| Message ID | 158634676645.707275.7536684877295305696.stgit@firesoul |
|---|---|
| State | RFC |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | [RFC,v2,01/33] xdp: add frame size to xdp_buff | expand |
From: Jesper Dangaard Brouer <brouer@redhat.com> Date: Wed, 08 Apr 2020 13:52:46 +0200 > diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c > index b8496037ef7f..1fb6b1004dcb 100644 > --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c > +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c > @@ -1507,6 +1507,23 @@ static inline unsigned int i40e_rx_offset(struct i40e_ring *rx_ring) > return ring_uses_build_skb(rx_ring) ? I40E_SKB_PAD : 0; > } > > +static inline unsigned int i40e_rx_frame_truesize(struct i40e_ring *rx_ring, > + unsigned int size) Please don't use inline in foo.c files. I noticed you properly elided this in the ice changes so I wonder why it showed up here :-)
On Wed, 08 Apr 2020 14:48:45 -0700 (PDT) David Miller <davem@davemloft.net> wrote: > From: Jesper Dangaard Brouer <brouer@redhat.com> > Date: Wed, 08 Apr 2020 13:52:46 +0200 > > > diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c > > index b8496037ef7f..1fb6b1004dcb 100644 > > --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c > > +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c > > @@ -1507,6 +1507,23 @@ static inline unsigned int i40e_rx_offset(struct i40e_ring *rx_ring) > > return ring_uses_build_skb(rx_ring) ? I40E_SKB_PAD : 0; > > } > > > > +static inline unsigned int i40e_rx_frame_truesize(struct i40e_ring *rx_ring, > > + unsigned int size) > > Please don't use inline in foo.c files. I noticed you properly elided this in > the ice changes so I wonder why it showed up here :-) Yes, I know I should not do this. It got here by copy-paste accident, as I first had ixgbe function in a header file, and later I decided to move this into the ixgbe C-file, but I had already copy-pasted this into i40e driver ;-)
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index b8496037ef7f..1fb6b1004dcb 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -1507,6 +1507,23 @@ static inline unsigned int i40e_rx_offset(struct i40e_ring *rx_ring) return ring_uses_build_skb(rx_ring) ? I40E_SKB_PAD : 0; } +static inline unsigned int i40e_rx_frame_truesize(struct i40e_ring *rx_ring, + unsigned int size) +{ + unsigned int truesize; + +#if (PAGE_SIZE < 8192) + truesize = i40e_rx_pg_size(rx_ring) / 2; /* Must be power-of-2 */ +#else + truesize = i40e_rx_offset(rx_ring) ? + SKB_DATA_ALIGN(size + i40e_rx_offset(rx_ring)) + + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) : + SKB_DATA_ALIGN(size); +#endif + return truesize; +} + + /** * i40e_alloc_mapped_page - recycle or make a new page * @rx_ring: ring to use @@ -2246,13 +2263,11 @@ static void i40e_rx_buffer_flip(struct i40e_ring *rx_ring, struct i40e_rx_buffer *rx_buffer, unsigned int size) { -#if (PAGE_SIZE < 8192) - unsigned int truesize = i40e_rx_pg_size(rx_ring) / 2; + unsigned int truesize = i40e_rx_frame_truesize(rx_ring, size); +#if (PAGE_SIZE < 8192) rx_buffer->page_offset ^= truesize; #else - unsigned int truesize = SKB_DATA_ALIGN(i40e_rx_offset(rx_ring) + size); - rx_buffer->page_offset += truesize; #endif } @@ -2335,6 +2350,9 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget) bool failure = false; struct xdp_buff xdp; +#if (PAGE_SIZE < 8192) + xdp.frame_sz = i40e_rx_frame_truesize(rx_ring, 0); +#endif xdp.rxq = &rx_ring->xdp_rxq; while (likely(total_rx_packets < (unsigned int)budget)) { @@ -2389,7 +2407,10 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget) xdp.data_hard_start = xdp.data - i40e_rx_offset(rx_ring); xdp.data_end = xdp.data + size; - +#if (PAGE_SIZE > 4096) + /* At larger PAGE_SIZE, frame_sz depend on len size */ + xdp.frame_sz = i40e_rx_frame_truesize(rx_ring, size); +#endif skb = i40e_run_xdp(rx_ring, &xdp); }
This driver uses different memory models depending on PAGE_SIZE at compile time. For PAGE_SIZE 4K it uses page splitting, meaning for normal MTU frame size is 2048 bytes (and headroom 192 bytes). For larger MTUs the driver still use page splitting, by allocating order-1 pages (8192 bytes) for RX frames. For PAGE_SIZE larger than 4K, driver instead advance its rx_buffer->page_offset with the frame size "truesize". For XDP frame size calculations, this mean that in PAGE_SIZE larger than 4K mode the frame_sz change on a per packet basis. For the page split 4K PAGE_SIZE mode, xdp.frame_sz is more constant and can be updated once outside the main NAPI loop. The default setting in the driver uses build_skb(), which provides the necessary headroom and tailroom for XDP-redirect in RX-frame (in both modes). There is one complication, which is legacy-rx mode (configurable via ethtool priv-flags). There are zero headroom in this mode, which is a requirement for XDP-redirect to work. The conversion to xdp_frame (convert_to_xdp_frame) will detect this insufficient space, and xdp_do_redirect() call will fail. This is deemed acceptable, as it allows other XDP actions to still work in legacy-mode. In legacy-mode + larger PAGE_SIZE due to lacking tailroom, we also accept that xdp_adjust_tail shrink doesn't work. Cc: intel-wired-lan@lists.osuosl.org Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Cc: Alexander Duyck <alexander.duyck@gmail.com> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> --- drivers/net/ethernet/intel/i40e/i40e_txrx.c | 31 +++++++++++++++++++++++---- 1 file changed, 26 insertions(+), 5 deletions(-)