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ice: Limit the ice_add_rx_frag to frag addition

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Refactor ice_fetch_rx_buf and ice_add_rx_frag in a way that we have
standalone functions that do either the skb construction or frag
addition to previously constructed skb.

The skb handling between rx_bufs is spread among various functions. The
ice_get_rx_buf will retrieve the skb pointer from rx_buf and if it is a
NULL pointer then we do the ice_construct_skb, otherwise we add a frag
to the current skb via ice_add_rx_frag. Then, on the ice_put_rx_buf the
skb pointer that belongs to rx_buf will be cleared. Moving further, if
the current frame is not EOP frame we assign the current skb to the
rx_buf that is pointed by updated next_to_clean indicator.

What is more during the buffer reuse let's assign each member of
ice_rx_buf individually so we avoid the unnecessary copy of skb.

Last but not least, this logic split will allow us for better code reuse
when adding a support for build_skb.

Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
This commit is contained in:
Maciej Fijalkowski 2019-02-13 10:51:06 -08:00 committed by Jeff Kirsher
parent 1d032bc77b
commit 712edbbb67
1 changed files with 79 additions and 81 deletions
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150
drivers/net/ethernet/intel/ice/ice_txrx.c
View File

@ -563,63 +563,29 @@ static bool ice_can_reuse_rx_page(struct ice_rx_buf *rx_buf)
}
/**
* ice_add_rx_frag - Add contents of Rx buffer to sk_buff
* ice_add_rx_frag - Add contents of Rx buffer to sk_buff as a frag
* @rx_buf: buffer containing page to add
* @skb: sk_buf to place the data into
* @size: the length of the packet
* @skb: sk_buff to place the data into
* @size: packet length from rx_desc
*
* This function will add the data contained in rx_buf->page to the skb.
* This is done either through a direct copy if the data in the buffer is
* less than the skb header size, otherwise it will just attach the page as
* a frag to the skb.
*
* The function will then update the page offset
* It will just attach the page as a frag to the skb.
* The function will then update the page offset.
*/
static void
ice_add_rx_frag(struct ice_rx_buf *rx_buf, struct sk_buff *skb,
unsigned int size)
{
#if (PAGE_SIZE < 8192)
unsigned int truesize = ICE_RXBUF_2048;
#if (PAGE_SIZE >= 8192)
unsigned int truesize = SKB_DATA_ALIGN(size);
#else
unsigned int truesize = ALIGN(size, L1_CACHE_BYTES);
#endif /* PAGE_SIZE < 8192) */
struct page *page = rx_buf->page;
unsigned int pull_len;
unsigned char *va;
unsigned int truesize = ICE_RXBUF_2048;
#endif
va = page_address(page) + rx_buf->page_offset;
if (unlikely(skb_is_nonlinear(skb)))
goto add_tail_frag;
skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_buf->page,
rx_buf->page_offset, size, truesize);
/* will the data fit in the skb we allocated? if so, just
* copy it as it is pretty small anyway
*/
if (size <= ICE_RX_HDR_SIZE) {
memcpy(__skb_put(skb, size), va, ALIGN(size, sizeof(long)));
rx_buf->pagecnt_bias++;
return;
}
/* we need the header to contain the greater of either ETH_HLEN or
* 60 bytes if the skb->len is less than 60 for skb_pad.
*/
pull_len = eth_get_headlen(va, ICE_RX_HDR_SIZE);
/* align pull length to size of long to optimize memcpy performance */
memcpy(__skb_put(skb, pull_len), va, ALIGN(pull_len, sizeof(long)));
/* the header from the frame that we're adding as a frag was added to
* linear part of skb so move the pointer past that header and
* reduce the size of data
*/
va += pull_len;
size -= pull_len;
add_tail_frag:
skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page,
(unsigned long)va & ~PAGE_MASK, size, truesize);
/* page is being used so we must update the page offset */
ice_rx_buf_adjust_pg_offset(rx_buf, truesize);
}
@ -642,25 +608,34 @@ ice_reuse_rx_page(struct ice_ring *rx_ring, struct ice_rx_buf *old_buf)
nta++;
rx_ring->next_to_alloc = (nta < rx_ring->count) ? nta : 0;
/* transfer page from old buffer to new buffer */
*new_buf = *old_buf;
/* Transfer page from old buffer to new buffer.
* Move each member individually to avoid possible store
* forwarding stalls and unnecessary copy of skb.
*/
new_buf->dma = old_buf->dma;
new_buf->page = old_buf->page;
new_buf->page_offset = old_buf->page_offset;
new_buf->pagecnt_bias = old_buf->pagecnt_bias;
}
/**
* ice_get_rx_buf - Fetch Rx buffer and synchronize data for use
* @rx_ring: Rx descriptor ring to transact packets on
* @skb: skb to be used
* @size: size of buffer to add to skb
*
* This function will pull an Rx buffer from the ring and synchronize it
* for use by the CPU.
*/
static struct ice_rx_buf *
ice_get_rx_buf(struct ice_ring *rx_ring, const unsigned int size)
ice_get_rx_buf(struct ice_ring *rx_ring, struct sk_buff **skb,
const unsigned int size)
{
struct ice_rx_buf *rx_buf;
rx_buf = &rx_ring->rx_buf[rx_ring->next_to_clean];
prefetchw(rx_buf->page);
*skb = rx_buf->skb;
/* we are reusing so sync this buffer for CPU use */
dma_sync_single_range_for_cpu(rx_ring->dev, rx_buf->dma,
@ -674,49 +649,63 @@ ice_get_rx_buf(struct ice_ring *rx_ring, const unsigned int size)
}
/**
* ice_fetch_rx_buf - Allocate skb and populate it
* ice_construct_skb - Allocate skb and populate it
* @rx_ring: Rx descriptor ring to transact packets on
* @rx_buf: Rx buffer to pull data from
* @size: the length of the packet
*
* This function allocates an skb on the fly, and populates it with the page
* data from the current receive descriptor, taking care to set up the skb
* correctly, as well as handling calling the page recycle function if
* necessary.
* 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 *
ice_fetch_rx_buf(struct ice_ring *rx_ring, struct ice_rx_buf *rx_buf,
ice_construct_skb(struct ice_ring *rx_ring, struct ice_rx_buf *rx_buf,
unsigned int size)
{
struct sk_buff *skb = rx_buf->skb;
if (likely(!skb)) {
u8 *page_addr = page_address(rx_buf->page) +
rx_buf->page_offset;
void *va = page_address(rx_buf->page) + rx_buf->page_offset;
unsigned int headlen;
struct sk_buff *skb;
/* prefetch first cache line of first page */
prefetch(page_addr);
prefetch(va);
#if L1_CACHE_BYTES < 128
prefetch((void *)(page_addr + L1_CACHE_BYTES));
prefetch((u8 *)va + L1_CACHE_BYTES);
#endif /* L1_CACHE_BYTES */
/* allocate a skb to store the frags */
skb = __napi_alloc_skb(&rx_ring->q_vector->napi,
ICE_RX_HDR_SIZE,
skb = __napi_alloc_skb(&rx_ring->q_vector->napi, ICE_RX_HDR_SIZE,
GFP_ATOMIC | __GFP_NOWARN);
if (unlikely(!skb)) {
rx_ring->rx_stats.alloc_buf_failed++;
rx_buf->pagecnt_bias++;
if (unlikely(!skb))
return NULL;
}
skb_record_rx_queue(skb, rx_ring->q_index);
} else {
rx_buf->skb = NULL;
}
/* Determine available headroom for copy */
headlen = size;
if (headlen > ICE_RX_HDR_SIZE)
headlen = eth_get_headlen(va, ICE_RX_HDR_SIZE);
/* pull page into skb */
ice_add_rx_frag(rx_buf, skb, size);
/* align pull length to size of long to optimize memcpy performance */
memcpy(__skb_put(skb, headlen), va, ALIGN(headlen, sizeof(long)));
/* if we exhaust the linear part then add what is left as a frag */
size -= headlen;
if (size) {
#if (PAGE_SIZE >= 8192)
unsigned int truesize = SKB_DATA_ALIGN(size);
#else
unsigned int truesize = ICE_RXBUF_2048;
#endif
skb_add_rx_frag(skb, 0, rx_buf->page,
rx_buf->page_offset + headlen, size, truesize);
/* buffer is used by skb, update page_offset */
ice_rx_buf_adjust_pg_offset(rx_buf, truesize);
} else {
/* buffer is unused, reset bias back to rx_buf; data was copied
* onto skb's linear part so there's no need for adjusting
* page offset and we can reuse this buffer as-is
*/
rx_buf->pagecnt_bias++;
}
return skb;
}
@ -744,6 +733,7 @@ static void ice_put_rx_buf(struct ice_ring *rx_ring, struct ice_rx_buf *rx_buf)
/* clear contents of buffer_info */
rx_buf->page = NULL;
rx_buf->skb = NULL;
}
/**
@ -1024,11 +1014,19 @@ static int ice_clean_rx_irq(struct ice_ring *rx_ring, int budget)
size = le16_to_cpu(rx_desc->wb.pkt_len) &
ICE_RX_FLX_DESC_PKT_LEN_M;
rx_buf = ice_get_rx_buf(rx_ring, size);
rx_buf = ice_get_rx_buf(rx_ring, &skb, size);
/* allocate (if needed) and populate skb */
skb = ice_fetch_rx_buf(rx_ring, rx_buf, size);
if (!skb)
if (skb)
ice_add_rx_frag(rx_buf, skb, size);
else
skb = ice_construct_skb(rx_ring, rx_buf, size);
/* exit if we failed to retrieve a buffer */
if (!skb) {
rx_ring->rx_stats.alloc_buf_failed++;
rx_buf->pagecnt_bias++;
break;
}
ice_put_rx_buf(rx_ring, rx_buf);
cleaned_count++;