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 360B8EE49AF for ; Wed, 23 Aug 2023 03:03:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232378AbjHWDDi (ORCPT ); Tue, 22 Aug 2023 23:03:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42104 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231223AbjHWDDg (ORCPT ); Tue, 22 Aug 2023 23:03:36 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E35FE93; Tue, 22 Aug 2023 20:03:33 -0700 (PDT) Received: from dggpemm500005.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4RVrY91nrfzNmYd; Wed, 23 Aug 2023 10:59:57 +0800 (CST) Received: from [10.69.30.204] (10.69.30.204) by dggpemm500005.china.huawei.com (7.185.36.74) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Wed, 23 Aug 2023 11:03:31 +0800 Subject: Re: [PATCH net-next v7 1/6] page_pool: frag API support for 32-bit arch with 64-bit DMA To: Jakub Kicinski , Alexander Duyck CC: Ilias Apalodimas , Mina Almasry , , , , , Lorenzo Bianconi , Liang Chen , Alexander Lobakin , Saeed Mahameed , Leon Romanovsky , Eric Dumazet , Jesper Dangaard Brouer References: <20230816100113.41034-1-linyunsheng@huawei.com> <20230816100113.41034-2-linyunsheng@huawei.com> <20230817091554.31bb3600@kernel.org> <20230817165744.73d61fb6@kernel.org> <20230818145145.4b357c89@kernel.org> <1b8e2681-ccd6-81e0-b696-8b6c26e31f26@huawei.com> <20230821113543.536b7375@kernel.org> <5bd4ba5d-c364-f3f6-bbeb-903d71102ea2@huawei.com> <20230822083821.58d5d26c@kernel.org> From: Yunsheng Lin Message-ID: <79a49ccd-b0c0-0b99-4b4d-c4a416d7e327@huawei.com> Date: Wed, 23 Aug 2023 11:03:31 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <20230822083821.58d5d26c@kernel.org> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.69.30.204] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm500005.china.huawei.com (7.185.36.74) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/8/22 23:38, Jakub Kicinski wrote: > On Tue, 22 Aug 2023 17:21:35 +0800 Yunsheng Lin wrote: >>> .. we should also add a: >>> >>> WARN_ONCE(1, "misaligned DMA address, please report to netdev@"); >> >> As the CONFIG_PHYS_ADDR_T_64BIT seems to used widely in x86/arm/mips/powerpc, >> I am not sure if we can really make the above assumption. >> >> https://elixir.free-electrons.com/linux/v6.4-rc6/K/ident/CONFIG_PHYS_ADDR_T_64BIT > > Huh, it's actually used a lot less than I anticipated! > > None of the x86/arm/mips/powerpc systems matter IMHO - the only _real_ Is there any particular reason that you think that the above systems does not really matter? As we have made a similar wrong assumption about those arches before, I am really trying to be more cautious about it. I searched through the web, some seems to be claiming that "32-bits is DEAD", I am not sure if there is some common agreement among the kernel community, is there any previous discussion about that?