[PATCH net-next 7/9] mlx4: removal of frag_sizes[]

[Eric Dumazet]

We will soon use order-0 pages, and frag truesize will more precisely
match real sizes.

In the new model, we prefer to use <= 2048 bytes fragments, so that
we can use page-recycle technique on PAGE_SIZE=4096 arches.

We will still pack as much frames as possible on arches with big
pages, like PowerPC.

Signed-off-by: Eric Dumazet <eduma...@google.com>
---
 drivers/net/ethernet/mellanox/mlx4/en_rx.c   | 24 ++++++++++--------------
 drivers/net/ethernet/mellanox/mlx4/mlx4_en.h |  8 --------
 2 files changed, 10 insertions(+), 22 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c 
b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
index 
6c95694f6390aa9fbc5f941a97e305815949..dd3bfcfea10c4545dfeda0f999449b13ca91 
100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
@@ -1178,13 +1178,6 @@ int mlx4_en_poll_rx_cq(struct napi_struct *napi, int 
budget)
        return done;
 }
 
-static const int frag_sizes[] = {
-       FRAG_SZ0,
-       FRAG_SZ1,
-       FRAG_SZ2,
-       FRAG_SZ3
-};
-
 void mlx4_en_calc_rx_buf(struct net_device *dev)
 {
        struct mlx4_en_priv *priv = netdev_priv(dev);
@@ -1208,13 +1201,16 @@ void mlx4_en_calc_rx_buf(struct net_device *dev)
                int buf_size = 0;
 
                while (buf_size < eff_mtu) {
-                       priv->frag_info[i].frag_size =
-                               (eff_mtu > buf_size + frag_sizes[i]) ?
-                                       frag_sizes[i] : eff_mtu - buf_size;
-                       priv->frag_info[i].frag_stride =
-                               ALIGN(priv->frag_info[i].frag_size,
-                                     SMP_CACHE_BYTES);
-                       buf_size += priv->frag_info[i].frag_size;
+                       int frag_size = eff_mtu - buf_size;
+
+                       if (i < MLX4_EN_MAX_RX_FRAGS - 1)
+                               frag_size = min(frag_size, 2048);
+
+                       priv->frag_info[i].frag_size = frag_size;
+
+                       priv->frag_info[i].frag_stride = ALIGN(frag_size,
+                                                              SMP_CACHE_BYTES);
+                       buf_size += frag_size;
                        i++;
                }
                priv->rx_page_order = MLX4_EN_ALLOC_PREFER_ORDER;
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h 
b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index 
c9916b75b94bc9364b2cbe6da06a5ea385c6..a5bb0103ad8fd3b3f4b3d16099b7bf7ba01b 
100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -104,14 +104,6 @@
 
 #define MLX4_EN_ALLOC_PREFER_ORDER     PAGE_ALLOC_COSTLY_ORDER
 
-/* Receive fragment sizes; we use at most 3 fragments (for 9600 byte MTU
- * and 4K allocations) */
-enum {
-       FRAG_SZ0 = 1536 - NET_IP_ALIGN,
-       FRAG_SZ1 = 4096,
-       FRAG_SZ2 = 4096,
-       FRAG_SZ3 = MLX4_EN_ALLOC_SIZE
-};
 #define MLX4_EN_MAX_RX_FRAGS   4
 
 /* Maximum ring sizes */
-- 
2.11.0.483.g087da7b7c-goog