cxgb3 - Feed Rx free list with pages

Populate Rx free list with pages.

Signed-off-by: Divy Le Ray <divy@chelsio.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

2 files changed, 235 insertions, 92 deletions

diff --git a/drivers/net/cxgb3/adapter.h b/drivers/net/cxgb3/adapter.h
index 01b99b901434..80c3d8f268a7 100644
--- a/drivers/net/cxgb3/adapter.h
+++ b/drivers/net/cxgb3/adapter.h
@@ -74,6 +74,11 @@ enum {				/* adapter flags */
 struct rx_desc;
 struct rx_sw_desc;
 
+struct sge_fl_page {
+        struct skb_frag_struct frag;
+        unsigned char *va;
+};
+
 struct sge_fl {                 /* SGE per free-buffer list state */
         unsigned int buf_size;  /* size of each Rx buffer */
         unsigned int credits;   /* # of available Rx buffers */
@@ -81,11 +86,13 @@ struct sge_fl {			/* SGE per free-buffer list state */
         unsigned int cidx;      /* consumer index */
         unsigned int pidx;      /* producer index */
         unsigned int gen;       /* free list generation */
+        unsigned int cntxt_id;  /* SGE context id for the free list */
+        struct sge_fl_page page;
         struct rx_desc *desc;   /* address of HW Rx descriptor ring */
         struct rx_sw_desc *sdesc;       /* address of SW Rx descriptor ring */
         dma_addr_t phys_addr;   /* physical address of HW ring start */
-        unsigned int cntxt_id;  /* SGE context id for the free list */
         unsigned long empty;    /* # of times queue ran out of buffers */
+        unsigned long alloc_failed; /* # of times buffer allocation failed */
 };
 
 /*
diff --git a/drivers/net/cxgb3/sge.c b/drivers/net/cxgb3/sge.c
index 4ff0ab60c6c7..c23783432e51 100644
--- a/drivers/net/cxgb3/sge.c
+++ b/drivers/net/cxgb3/sge.c
@@ -45,9 +45,25 @@
 #define USE_GTS 0
 
 #define SGE_RX_SM_BUF_SIZE 1536
+
+/*
+ * If USE_RX_PAGE is defined, the small freelist populated with (partial)
+ * pages instead of skbs. Pages are carved up into RX_PAGE_SIZE chunks (must
+ * be a multiple of the host page size).
+ */
+#define USE_RX_PAGE
+#define RX_PAGE_SIZE 2048
+
+/*
+ * skb freelist packets are copied into a new skb (and the freelist one is 
+ * reused) if their len is <= 
+ */
 #define SGE_RX_COPY_THRES  256
 
-# define SGE_RX_DROP_THRES 16
+/*
+ * Minimum number of freelist entries before we start dropping TUNNEL frames.
+ */
+#define SGE_RX_DROP_THRES 16
 
 /*
  * Period of the Tx buffer reclaim timer.  This timer does not need to run
@@ -85,7 +101,10 @@ struct tx_sw_desc {		/* SW state per Tx descriptor */
 };
 
 struct rx_sw_desc {             /* SW state per Rx descriptor */
-        struct sk_buff *skb;
+        union {
+                struct sk_buff *skb;
+                struct sge_fl_page page;
+        } t;
          DECLARE_PCI_UNMAP_ADDR(dma_addr);
 };
 
@@ -332,16 +351,27 @@ static void free_rx_bufs(struct pci_dev *pdev, struct sge_fl *q)
 
                 pci_unmap_single(pdev, pci_unmap_addr(d, dma_addr),
                                  q->buf_size, PCI_DMA_FROMDEVICE);
-                kfree_skb(d->skb);
-                d->skb = NULL;
+
+                if (q->buf_size != RX_PAGE_SIZE) {
+                        kfree_skb(d->t.skb);
+                        d->t.skb = NULL;
+                } else {
+                        if (d->t.page.frag.page)
+                                put_page(d->t.page.frag.page);
+                        d->t.page.frag.page = NULL;
+                }
                 if (++cidx == q->size)
                         cidx = 0;
         }
+
+        if (q->page.frag.page)
+                put_page(q->page.frag.page);
+        q->page.frag.page = NULL;
 }
 
 /**
  *      add_one_rx_buf - add a packet buffer to a free-buffer list
- *      @skb: the buffer to add
+ *      @va: va of the buffer to add
  *      @len: the buffer length
  *      @d: the HW Rx descriptor to write
  *      @sd: the SW Rx descriptor to write
@@ -351,14 +381,13 @@ static void free_rx_bufs(struct pci_dev *pdev, struct sge_fl *q)
  *      Add a buffer of the given length to the supplied HW and SW Rx
  *      descriptors.
  */
-static inline void add_one_rx_buf(struct sk_buff *skb, unsigned int len,
+static inline void add_one_rx_buf(unsigned char *va, unsigned int len,
                                   struct rx_desc *d, struct rx_sw_desc *sd,
                                   unsigned int gen, struct pci_dev *pdev)
 {
         dma_addr_t mapping;
 
-        sd->skb = skb;
-        mapping = pci_map_single(pdev, skb->data, len, PCI_DMA_FROMDEVICE);
+        mapping = pci_map_single(pdev, va, len, PCI_DMA_FROMDEVICE);
         pci_unmap_addr_set(sd, dma_addr, mapping);
 
         d->addr_lo = cpu_to_be32(mapping);
@@ -383,14 +412,47 @@ static void refill_fl(struct adapter *adap, struct sge_fl *q, int n, gfp_t gfp)
 {
         struct rx_sw_desc *sd = &q->sdesc[q->pidx];
         struct rx_desc *d = &q->desc[q->pidx];
+        struct sge_fl_page *p = &q->page;
 
         while (n--) {
-                struct sk_buff *skb = alloc_skb(q->buf_size, gfp);
+                unsigned char *va;
 
-                if (!skb)
-                        break;
+                if (unlikely(q->buf_size != RX_PAGE_SIZE)) {
+                        struct sk_buff *skb = alloc_skb(q->buf_size, gfp);
+
+                        if (!skb) {
+                                q->alloc_failed++;
+                                break;
+                        }
+                        va = skb->data;
+                        sd->t.skb = skb;
+                } else {
+                        if (!p->frag.page) {
+                                p->frag.page = alloc_pages(gfp, 0);
+                                if (unlikely(!p->frag.page)) {
+                                        q->alloc_failed++;
+                                        break;
+                                } else {
+                                        p->frag.size = RX_PAGE_SIZE;
+                                        p->frag.page_offset = 0;
+                                        p->va = page_address(p->frag.page);
+                                }
+                        }
+
+                        memcpy(&sd->t, p, sizeof(*p));
+                        va = p->va;
+
+                        p->frag.page_offset += RX_PAGE_SIZE;
+                        BUG_ON(p->frag.page_offset > PAGE_SIZE);
+                        p->va += RX_PAGE_SIZE;
+                        if (p->frag.page_offset == PAGE_SIZE)
+                                p->frag.page = NULL;
+                        else
+                                get_page(p->frag.page);
+                }
+
+                add_one_rx_buf(va, q->buf_size, d, sd, q->gen, adap->pdev);
 
-                add_one_rx_buf(skb, q->buf_size, d, sd, q->gen, adap->pdev);
                 d++;
                 sd++;
                 if (++q->pidx == q->size) {
@@ -425,7 +487,7 @@ static void recycle_rx_buf(struct adapter *adap, struct sge_fl *q,
         struct rx_desc *from = &q->desc[idx];
         struct rx_desc *to = &q->desc[q->pidx];
 
-        q->sdesc[q->pidx] = q->sdesc[idx];
+        memcpy(&q->sdesc[q->pidx], &q->sdesc[idx], sizeof(struct rx_sw_desc));
         to->addr_lo = from->addr_lo;    /* already big endian */
         to->addr_hi = from->addr_hi;    /* likewise */
         wmb();
@@ -458,7 +520,7 @@ static void recycle_rx_buf(struct adapter *adap, struct sge_fl *q,
  *      of the SW ring.
  */
 static void *alloc_ring(struct pci_dev *pdev, size_t nelem, size_t elem_size,
-                        size_t sw_size, dma_addr_t *phys, void *metadata)
+                        size_t sw_size, dma_addr_t * phys, void *metadata)
 {
         size_t len = nelem * elem_size;
         void *s = NULL;
@@ -588,61 +650,6 @@ static inline unsigned int flits_to_desc(unsigned int n)
 }
 
 /**
- *      get_packet - return the next ingress packet buffer from a free list
- *      @adap: the adapter that received the packet
- *      @fl: the SGE free list holding the packet
- *      @len: the packet length including any SGE padding
- *      @drop_thres: # of remaining buffers before we start dropping packets
- *
- *      Get the next packet from a free list and complete setup of the
- *      sk_buff.  If the packet is small we make a copy and recycle the
- *      original buffer, otherwise we use the original buffer itself.  If a
- *      positive drop threshold is supplied packets are dropped and their
- *      buffers recycled if (a) the number of remaining buffers is under the
- *      threshold and the packet is too big to copy, or (b) the packet should
- *      be copied but there is no memory for the copy.
- */
-static struct sk_buff *get_packet(struct adapter *adap, struct sge_fl *fl,
-                                  unsigned int len, unsigned int drop_thres)
-{
-        struct sk_buff *skb = NULL;
-        struct rx_sw_desc *sd = &fl->sdesc[fl->cidx];
-
-        prefetch(sd->skb->data);
-
-        if (len <= SGE_RX_COPY_THRES) {
-                skb = alloc_skb(len, GFP_ATOMIC);
-                if (likely(skb != NULL)) {
-                        __skb_put(skb, len);
-                        pci_dma_sync_single_for_cpu(adap->pdev,
-                                                    pci_unmap_addr(sd,
-                                                                   dma_addr),
-                                                    len, PCI_DMA_FROMDEVICE);
-                        memcpy(skb->data, sd->skb->data, len);
-                        pci_dma_sync_single_for_device(adap->pdev,
-                                                       pci_unmap_addr(sd,
-                                                                      dma_addr),
-                                                       len, PCI_DMA_FROMDEVICE);
-                } else if (!drop_thres)
-                        goto use_orig_buf;
-              recycle:
-                recycle_rx_buf(adap, fl, fl->cidx);
-                return skb;
-        }
-
-        if (unlikely(fl->credits < drop_thres))
-                goto recycle;
-
-      use_orig_buf:
-        pci_unmap_single(adap->pdev, pci_unmap_addr(sd, dma_addr),
-                         fl->buf_size, PCI_DMA_FROMDEVICE);
-        skb = sd->skb;
-        skb_put(skb, len);
-        __refill_fl(adap, fl);
-        return skb;
-}
-
-/**
  *      get_imm_packet - return the next ingress packet buffer from a response
  *      @resp: the response descriptor containing the packet data
  *
@@ -1676,7 +1683,6 @@ static void rx_eth(struct adapter *adap, struct sge_rspq *rq,
         struct cpl_rx_pkt *p = (struct cpl_rx_pkt *)(skb->data + pad);
         struct port_info *pi;
 
-        rq->eth_pkts++;
         skb_pull(skb, sizeof(*p) + pad);
         skb->dev = adap->port[p->iff];
         skb->dev->last_rx = jiffies;
@@ -1704,6 +1710,85 @@ static void rx_eth(struct adapter *adap, struct sge_rspq *rq,
                 netif_rx(skb);
 }
 
+#define SKB_DATA_SIZE 128
+
+static void skb_data_init(struct sk_buff *skb, struct sge_fl_page *p,
+                          unsigned int len)
+{
+        skb->len = len;
+        if (len <= SKB_DATA_SIZE) {
+                memcpy(skb->data, p->va, len);
+                skb->tail += len;
+                put_page(p->frag.page);
+        } else {
+                memcpy(skb->data, p->va, SKB_DATA_SIZE);
+                skb_shinfo(skb)->frags[0].page = p->frag.page;
+                skb_shinfo(skb)->frags[0].page_offset =
+                    p->frag.page_offset + SKB_DATA_SIZE;
+                skb_shinfo(skb)->frags[0].size = len - SKB_DATA_SIZE;
+                skb_shinfo(skb)->nr_frags = 1;
+                skb->data_len = len - SKB_DATA_SIZE;
+                skb->tail += SKB_DATA_SIZE;
+                skb->truesize += skb->data_len;
+        }
+}
+
+/**
+*      get_packet - return the next ingress packet buffer from a free list
+*      @adap: the adapter that received the packet
+*      @fl: the SGE free list holding the packet
+*      @len: the packet length including any SGE padding
+*      @drop_thres: # of remaining buffers before we start dropping packets
+*
+*      Get the next packet from a free list and complete setup of the
+*      sk_buff.  If the packet is small we make a copy and recycle the
+*      original buffer, otherwise we use the original buffer itself.  If a
+*      positive drop threshold is supplied packets are dropped and their
+*      buffers recycled if (a) the number of remaining buffers is under the
+*      threshold and the packet is too big to copy, or (b) the packet should
+*      be copied but there is no memory for the copy.
+*/
+static struct sk_buff *get_packet(struct adapter *adap, struct sge_fl *fl,
+                                  unsigned int len, unsigned int drop_thres)
+{
+        struct sk_buff *skb = NULL;
+        struct rx_sw_desc *sd = &fl->sdesc[fl->cidx];
+
+        prefetch(sd->t.skb->data);
+
+        if (len <= SGE_RX_COPY_THRES) {
+                skb = alloc_skb(len, GFP_ATOMIC);
+                if (likely(skb != NULL)) {
+                        struct rx_desc *d = &fl->desc[fl->cidx];
+                        dma_addr_t mapping =
+                            (dma_addr_t)((u64) be32_to_cpu(d->addr_hi) << 32 |
+                                         be32_to_cpu(d->addr_lo));
+
+                        __skb_put(skb, len);
+                        pci_dma_sync_single_for_cpu(adap->pdev, mapping, len,
+                                                    PCI_DMA_FROMDEVICE);
+                        memcpy(skb->data, sd->t.skb->data, len);
+                        pci_dma_sync_single_for_device(adap->pdev, mapping, len,
+                                                       PCI_DMA_FROMDEVICE);
+                } else if (!drop_thres)
+                        goto use_orig_buf;
+recycle:
+                recycle_rx_buf(adap, fl, fl->cidx);
+                return skb;
+        }
+
+        if (unlikely(fl->credits < drop_thres))
+                goto recycle;
+
+use_orig_buf:
+        pci_unmap_single(adap->pdev, pci_unmap_addr(sd, dma_addr),
+                         fl->buf_size, PCI_DMA_FROMDEVICE);
+        skb = sd->t.skb;
+        skb_put(skb, len);
+        __refill_fl(adap, fl);
+        return skb;
+}
+
 /**
  *      handle_rsp_cntrl_info - handles control information in a response
  *      @qs: the queue set corresponding to the response
@@ -1826,7 +1911,7 @@ static int process_responses(struct adapter *adap, struct sge_qset *qs,
         q->next_holdoff = q->holdoff_tmr;
 
         while (likely(budget_left && is_new_response(r, q))) {
-                int eth, ethpad = 0;
+                int eth, ethpad = 2;
                 struct sk_buff *skb = NULL;
                 u32 len, flags = ntohl(r->flags);
                 u32 rss_hi = *(const u32 *)r, rss_lo = r->rss_hdr.rss_hash_val;
@@ -1853,18 +1938,56 @@ static int process_responses(struct adapter *adap, struct sge_qset *qs,
                                 break;
                         }
                         q->imm_data++;
+                        ethpad = 0;
                 } else if ((len = ntohl(r->len_cq)) != 0) {
-                        struct sge_fl *fl;
+                        struct sge_fl *fl =
+                            (len & F_RSPD_FLQ) ? &qs->fl[1] : &qs->fl[0];
+
+                        if (fl->buf_size == RX_PAGE_SIZE) {
+                                struct rx_sw_desc *sd = &fl->sdesc[fl->cidx];
+                                struct sge_fl_page *p = &sd->t.page;
+
+                                prefetch(p->va);
+                                prefetch(p->va + L1_CACHE_BYTES);
+
+                                __refill_fl(adap, fl);
+
+                                pci_unmap_single(adap->pdev,
+                                                 pci_unmap_addr(sd, dma_addr),
+                                                 fl->buf_size,
+                                                 PCI_DMA_FROMDEVICE);
+
+                                if (eth) {
+                                        if (unlikely(fl->credits <
+                                                     SGE_RX_DROP_THRES))
+                                                goto eth_recycle;
+
+                                        skb = alloc_skb(SKB_DATA_SIZE,
+                                                        GFP_ATOMIC);
+                                        if (unlikely(!skb)) {
+eth_recycle:
+                                                q->rx_drops++;
+                                                recycle_rx_buf(adap, fl,
+                                                               fl->cidx);
+                                                goto eth_done;
+                                        }
+                                } else {
+                                        skb = alloc_skb(SKB_DATA_SIZE,
+                                                        GFP_ATOMIC);
+                                        if (unlikely(!skb))
+                                                goto no_mem;
+                                }
+
+                                skb_data_init(skb, p, G_RSPD_LEN(len));
+eth_done:
+                                fl->credits--;
+                                q->eth_pkts++;
+                        } else {
+                                fl->credits--;
+                                skb = get_packet(adap, fl, G_RSPD_LEN(len),
+                                                 eth ? SGE_RX_DROP_THRES : 0);
+                        }
 
-                        fl = (len & F_RSPD_FLQ) ? &qs->fl[1] : &qs->fl[0];
-                        fl->credits--;
-                        skb = get_packet(adap, fl, G_RSPD_LEN(len),
-                                         eth ? SGE_RX_DROP_THRES : 0);
-                        if (!skb)
-                                q->rx_drops++;
-                        else if (r->rss_hdr.opcode == CPL_TRACE_PKT)
-                                __skb_pull(skb, 2);
-                        ethpad = 2;
                         if (++fl->cidx == fl->size)
                                 fl->cidx = 0;
                 } else
@@ -1888,18 +2011,23 @@ static int process_responses(struct adapter *adap, struct sge_qset *qs,
                         q->credits = 0;
                 }
 
-                if (likely(skb != NULL)) {
+                if (skb) {
+                        /* Preserve the RSS info in csum & priority */
+                        skb->csum = rss_hi;
+                        skb->priority = rss_lo;
+
                         if (eth)
                                 rx_eth(adap, q, skb, ethpad);
                         else {
-                                /* Preserve the RSS info in csum & priority */
-                                skb->csum = rss_hi;
-                                skb->priority = rss_lo;
-                                ngathered = rx_offload(&adap->tdev, q, skb,
-                                                       offload_skbs, ngathered);
+                                if (unlikely(r->rss_hdr.opcode ==
+                                             CPL_TRACE_PKT))
+                                        __skb_pull(skb, ethpad);
+
+                                ngathered = rx_offload(&adap->tdev, q,
+                                                       skb, offload_skbs,
+                                                       ngathered);
                         }
                 }
-
                 --budget_left;
         }
 
@@ -2376,7 +2504,7 @@ static void sge_timer_cb(unsigned long data)
                 spin_unlock(&qs->txq[TXQ_OFLD].lock);
         }
         lock = (adap->flags & USING_MSIX) ? &qs->rspq.lock :
-                                            &adap->sge.qs[0].rspq.lock;
+            &adap->sge.qs[0].rspq.lock;
         if (spin_trylock_irq(lock)) {
                 if (!napi_is_scheduled(qs->netdev)) {
                         u32 status = t3_read_reg(adap, A_SG_RSPQ_FL_STATUS);
@@ -2392,7 +2520,7 @@ static void sge_timer_cb(unsigned long data)
                                         refill_rspq(adap, &qs->rspq, 1);
                                         qs->rspq.credits--;
                                         qs->rspq.restarted++;
-                                        t3_write_reg(adap, A_SG_RSPQ_FL_STATUS, 
+                                        t3_write_reg(adap, A_SG_RSPQ_FL_STATUS,
                                                      1 << qs->rspq.cntxt_id);
                                 }
                         }
@@ -2504,13 +2632,21 @@ int t3_sge_alloc_qset(struct adapter *adapter, unsigned int id, int nports,
             flits_to_desc(sgl_len(MAX_SKB_FRAGS + 1) + 3);
 
         if (ntxq == 1) {
+#ifdef USE_RX_PAGE
+                q->fl[0].buf_size = RX_PAGE_SIZE;
+#else
                 q->fl[0].buf_size = SGE_RX_SM_BUF_SIZE + 2 +
                     sizeof(struct cpl_rx_pkt);
+#endif
                 q->fl[1].buf_size = MAX_FRAME_SIZE + 2 +
                     sizeof(struct cpl_rx_pkt);
         } else {
+#ifdef USE_RX_PAGE
+                q->fl[0].buf_size = RX_PAGE_SIZE;
+#else
                 q->fl[0].buf_size = SGE_RX_SM_BUF_SIZE +
                     sizeof(struct cpl_rx_data);
+#endif
                 q->fl[1].buf_size = (16 * 1024) -
                     SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
         }
@@ -2704,7 +2840,7 @@ void __devinit t3_sge_prep(struct adapter *adap, struct sge_params *p)
                 q->polling = adap->params.rev > 0;
                 q->coalesce_usecs = 5;
                 q->rspq_size = 1024;
-                q->fl_size = 4096;
+                q->fl_size = 1024;
                 q->jumbo_size = 512;
                 q->txq_size[TXQ_ETH] = 1024;
                 q->txq_size[TXQ_OFLD] = 1024;