From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 50712211BA456 for ; Thu, 24 Jan 2019 15:21:57 -0800 (PST) Subject: [PATCH 3/5] mm/memory-hotplug: allow memory resources to be children From: Dave Hansen Date: Thu, 24 Jan 2019 15:14:45 -0800 References: <20190124231441.37A4A305@viggo.jf.intel.com> In-Reply-To: <20190124231441.37A4A305@viggo.jf.intel.com> Message-Id: <20190124231445.5D8EEDAF@viggo.jf.intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: linux-kernel@vger.kernel.org Cc: thomas.lendacky@amd.com, mhocko@suse.com, linux-nvdimm@lists.01.org, tiwai@suse.de, Dave Hansen , ying.huang@intel.com, linux-mm@kvack.org, jglisse@redhat.com, bp@suse.de, baiyaowei@cmss.chinamobile.com, zwisler@kernel.org, bhelgaas@google.com, fengguang.wu@intel.com, akpm@linux-foundation.org List-ID: From: Dave Hansen The mm/resource.c code is used to manage the physical address space. The current resource configuration can be viewed in /proc/iomem. An example of this is at the bottom of this description. The nvdimm subsystem "owns" the physical address resources which map to persistent memory and has resources inserted for them as "Persistent Memory". The best way to repurpose this for volatile use is to leave the existing resource in place, but add a "System RAM" resource underneath it. This clearly communicates the ownership relationship of this memory. The request_resource_conflict() API only deals with the top-level resources. Replace it with __request_region() which will search for !IORESOURCE_BUSY areas lower in the resource tree than the top level. We *could* also simply truncate the existing top-level "Persistent Memory" resource and take over the released address space. But, this means that if we ever decide to hot-unplug the "RAM" and give it back, we need to recreate the original setup, which may mean going back to the BIOS tables. This should have no real effect on the existing collision detection because the areas that truly conflict should be marked IORESOURCE_BUSY. 00000000-00000fff : Reserved 00001000-0009fbff : System RAM 0009fc00-0009ffff : Reserved 000a0000-000bffff : PCI Bus 0000:00 000c0000-000c97ff : Video ROM 000c9800-000ca5ff : Adapter ROM 000f0000-000fffff : Reserved 000f0000-000fffff : System ROM 00100000-9fffffff : System RAM 01000000-01e071d0 : Kernel code 01e071d1-027dfdff : Kernel data 02dc6000-0305dfff : Kernel bss a0000000-afffffff : Persistent Memory (legacy) a0000000-a7ffffff : System RAM b0000000-bffdffff : System RAM bffe0000-bfffffff : Reserved c0000000-febfffff : PCI Bus 0000:00 Signed-off-by: Dave Hansen Cc: Dan Williams Cc: Dave Jiang Cc: Ross Zwisler Cc: Vishal Verma Cc: Tom Lendacky Cc: Andrew Morton Cc: Michal Hocko Cc: linux-nvdimm@lists.01.org Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Cc: Huang Ying Cc: Fengguang Wu Cc: Borislav Petkov Cc: Bjorn Helgaas Cc: Yaowei Bai Cc: Takashi Iwai Cc: Jerome Glisse --- b/mm/memory_hotplug.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) diff -puN mm/memory_hotplug.c~mm-memory-hotplug-allow-memory-resource-to-be-child mm/memory_hotplug.c --- a/mm/memory_hotplug.c~mm-memory-hotplug-allow-memory-resource-to-be-child 2019-01-24 15:13:14.979199537 -0800 +++ b/mm/memory_hotplug.c 2019-01-24 15:13:14.983199537 -0800 @@ -98,19 +98,21 @@ void mem_hotplug_done(void) /* add this memory to iomem resource */ static struct resource *register_memory_resource(u64 start, u64 size) { - struct resource *res, *conflict; - res = kzalloc(sizeof(struct resource), GFP_KERNEL); - if (!res) - return ERR_PTR(-ENOMEM); + struct resource *res; + unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; + char *resource_name = "System RAM"; - res->name = "System RAM"; - res->start = start; - res->end = start + size - 1; - res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; - conflict = request_resource_conflict(&iomem_resource, res); - if (conflict) { - pr_debug("System RAM resource %pR cannot be added\n", res); - kfree(res); + /* + * Request ownership of the new memory range. This might be + * a child of an existing resource that was present but + * not marked as busy. + */ + res = __request_region(&iomem_resource, start, size, + resource_name, flags); + + if (!res) { + pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n", + start, start + size); return ERR_PTR(-EEXIST); } return res; _ _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm 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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 CE5EEC282C5 for ; Thu, 24 Jan 2019 23:22:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A154C218A2 for ; Thu, 24 Jan 2019 23:22:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728306AbfAXXWO (ORCPT ); Thu, 24 Jan 2019 18:22:14 -0500 Received: from mga01.intel.com ([192.55.52.88]:19850 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727845AbfAXXV4 (ORCPT ); Thu, 24 Jan 2019 18:21:56 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Jan 2019 15:21:55 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,518,1539673200"; d="scan'208";a="112454053" Received: from viggo.jf.intel.com (HELO localhost.localdomain) ([10.54.77.144]) by orsmga008.jf.intel.com with ESMTP; 24 Jan 2019 15:21:55 -0800 Subject: [PATCH 3/5] mm/memory-hotplug: allow memory resources to be children To: linux-kernel@vger.kernel.org Cc: Dave Hansen , dan.j.williams@intel.com, dave.jiang@intel.com, zwisler@kernel.org, vishal.l.verma@intel.com, thomas.lendacky@amd.com, akpm@linux-foundation.org, mhocko@suse.com, linux-nvdimm@lists.01.org, linux-mm@kvack.org, ying.huang@intel.com, fengguang.wu@intel.com, bp@suse.de, bhelgaas@google.com, baiyaowei@cmss.chinamobile.com, tiwai@suse.de, jglisse@redhat.com From: Dave Hansen Date: Thu, 24 Jan 2019 15:14:45 -0800 References: <20190124231441.37A4A305@viggo.jf.intel.com> In-Reply-To: <20190124231441.37A4A305@viggo.jf.intel.com> Message-Id: <20190124231445.5D8EEDAF@viggo.jf.intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dave Hansen The mm/resource.c code is used to manage the physical address space. The current resource configuration can be viewed in /proc/iomem. An example of this is at the bottom of this description. The nvdimm subsystem "owns" the physical address resources which map to persistent memory and has resources inserted for them as "Persistent Memory". The best way to repurpose this for volatile use is to leave the existing resource in place, but add a "System RAM" resource underneath it. This clearly communicates the ownership relationship of this memory. The request_resource_conflict() API only deals with the top-level resources. Replace it with __request_region() which will search for !IORESOURCE_BUSY areas lower in the resource tree than the top level. We *could* also simply truncate the existing top-level "Persistent Memory" resource and take over the released address space. But, this means that if we ever decide to hot-unplug the "RAM" and give it back, we need to recreate the original setup, which may mean going back to the BIOS tables. This should have no real effect on the existing collision detection because the areas that truly conflict should be marked IORESOURCE_BUSY. 00000000-00000fff : Reserved 00001000-0009fbff : System RAM 0009fc00-0009ffff : Reserved 000a0000-000bffff : PCI Bus 0000:00 000c0000-000c97ff : Video ROM 000c9800-000ca5ff : Adapter ROM 000f0000-000fffff : Reserved 000f0000-000fffff : System ROM 00100000-9fffffff : System RAM 01000000-01e071d0 : Kernel code 01e071d1-027dfdff : Kernel data 02dc6000-0305dfff : Kernel bss a0000000-afffffff : Persistent Memory (legacy) a0000000-a7ffffff : System RAM b0000000-bffdffff : System RAM bffe0000-bfffffff : Reserved c0000000-febfffff : PCI Bus 0000:00 Signed-off-by: Dave Hansen Cc: Dan Williams Cc: Dave Jiang Cc: Ross Zwisler Cc: Vishal Verma Cc: Tom Lendacky Cc: Andrew Morton Cc: Michal Hocko Cc: linux-nvdimm@lists.01.org Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Cc: Huang Ying Cc: Fengguang Wu Cc: Borislav Petkov Cc: Bjorn Helgaas Cc: Yaowei Bai Cc: Takashi Iwai Cc: Jerome Glisse --- b/mm/memory_hotplug.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) diff -puN mm/memory_hotplug.c~mm-memory-hotplug-allow-memory-resource-to-be-child mm/memory_hotplug.c --- a/mm/memory_hotplug.c~mm-memory-hotplug-allow-memory-resource-to-be-child 2019-01-24 15:13:14.979199537 -0800 +++ b/mm/memory_hotplug.c 2019-01-24 15:13:14.983199537 -0800 @@ -98,19 +98,21 @@ void mem_hotplug_done(void) /* add this memory to iomem resource */ static struct resource *register_memory_resource(u64 start, u64 size) { - struct resource *res, *conflict; - res = kzalloc(sizeof(struct resource), GFP_KERNEL); - if (!res) - return ERR_PTR(-ENOMEM); + struct resource *res; + unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; + char *resource_name = "System RAM"; - res->name = "System RAM"; - res->start = start; - res->end = start + size - 1; - res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; - conflict = request_resource_conflict(&iomem_resource, res); - if (conflict) { - pr_debug("System RAM resource %pR cannot be added\n", res); - kfree(res); + /* + * Request ownership of the new memory range. This might be + * a child of an existing resource that was present but + * not marked as busy. + */ + res = __request_region(&iomem_resource, start, size, + resource_name, flags); + + if (!res) { + pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n", + start, start + size); return ERR_PTR(-EEXIST); } return res; _ 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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 B0AABC282C6 for ; Thu, 24 Jan 2019 23:22:00 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6E9CE218D3 for ; Thu, 24 Jan 2019 23:22:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6E9CE218D3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C86D28E00B0; Thu, 24 Jan 2019 18:21:57 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id BE8628E00AC; Thu, 24 Jan 2019 18:21:57 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AFDD88E00B0; Thu, 24 Jan 2019 18:21:57 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from mail-pl1-f198.google.com (mail-pl1-f198.google.com [209.85.214.198]) by kanga.kvack.org (Postfix) with ESMTP id 657A58E00AC for ; Thu, 24 Jan 2019 18:21:57 -0500 (EST) Received: by mail-pl1-f198.google.com with SMTP id v12so4956627plp.16 for ; Thu, 24 Jan 2019 15:21:57 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:subject:to:cc :from:date:references:in-reply-to:message-id; bh=ILkCP7OxlYRImbbJu2pTk1APDNsU2c8oqx2F1FKKK+8=; b=NZbwrM9MknbnZwJ9gSkvY0jW+6QSrUIAalFppUiRzKh7TFVnhjhAsxI+tdhNhOYZmt CeIf8PBdMN5JBfxuZC1mNzDik6K1ywb4AAChDVNHOj5u6niWj1+zP/9Mes5uiW3BEsd/ TOiqp1X4iQQYSRqT3oSyPpGbDzSJXJrLO2cF40v7Gw58UBdMP3UUWPSKKvgMLSGB8oTD gpfBH9KN6YA1BfJ8WZM73bn4bIWTnIItrzQzgB02+BxbbFKXMZ/DrN1o8iDoNoLF/aVR 1M37AC41mOAkWZMHkQHQ2uknLTcZnbF5PxaLczgKf5KwW3CmhOZnF3xALcA9/rlqnooW sQRw== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of dave.hansen@linux.intel.com designates 192.55.52.151 as permitted sender) smtp.mailfrom=dave.hansen@linux.intel.com; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com X-Gm-Message-State: AJcUukflXgk5PAKAQQYPzcgihTefwWixf5DVonhOp4xlK3S9zn19whf1 jAjvJrz8mos/mjRNYk/YvSrOXM2RvxWg6FqKegOkXmCyODVnhenAGli9upuyLMDmnPdF1SWOy4Z qdAkZBj66KdM7jjbqlfs05oLIdrkDDAHCp2+JhXPQMbKG6BbmSkJ6byuZocF2zrpakg== X-Received: by 2002:a63:5723:: with SMTP id l35mr7514470pgb.228.1548372117048; Thu, 24 Jan 2019 15:21:57 -0800 (PST) X-Google-Smtp-Source: ALg8bN6/zn1qUDYrSDwsUOKQlZhfom9EOOZQOaZUCEVduQeHGk2wllrvSrPcqHEU+xZyfaX0vbFe X-Received: by 2002:a63:5723:: with SMTP id l35mr7514426pgb.228.1548372116125; Thu, 24 Jan 2019 15:21:56 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1548372116; cv=none; d=google.com; s=arc-20160816; b=vNEPd+rqodXrJxcWPUWWsvUcZsP85bAhxDvg5lYoZCMLKRElD9vTrfPx/LyVxHfsyW 2R1efraytM1uzBQVW6ecBIVXj+lwXtyI31kbJGUKNkOE0IO0XPYgFMkHCsqc/Jt25tMN kanVznehZgm1N8FjTlJ6JgWSYegcB74EG2Q7ONU3XdxY3kR/D3dhF8X1bJ3b+8RIhoUq AqUq/A9KGMhgaDrubGvUwYwOFcCBXWmOhSDWyncGX1HZPWcdfFWv3n0FYHtgadD2l9K5 9taYm7Jbc4dME3F7hjZL60Y80HZPaXuiecA5lY8dHmXMn5pMjOz0SHZcFfAutONb4785 TVlw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:in-reply-to:references:date:from:cc:to:subject; bh=ILkCP7OxlYRImbbJu2pTk1APDNsU2c8oqx2F1FKKK+8=; b=Blj5RxbUoCXYcVGyg6PDYMmK9evRNqchBLL2sqEx9WiZuwBdtSsgldNJ33AnI+4R37 BELMLI0tjNARoMAXS8ZMrsgs7usVtThwBkyjaiq5t45CsmqRu1PNk72x+iXe/Cb7VI5o e8b2+VGYA2VtudVlgkZBtLpiAcmI2tFS7G4n9fwqe7fkikNW7r0kg0ZSU8Dr91hULCYL G2J7edf7wtJIc0xAvP2Lm8OJRyu09Nh5z7PFlDNeC1sCrpOANUD0ROVgEtm2IGh8Q7Xu b3bOfDewEd7lqzs1h3Ih2KoCakGT91TdB1r4+D2Kw2N7kpZPrEh1iaAvLsP+UEg5X3cY pddA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of dave.hansen@linux.intel.com designates 192.55.52.151 as permitted sender) smtp.mailfrom=dave.hansen@linux.intel.com; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: from mga17.intel.com (mga17.intel.com. [192.55.52.151]) by mx.google.com with ESMTPS id p3si8871042plk.424.2019.01.24.15.21.55 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 24 Jan 2019 15:21:56 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of dave.hansen@linux.intel.com designates 192.55.52.151 as permitted sender) client-ip=192.55.52.151; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of dave.hansen@linux.intel.com designates 192.55.52.151 as permitted sender) smtp.mailfrom=dave.hansen@linux.intel.com; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Jan 2019 15:21:55 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,518,1539673200"; d="scan'208";a="112454053" Received: from viggo.jf.intel.com (HELO localhost.localdomain) ([10.54.77.144]) by orsmga008.jf.intel.com with ESMTP; 24 Jan 2019 15:21:55 -0800 Subject: [PATCH 3/5] mm/memory-hotplug: allow memory resources to be children To: linux-kernel@vger.kernel.org Cc: Dave Hansen ,dan.j.williams@intel.com,dave.jiang@intel.com,zwisler@kernel.org,vishal.l.verma@intel.com,thomas.lendacky@amd.com,akpm@linux-foundation.org,mhocko@suse.com,linux-nvdimm@lists.01.org,linux-mm@kvack.org,ying.huang@intel.com,fengguang.wu@intel.com,bp@suse.de,bhelgaas@google.com,baiyaowei@cmss.chinamobile.com,tiwai@suse.de,jglisse@redhat.com From: Dave Hansen Date: Thu, 24 Jan 2019 15:14:45 -0800 References: <20190124231441.37A4A305@viggo.jf.intel.com> In-Reply-To: <20190124231441.37A4A305@viggo.jf.intel.com> Message-Id: <20190124231445.5D8EEDAF@viggo.jf.intel.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Content-Type: text/plain; charset="UTF-8" Message-ID: <20190124231445.qhZUpck7gKND0ub4GrI2SlVdPs3Xl96J-I_s8n2iS3A@z> From: Dave Hansen The mm/resource.c code is used to manage the physical address space. The current resource configuration can be viewed in /proc/iomem. An example of this is at the bottom of this description. The nvdimm subsystem "owns" the physical address resources which map to persistent memory and has resources inserted for them as "Persistent Memory". The best way to repurpose this for volatile use is to leave the existing resource in place, but add a "System RAM" resource underneath it. This clearly communicates the ownership relationship of this memory. The request_resource_conflict() API only deals with the top-level resources. Replace it with __request_region() which will search for !IORESOURCE_BUSY areas lower in the resource tree than the top level. We *could* also simply truncate the existing top-level "Persistent Memory" resource and take over the released address space. But, this means that if we ever decide to hot-unplug the "RAM" and give it back, we need to recreate the original setup, which may mean going back to the BIOS tables. This should have no real effect on the existing collision detection because the areas that truly conflict should be marked IORESOURCE_BUSY. 00000000-00000fff : Reserved 00001000-0009fbff : System RAM 0009fc00-0009ffff : Reserved 000a0000-000bffff : PCI Bus 0000:00 000c0000-000c97ff : Video ROM 000c9800-000ca5ff : Adapter ROM 000f0000-000fffff : Reserved 000f0000-000fffff : System ROM 00100000-9fffffff : System RAM 01000000-01e071d0 : Kernel code 01e071d1-027dfdff : Kernel data 02dc6000-0305dfff : Kernel bss a0000000-afffffff : Persistent Memory (legacy) a0000000-a7ffffff : System RAM b0000000-bffdffff : System RAM bffe0000-bfffffff : Reserved c0000000-febfffff : PCI Bus 0000:00 Signed-off-by: Dave Hansen Cc: Dan Williams Cc: Dave Jiang Cc: Ross Zwisler Cc: Vishal Verma Cc: Tom Lendacky Cc: Andrew Morton Cc: Michal Hocko Cc: linux-nvdimm@lists.01.org Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Cc: Huang Ying Cc: Fengguang Wu Cc: Borislav Petkov Cc: Bjorn Helgaas Cc: Yaowei Bai Cc: Takashi Iwai Cc: Jerome Glisse --- b/mm/memory_hotplug.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) diff -puN mm/memory_hotplug.c~mm-memory-hotplug-allow-memory-resource-to-be-child mm/memory_hotplug.c --- a/mm/memory_hotplug.c~mm-memory-hotplug-allow-memory-resource-to-be-child 2019-01-24 15:13:14.979199537 -0800 +++ b/mm/memory_hotplug.c 2019-01-24 15:13:14.983199537 -0800 @@ -98,19 +98,21 @@ void mem_hotplug_done(void) /* add this memory to iomem resource */ static struct resource *register_memory_resource(u64 start, u64 size) { - struct resource *res, *conflict; - res = kzalloc(sizeof(struct resource), GFP_KERNEL); - if (!res) - return ERR_PTR(-ENOMEM); + struct resource *res; + unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; + char *resource_name = "System RAM"; - res->name = "System RAM"; - res->start = start; - res->end = start + size - 1; - res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; - conflict = request_resource_conflict(&iomem_resource, res); - if (conflict) { - pr_debug("System RAM resource %pR cannot be added\n", res); - kfree(res); + /* + * Request ownership of the new memory range. This might be + * a child of an existing resource that was present but + * not marked as busy. + */ + res = __request_region(&iomem_resource, start, size, + resource_name, flags); + + if (!res) { + pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n", + start, start + size); return ERR_PTR(-EEXIST); } return res; _