Re: [RFC net-next 07/14] Fix intel/ixgbe

On Tue, 2012-06-19 at 08:54 -0700, Alexander Duyck wrote:

On 06/19/2012 08:14 AM, Yuval Mintz wrote:

quoted

Signed-off-by: Yuval Mintz <redacted>
Signed-off-by: Eilon Greenstein <redacted>

Cc: Jeff Kirsher <redacted>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
index af1a531..21e4513 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c

@@ -802,7 +802,8 @@ static int ixgbe_set_interrupt_capability(struct ixgbe_adapter *adapter)
 	 * The default is to use pairs of vectors.
 	 */
 	v_budget = max(adapter->num_rx_queues, adapter->num_tx_queues);
-	v_budget = min_t(int, v_budget, num_online_cpus());
+	v_budget = min_t(int, v_budget, min_t(int, num_online_cpus(),
+					      DEFAULT_MAX_NUM_RSS_QUEUES));
 	v_budget += NON_Q_VECTORS;
 
 	/*

This patch doesn't limit the number of queues.  It is limiting the
number of interrupts.  The two are not directly related as we can
support multiple queues per interrupt.

Also this change assumes we are only using receive side scaling.  We
have other features such as DCB, FCoE, and Flow Director which require
additional queues.

You are right - but DEFAULT_MAX_NUM_RSS_QUEUES is there to limit the RSS
and not everything else. It is harder to determine what else should be
set to a lower value and the two goals were to limit the memory waste in
correlation to the number of CPUs and to have some unification between
the drivers - both goals are applicable mostly to the RSS and not so
much to DCB, FCoE and similar features.

Thanks,
Eilon