From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56EA8C001B2 for ; Fri, 9 Dec 2022 00:53:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229523AbiLIAxH (ORCPT ); Thu, 8 Dec 2022 19:53:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42566 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229521AbiLIAxF (ORCPT ); Thu, 8 Dec 2022 19:53:05 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F20CB72860; Thu, 8 Dec 2022 16:53:04 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B057FB826CB; Fri, 9 Dec 2022 00:53:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 55FB0C433F2; Fri, 9 Dec 2022 00:53:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1670547182; bh=0Be0x5lVmgi1YFBEAMFYn86z655fGVIeWjhZdVVj0iU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dTewMuM1hie8uAR35A863ritBqtZ5toHAg3Wpo1fQg+D0b15LsZiylOTTVi6m1/Nj v3cLbuW+Qp1yZHOHyj9qeoyBBpfW4DGTdA/mOHvoSGeG25KcbRc29nK1k47AtDDJpp DXdoMiXQnwosu7pDzqhl2BP/SueEjzAMmw/V1EB9W6tCd+073tKCVNmKgdQmin18C+ T6hGSJXSuKDAaUhjOP7ZTzGHWP4j5q4is5P7+20/tq6xJJEpxLF/Xs0qytSafzsC7B H0yCRO6xu0vzNmL7/J+cLboJMi3/uhfeNIEV9omjyEx0i89pPeb+mvlWKbwXBeaqo/ dtIiQsASC+bWg== Date: Thu, 8 Dec 2022 16:53:01 -0800 From: Saeed Mahameed To: Gerhard Engleder Cc: Maciej Fijalkowski , netdev@vger.kernel.org, bpf@vger.kernel.org, davem@davemloft.net, kuba@kernel.org, edumazet@google.com, pabeni@redhat.com, ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org, john.fastabend@gmail.com Subject: Re: [PATCH net-next v2 5/6] tsnep: Add RX queue info for XDP support Message-ID: References: <20221208054045.3600-1-gerhard@engleder-embedded.com> <20221208054045.3600-6-gerhard@engleder-embedded.com> <45d4de61-9a6e-be55-5a00-9e7ff464f4be@engleder-embedded.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <45d4de61-9a6e-be55-5a00-9e7ff464f4be@engleder-embedded.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 08 Dec 21:32, Gerhard Engleder wrote: >On 08.12.22 13:59, Maciej Fijalkowski wrote: >>On Thu, Dec 08, 2022 at 06:40:44AM +0100, Gerhard Engleder wrote: >>>Register xdp_rxq_info with page_pool memory model. This is needed for >>>XDP buffer handling. >>> >>>Signed-off-by: Gerhard Engleder >>>--- >>> drivers/net/ethernet/engleder/tsnep.h | 5 ++-- >>> drivers/net/ethernet/engleder/tsnep_main.c | 34 +++++++++++++++++----- >>> 2 files changed, 30 insertions(+), 9 deletions(-) >>> >>>diff --git a/drivers/net/ethernet/engleder/tsnep.h b/drivers/net/ethernet/engleder/tsnep.h >>>index 0e7fc36a64e1..70bc133d4a9d 100644 >>>--- a/drivers/net/ethernet/engleder/tsnep.h >>>+++ b/drivers/net/ethernet/engleder/tsnep.h >>>@@ -127,6 +127,7 @@ struct tsnep_rx { >>> u32 owner_counter; >>> int increment_owner_counter; >>> struct page_pool *page_pool; >>>+ struct xdp_rxq_info xdp_rxq; >> >>this occupies full cacheline, did you make sure that you don't break >>tsnep_rx layout with having xdp_rxq_info in the middle of the way? > >Actually I did no cacheline optimisation for this structure so far. >I saw that igb/igc put xdp_rxq_info to the end. Is this best practice >to prevent other variables in the same cacheline of xdp_rxq? a rule of thumb, organize the structure in the same order they are being accessed in the data path.. but this doesn't go without saying you need to do some layout testing via pahole for example.. It's up to you and the maintainer of this driver to decide how critical this is. Reviewed-by: Saeed Mahameed