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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 03460C433B4 for ; Mon, 3 May 2021 18:24:48 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 860DA610A7 for ; Mon, 3 May 2021 18:24:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 860DA610A7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id 411E1401B6; Mon, 3 May 2021 18:24:47 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 23Epmmxnp6gr; Mon, 3 May 2021 18:24:46 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp2.osuosl.org (Postfix) with ESMTP id 491E0400B8; Mon, 3 May 2021 18:24:46 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 32C07C000D; Mon, 3 May 2021 18:24:46 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [IPv6:2605:bc80:3010::137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 9CD51C0001 for ; Mon, 3 May 2021 18:24:44 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 9790D40E59 for ; Mon, 3 May 2021 18:24:44 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id uFpJB5vaDE7p for ; Mon, 3 May 2021 18:24:43 +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 smtp4.osuosl.org (Postfix) with ESMTPS id 3E1EB4024B for ; Mon, 3 May 2021 18:24:42 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 6C9EA68B05; Mon, 3 May 2021 20:24:35 +0200 (CEST) Date: Mon, 3 May 2021 20:24:35 +0200 From: Christoph Hellwig To: John Hubbard Subject: Re: [PATCH 01/16] PCI/P2PDMA: Pass gfp_mask flags to upstream_bridge_distance_warn() Message-ID: <20210503182434.GA17174@lst.de> References: <20210408170123.8788-1-logang@deltatee.com> <20210408170123.8788-2-logang@deltatee.com> <8ea5b5b3-e10f-121a-bd2a-07db83c6da01@deltatee.com> <3bced3a4-b826-46ab-3d98-d2dc6871bfe1@nvidia.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <3bced3a4-b826-46ab-3d98-d2dc6871bfe1@nvidia.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 , Matthew Wilcox , Jason Gunthorpe , Bjorn Helgaas , Daniel Vetter , linux-block@vger.kernel.org, Bjorn Helgaas , Dan Williams , Jakowski Andrzej , Xiong Jianxin , Robin Murphy , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Logan Gunthorpe , 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 Mon, May 03, 2021 at 11:17:31AM -0700, John Hubbard wrote: > That's the thing: memory failure should be exceedingly rare for this. > Therefore, just fail out entirely (which I don't expect we'll likely > ever see), instead of doing all this weird stuff to try to continue > on if you cannot allocate a single page. If you are in that case, the > system is not in a state that is going to run your dma p2p setup well > anyway. > > I think it's *less* complexity to allocate up front, fail early if > allocation fails, and then not have to deal with these really odd > quirks at the lower levels. Agreed. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu