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 7717FC433EF for ; Mon, 13 Dec 2021 09:00:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231806AbhLMJAG (ORCPT ); Mon, 13 Dec 2021 04:00:06 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:58916 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231788AbhLMJAF (ORCPT ); Mon, 13 Dec 2021 04:00:05 -0500 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 11D11B80DCF; Mon, 13 Dec 2021 09:00:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1284AC341C5; Mon, 13 Dec 2021 09:00:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1639386002; bh=9++Y8nJdu20L/simihE/HqS4ABBR4aerAapeSMPYOGo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=SzUo0SkJ0KSEzCje9uGr2oHpke1HoWUtJys+wrdWu190F+gE4CZk67IqNfkizAqzK yH2JXvj3FBjtLFtGF4RlTyzsmghX1noHWamoscvu0DSH6bte7e9/t4Ugg68lS1EcXG BAoxBJds+B/uoxzW31Yus/eB5R867pQyQ5iKqMbmqhGDMaVeir+lil6eAICrccycOx WQYaHyX+KEvhSwxC9SSB4xsmjvyCFGMX/98xfyVwNnYnFiszCaJk+3pZPpMJpmRr0i x373HnMR8C3qbaC5FTfFcnm9IFXvn6R7ZZeJ+CKYvLPzGIM9ag+Ol6b5tcVQSrSvbI byPMHYFDCEriw== Date: Mon, 13 Dec 2021 14:29:58 +0530 From: Vinod Koul To: Tudor.Ambarus@microchip.com Cc: Ludovic.Desroches@microchip.com, richard.genoud@gmail.com, gregkh@linuxfoundation.org, jirislaby@kernel.org, Nicolas.Ferre@microchip.com, alexandre.belloni@bootlin.com, mripard@kernel.org, linux-arm-kernel@lists.infradead.org, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org Subject: Re: [PATCH v2 08/13] dmaengine: at_xdmac: Move the free desc to the tail of the desc list Message-ID: References: <20211125090028.786832-1-tudor.ambarus@microchip.com> <20211125090028.786832-9-tudor.ambarus@microchip.com> <8523ca32-d36f-6e0b-0115-5e07553396f1@microchip.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8523ca32-d36f-6e0b-0115-5e07553396f1@microchip.com> Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On 13-12-21, 08:51, Tudor.Ambarus@microchip.com wrote: > Hi, Vinod, > > On 12/13/21 10:07 AM, Vinod Koul wrote: > > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > > > On 25-11-21, 11:00, Tudor Ambarus wrote: > >> So that we don't use the same desc over and over again. > > > > Please use full para in the changelog and not a continuation of the > > patch title! > > Ok, will add a better commit description. Here and in other patches where > your comment applies. Great! > > > > and why is wrong with using same desc over and over? Any benefits of not > > doing so? > > Not wrong, but if we move the free desc to the tail of the list, then the > sequence of descriptors is more track-able in case of debug. You would > know which descriptor should come next and you could easier catch > concurrency over descriptors for example. I saw virt-dma uses > list_splice_tail_init() as well, I found it a good idea, so I thought to > follow the core driver. Okay, I would be good to add this motivation in the change log. I am sure after few you would also wonder why you did this change :) -- ~Vinod