igb: defeature tx head writeback

This patch removes tx head writeback as it was found to not provide a
significant improvement in tx performance and on some systems has been seen
to cause a performance degredation due to partial cache line writes.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 3 deletions

diff --git a/drivers/net/igb/igb.h b/drivers/net/igb/igb.h
index 2121b8bc6ea7..c90632524fda 100644
--- a/drivers/net/igb/igb.h
+++ b/drivers/net/igb/igb.h
@@ -43,8 +43,6 @@ struct igb_adapter;
 #endif
 
 /* Interrupt defines */
-#define IGB_MAX_TX_CLEAN 72
-
 #define IGB_MIN_DYN_ITR 3000
 #define IGB_MAX_DYN_ITR 96000
 
@@ -127,7 +125,8 @@ struct igb_buffer {
                 /* TX */
                 struct {
                         unsigned long time_stamp;
-                        u32 length;
+                        u16 length;
+                        u16 next_to_watch;
                 };
                 /* RX */
                 struct {