Patchwork [net-next,15/15] ixgbe: Update DESC_NEEDED define to adjust for changes to MAX_SKB_FRAGS

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Submitter Jeff Kirsher
Date Feb. 16, 2013, 8:33 a.m.
Message ID <1361003616-3422-16-git-send-email-jeffrey.t.kirsher@intel.com>
Download mbox | patch
Permalink /patch/220947/
State Accepted
Delegated to: David Miller
Headers show

Comments

Jeff Kirsher - Feb. 16, 2013, 8:33 a.m.
From: Alexander Duyck <alexander.h.duyck@intel.com>

Recent changes have made it so that MAX_SKB_FRAGS is now never less than 16.
As a result we were seeing issues on systems with 64K pages as it would
cause DESC_NEEDED to increase to 68, and we would need over 136 descriptors
free before clean_tx_irq would wake the queue.

This patch makes it so that DESC_NEEDED is always MAX_SKB_FRAGS + 4.  This
should prevent any possible deadlocks on the systems with 64K pages as we will
now only require 42 descriptors to wake.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
index 196002b..a8e10cf 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
@@ -156,7 +156,7 @@  struct vf_macvlans {
 
 /* Tx Descriptors needed, worst case */
 #define TXD_USE_COUNT(S) DIV_ROUND_UP((S), IXGBE_MAX_DATA_PER_TXD)
-#define DESC_NEEDED ((MAX_SKB_FRAGS * TXD_USE_COUNT(PAGE_SIZE)) + 4)
+#define DESC_NEEDED (MAX_SKB_FRAGS + 4)
 
 /* wrapper around a pointer to a socket buffer,
  * so a DMA handle can be stored along with the buffer */