ibmveth: batch rx buffer replacement

At the moment we try and replenish the receive ring on every rx interrupt.
We even have a pool->threshold but aren't using it.

To limit the maximum latency incurred when refilling, change the threshold
from 1/2 to 7/8 and reduce the largest rx pool from 768 buffers to 512 which
should be more than enough.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Santiago Leon <santil@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 9 insertions, 6 deletions

diff --git a/drivers/net/ibmveth.c b/drivers/net/ibmveth.c
index d2cc6d3f401c..3515ef318eb0 100644
--- a/drivers/net/ibmveth.c
+++ b/drivers/net/ibmveth.c
@@ -178,7 +178,7 @@ static void ibmveth_init_buffer_pool(struct ibmveth_buff_pool *pool, u32 pool_in
         pool->size = pool_size;
         pool->index = pool_index;
         pool->buff_size = buff_size;
-        pool->threshold = pool_size / 2;
+        pool->threshold = pool_size * 7 / 8;
         pool->active = pool_active;
 }
 
@@ -315,10 +315,13 @@ static void ibmveth_replenish_task(struct ibmveth_adapter *adapter)
 
         adapter->replenish_task_cycles++;
 
-        for (i = (IbmVethNumBufferPools - 1); i >= 0; i--)
-                if(adapter->rx_buff_pool[i].active)
-                        ibmveth_replenish_buffer_pool(adapter,
-                                                     &adapter->rx_buff_pool[i]);
+        for (i = (IbmVethNumBufferPools - 1); i >= 0; i--) {
+                struct ibmveth_buff_pool *pool = &adapter->rx_buff_pool[i];
+
+                if (pool->active &&
+                    (atomic_read(&pool->available) < pool->threshold))
+                        ibmveth_replenish_buffer_pool(adapter, pool);
+        }
 
         adapter->rx_no_buffer = *(u64*)(((char*)adapter->buffer_list_addr) + 4096 - 8);
 }
diff --git a/drivers/net/ibmveth.h b/drivers/net/ibmveth.h
index ec76ace66c6b..f3ede8184b6d 100644
--- a/drivers/net/ibmveth.h
+++ b/drivers/net/ibmveth.h
@@ -102,7 +102,7 @@ static inline long h_illan_attributes(unsigned long unit_address,
 #define IBMVETH_MAX_BUF_SIZE (1024 * 128)
 
 static int pool_size[] = { 512, 1024 * 2, 1024 * 16, 1024 * 32, 1024 * 64 };
-static int pool_count[] = { 256, 768, 256, 256, 256 };
+static int pool_count[] = { 256, 512, 256, 256, 256 };
 static int pool_active[] = { 1, 1, 0, 0, 0};
 
 #define IBM_VETH_INVALID_MAP ((u16)0xffff)