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 AB09AC05027 for ; Mon, 23 Jan 2023 20:11:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232821AbjAWULx (ORCPT ); Mon, 23 Jan 2023 15:11:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44436 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233060AbjAWULv (ORCPT ); Mon, 23 Jan 2023 15:11:51 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF58936478; Mon, 23 Jan 2023 12:11:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Ngc+CXDl+DsRbq3lWnI7piUsiNzsOROjyFJIUEysZJs=; b=bzGhtmRO6jbeOsswarmJVeMnGJ PR20MTV7RYmNRA5+zVjh3RcdblbYIX4PfGRdkeeHrOAAV7hgxTnV1765Sf+h/I8B4try7AX2xbAMH kX6i05ioo31SJlQy0wRDHcgHiNtCRQXKQCMqs/zCWD3tGqW94g9gx8HCkkuLKi4yAzCjaYVc8fBGr TWgqD8jt+62nusrZ/wgiFi56Ux+3t2Bnaj3HTWys8MriCwhBHt6Y24JfixJ/WPUoRUIGNwMsRNnj1 pCw2z0L/V4dWwjgEkLiqcH7V47hwyDBHv0XTxRr5vJ7mL8PdD0MVQdl9hXxA/GnuUlUlTGr9i8bf+ Nd/0SwTA==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pK3AE-004Uoy-A2; Mon, 23 Jan 2023 20:11:34 +0000 Date: Mon, 23 Jan 2023 20:11:34 +0000 From: Matthew Wilcox To: Dan Williams Cc: Jason Gunthorpe via Lsf-pc , lsf-pc@lists.linuxfoundation.org, linux-mm@kvack.org, iommu@lists.linux.dev, linux-rdma@vger.kernel.org, nvdimm@lists.linux.dev, John Hubbard , Ming Lei , linux-block@vger.kernel.org, dri-devel@lists.freedesktop.org, netdev@vger.kernel.org, Joao Martins , Logan Gunthorpe , Christoph Hellwig Subject: Re: [Lsf-pc] [LSF/MM/BPF proposal]: Physr discussion Message-ID: References: <63cee1d3eaaef_3a36e529488@dwillia2-xfh.jf.intel.com.notmuch> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <63cee1d3eaaef_3a36e529488@dwillia2-xfh.jf.intel.com.notmuch> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Jan 23, 2023 at 11:36:51AM -0800, Dan Williams wrote: > Jason Gunthorpe via Lsf-pc wrote: > > I would like to have a session at LSF to talk about Matthew's > > physr discussion starter: > > > > https://lore.kernel.org/linux-mm/YdyKWeU0HTv8m7wD@casper.infradead.org/ > > > > I have become interested in this with some immediacy because of > > IOMMUFD and this other discussion with Christoph: > > > > https://lore.kernel.org/kvm/4-v2-472615b3877e+28f7-vfio_dma_buf_jgg@nvidia.com/ > > I think this is a worthwhile discussion. My main hangup with 'struct > page' elimination in general is that if anything needs to be allocated You're the first one to bring up struct page elimination. Neither Jason nor I have that as our motivation. But there are reasons why struct page is a bad data structure, and Xen proves that you don't need to have such a data structure in order to do I/O. > When I read "general interest across all the driver subsystems" it is > hard not to ask "have all possible avenues to enable 'struct page' been > exhausted?" Yes, we should definitely expend yet more resources chasing a poor implementation.