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=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 0B4E6C433E0 for ; Tue, 28 Jul 2020 09:13:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E060C20759 for ; Tue, 28 Jul 2020 09:13:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728099AbgG1JNj (ORCPT ); Tue, 28 Jul 2020 05:13:39 -0400 Received: from verein.lst.de ([213.95.11.211]:47388 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728021AbgG1JNj (ORCPT ); Tue, 28 Jul 2020 05:13:39 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id CE5F668B05; Tue, 28 Jul 2020 11:13:35 +0200 (CEST) Date: Tue, 28 Jul 2020 11:13:35 +0200 From: Christoph Hellwig To: Nicolas Saenz Julienne Cc: Christoph Hellwig , Amit Pundir , Marek Szyprowski , Robin Murphy , David Rientjes , linux-rpi-kernel@lists.infradead.org, jeremy.linton@arm.com, iommu@lists.linux-foundation.org, lkml , John Stultz , Sumit Semwal Subject: Re: [PATCH] dma-pool: Do not allocate pool memory from CMA Message-ID: <20200728091335.GA23744@lst.de> References: <011994f8a717a00dcd9ed7682a1ddeb421c2c43f.camel@suse.de> <01831596e4a2a6c9c066138b23bd30435f8e5569.camel@suse.de> <6db722947546221ed99d3f473f78e1a6de65d7d6.camel@suse.de> <0dc1e922bf87fa73790e7471b3974528dd261486.camel@suse.de> <20200724134114.GA3152@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 27, 2020 at 07:56:56PM +0200, Nicolas Saenz Julienne wrote: > Hi Christoph, > thanks for having a look at this! > > On Fri, 2020-07-24 at 15:41 +0200, Christoph Hellwig wrote: > > Yes, the iommu is an interesting case, and the current code is > > wrong for that. > > Care to expand on this? I do get that checking dma_coherent_ok() on memory > that'll later on be mapped into an iommu is kind of silly, although I think > harmless in Amir's specific case, since devices have wide enough dma-ranges. Is > there more to it? I think the problem is that it can lead to not finding suitable memory. > > > Can you try the patch below? It contains a modified version of Nicolas' > > patch to try CMA again for the expansion and a new (for now hackish) way to > > not apply the addressability check for dma-iommu allocations. > > > > diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c > > index 6bc74a2d51273e..ec5e525d2b9309 100644 > > --- a/kernel/dma/pool.c > > +++ b/kernel/dma/pool.c > > @@ -3,7 +3,9 @@ > > * Copyright (C) 2012 ARM Ltd. > > * Copyright (C) 2020 Google LLC > > */ > > +#include > > #include > > +#include > > #include > > #include > > #include > > @@ -55,6 +57,31 @@ static void dma_atomic_pool_size_add(gfp_t gfp, size_t > > size) > > pool_size_kernel += size; > > } > > > > +static bool cma_in_zone(gfp_t gfp) > > +{ > > + phys_addr_t end; > > + unsigned long size; > > + struct cma *cma; > > + > > + cma = dev_get_cma_area(NULL); > > + if (!cma) > > + return false; > > + > > + size = cma_get_size(cma); > > + if (!size) > > + return false; > > + end = cma_get_base(cma) - memblock_start_of_DRAM() + size - 1; > > + > > + /* CMA can't cross zone boundaries, see cma_activate_area() */ > > + if (IS_ENABLED(CONFIG_ZONE_DMA) && (gfp & GFP_DMA) && > > + end <= DMA_BIT_MASK(zone_dma_bits)) > > + return true; > > + if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32) && > > + end <= DMA_BIT_MASK(32)) > > + return true; > > + return true; > > IIUC this will always return true given a CMA is present. Which reverts to the > previous behaviour (previous as in breaking some rpi4 setups), isn't it? Was that really what broke the PI? I'll try to get the split out series today, which might have a few more tweaks, and then we'll need to test it both on these rpi4 setups and Amits phone.