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Message-ID: <20250828160806.84557-1-enjuk@amazon.com>
Date: Fri, 29 Aug 2025 01:08:04 +0900
From: Kohei Enju <enjuk@...zon.com>
To: <pmenzel@...gen.mpg.de>
CC: <andrew+netdev@...n.ch>, <anthony.l.nguyen@...el.com>,
<davem@...emloft.net>, <edumazet@...gle.com>, <enjuk@...zon.com>,
<intel-wired-lan@...ts.osuosl.org>, <kohei.enju@...il.com>,
<kuba@...nel.org>, <netdev@...r.kernel.org>, <pabeni@...hat.com>,
<przemyslaw.kitszel@...el.com>
Subject: Re: [Intel-wired-lan] [PATCH iwl-next v1] ixgbe: preserve RSS indirection table across admin down/up
On Sun, 24 Aug 2025 20:00:32 +0200, Paul Menzel wrote:
> Dear Kohei,
>
>
> Thank you for your patch.
>
> Am 24.08.25 um 13:20 schrieb Kohei Enju:
> > 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.
> >
> > By adopting the same approach used in igc and igb drivers which
> > reinitializes the RSS indirection table only when the queue count
> > changes, let's make user configuration persistent as long as queue count
> > remains 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 <enjuk@...zon.com>
> > ---
> > drivers/net/ethernet/intel/ixgbe/ixgbe.h | 1 +
> > drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 37 +++++++++++++------
> > 2 files changed, 27 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
> > index 14d275270123..d8b088c90b05 100644
> > --- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
> > +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
> > @@ -838,6 +838,7 @@ struct ixgbe_adapter {
> > */
> > #define IXGBE_MAX_RETA_ENTRIES 512
> > u8 rss_indir_tbl[IXGBE_MAX_RETA_ENTRIES];
> > + u16 last_rss_i;
> >
> > #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 80e6a2ef1350..dc5a8373b0c3 100644
> > --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> > +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> > @@ -4318,14 +4318,22 @@ 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 or queue count
> > + * change, otherwise preserve user configurations. Then always
> > + * write to hardware.
> > + */
> > + if (adapter->last_rss_i != rss_i) {
> > + memset(adapter->rss_indir_tbl, 0,
> > + sizeof(adapter->rss_indir_tbl));
> > +
> > + for (i = 0, j = 0; i < reta_entries; i++, j++) {
> > + 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;
> > }
> >
> > ixgbe_store_reta(adapter);
> > @@ -4347,12 +4355,19 @@ 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 or queue count
> > + * change, otherwise preserve user configurations. Then always
> > + * write to hardware.
> > + */
> > + if (adapter->last_rss_i != rss_i) {
> > + for (i = 0, j = 0; i < 64; 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;
> > }
> >
> > ixgbe_store_vfreta(adapter);
>
> Reviewed-by: Paul Menzel <pmenzel@...gen.mpg.de>
Thank you for reviewing v1, Paul.
I've posted v2 with additional logic to check reta_entries changes.
Since v2 includes a functional change, I haven't carried forward your
Reviewed-by: tag.
>
> Kind regards,
>
> Paul
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