From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk1-f200.google.com (mail-qk1-f200.google.com [209.85.222.200]) by kanga.kvack.org (Postfix) with ESMTP id 0204E6B30CE for ; Fri, 23 Nov 2018 05:48:53 -0500 (EST) Received: by mail-qk1-f200.google.com with SMTP id z126so11417314qka.10 for ; Fri, 23 Nov 2018 02:48:52 -0800 (PST) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id 88si9406007qte.245.2018.11.23.02.48.51 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 23 Nov 2018 02:48:52 -0800 (PST) Subject: Re: [PATCH v8 4/7] mm, devm_memremap_pages: Add MEMORY_DEVICE_PRIVATE support References: <154275556908.76910.8966087090637564219.stgit@dwillia2-desk3.amr.corp.intel.com> <154275559036.76910.12434636179931292607.stgit@dwillia2-desk3.amr.corp.intel.com> From: David Hildenbrand Message-ID: <0d1be2d5-8682-84aa-cbbd-f7ee01d77b12@redhat.com> Date: Fri, 23 Nov 2018 11:48:48 +0100 MIME-Version: 1.0 In-Reply-To: <154275559036.76910.12434636179931292607.stgit@dwillia2-desk3.amr.corp.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Dan Williams , akpm@linux-foundation.org Cc: =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Christoph Hellwig , Logan Gunthorpe , torvalds@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org On 21.11.18 00:13, Dan Williams wrote: > In preparation for consolidating all ZONE_DEVICE enabling via > devm_memremap_pages(), teach it how to handle the constraints of > MEMORY_DEVICE_PRIVATE ranges. > > Reviewed-by: Jérôme Glisse > [jglisse: call move_pfn_range_to_zone for MEMORY_DEVICE_PRIVATE] > Acked-by: Christoph Hellwig > Reported-by: Logan Gunthorpe > Reviewed-by: Logan Gunthorpe > Signed-off-by: Dan Williams > --- > kernel/memremap.c | 53 +++++++++++++++++++++++++++++++++++++++++------------ > 1 file changed, 41 insertions(+), 12 deletions(-) > > diff --git a/kernel/memremap.c b/kernel/memremap.c > index 5e45f0c327a5..3eef989ef035 100644 > --- a/kernel/memremap.c > +++ b/kernel/memremap.c > @@ -98,9 +98,15 @@ static void devm_memremap_pages_release(void *data) > - align_start; > > mem_hotplug_begin(); > - arch_remove_memory(align_start, align_size, pgmap->altmap_valid ? > - &pgmap->altmap : NULL); > - kasan_remove_zero_shadow(__va(align_start), align_size); > + if (pgmap->type == MEMORY_DEVICE_PRIVATE) { > + pfn = align_start >> PAGE_SHIFT; > + __remove_pages(page_zone(pfn_to_page(pfn)), pfn, > + align_size >> PAGE_SHIFT, NULL); > + } else { > + arch_remove_memory(align_start, align_size, > + pgmap->altmap_valid ? &pgmap->altmap : NULL); > + kasan_remove_zero_shadow(__va(align_start), align_size); > + } > mem_hotplug_done(); > > untrack_pfn(NULL, PHYS_PFN(align_start), align_size); > @@ -187,17 +193,40 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap) > goto err_pfn_remap; > > mem_hotplug_begin(); > - error = kasan_add_zero_shadow(__va(align_start), align_size); > - if (error) { > - mem_hotplug_done(); > - goto err_kasan; > + > + /* > + * For device private memory we call add_pages() as we only need to > + * allocate and initialize struct page for the device memory. More- > + * over the device memory is un-accessible thus we do not want to > + * create a linear mapping for the memory like arch_add_memory() > + * would do. > + * > + * For all other device memory types, which are accessible by > + * the CPU, we do want the linear mapping and thus use > + * arch_add_memory(). > + */ I consider this comment really useful. :) Short question: Right now, MEMORY_DEVICE_PRIVATE always indicates HMM, correct? (I am just confused by the naming but I assume MEMORY_DEVICE_PRIVATE is more generic than HMM) -- Thanks, David / dhildenb