From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 23547848A for ; Sun, 10 Dec 2023 11:44:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="p4+pgFo1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36A27C433C8; Sun, 10 Dec 2023 11:44:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1702208675; bh=kdBLoAjjIs/FLrxJuUWkVq0Dh/+ngOXVVslrqDTXYY8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=p4+pgFo1CTvbw62XVJm43KD2KFk3ccVkmULsvKIRZslSEP0Znk4r3i4mRI9BT2mAA FCC2SbDVBABkTKprMHO69akdVBDYHzc1SZVOFO5Q0glpWCkwKUb/hVDPyy6kutyVBT n+hcLfPUtOu2HJXx7OlEHrD90Wd2eXcb7+nMtd0lnTvUic+HPFyuEh6fZt8JpPF7F0 mwRNU0VzGEiDe6IfD8/0exSEjl6Il8KzcbFKs2V+V5jc4qXMEs7C4xOcdEpPynVHtC t3rjzcd8MLuCOpTyZ60akmjENnyy+LVv6d7PdLg95Q42/Qi2J9IeMy8To2+K6GrW9/ PfGHzKLyIG9og== Date: Sun, 10 Dec 2023 11:44:31 +0000 From: Simon Horman To: Jacob Keller Cc: Intel Wired LAN , netdev@vger.kernel.org, Przemek Kitszel , Anthony Nguyen , Ivan Vecera Subject: Re: [PATCH iwl-net] ice: stop trashing VF VSI aggregator node ID information Message-ID: <20231210114431.GG5817@kernel.org> References: <20231206201905.846723-1-jacob.e.keller@intel.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231206201905.846723-1-jacob.e.keller@intel.com> + Ivan Vecera On Wed, Dec 06, 2023 at 12:19:05PM -0800, Jacob Keller wrote: > When creating new VSIs, they are assigned into an aggregator node in the > scheduler tree. Information about which aggregator node a VSI is assigned > into is maintained by the vsi->agg_node structure. In ice_vsi_decfg(), this > information is being destroyed, by overwriting the valid flag and the > agg_id field to zero. > > For VF VSIs, this breaks the aggregator node configuration replay, which > depends on this information. This results in VFs being inserted into the > default aggregator node. The resulting configuration will have unexpected > Tx bandwidth sharing behavior. > > This was broken by commit 6624e780a577 ("ice: split ice_vsi_setup into > smaller functions"), which added the block to reset the agg_node data. > > The vsi->agg_node structure is not managed by the scheduler code, but is > instead a wrapper around an aggregator node ID that is tracked at the VSI > layer. Its been around for a long time, and its primary purpose was for > handling VFs. The SR-IOV VF reset flow does not make use of the standard VSI > rebuild/replay logic, and uses vsi->agg_node as part of its handling to > rebuild the aggregator node configuration. > > The logic for aggregator nodes stretches back to early ice driver code from > commit b126bd6bcd67 ("ice: create scheduler aggregator node config and move > VSIs") > > The logic in ice_vsi_decfg() which trashes the ice_agg_node data is clearly > wrong. It destroys information that is necessary for handling VF reset,. It > is also not the correct way to actually remove a VSI from an aggregator > node. For that, we need to implement logic in the scheduler code. Further, > non-VF VSIs properly replay their aggregator configuration using existing > scheduler replay logic. > > To fix the VF replay logic, remove this broken aggregator node cleanup > logic. This is the simplest way to immediately fix this. > > This ensures that VFs will have proper aggregate configuration after a > reset. This is especially important since VFs often perform resets as part > of their reconfiguration flows. Without fixing this, VFs will be placed in > the default aggregator node and Tx bandwidth will not be shared in the > expected and configured manner. > > Fixes: 6624e780a577 ("ice: split ice_vsi_setup into smaller functions") > Signed-off-by: Jacob Keller > Reviewed-by: Przemek Kitszel > --- > This is the simplest fix to resolve the aggregator node problem. However, I > think we should clean this up properly. I don't know why the VF VSIs have > their own custom code for replaying aggregator configuration. I also think > its odd that there is both structures to track aggregator information in > ice_sched.c, but we use a separate structure in ice.h for the ice_vsi > structure. I plan to investigate this and clean it up in next. However, I > wanted to get a smaller fix out to net sooner rather than later. Less is more, for now :) Reviewed-by: Simon Horman I've added Ivan to the CC list in case he wants to review this too. > > drivers/net/ethernet/intel/ice/ice_lib.c | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c > index 4b1e56396293..de7ba87af45d 100644 > --- a/drivers/net/ethernet/intel/ice/ice_lib.c > +++ b/drivers/net/ethernet/intel/ice/ice_lib.c > @@ -2620,10 +2620,6 @@ void ice_vsi_decfg(struct ice_vsi *vsi) > if (vsi->type == ICE_VSI_VF && > vsi->agg_node && vsi->agg_node->valid) > vsi->agg_node->num_vsis--; > - if (vsi->agg_node) { > - vsi->agg_node->valid = false; > - vsi->agg_node->agg_id = 0; > - } > } > > /** > -- > 2.41.0 >