netdev - Re: [PATCH] net: ice: Perform accurate aRFS flow match

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250520150619.GZ365796@horms.kernel.org>
Date: Tue, 20 May 2025 16:06:19 +0100
From: Simon Horman <horms@...nel.org>
To: Krishna Kumar <krikku@...il.com>
Cc: netdev@...r.kernel.org, davem@...emloft.net, anthony.l.nguyen@...el.com,
	przemyslaw.kitszel@...el.com, edumazet@...gle.com,
	intel-wired-lan@...ts.osuosl.org, andrew+netdev@...n.ch,
	kuba@...nel.org, pabeni@...hat.com, sridhar.samudrala@...el.com,
	ahmed.zaki@...el.com, krishna.ku@...pkart.com
Subject: Re: [PATCH] net: ice: Perform accurate aRFS flow match

On Tue, May 20, 2025 at 10:32:05AM +0530, Krishna Kumar wrote:
> This patch fixes an issue seen in a large-scale deployment under heavy
> incoming pkts where the aRFS flow wrongly matches a flow and reprograms the
> NIC with wrong settings. That mis-steering causes RX-path latency spikes
> and noisy neighbor effects when many connections collide on the same has
> (some of our production servers have 20-30K connections).

...

> 
> Signed-off-by: Krishna Kumar <krikku@...il.com>

Hi Krishna,

As a fix if this should probably have a Fixes tag.

And it would be useful to denote the target tree in the subject.

E.g. [PATCH iwl-net] ...

> ---
>  drivers/net/ethernet/intel/ice/ice_arfs.c | 45 +++++++++++++++++++++++
>  1 file changed, 45 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_arfs.c b/drivers/net/ethernet/intel/ice/ice_arfs.c
> index 2bc5c7f59844..b36bd189bd64 100644
> --- a/drivers/net/ethernet/intel/ice/ice_arfs.c
> +++ b/drivers/net/ethernet/intel/ice/ice_arfs.c
> @@ -377,6 +377,47 @@ ice_arfs_is_perfect_flow_set(struct ice_hw *hw, __be16 l3_proto, u8 l4_proto)
>  	return false;
>  }
>  
> +/**
> + * ice_arfs_cmp - Check if aRFS filter matches this flow.
> + * @fltr_info: filter info of the saved ARFS entry.
> + * @fk: flow dissector keys.
> + * n_proto:  One of htons(IPv4) or htons(IPv6).
> + * ip_proto: One of IPPROTO_TCP or IPPROTO_UDP.

nit: A '@' is required to document function parameters.

 * @nproto: ...
 * @ip_proto: ...

> + *
> + * Since this function assumes limited values for n_proto and ip_proto, it
> + * is meant to be called only from ice_rx_flow_steer().

Please also document the return value using "Return: " or "Returns: ".

Flagged by ./scripts/kernel-doc -Wall -none

> + */

...