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 C468232E747; Wed, 17 Sep 2025 12:54:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758113689; cv=none; b=EDawOLsV5gseakTEaJNNMB5n01n3YKXvEQ2lCIMVcAHMLjqOxD/rqFSFrKbxUg1EDBdHSUwA0nWdVi5yR/wj79bmBi5x+dStqGRKT3TkeYym1i4drgqO1N/+02PWrV9Omdr4x63JPxA4DF1ZSUUNFjIyge1LJ4Vij6WfT2z3p6c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758113689; c=relaxed/simple; bh=QKyCgcFoodzH/FjHW6Oo6xspEoVjKBY4bFc4QI/M+Lo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=lcT1//uofUZvtgos10ojkPQ7gEtgeg8Cto3dstwVUukJs96toSb6w6dzzemjQEsnAMQE+sHTUY03NQcrACpAfS9GgK/++CER2ox1yhxoiAnczkCuPUfMafUr/5u+BRomlmklmI8nPjmtKlaASEspHALf3feqHU7lVBqT27UqGsY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=E3BYJEyu; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="E3BYJEyu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0F0F7C4CEF0; Wed, 17 Sep 2025 12:54:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758113689; bh=QKyCgcFoodzH/FjHW6Oo6xspEoVjKBY4bFc4QI/M+Lo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=E3BYJEyum9F9Q9bMawWXWL3Po3Ae+atpsDwX3Q+FQ75o8JTZ/2kkUo3PqeTZ+1/D+ 2UkXr1resBwbZJQV25aHZFcI0Ub8i4GeZVlRfq80lde8kBUypbzt6CFgm8/m959PVd q6TufeMBhErGqmhZRTtAS5ZlyRnf9M+9rrx78/OkMTIftqTYBS7VkaBCtdK1yKvuZE wl9tSSREmvXChtnHrPT+8mu0U4nE8x+DDSUeyMXp4hEo6ppYvz5CO1JivPT1FqbAeu ypGY14Snsf+iSzoSFEkRwCNBABSgrYkz55x+Tr6SFLH3K1ssPR7gPF9DWAWLiPVGeg aiM6n8LLloK8g== Date: Wed, 17 Sep 2025 13:54:43 +0100 From: Simon Horman To: Tariq Toukan Cc: Eric Dumazet , Jakub Kicinski , Paolo Abeni , Andrew Lunn , "David S. Miller" , Jiri Pirko , Jonathan Corbet , Leon Romanovsky , Jason Gunthorpe , Saeed Mahameed , Mark Bloch , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , netdev@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, bpf@vger.kernel.org, Gal Pressman , Cosmin Ratiu , Dragos Tatulea , Jiri Pirko , Jason Gunthorpe Subject: Re: [PATCH net-next V2 06/10] net/mlx5e: Prepare for using different CQ doorbells Message-ID: <20250917125443.GG394836@horms.kernel.org> References: <1758031904-634231-1-git-send-email-tariqt@nvidia.com> <1758031904-634231-7-git-send-email-tariqt@nvidia.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: <1758031904-634231-7-git-send-email-tariqt@nvidia.com> On Tue, Sep 16, 2025 at 05:11:40PM +0300, Tariq Toukan wrote: > From: Cosmin Ratiu > > Completion queues (CQs) in mlx5 use the same global doorbell, which may > become contended when accessed concurrently from many cores. > > This patch prepares the CQ management code for supporting different > doorbells per CQ. This will be used in downstream patches to allow > separate doorbells to be used by channels CQs. > > The main change is moving the 'uar' pointer from struct mlx5_core_cq to > struct mlx5e_cq, as the uar page to be used is better off stored > directly there. Other users of mlx5_core_cq also store the UAR to be > used separately and therefore the pointer being removed is dead weight > for them. As evidence, in this patch there are two users which set the > mcq.uar pointer but didn't use it, Software Steering and old Innova CQ > creation code. Instead, they rang the doorbell directly from another > pointer. > > The 'uar' pointer added to struct mlx5e_cq remains in a hot cacheline > (as before), because it may get accessed for each packet. > > Signed-off-by: Cosmin Ratiu > Reviewed-by: Dragos Tatulea > Signed-off-by: Tariq Toukan Reviewed-by: Simon Horman