search for: mergeable_len_to_ctx

...ndex 1f8c15c..8fae9a8 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -270,6 +270,23 @@ static void skb_xmit_done(struct virtqueue *vq) > netif_wake_subqueue(vi->dev, vq2txq(vq)); > } > > +#define MRG_CTX_HEADER_SHIFT 22 > +static void *mergeable_len_to_ctx(unsigned int truesize, > + unsigned int headroom) > +{ > + return (void *)(unsigned long)((headroom << MRG_CTX_HEADER_SHIFT) | truesize); > +} > + > +static unsigned int mergeable_ctx_to_headroom(void *mrg_ctx) > +{ > + return (unsigned long)mrg_ctx >> MRG_C...

...ndex 1f8c15c..8fae9a8 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -270,6 +270,23 @@ static void skb_xmit_done(struct virtqueue *vq) > netif_wake_subqueue(vi->dev, vq2txq(vq)); > } > > +#define MRG_CTX_HEADER_SHIFT 22 > +static void *mergeable_len_to_ctx(unsigned int truesize, > + unsigned int headroom) > +{ > + return (void *)(unsigned long)((headroom << MRG_CTX_HEADER_SHIFT) | truesize); > +} > + > +static unsigned int mergeable_ctx_to_headroom(void *mrg_ctx) > +{ > + return (unsigned long)mrg_ctx >> MRG_C...

...irtio_net.c b/drivers/net/virtio_net.c index 1f8c15c..8fae9a8 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -270,6 +270,23 @@ static void skb_xmit_done(struct virtqueue *vq) netif_wake_subqueue(vi->dev, vq2txq(vq)); } +#define MRG_CTX_HEADER_SHIFT 22 +static void *mergeable_len_to_ctx(unsigned int truesize, + unsigned int headroom) +{ + return (void *)(unsigned long)((headroom << MRG_CTX_HEADER_SHIFT) | truesize); +} + +static unsigned int mergeable_ctx_to_headroom(void *mrg_ctx) +{ + return (unsigned long)mrg_ctx >> MRG_CTX_HEADER_SHIFT; +} + +static unsigned i...

...eaving hole at front of pkt */ get_page(alloc_frag->page); @@ -1205,11 +1206,12 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi, * the current buffer. */ len += hole; + truesize += hole; alloc_frag->offset += hole; } sg_init_one(rq->sg, buf, len); - ctx = mergeable_len_to_ctx(len, headroom); + ctx = mergeable_len_to_ctx(truesize, headroom); err = virtqueue_add_inbuf_ctx(rq->vq, rq->sg, 1, buf, ctx, gfp); if (err < 0) put_page(virt_to_head_page(buf)); -- 2.20.1

...etect that. > @@ -1205,11 +1206,12 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi, > * the current buffer. > */ > len += hole; > + truesize += hole; > alloc_frag->offset += hole; > } > > sg_init_one(rq->sg, buf, len); > - ctx = mergeable_len_to_ctx(len, headroom); > + ctx = mergeable_len_to_ctx(truesize, headroom); > err = virtqueue_add_inbuf_ctx(rq->vq, rq->sg, 1, buf, ctx, gfp); > if (err < 0) > put_page(virt_to_head_page(buf)); > -- > 2.20.1

...etect that. > @@ -1205,11 +1206,12 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi, > * the current buffer. > */ > len += hole; > + truesize += hole; > alloc_frag->offset += hole; > } > > sg_init_one(rq->sg, buf, len); > - ctx = mergeable_len_to_ctx(len, headroom); > + ctx = mergeable_len_to_ctx(truesize, headroom); > err = virtqueue_add_inbuf_ctx(rq->vq, rq->sg, 1, buf, ctx, gfp); > if (err < 0) > put_page(virt_to_head_page(buf)); > -- > 2.20.1

We tried to reserve space for vnet header before xdp.data_hard_start. But this is useless since the packet could be modified by XDP which may invalidate the information stored in the header and there's no way for XDP to know the existence of the vnet header currently. So let's just not reserve space for vnet header in this case. Cc: Jesper Dangaard Brouer <brouer at redhat.com>

We tried to reserve space for vnet header before xdp.data_hard_start. But this is useless since the packet could be modified by XDP which may invalidate the information stored in the header and there's no way for XDP to know the existence of the vnet header currently. So let's just not reserve space for vnet header in this case. Cc: Jesper Dangaard Brouer <brouer at redhat.com>

...6 +813,7 @@ static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq, Let's document that ctx API is used a bit differently here: /* Unlike mergeable buffers, all buffers are allocated to the same size, * except for the headroom. For this reason we do not need to use * mergeable_len_to_ctx here - it is enough to store the headroom as the * context ignoring the truesize. */ as an alternative, reuse the same format as mergeable buffers. > struct page_frag *alloc_frag = &rq->alloc_frag; > char *buf; > unsigned int xdp_headroom = virtnet_get_headroom(vi); > +...

...6 +813,7 @@ static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq, Let's document that ctx API is used a bit differently here: /* Unlike mergeable buffers, all buffers are allocated to the same size, * except for the headroom. For this reason we do not need to use * mergeable_len_to_ctx here - it is enough to store the headroom as the * context ignoring the truesize. */ as an alternative, reuse the same format as mergeable buffers. > struct page_frag *alloc_frag = &rq->alloc_frag; > char *buf; > unsigned int xdp_headroom = virtnet_get_headroom(vi); > +...

Hi: This series brings two optimizations for virtio-net XDP: - avoid reset during XDP set - turn off offloads on demand Please review. Thanks Jason Wang (5): virtio_ring: allow to store zero as the ctx virtio-net: pack headroom into ctx for mergeable buffer virtio-net: switch to use new ctx API for small buffer virtio-net: do not reset during XDP set virtio-net: switch off offloads

Hi: This series brings two optimizations for virtio-net XDP: - avoid reset during XDP set - turn off offloads on demand Please review. Thanks Jason Wang (5): virtio_ring: allow to store zero as the ctx virtio-net: pack headroom into ctx for mergeable buffer virtio-net: switch to use new ctx API for small buffer virtio-net: do not reset during XDP set virtio-net: switch off offloads

Hi: This series brings two optimizations for virtio-net XDP: - avoid reset during XDP set - turn off offloads on demand Changes from V1: - Various tweaks on commit logs and comments - Use virtnet_napi_enable() when enabling NAPI on XDP set - Copy the small buffer packet only if xdp_headroom is smaller than required Please review. Thanks Jason Wang (5): virtio_ring: allow to store zero as

Hi: This series brings two optimizations for virtio-net XDP: - avoid reset during XDP set - turn off offloads on demand Changes from V1: - Various tweaks on commit logs and comments - Use virtnet_napi_enable() when enabling NAPI on XDP set - Copy the small buffer packet only if xdp_headroom is smaller than required Please review. Thanks Jason Wang (5): virtio_ring: allow to store zero as

...rr = virtnet_add_inbuf(rq, vi->big_packets_num_skbfrags + 2, > + first, NULL, gfp); > if (err < 0) > give_pages(rq, first); > > @@ -1645,7 +1750,7 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi, > > sg_init_one(rq->sg, buf, len); > ctx = mergeable_len_to_ctx(len + room, headroom); > - err = virtqueue_add_inbuf_ctx(rq->vq, rq->sg, 1, buf, ctx, gfp); > + err = virtnet_add_inbuf(rq, 1, buf, ctx, gfp); > if (err < 0) > put_page(virt_to_head_page(buf)); > > @@ -1768,13 +1873,13 @@ static int virtnet_receive(struct receive_q...

## About DMA APIs Now, virtio may can not work with DMA APIs when virtio features do not have VIRTIO_F_ACCESS_PLATFORM. 1. I tried to let DMA APIs return phy address by virtio-device. But DMA APIs just work with the "real" devices. 2. I tried to let xsk support callballs to get phy address from virtio-net driver as the dma address. But the maintainers of xsk may want to use

## About DMA APIs Now, virtio may can not work with DMA APIs when virtio features do not have VIRTIO_F_ACCESS_PLATFORM. 1. I tried to let DMA APIs return phy address by virtio-device. But DMA APIs just work with the "real" devices. 2. I tried to let xsk support callballs to get phy address from virtio-net driver as the dma address. But the maintainers of xsk may want to use

## About DMA APIs Now, virtio may can not work with DMA APIs when virtio features do not have VIRTIO_F_ACCESS_PLATFORM. 1. I tried to let DMA APIs return phy address by virtio-device. But DMA APIs just work with the "real" devices. 2. I tried to let xsk support callballs to get phy address from virtio-net driver as the dma address. But the maintainers of xsk may want to use