From: Alexander Duyck alexander.h.duyck@linux.intel.com

There were a couple cases where the ITR value generated via the adaptive ITR scheme could exceed 126. This resulted in the value becoming either 0 or something less than 10. Switching back and forth between a value less than 10 and a value greater than 10 can cause issues as certain hardware features such as RSC to not function well when the ITR value has dropped that low.

CC: stable@vger.kernel.org Fixes: b4ded8327fea ("ixgbe: Update adaptive ITR algorithm") Reported-by: Gregg Leventhal gleventhal@janestreet.com Signed-off-by: Alexander Duyck alexander.h.duyck@linux.intel.com Tested-by: Andrew Bowers andrewx.bowers@intel.com Signed-off-by: Jeff Kirsher jeffrey.t.kirsher@intel.com --- drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c index 7882148abb43..77ca9005dc41 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c @@ -2621,7 +2621,7 @@ static void ixgbe_update_itr(struct ixgbe_q_vector *q_vector, /* 16K ints/sec to 9.2K ints/sec */ avg_wire_size *= 15; avg_wire_size += 11452; - } else if (avg_wire_size <= 1980) { + } else if (avg_wire_size < 1968) { /* 9.2K ints/sec to 8K ints/sec */ avg_wire_size *= 5; avg_wire_size += 22420; @@ -2654,6 +2654,8 @@ static void ixgbe_update_itr(struct ixgbe_q_vector *q_vector, case IXGBE_LINK_SPEED_2_5GB_FULL: case IXGBE_LINK_SPEED_1GB_FULL: case IXGBE_LINK_SPEED_10_FULL: + if (avg_wire_size > 8064) + avg_wire_size = 8064; itr += DIV_ROUND_UP(avg_wire_size, IXGBE_ITR_ADAPTIVE_MIN_INC * 64) * IXGBE_ITR_ADAPTIVE_MIN_INC;