> -----Original Message-----
> From: Intel-wired-lan <[email protected]> On Behalf
> Of Kohei Enju
> Sent: Thursday, August 28, 2025 6:01 PM
> To: [email protected]; [email protected]
> Cc: Nguyen, Anthony L <[email protected]>; Kitszel,
> Przemyslaw <[email protected]>; Andrew Lunn
> <[email protected]>; David S. Miller <[email protected]>; Eric
> Dumazet <[email protected]>; Jakub Kicinski <[email protected]>;
> Paolo Abeni <[email protected]>; [email protected]; Kohei Enju
> <[email protected]>
> Subject: [Intel-wired-lan] [PATCH iwl-next v2] ixgbe: preserve RSS
> indirection table across admin down/up
>
> Currently, the RSS indirection table configured by user via ethtool
> is
> reinitialized to default values during interface resets (e.g., admin
> down/up, MTU change). As for RSS hash key, commit 3dfbfc7ebb95
> ("ixgbe:
> Check for RSS key before setting value") made it persistent across
> interface resets.
>
> Adopt the same approach used in igc and igb drivers which
> reinitializes
> the RSS indirection table only when the queue count changes. Since
> the
> number of RETA entries can also change in ixgbe, let's make user
> configuration persistent as long as both queue count and the number
> of
> RETA entries remain unchanged.
>
> Tested on Intel Corporation 82599ES 10-Gigabit SFI/SFP+ Network
> Connection.
>
> Test:
> Set custom indirection table and check the value after interface
> down/up
>
> # ethtool --set-rxfh-indir ens5 equal 2
> # ethtool --show-rxfh-indir ens5 | head -5
>
> RX flow hash indirection table for ens5 with 12 RX ring(s):
> 0: 0 1 0 1 0 1 0 1
> 8: 0 1 0 1 0 1 0 1
> 16: 0 1 0 1 0 1 0 1
> # ip link set dev ens5 down && ip link set dev ens5 up
>
> Without patch:
> # ethtool --show-rxfh-indir ens5 | head -5
>
> RX flow hash indirection table for ens5 with 12 RX ring(s):
> 0: 0 1 2 3 4 5 6 7
> 8: 8 9 10 11 0 1 2 3
> 16: 4 5 6 7 8 9 10 11
>
> With patch:
> # ethtool --show-rxfh-indir ens5 | head -5
>
> RX flow hash indirection table for ens5 with 12 RX ring(s):
> 0: 0 1 0 1 0 1 0 1
> 8: 0 1 0 1 0 1 0 1
> 16: 0 1 0 1 0 1 0 1
>
> Signed-off-by: Kohei Enju <[email protected]>
> ---
> Changes:
> v1->v2:
> - add check for reta_entries in addition to rss_i
> - update the commit message to reflect the additional check
> v1: https://lore.kernel.org/intel-wired-lan/20250824112037.32692-
> [email protected]/
> ---
> drivers/net/ethernet/intel/ixgbe/ixgbe.h | 2 +
> drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 41 +++++++++++++---
> ---
> 2 files changed, 31 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
> b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
> index 14d275270123..da3b23bdcce1 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
> @@ -838,6 +838,8 @@ struct ixgbe_adapter {
> */
> #define IXGBE_MAX_RETA_ENTRIES 512
> u8 rss_indir_tbl[IXGBE_MAX_RETA_ENTRIES];
> + u32 last_reta_entries;
> + u16 last_rss_i;
last_rss_i is cryptic; please, consider last_rss_indices (or similar)
>
> #define IXGBE_RSS_KEY_SIZE 40 /* size of RSS Hash Key in bytes
> */
> u32 *rss_key;
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> index 27040076f068..05dfb06173d4 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> @@ -4323,14 +4323,21 @@ static void ixgbe_setup_reta(struct
> ixgbe_adapter *adapter)
> /* Fill out hash function seeds */
> ixgbe_store_key(adapter);
>
> - /* Fill out redirection table */
> - memset(adapter->rss_indir_tbl, 0, sizeof(adapter-
> >rss_indir_tbl));
> + /* Update redirection table in memory on first init, queue
> count change,
> + * or reta entries change, otherwise preserve user
> configurations. Then
> + * always write to hardware.
> + */
> + if (adapter->last_rss_i != rss_i ||
> + adapter->last_reta_entries != reta_entries) {
> + for (i = 0, j = 0; i < reta_entries; i++, j++) {
You can avoid the top-of-loop equality test by using modulo, which reads
easier, like:
for (i = 0, j = 0; i < reta_entries; i++, j++)
adapter->rss_indir_tbl[i] = j % rss_i;
> + if (j == rss_i)
> + j = 0;
>
> - for (i = 0, j = 0; i < reta_entries; i++, j++) {
> - if (j == rss_i)
> - j = 0;
> + adapter->rss_indir_tbl[i] = j;
> + }
>
> - adapter->rss_indir_tbl[i] = j;
> + adapter->last_rss_i = rss_i;
> + adapter->last_reta_entries = reta_entries;
> }
>
> ixgbe_store_reta(adapter);
> @@ -4338,8 +4345,9 @@ static void ixgbe_setup_reta(struct
> ixgbe_adapter *adapter)
>
> static void ixgbe_setup_vfreta(struct ixgbe_adapter *adapter)
> {
> - struct ixgbe_hw *hw = &adapter->hw;
> u16 rss_i = adapter->ring_feature[RING_F_RSS].indices;
> + struct ixgbe_hw *hw = &adapter->hw;
> + u32 reta_entries = 64;
Magic number. Can you #define IXGBE_VFRETA_ENTRIES 64 ?
> int i, j;
>
> /* Fill out hash function seeds */
> @@ -4352,12 +4360,21 @@ static void ixgbe_setup_vfreta(struct
> ixgbe_adapter *adapter)
> *(adapter->rss_key + i));
> }
>
> - /* Fill out the redirection table */
> - for (i = 0, j = 0; i < 64; i++, j++) {
> - if (j == rss_i)
> - j = 0;
> + /* Update redirection table in memory on first init, queue
> count change,
> + * or reta entries change, otherwise preserve user
> configurations. Then
> + * always write to hardware.
> + */
> + if (adapter->last_rss_i != rss_i ||
> + adapter->last_reta_entries != reta_entries) {
> + for (i = 0, j = 0; i < reta_entries; i++, j++) {
> + if (j == rss_i)
> + j = 0;
> +
> + adapter->rss_indir_tbl[i] = j;
> + }
>
> - adapter->rss_indir_tbl[i] = j;
> + adapter->last_rss_i = rss_i;
> + adapter->last_reta_entries = reta_entries;
> }
>
> ixgbe_store_vfreta(adapter);
> --
> 2.51.0
