Author: hselasky
Date: Mon Sep 10 08:03:52 2018
New Revision: 338549
URL: https://svnweb.freebsd.org/changeset/base/338549
Log:
MFC r338489:
Maximum number of mbuf frags is off-by-one for worst case scenario in
mlx5en(4).
Inspecting the PRM no more than 0x3F data segments, DS, of size 16 bytes is
allowed.
Worst case scenario summary of DS usage:
Header is fixed: 2 DS
Maximum inlining: 98 => (98 - 2) / 16 = 6 DS
Remainder: 0x3F - 2 - 6 = 55 DS (mbuf frags)
Previously a value of 56 DS was used and this would work in the
normal case because not all inline data area was used up.
Sponsored by: Mellanox Technologies
Modified:
stable/10/sys/dev/mlx5/mlx5_en/en.h
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/sys/dev/mlx5/mlx5_en/en.h
==============================================================================
--- stable/10/sys/dev/mlx5/mlx5_en/en.h Mon Sep 10 08:02:02 2018
(r338548)
+++ stable/10/sys/dev/mlx5/mlx5_en/en.h Mon Sep 10 08:03:52 2018
(r338549)
@@ -125,7 +125,8 @@
#define MLX5E_MAX_TX_MBUF_SIZE 65536 /* bytes */
#define MLX5E_MAX_TX_MBUF_FRAGS \
((MLX5_SEND_WQE_MAX_WQEBBS * MLX5_SEND_WQEBB_NUM_DS) - \
- (MLX5E_MAX_TX_HEADER / MLX5_SEND_WQE_DS)) /* units */
+ (MLX5E_MAX_TX_HEADER / MLX5_SEND_WQE_DS) - \
+ 1 /* the maximum value of the DS counter is 0x3F and not 0x40 */) /*
units */
#define MLX5E_MAX_TX_INLINE \
(MLX5E_MAX_TX_HEADER - sizeof(struct mlx5e_tx_wqe) + \
sizeof(((struct mlx5e_tx_wqe *)0)->eth.inline_hdr_start)) /* bytes */
_______________________________________________
svn-src-all@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
