cxgb3: ring rx door bell less frequently

Ring free lists door bell less frequently,
specifically every quarter of the active FL
size.

Signed-off-by: Divy Le Ray <divy@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/cxgb3/adapter.h b/drivers/net/cxgb3/adapter.h
index fbe1569..95dce48 100644 (file)
--- a/drivers/net/cxgb3/adapter.h
+++ b/drivers/net/cxgb3/adapter.h
@@ -91,6 +91,7 @@ struct rx_sw_desc;
 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 */
+       unsigned int pend_cred;     /* new buffers since last FL DB ring */
        unsigned int size;          /* capacity of free list */
        unsigned int cidx;          /* consumer index */
        unsigned int pidx;          /* producer index */

diff --git a/drivers/net/cxgb3/sge.c b/drivers/net/cxgb3/sge.c
index 8205aa4..882beaf 100644 (file)
--- a/drivers/net/cxgb3/sge.c
+++ b/drivers/net/cxgb3/sge.c
@@ -63,6 +63,10 @@
 #define SGE_RX_DROP_THRES 16
 
 /*
+ * Max number of Rx buffers we replenish at a time.
+ */
+#define MAX_RX_REFILL 16U
+/*
  * Period of the Tx buffer reclaim timer.  This timer does not need to run
  * frequently as Tx buffers are usually reclaimed by new Tx packets.
  */
@@ -423,6 +427,14 @@ static int alloc_pg_chunk(struct sge_fl *q, struct rx_sw_desc *sd, gfp_t gfp,
        return 0;
 }
 
+static inline void ring_fl_db(struct adapter *adap, struct sge_fl *q)
+{
+       if (q->pend_cred >= q->credits / 4) {
+               q->pend_cred = 0;
+               t3_write_reg(adap, A_SG_KDOORBELL, V_EGRCNTX(q->cntxt_id));
+       }
+}
+
 /**
  *     refill_fl - refill an SGE free-buffer list
  *     @adapter: the adapter
@@ -478,19 +490,19 @@ nomem:                            q->alloc_failed++;
                        sd = q->sdesc;
                        d = q->desc;
                }
-               q->credits++;
                count++;
        }
-       wmb();
-       if (likely(count))
-               t3_write_reg(adap, A_SG_KDOORBELL, V_EGRCNTX(q->cntxt_id));
+
+       q->credits += count;
+       q->pend_cred += count;
+       ring_fl_db(adap, q);
 
        return count;
 }
 
 static inline void __refill_fl(struct adapter *adap, struct sge_fl *fl)
 {
-       refill_fl(adap, fl, min(16U, fl->size - fl->credits),
+       refill_fl(adap, fl, min(MAX_RX_REFILL, fl->size - fl->credits),
                  GFP_ATOMIC | __GFP_COMP);
 }
 
@@ -515,13 +527,15 @@ static void recycle_rx_buf(struct adapter *adap, struct sge_fl *q,
        wmb();
        to->len_gen = cpu_to_be32(V_FLD_GEN1(q->gen));
        to->gen2 = cpu_to_be32(V_FLD_GEN2(q->gen));
-       q->credits++;
 
        if (++q->pidx == q->size) {
                q->pidx = 0;
                q->gen ^= 1;
        }
-       t3_write_reg(adap, A_SG_KDOORBELL, V_EGRCNTX(q->cntxt_id));
+
+       q->credits++;
+       q->pend_cred++;
+       ring_fl_db(adap, q);
 }
 
 /**
@@ -732,7 +746,9 @@ recycle:
                return skb;
        }
 
-       if (unlikely(fl->credits < drop_thres))
+       if (unlikely(fl->credits < drop_thres) &&
+           refill_fl(adap, fl, min(MAX_RX_REFILL, fl->size - fl->credits - 1),
+                     GFP_ATOMIC | __GFP_COMP) == 0)
                goto recycle;
 
 use_orig_buf: