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 X-Spam-Level: X-Spam-Status: No, score=-7.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 40814C43461 for ; Mon, 7 Sep 2020 12:33:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E5F072075A for ; Mon, 7 Sep 2020 12:33:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="HwvTIjsP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729180AbgIGMdf (ORCPT ); Mon, 7 Sep 2020 08:33:35 -0400 Received: from hqnvemgate24.nvidia.com ([216.228.121.143]:2294 "EHLO hqnvemgate24.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729174AbgIGMcp (ORCPT ); Mon, 7 Sep 2020 08:32:45 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Mon, 07 Sep 2020 05:30:32 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Mon, 07 Sep 2020 05:32:45 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Mon, 07 Sep 2020 05:32:45 -0700 Received: from [172.27.12.170] (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Mon, 7 Sep 2020 12:32:39 +0000 Subject: Re: [PATCH rdma-next 1/4] lib/scatterlist: Refactor sg_alloc_table_from_pages To: Christoph Hellwig , Leon Romanovsky CC: Doug Ledford , Jason Gunthorpe , , References: <20200903121853.1145976-1-leon@kernel.org> <20200903155434.1153934-1-leon@kernel.org> <20200907072912.GA19875@lst.de> From: Maor Gottlieb Message-ID: <2a4b0211-c7a0-2a82-1335-7ed935b92aa2@nvidia.com> Date: Mon, 7 Sep 2020 15:32:31 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.2.1 MIME-Version: 1.0 In-Reply-To: <20200907072912.GA19875@lst.de> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: quoted-printable Content-Language: en-US X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL111.nvidia.com (172.20.187.18) To HQMAIL107.nvidia.com (172.20.187.13) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1599481832; bh=vB36ZS5TzpC7eMfT9U7YXNMKeTt+DU0w5HUuBJIhjA4=; h=X-PGP-Universal:Subject:To:CC:References:From:Message-ID:Date: User-Agent:MIME-Version:In-Reply-To:Content-Type: Content-Transfer-Encoding:Content-Language:X-Originating-IP: X-ClientProxiedBy; b=HwvTIjsPofXA543PAtAD1r3ScN+KadLzOwar93ZxiWVjM8VyccMcIar+1DOnCCcai uhFBsFPWKk7jKIACRKr8HrkT/t9uazUFSTwobWPM3lIjyJ1fcojYgpMAqLj+T87rDZ kRTscExWfk0xbDVojnXFZEZ0BZ5O4rsf1080PS/pyHDPX0ZqIPezBRtwC1Y83EtO6H 9jvovM47QjLjFYlB72OLAJnEl8wosASxncaRATb9mquJYrVGmNTqAOlwJm6MmYyB9i 3BpcYM6PgceiapPcWZ5H4vB/aDB37RcBrlADijfA38zGcZnMTTjeZnqsQWbLCeh8ng 3ysl5fd3FtOuw== Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On 9/7/2020 10:29 AM, Christoph Hellwig wrote: > On Thu, Sep 03, 2020 at 06:54:34PM +0300, Leon Romanovsky wrote: >> From: Maor Gottlieb >> >> Currently, sg_alloc_table_from_pages doesn't support dynamic chaining of >> SG entries. Therefore it requires from user to allocate all the pages in >> advance and hold them in a large buffer. Such a buffer consumes a lot of >> temporary memory in HPC systems which do a very large memory registratio= n. >> >> The next patches introduce API for dynamically allocation from pages and >> it requires us to do the following: >> * Extract the code to alloc_from_pages_common. >> * Change the build of the table to iterate on the chunks and not on th= e >> SGEs. It will allow dynamic allocation of more SGEs. >> >> Since sg_alloc_table_from_pages allocate exactly the number of chunks, >> therefore chunks are equal to the number of SG entries. > Given how few users __sg_alloc_table_from_pages has, what about just > switching it to your desired calling conventions without another helper? I tried it now. It didn't save a lot.=C2=A0 Please give me your decision an= d=20 if needed I will update accordingly.