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 9453EC433FE for ; Tue, 21 Dec 2021 09:06:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234926AbhLUJGw (ORCPT ); Tue, 21 Dec 2021 04:06:52 -0500 Received: from verein.lst.de ([213.95.11.211]:46077 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233810AbhLUJGw (ORCPT ); Tue, 21 Dec 2021 04:06:52 -0500 Received: by verein.lst.de (Postfix, from userid 2407) id C06A968B05; Tue, 21 Dec 2021 10:06:48 +0100 (CET) Date: Tue, 21 Dec 2021 10:06:48 +0100 From: Christoph Hellwig To: Logan Gunthorpe Cc: linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Stephen Bates , Christoph Hellwig , Dan Williams , Jason Gunthorpe , Christian =?iso-8859-1?Q?K=F6nig?= , John Hubbard , Don Dutile , Matthew Wilcox , Daniel Vetter , Jakowski Andrzej , Minturn Dave B , Jason Ekstrand , Dave Hansen , Xiong Jianxin , Bjorn Helgaas , Ira Weiny , Robin Murphy , Martin Oliveira , Chaitanya Kulkarni Subject: Re: [PATCH v4 21/23] mm: use custom page_free for P2PDMA pages Message-ID: <20211221090648.GE7949@lst.de> References: <20211117215410.3695-1-logang@deltatee.com> <20211117215410.3695-22-logang@deltatee.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211117215410.3695-22-logang@deltatee.com> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Wed, Nov 17, 2021 at 02:54:08PM -0700, Logan Gunthorpe wrote: > When P2PDMA pages are passed to userspace, they will need to be > reference counted properly and returned to their genalloc after their > reference count returns to 1. This is accomplished with the existing > DEV_PAGEMAP_OPS and the .page_free() operation. > > Change CONFIG_P2PDMA to select CONFIG_DEV_PAGEMAP_OPS and add > MEMORY_DEVICE_PCI_P2PDMA to page_is_devmap_managed(), > devmap_managed_enable_[put|get]() and free_devmap_managed_page(). Uuuh. We are trying hard to kill off this magic free at refcount 1 behavior in the amdgpu device coherent series. We really should not add more of this. 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 smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 882C0C433FE for ; Tue, 21 Dec 2021 09:06:55 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 3A76360E6A; Tue, 21 Dec 2021 09:06:55 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id laLm52F2Mc_C; Tue, 21 Dec 2021 09:06:54 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp3.osuosl.org (Postfix) with ESMTPS id 2F3CE605DB; Tue, 21 Dec 2021 09:06:54 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 1638CC002F; Tue, 21 Dec 2021 09:06:54 +0000 (UTC) Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) by lists.linuxfoundation.org (Postfix) with ESMTP id A2C42C0012 for ; Tue, 21 Dec 2021 09:06:52 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id 8312C8175E for ; Tue, 21 Dec 2021 09:06:52 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 1DuYtqtiBIuF for ; Tue, 21 Dec 2021 09:06:52 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by smtp1.osuosl.org (Postfix) with ESMTPS id 009998175A for ; Tue, 21 Dec 2021 09:06:51 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id C06A968B05; Tue, 21 Dec 2021 10:06:48 +0100 (CET) Date: Tue, 21 Dec 2021 10:06:48 +0100 From: Christoph Hellwig To: Logan Gunthorpe Subject: Re: [PATCH v4 21/23] mm: use custom page_free for P2PDMA pages Message-ID: <20211221090648.GE7949@lst.de> References: <20211117215410.3695-1-logang@deltatee.com> <20211117215410.3695-22-logang@deltatee.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20211117215410.3695-22-logang@deltatee.com> User-Agent: Mutt/1.5.17 (2007-11-01) Cc: linux-pci@vger.kernel.org, Dave Hansen , linux-nvme@lists.infradead.org, Stephen Bates , linux-mm@kvack.org, Jason Ekstrand , Ira Weiny , Christoph Hellwig , Minturn Dave B , Martin Oliveira , Matthew Wilcox , Jason Gunthorpe , Chaitanya Kulkarni , Bjorn Helgaas , Daniel Vetter , John Hubbard , linux-block@vger.kernel.org, Dan Williams , Jakowski Andrzej , Xiong Jianxin , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Robin Murphy , Christian =?iso-8859-1?Q?K=F6nig?= X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Wed, Nov 17, 2021 at 02:54:08PM -0700, Logan Gunthorpe wrote: > When P2PDMA pages are passed to userspace, they will need to be > reference counted properly and returned to their genalloc after their > reference count returns to 1. This is accomplished with the existing > DEV_PAGEMAP_OPS and the .page_free() operation. > > Change CONFIG_P2PDMA to select CONFIG_DEV_PAGEMAP_OPS and add > MEMORY_DEVICE_PCI_P2PDMA to page_is_devmap_managed(), > devmap_managed_enable_[put|get]() and free_devmap_managed_page(). Uuuh. We are trying hard to kill off this magic free at refcount 1 behavior in the amdgpu device coherent series. We really should not add more of this. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu