struct vring_desc); + if (descs > 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 +667,25 @@ 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); + + if (vq->indirect_cache == NULL) + vq->indirect_alloc_thresh = 0; + } + } vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); @@ -685,6 +709,8 @@ 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 418f933..058b6dd 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> --- 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 | 34 ++++++++++++++++++++++++++++++---- include/linux/virtio.h | 1 + net/9p/trans_virtio.c | 5 +++++ 8 files changed, 56 insertions(+), 4 deletions(-)