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i40e: add support for XDP multi-buffer Rx

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This patch adds multi-buffer support for the i40e_driver.

i40e_clean_rx_irq() is modified to collate all the buffers of a packet
before calling the XDP program. xdp_buff is built for the first frag of
the packet and subsequent frags are added to it. 'next_to_process' is
incremented for all non-EOP frags while 'next_to_clean' stays at the
first descriptor of the packet. XDP program is called only on receiving
EOP frag.

New functions are added for adding frags to xdp_buff and for post
processing of the buffers once the xdp prog has run. For XDP_PASS this
results in a skb with multiple fragments.

i40e_build_skb() builds the skb around xdp buffer that already contains
frags data. So i40e_add_rx_frag() helper function is now removed. Since
fields before 'dataref' in skb_shared_info are cleared during
napi_skb_build(), xdp_update_skb_shared_info() is called to set those.

For i40e_construct_skb(), all the frags data needs to be copied from
xdp_buffer's shared_skb_info to newly constructed skb's shared_skb_info.

This also means 'skb' does not need to be preserved across i40e_napi_poll()
calls and hence is removed from i40e_ring structure.

Previously i40e_alloc_rx_buffers() was called for every 32 cleaned
buffers. For multi-buffers this may not be optimal as there may be more
cleaned buffers in each i40e_clean_rx_irq() call. So this is now called
when at least half of the ring size has been cleaned.

Signed-off-by: Tirthendu Sarkar <tirthendu.sarkar@intel.com>
Tested-by: Chandan Kumar Rout <chandanx.rout@intel.com> (A Contingent Worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
This commit is contained in:
Tirthendu Sarkar 2023-03-10 00:26:15 +05:30 committed by Tony Nguyen
parent 01aa49e31e
commit e213ced19b
3 changed files with 217 additions and 124 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
drivers/net/ethernet/intel/i40e/i40e_main.c
View file

@ -2919,7 +2919,7 @@ static int i40e_max_vsi_frame_size(struct i40e_vsi *vsi,
u16 rx_buf_len = i40e_calculate_vsi_rx_buf_len(vsi);
u16 chain_len;
if (xdp_prog)
if (xdp_prog && !xdp_prog->aux->xdp_has_frags)
chain_len = 1;
else
chain_len = I40E_MAX_CHAINED_RX_BUFFERS;
@ -13337,7 +13337,7 @@ static int i40e_xdp_setup(struct i40e_vsi *vsi, struct bpf_prog *prog,
/* Don't allow frames that span over multiple buffers */
if (vsi->netdev->mtu > frame_size - I40E_PACKET_HDR_PAD) {
NL_SET_ERR_MSG_MOD(extack, "MTU too large to enable XDP");
NL_SET_ERR_MSG_MOD(extack, "MTU too large for linear frames and XDP prog does not support frags");
return -EINVAL;
}
@ -13823,7 +13823,8 @@ static int i40e_config_netdev(struct i40e_vsi *vsi)
netdev->xdp_features = NETDEV_XDP_ACT_BASIC |
NETDEV_XDP_ACT_REDIRECT |
NETDEV_XDP_ACT_XSK_ZEROCOPY;
NETDEV_XDP_ACT_XSK_ZEROCOPY |
NETDEV_XDP_ACT_RX_SG;
} else {
/* Relate the VSI_VMDQ name to the VSI_MAIN name. Note that we
* are still limited by IFNAMSIZ, but we're adding 'v%d\0' to

326
drivers/net/ethernet/intel/i40e/i40e_txrx.c
View file

@ -1477,9 +1477,6 @@ void i40e_clean_rx_ring(struct i40e_ring *rx_ring)
if (!rx_ring->rx_bi)
return;
dev_kfree_skb(rx_ring->skb);
rx_ring->skb = NULL;
if (rx_ring->xsk_pool) {
i40e_xsk_clean_rx_ring(rx_ring);
goto skip_free;
@ -2033,36 +2030,6 @@ static void i40e_rx_buffer_flip(struct i40e_rx_buffer *rx_buffer,
#endif
}
/**
* i40e_add_rx_frag - Add contents of Rx buffer to sk_buff
* @rx_ring: rx descriptor ring to transact packets on
* @rx_buffer: buffer containing page to add
* @skb: sk_buff to place the data into
* @size: packet length from rx_desc
*
* This function will add the data contained in rx_buffer->page to the skb.
* It will just attach the page as a frag to the skb.
*
* The function will then update the page offset.
**/
static void i40e_add_rx_frag(struct i40e_ring *rx_ring,
struct i40e_rx_buffer *rx_buffer,
struct sk_buff *skb,
unsigned int size)
{
#if (PAGE_SIZE < 8192)
unsigned int truesize = i40e_rx_pg_size(rx_ring) / 2;
#else
unsigned int truesize = SKB_DATA_ALIGN(size + rx_ring->rx_offset);
#endif
skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_buffer->page,
rx_buffer->page_offset, size, truesize);
/* page is being used so we must update the page offset */
i40e_rx_buffer_flip(rx_buffer, truesize);
}
/**
* i40e_get_rx_buffer - Fetch Rx buffer and synchronize data for use
* @rx_ring: rx descriptor ring to transact packets on
@ -2099,20 +2066,82 @@ static struct i40e_rx_buffer *i40e_get_rx_buffer(struct i40e_ring *rx_ring,
}
/**
* i40e_construct_skb - Allocate skb and populate it
* i40e_put_rx_buffer - Clean up used buffer and either recycle or free
* @rx_ring: rx descriptor ring to transact packets on
* @rx_buffer: rx buffer to pull data from
*
* This function will clean up the contents of the rx_buffer. It will
* either recycle the buffer or unmap it and free the associated resources.
*/
static void i40e_put_rx_buffer(struct i40e_ring *rx_ring,
struct i40e_rx_buffer *rx_buffer)
{
if (i40e_can_reuse_rx_page(rx_buffer, &rx_ring->rx_stats)) {
/* hand second half of page back to the ring */
i40e_reuse_rx_page(rx_ring, rx_buffer);
} else {
/* we are not reusing the buffer so unmap it */
dma_unmap_page_attrs(rx_ring->dev, rx_buffer->dma,
i40e_rx_pg_size(rx_ring),
DMA_FROM_DEVICE, I40E_RX_DMA_ATTR);
__page_frag_cache_drain(rx_buffer->page,
rx_buffer->pagecnt_bias);
/* clear contents of buffer_info */
rx_buffer->page = NULL;
}
}
/**
* i40e_process_rx_buffs- Processing of buffers post XDP prog or on error
* @rx_ring: Rx descriptor ring to transact packets on
* @xdp_res: Result of the XDP program
* @xdp: xdp_buff pointing to the data
**/
static void i40e_process_rx_buffs(struct i40e_ring *rx_ring, int xdp_res,
struct xdp_buff *xdp)
{
u32 next = rx_ring->next_to_clean;
struct i40e_rx_buffer *rx_buffer;
xdp->flags = 0;
while (1) {
rx_buffer = i40e_rx_bi(rx_ring, next);
if (++next == rx_ring->count)
next = 0;
if (!rx_buffer->page)
continue;
if (xdp_res == I40E_XDP_CONSUMED)
rx_buffer->pagecnt_bias++;
else
i40e_rx_buffer_flip(rx_buffer, xdp->frame_sz);
/* EOP buffer will be put in i40e_clean_rx_irq() */
if (next == rx_ring->next_to_process)
return;
i40e_put_rx_buffer(rx_ring, rx_buffer);
}
}
/**
* i40e_construct_skb - Allocate skb and populate it
* @rx_ring: rx descriptor ring to transact packets on
* @xdp: xdp_buff pointing to the data
* @nr_frags: number of buffers for the packet
*
* This function allocates an skb. It then populates it with the page
* data from the current receive descriptor, taking care to set up the
* skb correctly.
*/
static struct sk_buff *i40e_construct_skb(struct i40e_ring *rx_ring,
struct i40e_rx_buffer *rx_buffer,
struct xdp_buff *xdp)
struct xdp_buff *xdp,
u32 nr_frags)
{
unsigned int size = xdp->data_end - xdp->data;
struct i40e_rx_buffer *rx_buffer;
unsigned int headlen;
struct sk_buff *skb;
@ -2152,13 +2181,17 @@ static struct sk_buff *i40e_construct_skb(struct i40e_ring *rx_ring,
memcpy(__skb_put(skb, headlen), xdp->data,
ALIGN(headlen, sizeof(long)));
rx_buffer = i40e_rx_bi(rx_ring, rx_ring->next_to_clean);
/* update all of the pointers */
size -= headlen;
if (size) {
if (unlikely(nr_frags >= MAX_SKB_FRAGS)) {
dev_kfree_skb(skb);
return NULL;
}
skb_add_rx_frag(skb, 0, rx_buffer->page,
rx_buffer->page_offset + headlen,
size, xdp->frame_sz);
/* buffer is used by skb, update page_offset */
i40e_rx_buffer_flip(rx_buffer, xdp->frame_sz);
} else {
@ -2166,21 +2199,40 @@ static struct sk_buff *i40e_construct_skb(struct i40e_ring *rx_ring,
rx_buffer->pagecnt_bias++;
}
if (unlikely(xdp_buff_has_frags(xdp))) {
struct skb_shared_info *sinfo, *skinfo = skb_shinfo(skb);
sinfo = xdp_get_shared_info_from_buff(xdp);
memcpy(&skinfo->frags[skinfo->nr_frags], &sinfo->frags[0],
sizeof(skb_frag_t) * nr_frags);
xdp_update_skb_shared_info(skb, skinfo->nr_frags + nr_frags,
sinfo->xdp_frags_size,
nr_frags * xdp->frame_sz,
xdp_buff_is_frag_pfmemalloc(xdp));
/* First buffer has already been processed, so bump ntc */
if (++rx_ring->next_to_clean == rx_ring->count)
rx_ring->next_to_clean = 0;
i40e_process_rx_buffs(rx_ring, I40E_XDP_PASS, xdp);
}
return skb;
}
/**
* i40e_build_skb - Build skb around an existing buffer
* @rx_ring: Rx descriptor ring to transact packets on
* @rx_buffer: Rx buffer to pull data from
* @xdp: xdp_buff pointing to the data
* @nr_frags: number of buffers for the packet
*
* This function builds an skb around an existing Rx buffer, taking care
* to set up the skb correctly and avoid any memcpy overhead.
*/
static struct sk_buff *i40e_build_skb(struct i40e_ring *rx_ring,
struct i40e_rx_buffer *rx_buffer,
struct xdp_buff *xdp)
struct xdp_buff *xdp,
u32 nr_frags)
{
unsigned int metasize = xdp->data - xdp->data_meta;
struct sk_buff *skb;
@ -2203,38 +2255,27 @@ static struct sk_buff *i40e_build_skb(struct i40e_ring *rx_ring,
if (metasize)
skb_metadata_set(skb, metasize);
/* buffer is used by skb, update page_offset */
i40e_rx_buffer_flip(rx_buffer, xdp->frame_sz);
if (unlikely(xdp_buff_has_frags(xdp))) {
struct skb_shared_info *sinfo;
sinfo = xdp_get_shared_info_from_buff(xdp);
xdp_update_skb_shared_info(skb, nr_frags,
sinfo->xdp_frags_size,
nr_frags * xdp->frame_sz,
xdp_buff_is_frag_pfmemalloc(xdp));
i40e_process_rx_buffs(rx_ring, I40E_XDP_PASS, xdp);
} else {
struct i40e_rx_buffer *rx_buffer;
rx_buffer = i40e_rx_bi(rx_ring, rx_ring->next_to_clean);
/* buffer is used by skb, update page_offset */
i40e_rx_buffer_flip(rx_buffer, xdp->frame_sz);
}
return skb;
}
/**
* i40e_put_rx_buffer - Clean up used buffer and either recycle or free
* @rx_ring: rx descriptor ring to transact packets on
* @rx_buffer: rx buffer to pull data from
*
* This function will clean up the contents of the rx_buffer. It will
* either recycle the buffer or unmap it and free the associated resources.
*/
static void i40e_put_rx_buffer(struct i40e_ring *rx_ring,
struct i40e_rx_buffer *rx_buffer)
{
if (i40e_can_reuse_rx_page(rx_buffer, &rx_ring->rx_stats)) {
/* hand second half of page back to the ring */
i40e_reuse_rx_page(rx_ring, rx_buffer);
} else {
/* we are not reusing the buffer so unmap it */
dma_unmap_page_attrs(rx_ring->dev, rx_buffer->dma,
i40e_rx_pg_size(rx_ring),
DMA_FROM_DEVICE, I40E_RX_DMA_ATTR);
__page_frag_cache_drain(rx_buffer->page,
rx_buffer->pagecnt_bias);
/* clear contents of buffer_info */
rx_buffer->page = NULL;
}
}
/**
* i40e_is_non_eop - process handling of non-EOP buffers
* @rx_ring: Rx ring being processed
@ -2387,6 +2428,55 @@ static void i40e_inc_ntp(struct i40e_ring *rx_ring)
prefetch(I40E_RX_DESC(rx_ring, ntp));
}
/**
* i40e_add_xdp_frag: Add a frag to xdp_buff
* @xdp: xdp_buff pointing to the data
* @nr_frags: return number of buffers for the packet
* @rx_buffer: rx_buffer holding data of the current frag
* @size: size of data of current frag
*/
static int i40e_add_xdp_frag(struct xdp_buff *xdp, u32 *nr_frags,
struct i40e_rx_buffer *rx_buffer, u32 size)
{
struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp);
if (!xdp_buff_has_frags(xdp)) {
sinfo->nr_frags = 0;
sinfo->xdp_frags_size = 0;
xdp_buff_set_frags_flag(xdp);
} else if (unlikely(sinfo->nr_frags >= MAX_SKB_FRAGS)) {
/* Overflowing packet: All frags need to be dropped */
return -ENOMEM;
}
__skb_fill_page_desc_noacc(sinfo, sinfo->nr_frags++, rx_buffer->page,
rx_buffer->page_offset, size);
sinfo->xdp_frags_size += size;
if (page_is_pfmemalloc(rx_buffer->page))
xdp_buff_set_frag_pfmemalloc(xdp);
*nr_frags = sinfo->nr_frags;
return 0;
}
/**
* i40e_consume_xdp_buff - Consume all the buffers of the packet and update ntc
* @rx_ring: rx descriptor ring to transact packets on
* @xdp: xdp_buff pointing to the data
* @rx_buffer: rx_buffer of eop desc
*/
static void i40e_consume_xdp_buff(struct i40e_ring *rx_ring,
struct xdp_buff *xdp,
struct i40e_rx_buffer *rx_buffer)
{
i40e_process_rx_buffs(rx_ring, I40E_XDP_CONSUMED, xdp);
i40e_put_rx_buffer(rx_ring, rx_buffer);
rx_ring->next_to_clean = rx_ring->next_to_process;
xdp->data = NULL;
}
/**
* i40e_clean_rx_irq - Clean completed descriptors from Rx ring - bounce buf
* @rx_ring: rx descriptor ring to transact packets on
@ -2405,9 +2495,9 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget,
{
unsigned int total_rx_bytes = 0, total_rx_packets = 0;
u16 cleaned_count = I40E_DESC_UNUSED(rx_ring);
u16 clean_threshold = rx_ring->count / 2;
unsigned int offset = rx_ring->rx_offset;
struct xdp_buff *xdp = &rx_ring->xdp;
struct sk_buff *skb = rx_ring->skb;
unsigned int xdp_xmit = 0;
struct bpf_prog *xdp_prog;
bool failure = false;
@ -2419,11 +2509,14 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget,
u16 ntp = rx_ring->next_to_process;
struct i40e_rx_buffer *rx_buffer;
union i40e_rx_desc *rx_desc;
struct sk_buff *skb;
unsigned int size;
u32 nfrags = 0;
bool neop;
u64 qword;
/* return some buffers to hardware, one at a time is too slow */
if (cleaned_count >= I40E_RX_BUFFER_WRITE) {
if (cleaned_count >= clean_threshold) {
failure = failure ||
i40e_alloc_rx_buffers(rx_ring, cleaned_count);
cleaned_count = 0;
@ -2461,76 +2554,83 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget,
break;
i40e_trace(clean_rx_irq, rx_ring, rx_desc, xdp);
/* retrieve a buffer from the ring */
rx_buffer = i40e_get_rx_buffer(rx_ring, size);
/* retrieve a buffer from the ring */
if (!skb) {
neop = i40e_is_non_eop(rx_ring, rx_desc);
i40e_inc_ntp(rx_ring);
if (!xdp->data) {
unsigned char *hard_start;
hard_start = page_address(rx_buffer->page) +
rx_buffer->page_offset - offset;
xdp_prepare_buff(xdp, hard_start, offset, size, true);
xdp_buff_clear_frags_flag(xdp);
#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
xdp_res = i40e_run_xdp(rx_ring, xdp, xdp_prog);
} else if (i40e_add_xdp_frag(xdp, &nfrags, rx_buffer, size) &&
!neop) {
/* Overflowing packet: Drop all frags on EOP */
i40e_consume_xdp_buff(rx_ring, xdp, rx_buffer);
break;
}
if (neop)
continue;
xdp_res = i40e_run_xdp(rx_ring, xdp, xdp_prog);
if (xdp_res) {
if (xdp_res & (I40E_XDP_TX | I40E_XDP_REDIR)) {
xdp_xmit |= xdp_res;
xdp_xmit |= xdp_res & (I40E_XDP_TX | I40E_XDP_REDIR);
if (unlikely(xdp_buff_has_frags(xdp))) {
i40e_process_rx_buffs(rx_ring, xdp_res, xdp);
size = xdp_get_buff_len(xdp);
} else if (xdp_res & (I40E_XDP_TX | I40E_XDP_REDIR)) {
i40e_rx_buffer_flip(rx_buffer, xdp->frame_sz);
} else {
rx_buffer->pagecnt_bias++;
}
total_rx_bytes += size;
total_rx_packets++;
} else if (skb) {
i40e_add_rx_frag(rx_ring, rx_buffer, skb, size);
} else if (ring_uses_build_skb(rx_ring)) {
skb = i40e_build_skb(rx_ring, rx_buffer, xdp);
} else {
skb = i40e_construct_skb(rx_ring, rx_buffer, xdp);
if (ring_uses_build_skb(rx_ring))
skb = i40e_build_skb(rx_ring, xdp, nfrags);
else
skb = i40e_construct_skb(rx_ring, xdp, nfrags);
/* drop if we failed to retrieve a buffer */
if (!skb) {
rx_ring->rx_stats.alloc_buff_failed++;
i40e_consume_xdp_buff(rx_ring, xdp, rx_buffer);
break;
}
if (i40e_cleanup_headers(rx_ring, skb, rx_desc))
goto process_next;
/* probably a little skewed due to removing CRC */
total_rx_bytes += skb->len;
/* populate checksum, VLAN, and protocol */
i40e_process_skb_fields(rx_ring, rx_desc, skb);
i40e_trace(clean_rx_irq_rx, rx_ring, rx_desc, xdp);
napi_gro_receive(&rx_ring->q_vector->napi, skb);
}
/* exit if we failed to retrieve a buffer */
if (!xdp_res && !skb) {
rx_ring->rx_stats.alloc_buff_failed++;
rx_buffer->pagecnt_bias++;
break;
}
i40e_put_rx_buffer(rx_ring, rx_buffer);
cleaned_count++;
i40e_inc_ntp(rx_ring);
rx_ring->next_to_clean = rx_ring->next_to_process;
if (i40e_is_non_eop(rx_ring, rx_desc))
continue;
if (xdp_res || i40e_cleanup_headers(rx_ring, skb, rx_desc)) {
skb = NULL;
continue;
}
/* probably a little skewed due to removing CRC */
total_rx_bytes += skb->len;
/* populate checksum, VLAN, and protocol */
i40e_process_skb_fields(rx_ring, rx_desc, skb);
i40e_trace(clean_rx_irq_rx, rx_ring, rx_desc, xdp);
napi_gro_receive(&rx_ring->q_vector->napi, skb);
skb = NULL;
/* update budget accounting */
total_rx_packets++;
process_next:
cleaned_count += nfrags + 1;
i40e_put_rx_buffer(rx_ring, rx_buffer);
rx_ring->next_to_clean = rx_ring->next_to_process;
xdp->data = NULL;
}
i40e_finalize_xdp_rx(rx_ring, xdp_xmit);
rx_ring->skb = skb;
i40e_update_rx_stats(rx_ring, total_rx_bytes, total_rx_packets);

8
drivers/net/ethernet/intel/i40e/i40e_txrx.h
View file

@ -392,14 +392,6 @@ struct i40e_ring {
struct rcu_head rcu; /* to avoid race on free */
u16 next_to_alloc;
struct sk_buff *skb; /* When i40e_clean_rx_ring_irq() must
* return before it sees the EOP for
* the current packet, we save that skb
* here and resume receiving this
* packet the next time
* i40e_clean_rx_ring_irq() is called
* for this ring.
*/
struct i40e_channel *ch;
u16 rx_offset;