search for: virtqueue_add_outbuf_urgent

...cleared unconditionally in virtqueue_disable_cb(). So virtqueue_enable_cb() was used to not only publish a new event index but also enable the urgent descriptor. And virtqueue_disable_cb() disabled all interrupts including the urgent descriptor. Guest won't get urgent interrupts by just adding virtqueue_add_outbuf_urgent() since what it needs is to enable and disable interrupt for !urgent descriptor. Btw, not sure "urgent" is a suitable name, since interrupt is often slow in kvm guest. And in fact virtio-net will probably use "urgent" descriptor for those packets (e.g stream packets who can be...

...cleared unconditionally in virtqueue_disable_cb(). So virtqueue_enable_cb() was used to not only publish a new event index but also enable the urgent descriptor. And virtqueue_disable_cb() disabled all interrupts including the urgent descriptor. Guest won't get urgent interrupts by just adding virtqueue_add_outbuf_urgent() since what it needs is to enable and disable interrupt for !urgent descriptor. Btw, not sure "urgent" is a suitable name, since interrupt is often slow in kvm guest. And in fact virtio-net will probably use "urgent" descriptor for those packets (e.g stream packets who can be...

.... > + * @gfp: how to do memory allocations (if necessary). > + * > + * Caller must ensure we don't call this with other virtqueue operations > + * at the same time (except where noted). > + * > + * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO). > + */ > +int virtqueue_add_outbuf_urgent(struct virtqueue *vq, > + struct scatterlist sg[], unsigned int num, > + void *data, > + gfp_t gfp) > +{ > + return virtqueue_add(vq, true, &sg, sg_next_arr, num, 0, 1, 0, data, gfp); > +} > +EXPORT_SYMBOL_GPL(virtqueue_add_outbuf_urgent); > + > +/** > *...

...@data: the token identifying the buffer. + * @gfp: how to do memory allocations (if necessary). + * + * Caller must ensure we don't call this with other virtqueue operations + * at the same time (except where noted). + * + * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO). + */ +int virtqueue_add_outbuf_urgent(struct virtqueue *vq, + struct scatterlist sg[], unsigned int num, + void *data, + gfp_t gfp) +{ + return virtqueue_add(vq, true, &sg, sg_next_arr, num, 0, 1, 0, data, gfp); +} +EXPORT_SYMBOL_GPL(virtqueue_add_outbuf_urgent); + +/** * virtqueue_add_inbuf - expose input buffers to oth...

...@data: the token identifying the buffer. + * @gfp: how to do memory allocations (if necessary). + * + * Caller must ensure we don't call this with other virtqueue operations + * at the same time (except where noted). + * + * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO). + */ +int virtqueue_add_outbuf_urgent(struct virtqueue *vq, + struct scatterlist sg[], unsigned int num, + void *data, + gfp_t gfp) +{ + return virtqueue_add(vq, true, &sg, sg_next_arr, num, 0, 1, 0, data, gfp); +} +EXPORT_SYMBOL_GPL(virtqueue_add_outbuf_urgent); + +/** * virtqueue_add_inbuf - expose input buffers to oth...

.... > >> So virtqueue_enable_cb() was >> used to not only publish a new event index but also enable the urgent >> descriptor. And virtqueue_disable_cb() disabled all interrupts including >> the urgent descriptor. Guest won't get urgent interrupts by just adding >> virtqueue_add_outbuf_urgent() since what it needs is to enable and >> disable interrupt for !urgent descriptor. > Right, we want a new API that advances event index but does not > set VRING_AVAIL_F_NO_INTERRUPT. > IMO still want to set VRING_AVAIL_F_NO_INTERRUPT when handling tx > interrupts, to avoid interr...

.... > >> So virtqueue_enable_cb() was >> used to not only publish a new event index but also enable the urgent >> descriptor. And virtqueue_disable_cb() disabled all interrupts including >> the urgent descriptor. Guest won't get urgent interrupts by just adding >> virtqueue_add_outbuf_urgent() since what it needs is to enable and >> disable interrupt for !urgent descriptor. > Right, we want a new API that advances event index but does not > set VRING_AVAIL_F_NO_INTERRUPT. > IMO still want to set VRING_AVAIL_F_NO_INTERRUPT when handling tx > interrupts, to avoid interr...

...reverse actually, right? > So virtqueue_enable_cb() was > used to not only publish a new event index but also enable the urgent > descriptor. And virtqueue_disable_cb() disabled all interrupts including > the urgent descriptor. Guest won't get urgent interrupts by just adding > virtqueue_add_outbuf_urgent() since what it needs is to enable and > disable interrupt for !urgent descriptor. Right, we want a new API that advances event index but does not set VRING_AVAIL_F_NO_INTERRUPT. IMO still want to set VRING_AVAIL_F_NO_INTERRUPT when handling tx interrupts, to avoid interrupt storms. > Btw,...

Hello all: We free old transmitted packets in ndo_start_xmit() currently, so any packet must be orphaned also there. This was used to reduce the overhead of tx interrupt to achieve better performance. But this may not work for some protocols such as TCP stream. TCP depends on the value of sk_wmem_alloc to implement various optimization for small packets stream such as TCP small queue and auto

Hello all: We free old transmitted packets in ndo_start_xmit() currently, so any packet must be orphaned also there. This was used to reduce the overhead of tx interrupt to achieve better performance. But this may not work for some protocols such as TCP stream. TCP depends on the value of sk_wmem_alloc to implement various optimization for small packets stream such as TCP small queue and auto

On 07/01/2014 06:49 PM, Michael S. Tsirkin wrote: > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > --- > drivers/vhost/vhost.h | 19 +++++++++++++------ > drivers/vhost/net.c | 30 +++++++++++++++++++++--------- > drivers/vhost/scsi.c | 23 +++++++++++++++-------- > drivers/vhost/test.c | 5 +++-- > drivers/vhost/vhost.c | 23 ++++++++++++++++------- >

On 07/01/2014 06:49 PM, Michael S. Tsirkin wrote: > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > --- > drivers/vhost/vhost.h | 19 +++++++++++++------ > drivers/vhost/net.c | 30 +++++++++++++++++++++--------- > drivers/vhost/scsi.c | 23 +++++++++++++++-------- > drivers/vhost/test.c | 5 +++-- > drivers/vhost/vhost.c | 23 ++++++++++++++++------- >

...changed, 51 insertions(+), 4 deletions(-) diff --git a/include/linux/virtio.h b/include/linux/virtio.h index b46671e..14625a6 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -39,6 +39,12 @@ int virtqueue_add_outbuf(struct virtqueue *vq, void *data, gfp_t gfp); +int virtqueue_add_outbuf_urgent(struct virtqueue *vq, + struct scatterlist sg[], unsigned int num, + void *data, + gfp_t gfp); + + int virtqueue_add_inbuf(struct virtqueue *vq, struct scatterlist sg[], unsigned int num, void *data, diff --git a/include/uapi/linux/virtio_ring.h b/include/uapi/linux/virtio_ring.h...

...changed, 51 insertions(+), 4 deletions(-) diff --git a/include/linux/virtio.h b/include/linux/virtio.h index b46671e..14625a6 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -39,6 +39,12 @@ int virtqueue_add_outbuf(struct virtqueue *vq, void *data, gfp_t gfp); +int virtqueue_add_outbuf_urgent(struct virtqueue *vq, + struct scatterlist sg[], unsigned int num, + void *data, + gfp_t gfp); + + int virtqueue_add_inbuf(struct virtqueue *vq, struct scatterlist sg[], unsigned int num, void *data, diff --git a/include/uapi/linux/virtio_ring.h b/include/uapi/linux/virtio_ring.h...

...int xmit_skb(struct send_queue *sq, struct sk_buff *skb) > sg_set_buf(sq->sg, hdr, hdr_len); > num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1; > } > - return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC); > + if (urgent) > + return virtqueue_add_outbuf_urgent(sq->vq, sq->sg, num_sg, > + skb, GFP_ATOMIC); > + else > + return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, > + GFP_ATOMIC); > +} > + > +static bool virtnet_skb_needs_intr(struct sk_buff *skb) > +{ > + union { > + unsigned char *ne...

...t; @@ -908,7 +948,43 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) sg_set_buf(sq->sg, hdr, hdr_len); num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1; } - return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC); + if (urgent) + return virtqueue_add_outbuf_urgent(sq->vq, sq->sg, num_sg, + skb, GFP_ATOMIC); + else + return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, + GFP_ATOMIC); +} + +static bool virtnet_skb_needs_intr(struct sk_buff *skb) +{ + union { + unsigned char *network; + struct iphdr *ipv4; + struct ipv6hdr *i...

...t; @@ -908,7 +948,43 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) sg_set_buf(sq->sg, hdr, hdr_len); num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1; } - return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC); + if (urgent) + return virtqueue_add_outbuf_urgent(sq->vq, sq->sg, num_sg, + skb, GFP_ATOMIC); + else + return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, + GFP_ATOMIC); +} + +static bool virtnet_skb_needs_intr(struct sk_buff *skb) +{ + union { + unsigned char *network; + struct iphdr *ipv4; + struct ipv6hdr *i...