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igb: Map entire page and sync half instead of mapping and unmapping half pages

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This change makes it so that we map the entire page and just sync half of
it for the device at a time.  The advantage to this approach is that we can
avoid the locking on map/unmap seen in many IOMMU implementations.

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 2012-09-25 00:31:02 +00:00 committed by Jeff Kirsher
parent db2ee5bdf5
commit cbc8e55f6f
3 changed files with 180 additions and 56 deletions
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1
drivers/net/ethernet/intel/igb/igb.h
View File

@ -239,6 +239,7 @@ struct igb_ring {
/* everything past this point are written often */
u16 next_to_clean ____cacheline_aligned_in_smp;
u16 next_to_use;
u16 next_to_alloc;
union {
/* TX */

26
drivers/net/ethernet/intel/igb/igb_ethtool.c
View File

@ -1694,7 +1694,7 @@ static int igb_check_lbtest_frame(struct igb_rx_buffer *rx_buffer,
frame_size >>= 1;
data = kmap(rx_buffer->page) + rx_buffer->page_offset;
data = kmap(rx_buffer->page);
if (data[3] != 0xFF ||
data[frame_size + 10] != 0xBE ||
@ -1713,9 +1713,7 @@ static int igb_clean_test_rings(struct igb_ring *rx_ring,
union e1000_adv_rx_desc *rx_desc;
struct igb_rx_buffer *rx_buffer_info;
struct igb_tx_buffer *tx_buffer_info;
struct netdev_queue *txq;
u16 rx_ntc, tx_ntc, count = 0;
unsigned int total_bytes = 0, total_packets = 0;
/* initialize next to clean and descriptor values */
rx_ntc = rx_ring->next_to_clean;
@ -1726,21 +1724,24 @@ static int igb_clean_test_rings(struct igb_ring *rx_ring,
/* check rx buffer */
rx_buffer_info = &rx_ring->rx_buffer_info[rx_ntc];
/* unmap rx buffer, will be remapped by alloc_rx_buffers */
dma_unmap_single(rx_ring->dev,
rx_buffer_info->dma,
PAGE_SIZE / 2,
DMA_FROM_DEVICE);
rx_buffer_info->dma = 0;
/* sync Rx buffer for CPU read */
dma_sync_single_for_cpu(rx_ring->dev,
rx_buffer_info->dma,
PAGE_SIZE / 2,
DMA_FROM_DEVICE);
/* verify contents of skb */
if (igb_check_lbtest_frame(rx_buffer_info, size))
count++;
/* sync Rx buffer for device write */
dma_sync_single_for_device(rx_ring->dev,
rx_buffer_info->dma,
PAGE_SIZE / 2,
DMA_FROM_DEVICE);
/* unmap buffer on tx side */
tx_buffer_info = &tx_ring->tx_buffer_info[tx_ntc];
total_bytes += tx_buffer_info->bytecount;
total_packets += tx_buffer_info->gso_segs;
igb_unmap_and_free_tx_resource(tx_ring, tx_buffer_info);
/* increment rx/tx next to clean counters */
@ -1755,8 +1756,7 @@ static int igb_clean_test_rings(struct igb_ring *rx_ring,
rx_desc = IGB_RX_DESC(rx_ring, rx_ntc);
}
txq = netdev_get_tx_queue(tx_ring->netdev, tx_ring->queue_index);
netdev_tx_completed_queue(txq, total_packets, total_bytes);
netdev_tx_reset_queue(txring_txq(tx_ring));
/* re-map buffers to ring, store next to clean values */
igb_alloc_rx_buffers(rx_ring, count);

209
drivers/net/ethernet/intel/igb/igb_main.c
View File

@ -2785,6 +2785,7 @@ int igb_setup_rx_resources(struct igb_ring *rx_ring)
if (!rx_ring->desc)
goto err;
rx_ring->next_to_alloc = 0;
rx_ring->next_to_clean = 0;
rx_ring->next_to_use = 0;
@ -3312,16 +3313,16 @@ static void igb_clean_rx_ring(struct igb_ring *rx_ring)
for (i = 0; i < rx_ring->count; i++) {
struct igb_rx_buffer *buffer_info = &rx_ring->rx_buffer_info[i];
if (buffer_info->dma)
dma_unmap_page(rx_ring->dev,
buffer_info->dma,
PAGE_SIZE / 2,
DMA_FROM_DEVICE);
buffer_info->dma = 0;
if (buffer_info->page)
__free_page(buffer_info->page);
if (!buffer_info->page)
continue;
dma_unmap_page(rx_ring->dev,
buffer_info->dma,
PAGE_SIZE,
DMA_FROM_DEVICE);
__free_page(buffer_info->page);
buffer_info->page = NULL;
buffer_info->page_offset = 0;
}
size = sizeof(struct igb_rx_buffer) * rx_ring->count;
@ -3330,6 +3331,7 @@ static void igb_clean_rx_ring(struct igb_ring *rx_ring)
/* Zero out the descriptor ring */
memset(rx_ring->desc, 0, rx_ring->size);
rx_ring->next_to_alloc = 0;
rx_ring->next_to_clean = 0;
rx_ring->next_to_use = 0;
}
@ -5828,6 +5830,104 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector)
return !!budget;
}
/**
* igb_reuse_rx_page - page flip buffer and store it back on the ring
* @rx_ring: rx descriptor ring to store buffers on
* @old_buff: donor buffer to have page reused
*
* Synchronizes page for reuse by the adapter
**/
static void igb_reuse_rx_page(struct igb_ring *rx_ring,
struct igb_rx_buffer *old_buff)
{
struct igb_rx_buffer *new_buff;
u16 nta = rx_ring->next_to_alloc;
new_buff = &rx_ring->rx_buffer_info[nta];
/* update, and store next to alloc */
nta++;
rx_ring->next_to_alloc = (nta < rx_ring->count) ? nta : 0;
/* transfer page from old buffer to new buffer */
memcpy(new_buff, old_buff, sizeof(struct igb_rx_buffer));
/* sync the buffer for use by the device */
dma_sync_single_range_for_device(rx_ring->dev, old_buff->dma,
old_buff->page_offset,
PAGE_SIZE / 2,
DMA_FROM_DEVICE);
}
/**
* 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
*
* 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,
struct igb_rx_buffer *rx_buffer,
union e1000_adv_rx_desc *rx_desc,
struct sk_buff *skb)
{
struct page *page = rx_buffer->page;
unsigned int size = le16_to_cpu(rx_desc->wb.upper.length);
if ((size <= IGB_RX_HDR_LEN) && !skb_is_nonlinear(skb)) {
unsigned char *va = page_address(page) + rx_buffer->page_offset;
#ifdef CONFIG_IGB_PTP
if (igb_test_staterr(rx_desc, E1000_RXDADV_STAT_TSIP)) {
igb_ptp_rx_pktstamp(rx_ring->q_vector, va, skb);
va += IGB_TS_HDR_LEN;
size -= IGB_TS_HDR_LEN;
}
#endif
memcpy(__skb_put(skb, size), va, ALIGN(size, sizeof(long)));
/* we can reuse buffer as-is, just make sure it is local */
if (likely(page_to_nid(page) == numa_node_id()))
return true;
/* this page cannot be reused so discard it */
put_page(page);
return false;
}
skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page,
rx_buffer->page_offset, size, PAGE_SIZE / 2);
/* avoid re-using remote pages */
if (unlikely(page_to_nid(page) != numa_node_id()))
return false;
/* if we are only owner of page we can reuse it */
if (unlikely(page_count(page) != 1))
return false;
/* flip page offset to other buffer */
rx_buffer->page_offset ^= PAGE_SIZE / 2;
/*
* since we are the only owner of the page and we need to
* increment it, just set the value to 2 in order to avoid
* an unnecessary locked operation
*/
atomic_set(&page->_count, 2);
return true;
}
static inline void igb_rx_checksum(struct igb_ring *ring,
union e1000_adv_rx_desc *rx_desc,
struct sk_buff *skb)
@ -5985,6 +6085,7 @@ static unsigned int igb_get_headlen(unsigned char *data,
/**
* igb_pull_tail - igb specific version of skb_pull_tail
* @rx_ring: rx descriptor ring packet is being transacted on
* @rx_desc: pointer to the EOP Rx descriptor
* @skb: pointer to current skb being adjusted
*
* This function is an igb specific version of __pskb_pull_tail. The
@ -6131,7 +6232,6 @@ static bool igb_clean_rx_irq(struct igb_q_vector *q_vector, int budget)
struct igb_ring *rx_ring = q_vector->rx.ring;
union e1000_adv_rx_desc *rx_desc;
struct sk_buff *skb = rx_ring->skb;
const int current_node = numa_node_id();
unsigned int total_bytes = 0, total_packets = 0;
u16 cleaned_count = igb_desc_unused(rx_ring);
u16 i = rx_ring->next_to_clean;
@ -6186,20 +6286,25 @@ static bool igb_clean_rx_irq(struct igb_q_vector *q_vector, int budget)
prefetchw(skb->data);
}
skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page,
buffer_info->page_offset,
le16_to_cpu(rx_desc->wb.upper.length),
PAGE_SIZE / 2);
/* we are reusing so sync this buffer for CPU use */
dma_sync_single_range_for_cpu(rx_ring->dev,
buffer_info->dma,
buffer_info->page_offset,
PAGE_SIZE / 2,
DMA_FROM_DEVICE);
if ((page_count(buffer_info->page) != 1) ||
(page_to_nid(buffer_info->page) != current_node))
buffer_info->page = NULL;
else
get_page(buffer_info->page);
/* pull page into skb */
if (igb_add_rx_frag(rx_ring, buffer_info, rx_desc, skb)) {
/* hand second half of page back to the ring */
igb_reuse_rx_page(rx_ring, buffer_info);
} else {
/* we are not reusing the buffer so unmap it */
dma_unmap_page(rx_ring->dev, buffer_info->dma,
PAGE_SIZE, DMA_FROM_DEVICE);
}
dma_unmap_page(rx_ring->dev, buffer_info->dma,
PAGE_SIZE / 2, DMA_FROM_DEVICE);
buffer_info->dma = 0;
/* clear contents of buffer_info */
buffer_info->page = NULL;
if (!igb_test_staterr(rx_desc, E1000_RXD_STAT_EOP))
goto next_desc;
@ -6259,32 +6364,36 @@ static bool igb_alloc_mapped_page(struct igb_ring *rx_ring,
struct igb_rx_buffer *bi)
{
struct page *page = bi->page;
dma_addr_t dma = bi->dma;
unsigned int page_offset = bi->page_offset ^ (PAGE_SIZE / 2);
dma_addr_t dma;
if (dma)
/* since we are recycling buffers we should seldom need to alloc */
if (likely(page))
return true;
if (!page) {
page = __skb_alloc_page(GFP_ATOMIC | __GFP_COLD, NULL);
if (unlikely(!page)) {
rx_ring->rx_stats.alloc_failed++;
return false;
}
bi->page = page;
/* alloc new page for storage */
page = __skb_alloc_page(GFP_ATOMIC | __GFP_COLD, NULL);
if (unlikely(!page)) {
rx_ring->rx_stats.alloc_failed++;
return false;
}
dma = dma_map_page(rx_ring->dev, page,
page_offset, PAGE_SIZE / 2,
DMA_FROM_DEVICE);
/* map page for use */
dma = dma_map_page(rx_ring->dev, page, 0, PAGE_SIZE, DMA_FROM_DEVICE);
/*
* if mapping failed free memory back to system since
* there isn't much point in holding memory we can't use
*/
if (dma_mapping_error(rx_ring->dev, dma)) {
__free_page(page);
rx_ring->rx_stats.alloc_failed++;
return false;
}
bi->dma = dma;
bi->page_offset = page_offset;
bi->page = page;
bi->page_offset = 0;
return true;
}
@ -6299,17 +6408,23 @@ void igb_alloc_rx_buffers(struct igb_ring *rx_ring, u16 cleaned_count)
struct igb_rx_buffer *bi;
u16 i = rx_ring->next_to_use;
/* nothing to do */
if (!cleaned_count)
return;
rx_desc = IGB_RX_DESC(rx_ring, i);
bi = &rx_ring->rx_buffer_info[i];
i -= rx_ring->count;
while (cleaned_count--) {
do {
if (!igb_alloc_mapped_page(rx_ring, bi))
break;
/* Refresh the desc even if buffer_addrs didn't change
* because each write-back erases this info. */
rx_desc->read.pkt_addr = cpu_to_le64(bi->dma);
/*
* Refresh the desc even if buffer_addrs didn't change
* because each write-back erases this info.
*/
rx_desc->read.pkt_addr = cpu_to_le64(bi->dma + bi->page_offset);
rx_desc++;
bi++;
@ -6322,17 +6437,25 @@ void igb_alloc_rx_buffers(struct igb_ring *rx_ring, u16 cleaned_count)
/* clear the hdr_addr for the next_to_use descriptor */
rx_desc->read.hdr_addr = 0;
}
cleaned_count--;
} while (cleaned_count);
i += rx_ring->count;
if (rx_ring->next_to_use != i) {
/* record the next descriptor to use */
rx_ring->next_to_use = i;
/* Force memory writes to complete before letting h/w
/* update next to alloc since we have filled the ring */
rx_ring->next_to_alloc = i;
/*
* Force memory writes to complete before letting h/w
* know there are new descriptors to fetch. (Only
* applicable for weak-ordered memory model archs,
* such as IA-64). */
* such as IA-64).
*/
wmb();
writel(i, rx_ring->tail);
}