| Message ID | 1500295441-19339-3-git-send-email-jasowang@redhat.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
On Mon, Jul 17, 2017 at 08:43:58PM +0800, Jason Wang wrote: > Pack headroom into ctx, then during XDP set, we could know the size of > headroom and copy if needed. This is required for avoiding reset on > XDP. Not really when XDP is set - it's when buffers are used. virtio-net: pack headroom into ctx for mergeable buffers Pack headroom into ctx - this way when we get a buffer we can figure out the actual headroom that was allocated for the buffer. Will be helpful to optimize switching between XDP and non-XDP modes which have different headroom requirements. > > Signed-off-by: Jason Wang <jasowang@redhat.com> > --- > drivers/net/virtio_net.c | 29 ++++++++++++++++++++++++----- > 1 file changed, 24 insertions(+), 5 deletions(-) > > diff --git a/drivers/net/virtio_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 int mergeable_ctx_to_truesize(void *mrg_ctx) > +{ > + return (unsigned long)mrg_ctx & ((1 << MRG_CTX_HEADER_SHIFT) - 1); > +} > + > /* Called from bottom half context */ > static struct sk_buff *page_to_skb(struct virtnet_info *vi, > struct receive_queue *rq, > @@ -639,13 +656,14 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > } > rcu_read_unlock(); > > - if (unlikely(len > (unsigned long)ctx)) { > + truesize = mergeable_ctx_to_truesize(ctx); > + if (unlikely(len > truesize)) { > pr_debug("%s: rx error: len %u exceeds truesize %lu\n", > dev->name, len, (unsigned long)ctx); > dev->stats.rx_length_errors++; > goto err_skb; > } > - truesize = (unsigned long)ctx; > + > head_skb = page_to_skb(vi, rq, page, offset, len, truesize); > curr_skb = head_skb; > > @@ -665,13 +683,14 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > } > > page = virt_to_head_page(buf); > - if (unlikely(len > (unsigned long)ctx)) { > + > + truesize = mergeable_ctx_to_truesize(ctx); > + if (unlikely(len > truesize)) { > pr_debug("%s: rx error: len %u exceeds truesize %lu\n", > dev->name, len, (unsigned long)ctx); > dev->stats.rx_length_errors++; > goto err_skb; > } > - truesize = (unsigned long)ctx; > > num_skb_frags = skb_shinfo(curr_skb)->nr_frags; > if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) { > @@ -889,7 +908,7 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi, > > buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset; > buf += headroom; /* advance address leaving hole at front of pkt */ > - ctx = (void *)(unsigned long)len; > + ctx = mergeable_len_to_ctx(len, headroom); > get_page(alloc_frag->page); > alloc_frag->offset += len + headroom; > hole = alloc_frag->size - alloc_frag->offset; > -- > 2.7.4
On 2017年07月19日 02:59, Michael S. Tsirkin wrote: > On Mon, Jul 17, 2017 at 08:43:58PM +0800, Jason Wang wrote: >> Pack headroom into ctx, then during XDP set, we could know the size of >> headroom and copy if needed. This is required for avoiding reset on >> XDP. > Not really when XDP is set - it's when buffers are used. Of course :) > > virtio-net: pack headroom into ctx for mergeable buffers > > Pack headroom into ctx - this way when we get a buffer we can figure out > the actual headroom that was allocated for the buffer. Will be helpful > to optimize switching between XDP and non-XDP modes which have different > headroom requirements. Thanks, let me use this as the commit log. > >> Signed-off-by: Jason Wang <jasowang@redhat.com> >> --- >> drivers/net/virtio_net.c | 29 ++++++++++++++++++++++++----- >> 1 file changed, 24 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/net/virtio_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 int mergeable_ctx_to_truesize(void *mrg_ctx) >> +{ >> + return (unsigned long)mrg_ctx & ((1 << MRG_CTX_HEADER_SHIFT) - 1); >> +} >> + >> /* Called from bottom half context */ >> static struct sk_buff *page_to_skb(struct virtnet_info *vi, >> struct receive_queue *rq, >> @@ -639,13 +656,14 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, >> } >> rcu_read_unlock(); >> >> - if (unlikely(len > (unsigned long)ctx)) { >> + truesize = mergeable_ctx_to_truesize(ctx); >> + if (unlikely(len > truesize)) { >> pr_debug("%s: rx error: len %u exceeds truesize %lu\n", >> dev->name, len, (unsigned long)ctx); >> dev->stats.rx_length_errors++; >> goto err_skb; >> } >> - truesize = (unsigned long)ctx; >> + >> head_skb = page_to_skb(vi, rq, page, offset, len, truesize); >> curr_skb = head_skb; >> >> @@ -665,13 +683,14 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, >> } >> >> page = virt_to_head_page(buf); >> - if (unlikely(len > (unsigned long)ctx)) { >> + >> + truesize = mergeable_ctx_to_truesize(ctx); >> + if (unlikely(len > truesize)) { >> pr_debug("%s: rx error: len %u exceeds truesize %lu\n", >> dev->name, len, (unsigned long)ctx); >> dev->stats.rx_length_errors++; >> goto err_skb; >> } >> - truesize = (unsigned long)ctx; >> >> num_skb_frags = skb_shinfo(curr_skb)->nr_frags; >> if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) { >> @@ -889,7 +908,7 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi, >> >> buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset; >> buf += headroom; /* advance address leaving hole at front of pkt */ >> - ctx = (void *)(unsigned long)len; >> + ctx = mergeable_len_to_ctx(len, headroom); >> get_page(alloc_frag->page); >> alloc_frag->offset += len + headroom; >> hole = alloc_frag->size - alloc_frag->offset; >> -- >> 2.7.4
diff --git a/drivers/net/virtio_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 int mergeable_ctx_to_truesize(void *mrg_ctx) +{ + return (unsigned long)mrg_ctx & ((1 << MRG_CTX_HEADER_SHIFT) - 1); +} + /* Called from bottom half context */ static struct sk_buff *page_to_skb(struct virtnet_info *vi, struct receive_queue *rq, @@ -639,13 +656,14 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, } rcu_read_unlock(); - if (unlikely(len > (unsigned long)ctx)) { + truesize = mergeable_ctx_to_truesize(ctx); + if (unlikely(len > truesize)) { pr_debug("%s: rx error: len %u exceeds truesize %lu\n", dev->name, len, (unsigned long)ctx); dev->stats.rx_length_errors++; goto err_skb; } - truesize = (unsigned long)ctx; + head_skb = page_to_skb(vi, rq, page, offset, len, truesize); curr_skb = head_skb; @@ -665,13 +683,14 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, } page = virt_to_head_page(buf); - if (unlikely(len > (unsigned long)ctx)) { + + truesize = mergeable_ctx_to_truesize(ctx); + if (unlikely(len > truesize)) { pr_debug("%s: rx error: len %u exceeds truesize %lu\n", dev->name, len, (unsigned long)ctx); dev->stats.rx_length_errors++; goto err_skb; } - truesize = (unsigned long)ctx; num_skb_frags = skb_shinfo(curr_skb)->nr_frags; if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) { @@ -889,7 +908,7 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi, buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset; buf += headroom; /* advance address leaving hole at front of pkt */ - ctx = (void *)(unsigned long)len; + ctx = mergeable_len_to_ctx(len, headroom); get_page(alloc_frag->page); alloc_frag->offset += len + headroom; hole = alloc_frag->size - alloc_frag->offset;
Pack headroom into ctx, then during XDP set, we could know the size of headroom and copy if needed. This is required for avoiding reset on XDP. Signed-off-by: Jason Wang <jasowang@redhat.com> --- drivers/net/virtio_net.c | 29 ++++++++++++++++++++++++----- 1 file changed, 24 insertions(+), 5 deletions(-)