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igb: Break out Rx buffer page management 

At this point we have 2 to 3 paths that can be taken depending on what Rx
modes are enabled.  In order to better support that and improve the
maintainability I am breaking out the common bits from those paths and
making them into their own functions.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
This commit is contained in:
Alexander Duyck 2017-02-06 18:27:26 -08:00 committed by Jeff Kirsher
parent e3cdf68d4a
commit e014272672
1 changed files with 121 additions and 114 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

235
drivers/net/ethernet/intel/igb/igb_main.c
View File

@ -6886,8 +6886,14 @@ static void igb_reuse_rx_page(struct igb_ring *rx_ring,
nta++;
rx_ring->next_to_alloc = (nta < rx_ring->count) ? nta : 0;
/* transfer page from old buffer to new buffer */
*new_buff = *old_buff;
/* Transfer page from old buffer to new buffer.
* Move each member individually to avoid possible store
* forwarding stalls.
*/
new_buff->dma = old_buff->dma;
new_buff->page = old_buff->page;
new_buff->page_offset = old_buff->page_offset;
new_buff->pagecnt_bias = old_buff->pagecnt_bias;
}
static inline bool igb_page_is_reserved(struct page *page)
@ -6895,11 +6901,10 @@ static inline bool igb_page_is_reserved(struct page *page)
return (page_to_nid(page) != numa_mem_id()) || page_is_pfmemalloc(page);
}
static bool igb_can_reuse_rx_page(struct igb_rx_buffer *rx_buffer,
struct page *page,
const unsigned int truesize)
static bool igb_can_reuse_rx_page(struct igb_rx_buffer *rx_buffer)
{
unsigned int pagecnt_bias = rx_buffer->pagecnt_bias--;
unsigned int pagecnt_bias = rx_buffer->pagecnt_bias;
struct page *page = rx_buffer->page;
/* avoid re-using remote pages */
if (unlikely(igb_page_is_reserved(page)))
@ -6907,14 +6912,9 @@ static bool igb_can_reuse_rx_page(struct igb_rx_buffer *rx_buffer,
#if (PAGE_SIZE < 8192)
/* if we are only owner of page we can reuse it */
if (unlikely(page_ref_count(page) != pagecnt_bias))
if (unlikely((page_ref_count(page) - pagecnt_bias) > 1))
return false;
/* flip page offset to other buffer */
rx_buffer->page_offset ^= truesize;
#else
/* move offset up to the next cache line */
rx_buffer->page_offset += truesize;
#define IGB_LAST_OFFSET \
(SKB_WITH_OVERHEAD(PAGE_SIZE) - IGB_RXBUFFER_2048)
@ -6926,7 +6926,7 @@ static bool igb_can_reuse_rx_page(struct igb_rx_buffer *rx_buffer,
* the pagecnt_bias and page count so that we fully restock the
* number of references the driver holds.
*/
if (unlikely(pagecnt_bias == 1)) {
if (unlikely(!pagecnt_bias)) {
page_ref_add(page, USHRT_MAX);
rx_buffer->pagecnt_bias = USHRT_MAX;
}
@ -6938,25 +6938,16 @@ static bool igb_can_reuse_rx_page(struct igb_rx_buffer *rx_buffer,
* igb_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
* @rx_desc: descriptor containing length of buffer written by hardware
* @skb: sk_buff to place the data into
* @size: size of buffer to be added
*
* This function will add the data contained in rx_buffer->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 if necessary and return
* true if the buffer can be reused by the adapter.
**/
static bool igb_add_rx_frag(struct igb_ring *rx_ring,
static void igb_add_rx_frag(struct igb_ring *rx_ring,
struct igb_rx_buffer *rx_buffer,
unsigned int size,
union e1000_adv_rx_desc *rx_desc,
struct sk_buff *skb)
struct sk_buff *skb,
unsigned int size)
{
struct page *page = rx_buffer->page;
void *va = page_address(page) + rx_buffer->page_offset;
#if (PAGE_SIZE < 8192)
unsigned int truesize = igb_rx_pg_size(rx_ring) / 2;
#else
@ -6964,10 +6955,39 @@ static bool igb_add_rx_frag(struct igb_ring *rx_ring,
SKB_DATA_ALIGN(IGB_SKB_PAD + size) :
SKB_DATA_ALIGN(size);
#endif
unsigned int pull_len;
skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, rx_buffer->page,
rx_buffer->page_offset, size, truesize);
#if (PAGE_SIZE < 8192)
rx_buffer->page_offset ^= truesize;
#else
rx_buffer->page_offset += truesize;
#endif
}
if (unlikely(skb_is_nonlinear(skb)))
goto add_tail_frag;
static struct sk_buff *igb_construct_skb(struct igb_ring *rx_ring,
struct igb_rx_buffer *rx_buffer,
union e1000_adv_rx_desc *rx_desc,
unsigned int size)
{
void *va = page_address(rx_buffer->page) + rx_buffer->page_offset;
#if (PAGE_SIZE < 8192)
unsigned int truesize = igb_rx_pg_size(rx_ring) / 2;
#else
unsigned int truesize = SKB_DATA_ALIGN(size);
#endif
unsigned int headlen;
struct sk_buff *skb;
/* prefetch first cache line of first page */
prefetch(va);
#if L1_CACHE_BYTES < 128
prefetch(va + L1_CACHE_BYTES);
#endif
/* allocate a skb to store the frags */
skb = napi_alloc_skb(&rx_ring->q_vector->napi, IGB_RX_HDR_LEN);
if (unlikely(!skb))
return NULL;
if (unlikely(igb_test_staterr(rx_desc, E1000_RXDADV_STAT_TSIP))) {
igb_ptp_rx_pktstamp(rx_ring->q_vector, va, skb);
@ -6975,95 +6995,29 @@ static bool igb_add_rx_frag(struct igb_ring *rx_ring,
size -= IGB_TS_HDR_LEN;
}
if (likely(size <= IGB_RX_HDR_LEN)) {
memcpy(__skb_put(skb, size), va, ALIGN(size, sizeof(long)));
/* page is not reserved, we can reuse buffer as-is */
if (likely(!igb_page_is_reserved(page)))
return true;
/* this page cannot be reused so discard it */
return false;
}
/* 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, IGB_RX_HDR_LEN);
/* Determine available headroom for copy */
headlen = size;
if (headlen > IGB_RX_HDR_LEN)
headlen = eth_get_headlen(va, IGB_RX_HDR_LEN);
/* align pull length to size of long to optimize memcpy performance */
memcpy(__skb_put(skb, pull_len), va, ALIGN(pull_len, sizeof(long)));
memcpy(__skb_put(skb, headlen), va, ALIGN(headlen, sizeof(long)));
/* update all of the pointers */
va += pull_len;
size -= pull_len;
add_tail_frag:
skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page,
va - page_address(page), size, truesize);
return igb_can_reuse_rx_page(rx_buffer, page, truesize);
}
static struct sk_buff *igb_fetch_rx_buffer(struct igb_ring *rx_ring,
union e1000_adv_rx_desc *rx_desc,
struct sk_buff *skb)
{
unsigned int size = le16_to_cpu(rx_desc->wb.upper.length);
struct igb_rx_buffer *rx_buffer;
struct page *page;
rx_buffer = &rx_ring->rx_buffer_info[rx_ring->next_to_clean];
page = rx_buffer->page;
prefetchw(page);
/* we are reusing so sync this buffer for CPU use */
dma_sync_single_range_for_cpu(rx_ring->dev,
rx_buffer->dma,
rx_buffer->page_offset,
size,
DMA_FROM_DEVICE);
if (likely(!skb)) {
void *va = page_address(page) + rx_buffer->page_offset;
/* prefetch first cache line of first page */
prefetch(va);
#if L1_CACHE_BYTES < 128
prefetch(va + L1_CACHE_BYTES);
size -= headlen;
if (size) {
skb_add_rx_frag(skb, 0, rx_buffer->page,
(va + headlen) - page_address(rx_buffer->page),
size, truesize);
#if (PAGE_SIZE < 8192)
rx_buffer->page_offset ^= truesize;
#else
rx_buffer->page_offset += truesize;
#endif
/* allocate a skb to store the frags */
skb = napi_alloc_skb(&rx_ring->q_vector->napi, IGB_RX_HDR_LEN);
if (unlikely(!skb)) {
rx_ring->rx_stats.alloc_failed++;
return NULL;
}
/* we will be copying header into skb->data in
* pskb_may_pull so it is in our interest to prefetch
* it now to avoid a possible cache miss
*/
prefetchw(skb->data);
}
/* pull page into skb */
if (igb_add_rx_frag(rx_ring, rx_buffer, size, rx_desc, skb)) {
/* hand second half of page back to the ring */
igb_reuse_rx_page(rx_ring, rx_buffer);
} else {
/* We are not reusing the buffer so unmap it and free
* any references we are holding to it
*/
dma_unmap_page_attrs(rx_ring->dev, rx_buffer->dma,
igb_rx_pg_size(rx_ring), DMA_FROM_DEVICE,
IGB_RX_DMA_ATTR);
__page_frag_cache_drain(page, rx_buffer->pagecnt_bias);
rx_buffer->pagecnt_bias++;
}
/* clear contents of rx_buffer */
rx_buffer->page = NULL;
return skb;
}
@ -7221,6 +7175,47 @@ static void igb_process_skb_fields(struct igb_ring *rx_ring,
skb->protocol = eth_type_trans(skb, rx_ring->netdev);
}
static struct igb_rx_buffer *igb_get_rx_buffer(struct igb_ring *rx_ring,
const unsigned int size)
{
struct igb_rx_buffer *rx_buffer;
rx_buffer = &rx_ring->rx_buffer_info[rx_ring->next_to_clean];
prefetchw(rx_buffer->page);
/* we are reusing so sync this buffer for CPU use */
dma_sync_single_range_for_cpu(rx_ring->dev,
rx_buffer->dma,
rx_buffer->page_offset,
size,
DMA_FROM_DEVICE);
rx_buffer->pagecnt_bias--;
return rx_buffer;
}
static void igb_put_rx_buffer(struct igb_ring *rx_ring,
struct igb_rx_buffer *rx_buffer)
{
if (igb_can_reuse_rx_page(rx_buffer)) {
/* hand second half of page back to the ring */
igb_reuse_rx_page(rx_ring, rx_buffer);
} else {
/* We are not reusing the buffer so unmap it and free
* any references we are holding to it
*/
dma_unmap_page_attrs(rx_ring->dev, rx_buffer->dma,
igb_rx_pg_size(rx_ring), DMA_FROM_DEVICE,
IGB_RX_DMA_ATTR);
__page_frag_cache_drain(rx_buffer->page,
rx_buffer->pagecnt_bias);
}
/* clear contents of rx_buffer */
rx_buffer->page = NULL;
}
static int igb_clean_rx_irq(struct igb_q_vector *q_vector, const int budget)
{
struct igb_ring *rx_ring = q_vector->rx.ring;
@ -7230,6 +7225,8 @@ static int igb_clean_rx_irq(struct igb_q_vector *q_vector, const int budget)
while (likely(total_packets < budget)) {
union e1000_adv_rx_desc *rx_desc;
struct igb_rx_buffer *rx_buffer;
unsigned int size;
/* return some buffers to hardware, one at a time is too slow */
if (cleaned_count >= IGB_RX_BUFFER_WRITE) {
@ -7238,8 +7235,8 @@ static int igb_clean_rx_irq(struct igb_q_vector *q_vector, const int budget)
}
rx_desc = IGB_RX_DESC(rx_ring, rx_ring->next_to_clean);
if (!rx_desc->wb.upper.length)
size = le16_to_cpu(rx_desc->wb.upper.length);
if (!size)
break;
/* This memory barrier is needed to keep us from reading
@ -7248,13 +7245,23 @@ static int igb_clean_rx_irq(struct igb_q_vector *q_vector, const int budget)
*/
dma_rmb();
rx_buffer = igb_get_rx_buffer(rx_ring, size);
/* retrieve a buffer from the ring */
skb = igb_fetch_rx_buffer(rx_ring, rx_desc, skb);
if (skb)
igb_add_rx_frag(rx_ring, rx_buffer, skb, size);
else
skb = igb_construct_skb(rx_ring, rx_buffer,
rx_desc, size);
/* exit if we failed to retrieve a buffer */
if (!skb)
if (!skb) {
rx_ring->rx_stats.alloc_failed++;
rx_buffer->pagecnt_bias++;
break;
}
igb_put_rx_buffer(rx_ring, rx_buffer);
cleaned_count++;
/* fetch next buffer in frame if non-eop */