From patchwork Thu Jan 24 23:14:42 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Hansen X-Patchwork-Id: 10780279 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D72911515 for ; Thu, 24 Jan 2019 23:21:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C48B72FDEE for ; Thu, 24 Jan 2019 23:21:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B8B5F2FE60; Thu, 24 Jan 2019 23:21:53 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 621F82FDEE for ; Thu, 24 Jan 2019 23:21:53 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 590AF211BA44A; Thu, 24 Jan 2019 15:21:53 -0800 (PST) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: None (no SPF record) identity=mailfrom; client-ip=134.134.136.126; helo=mga18.intel.com; envelope-from=dave.hansen@linux.intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) (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 46B3221B02822 for ; Thu, 24 Jan 2019 15:21:52 -0800 (PST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Jan 2019 15:21:52 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,518,1539673200"; d="scan'208";a="121111369" Received: from viggo.jf.intel.com (HELO localhost.localdomain) ([10.54.77.144]) by orsmga003.jf.intel.com with ESMTP; 24 Jan 2019 15:21:52 -0800 Subject: [PATCH 1/5] mm/resource: return real error codes from walk failures To: linux-kernel@vger.kernel.org From: Dave Hansen Date: Thu, 24 Jan 2019 15:14:42 -0800 References: <20190124231441.37A4A305@viggo.jf.intel.com> In-Reply-To: <20190124231441.37A4A305@viggo.jf.intel.com> Message-Id: <20190124231442.EFD29EE0@viggo.jf.intel.com> X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 MIME-Version: 1.0 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP From: Dave Hansen walk_system_ram_range() can return an error code either becuase *it* failed, or because the 'func' that it calls returned an error. The memory hotplug does the following: ret = walk_system_ram_range(..., func); if (ret) return ret; and 'ret' makes it out to userspace, eventually. The problem is, walk_system_ram_range() failues that result from *it* failing (as opposed to 'func') return -1. That leads to a very odd -EPERM (-1) return code out to userspace. Make walk_system_ram_range() return -EINVAL for internal failures to keep userspace less confused. This return code is compatible with all the callers that I audited. 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 Reviewed-by: Bjorn Helgaas Acked-by: Michael Ellerman (powerpc) --- b/kernel/resource.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff -puN kernel/resource.c~memory-hotplug-walk_system_ram_range-returns-neg-1 kernel/resource.c --- a/kernel/resource.c~memory-hotplug-walk_system_ram_range-returns-neg-1 2019-01-24 15:13:13.950199540 -0800 +++ b/kernel/resource.c 2019-01-24 15:13:13.954199540 -0800 @@ -375,7 +375,7 @@ static int __walk_iomem_res_desc(resourc int (*func)(struct resource *, void *)) { struct resource res; - int ret = -1; + int ret = -EINVAL; while (start < end && !find_next_iomem_res(start, end, flags, desc, first_lvl, &res)) { @@ -453,7 +453,7 @@ int walk_system_ram_range(unsigned long unsigned long flags; struct resource res; unsigned long pfn, end_pfn; - int ret = -1; + int ret = -EINVAL; start = (u64) start_pfn << PAGE_SHIFT; end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1; From patchwork Thu Jan 24 23:14:44 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Hansen X-Patchwork-Id: 10780283 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0C2951515 for ; Thu, 24 Jan 2019 23:21:56 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EDC742FDEE for ; Thu, 24 Jan 2019 23:21:55 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E26712FE60; Thu, 24 Jan 2019 23:21:55 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 81FC42FE39 for ; Thu, 24 Jan 2019 23:21:55 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 7976C211BA44E; Thu, 24 Jan 2019 15:21:55 -0800 (PST) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: None (no SPF record) identity=mailfrom; client-ip=134.134.136.20; helo=mga02.intel.com; envelope-from=dave.hansen@linux.intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) (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 E2C4F211BA449 for ; Thu, 24 Jan 2019 15:21:53 -0800 (PST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Jan 2019 15:21:53 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,518,1539673200"; d="scan'208";a="294207413" Received: from viggo.jf.intel.com (HELO localhost.localdomain) ([10.54.77.144]) by orsmga005.jf.intel.com with ESMTP; 24 Jan 2019 15:21:53 -0800 Subject: [PATCH 2/5] mm/resource: move HMM pr_debug() deeper into resource code To: linux-kernel@vger.kernel.org From: Dave Hansen Date: Thu, 24 Jan 2019 15:14:44 -0800 References: <20190124231441.37A4A305@viggo.jf.intel.com> In-Reply-To: <20190124231441.37A4A305@viggo.jf.intel.com> Message-Id: <20190124231444.38182DD8@viggo.jf.intel.com> X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: thomas.lendacky@amd.com, mhocko@suse.com, linux-nvdimm@lists.01.org, Dave Hansen , ying.huang@intel.com, linux-mm@kvack.org, jglisse@redhat.com, zwisler@kernel.org, fengguang.wu@intel.com, akpm@linux-foundation.org MIME-Version: 1.0 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP From: Dave Hansen HMM consumes physical address space for its own use, even though nothing is mapped or accessible there. It uses a special resource description (IORES_DESC_DEVICE_PRIVATE_MEMORY) to uniquely identify these areas. When HMM consumes address space, it makes a best guess about what to consume. However, it is possible that a future memory or device hotplug can collide with the reserved area. In the case of these conflicts, there is an error message in register_memory_resource(). Later patches in this series move register_memory_resource() from using request_resource_conflict() to __request_region(). Unfortunately, __request_region() does not return the conflict like the previous function did, which makes it impossible to check for IORES_DESC_DEVICE_PRIVATE_MEMORY in a conflicting resource. Instead of warning in register_memory_resource(), move the check into the core resource code itself (__request_region()) where the conflicting resource _is_ available. This has the added bonus of producing a warning in case of HMM conflicts with devices *or* RAM address space, as opposed to the RAM- only warnings that were there previously. 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: Jerome Glisse Reviewed-by: Jerome Glisse --- b/kernel/resource.c | 10 ++++++++++ b/mm/memory_hotplug.c | 5 ----- 2 files changed, 10 insertions(+), 5 deletions(-) diff -puN kernel/resource.c~move-request_region-check kernel/resource.c --- a/kernel/resource.c~move-request_region-check 2019-01-24 15:13:14.453199539 -0800 +++ b/kernel/resource.c 2019-01-24 15:13:14.458199539 -0800 @@ -1123,6 +1123,16 @@ struct resource * __request_region(struc conflict = __request_resource(parent, res); if (!conflict) break; + /* + * mm/hmm.c reserves physical addresses which then + * become unavailable to other users. Conflicts are + * not expected. Be verbose if one is encountered. + */ + if (conflict->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) { + pr_debug("Resource conflict with unaddressable " + "device memory at %#010llx !\n", + (unsigned long long)start); + } if (conflict != parent) { if (!(conflict->flags & IORESOURCE_BUSY)) { parent = conflict; diff -puN mm/memory_hotplug.c~move-request_region-check mm/memory_hotplug.c --- a/mm/memory_hotplug.c~move-request_region-check 2019-01-24 15:13:14.455199539 -0800 +++ b/mm/memory_hotplug.c 2019-01-24 15:13:14.459199539 -0800 @@ -109,11 +109,6 @@ static struct resource *register_memory_ res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; conflict = request_resource_conflict(&iomem_resource, res); if (conflict) { - if (conflict->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) { - pr_debug("Device unaddressable memory block " - "memory hotplug at %#010llx !\n", - (unsigned long long)start); - } pr_debug("System RAM resource %pR cannot be added\n", res); kfree(res); return ERR_PTR(-EEXIST); From patchwork Thu Jan 24 23:14:45 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Hansen X-Patchwork-Id: 10780287 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 478681399 for ; Thu, 24 Jan 2019 23:21:59 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 322D92FE60 for ; Thu, 24 Jan 2019 23:21:59 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 23E092FE64; Thu, 24 Jan 2019 23:21:59 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id A2D4A2FDEE for ; Thu, 24 Jan 2019 23:21:58 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 98D9F211BA45A; Thu, 24 Jan 2019 15:21:58 -0800 (PST) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: None (no SPF record) identity=mailfrom; client-ip=192.55.52.93; helo=mga11.intel.com; envelope-from=dave.hansen@linux.intel.com; receiver=linux-nvdimm@lists.01.org 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) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Jan 2019 15:21:57 -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 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-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 MIME-Version: 1.0 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP 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 patchwork Thu Jan 24 23:14:47 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Hansen X-Patchwork-Id: 10780289 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 65A1C1390 for ; Thu, 24 Jan 2019 23:21:59 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 514912FDEE for ; Thu, 24 Jan 2019 23:21:59 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 453462FE39; Thu, 24 Jan 2019 23:21:59 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id D25B02FE39 for ; Thu, 24 Jan 2019 23:21:58 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id B4C8A2194D3B8; Thu, 24 Jan 2019 15:21:58 -0800 (PST) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: None (no SPF record) identity=mailfrom; client-ip=192.55.52.151; helo=mga17.intel.com; envelope-from=dave.hansen@linux.intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) (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 74DAD211BA45B for ; Thu, 24 Jan 2019 15:21:57 -0800 (PST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Jan 2019 15:21:57 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,518,1539673200"; d="scan'208";a="109574602" Received: from viggo.jf.intel.com (HELO localhost.localdomain) ([10.54.77.144]) by orsmga007.jf.intel.com with ESMTP; 24 Jan 2019 15:21:56 -0800 Subject: [PATCH 4/5] dax/kmem: let walk_system_ram_range() search child resources To: linux-kernel@vger.kernel.org From: Dave Hansen Date: Thu, 24 Jan 2019 15:14:47 -0800 References: <20190124231441.37A4A305@viggo.jf.intel.com> In-Reply-To: <20190124231441.37A4A305@viggo.jf.intel.com> Message-Id: <20190124231447.74358AA5@viggo.jf.intel.com> X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 MIME-Version: 1.0 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP From: Dave Hansen In the process of onlining memory, we use walk_system_ram_range() to find the actual RAM areas inside of the area being onlined. However, it currently only finds memory resources which are "top-level" iomem_resources. Children are not currently searched which causes it to skip System RAM in areas like this (in the format of /proc/iomem): a0000000-bfffffff : Persistent Memory (legacy) a0000000-afffffff : System RAM Changing the true->false here allows children to be searched as well. We need this because we add a new "System RAM" resource underneath the "persistent memory" resource when we use persistent memory in a volatile mode. 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/kernel/resource.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff -puN kernel/resource.c~mm-walk_system_ram_range-search-child-resources kernel/resource.c --- a/kernel/resource.c~mm-walk_system_ram_range-search-child-resources 2019-01-24 15:13:15.482199536 -0800 +++ b/kernel/resource.c 2019-01-24 15:13:15.486199536 -0800 @@ -445,6 +445,9 @@ int walk_mem_res(u64 start, u64 end, voi * This function calls the @func callback against all memory ranges of type * System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY. * It is to be used only for System RAM. + * + * This will find System RAM ranges that are children of top-level resources + * in addition to top-level System RAM resources. */ int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages, void *arg, int (*func)(unsigned long, unsigned long, void *)) @@ -460,7 +463,7 @@ int walk_system_ram_range(unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; while (start < end && !find_next_iomem_res(start, end, flags, IORES_DESC_NONE, - true, &res)) { + false, &res)) { pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT; end_pfn = (res.end + 1) >> PAGE_SHIFT; if (end_pfn > pfn) From patchwork Thu Jan 24 23:14:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Hansen X-Patchwork-Id: 10780293 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0A5721399 for ; Thu, 24 Jan 2019 23:22:01 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E9E6D2FDEE for ; Thu, 24 Jan 2019 23:22:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DE4DF2FE60; Thu, 24 Jan 2019 23:22:00 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 35F972FDEE for ; Thu, 24 Jan 2019 23:22:00 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id CB056211BA446; Thu, 24 Jan 2019 15:21:59 -0800 (PST) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: None (no SPF record) identity=mailfrom; client-ip=134.134.136.100; helo=mga07.intel.com; envelope-from=dave.hansen@linux.intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) (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 B0BB52194D387 for ; Thu, 24 Jan 2019 15:21:58 -0800 (PST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 24 Jan 2019 15:21:58 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,518,1539673200"; d="scan'208";a="269699706" Received: from viggo.jf.intel.com (HELO localhost.localdomain) ([10.54.77.144]) by orsmga004.jf.intel.com with ESMTP; 24 Jan 2019 15:21:58 -0800 Subject: [PATCH 5/5] dax: "Hotplug" persistent memory for use like normal RAM To: linux-kernel@vger.kernel.org From: Dave Hansen Date: Thu, 24 Jan 2019 15:14:48 -0800 References: <20190124231441.37A4A305@viggo.jf.intel.com> In-Reply-To: <20190124231441.37A4A305@viggo.jf.intel.com> Message-Id: <20190124231448.E102D18E@viggo.jf.intel.com> X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 MIME-Version: 1.0 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP From: Dave Hansen This is intended for use with NVDIMMs that are physically persistent (physically like flash) so that they can be used as a cost-effective RAM replacement. Intel Optane DC persistent memory is one implementation of this kind of NVDIMM. Currently, a persistent memory region is "owned" by a device driver, either the "Direct DAX" or "Filesystem DAX" drivers. These drivers allow applications to explicitly use persistent memory, generally by being modified to use special, new libraries. (DIMM-based persistent memory hardware/software is described in great detail here: Documentation/nvdimm/nvdimm.txt). However, this limits persistent memory use to applications which *have* been modified. To make it more broadly usable, this driver "hotplugs" memory into the kernel, to be managed and used just like normal RAM would be. To make this work, management software must remove the device from being controlled by the "Device DAX" infrastructure: echo -n dax0.0 > /sys/bus/dax/drivers/device_dax/remove_id echo -n dax0.0 > /sys/bus/dax/drivers/device_dax/unbind and then bind it to this new driver: echo -n dax0.0 > /sys/bus/dax/drivers/kmem/new_id echo -n dax0.0 > /sys/bus/dax/drivers/kmem/bind After this, there will be a number of new memory sections visible in sysfs that can be onlined, or that may get onlined by existing udev-initiated memory hotplug rules. This rebinding procedure is currently a one-way trip. Once memory is bound to "kmem", it's there permanently and can not be unbound and assigned back to device_dax. The kmem driver will never bind to a dax device unless the device is *explicitly* bound to the driver. There are two reasons for this: One, since it is a one-way trip, it can not be undone if bound incorrectly. Two, the kmem driver destroys data on the device. Think of if you had good data on a pmem device. It would be catastrophic if you compile-in "kmem", but leave out the "device_dax" driver. kmem would take over the device and write volatile data all over your good data. This inherits any existing NUMA information for the newly-added memory from the persistent memory device that came from the firmware. On Intel platforms, the firmware has guarantees that require each socket's persistent memory to be in a separate memory-only NUMA node. That means that this patch is not expected to create NUMA nodes, but will simply hotplug memory into existing nodes. Because NUMA nodes are created, the existing NUMA APIs and tools are sufficient to create policies for applications or memory areas to have affinity for or an aversion to using this memory. There is currently some metadata at the beginning of pmem regions. The section-size memory hotplug restrictions, plus this small reserved area can cause the "loss" of a section or two of capacity. This should be fixable in follow-on patches. But, as a first step, losing 256MB of memory (worst case) out of hundreds of gigabytes is a good tradeoff vs. the required code to fix this up precisely. This calculation is also the reason we export memory_block_size_bytes(). 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/drivers/base/memory.c | 1 b/drivers/dax/Kconfig | 16 +++++++ b/drivers/dax/Makefile | 1 b/drivers/dax/kmem.c | 108 ++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 126 insertions(+) diff -puN drivers/base/memory.c~dax-kmem-try-4 drivers/base/memory.c --- a/drivers/base/memory.c~dax-kmem-try-4 2019-01-24 15:13:15.987199535 -0800 +++ b/drivers/base/memory.c 2019-01-24 15:13:15.994199535 -0800 @@ -88,6 +88,7 @@ unsigned long __weak memory_block_size_b { return MIN_MEMORY_BLOCK_SIZE; } +EXPORT_SYMBOL_GPL(memory_block_size_bytes); static unsigned long get_memory_block_size(void) { diff -puN drivers/dax/Kconfig~dax-kmem-try-4 drivers/dax/Kconfig --- a/drivers/dax/Kconfig~dax-kmem-try-4 2019-01-24 15:13:15.988199535 -0800 +++ b/drivers/dax/Kconfig 2019-01-24 15:13:15.994199535 -0800 @@ -32,6 +32,22 @@ config DEV_DAX_PMEM Say M if unsure +config DEV_DAX_KMEM + tristate "KMEM DAX: volatile-use of persistent memory" + default DEV_DAX + depends on DEV_DAX + depends on MEMORY_HOTPLUG # for add_memory() and friends + help + Support access to persistent memory as if it were RAM. This + allows easier use of persistent memory by unmodified + applications. + + To use this feature, a DAX device must be unbound from the + device_dax driver (PMEM DAX) and bound to this kmem driver + on each boot. + + Say N if unsure. + config DEV_DAX_PMEM_COMPAT tristate "PMEM DAX: support the deprecated /sys/class/dax interface" depends on DEV_DAX_PMEM diff -puN /dev/null drivers/dax/kmem.c --- /dev/null 2018-12-03 08:41:47.355756491 -0800 +++ b/drivers/dax/kmem.c 2019-01-24 15:13:15.994199535 -0800 @@ -0,0 +1,108 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright(c) 2016-2018 Intel Corporation. All rights reserved. */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "dax-private.h" +#include "bus.h" + +int dev_dax_kmem_probe(struct device *dev) +{ + struct dev_dax *dev_dax = to_dev_dax(dev); + struct resource *res = &dev_dax->region->res; + resource_size_t kmem_start; + resource_size_t kmem_size; + resource_size_t kmem_end; + struct resource *new_res; + int numa_node; + int rc; + + /* + * Ensure good NUMA information for the persistent memory. + * Without this check, there is a risk that slow memory + * could be mixed in a node with faster memory, causing + * unavoidable performance issues. + */ + numa_node = dev_dax->target_node; + if (numa_node < 0) { + dev_warn(dev, "rejecting DAX region %pR with invalid node: %d\n", + res, numa_node); + return -EINVAL; + } + + /* Hotplug starting at the beginning of the next block: */ + kmem_start = ALIGN(res->start, memory_block_size_bytes()); + + kmem_size = resource_size(res); + /* Adjust the size down to compensate for moving up kmem_start: */ + kmem_size -= kmem_start - res->start; + /* Align the size down to cover only complete blocks: */ + kmem_size &= ~(memory_block_size_bytes() - 1); + kmem_end = kmem_start+kmem_size; + + /* Region is permanently reserved. Hot-remove not yet implemented. */ + new_res = request_mem_region(kmem_start, kmem_size, dev_name(dev)); + if (!new_res) { + dev_warn(dev, "could not reserve region [%pa-%pa]\n", + &kmem_start, &kmem_end); + return -EBUSY; + } + + /* + * Set flags appropriate for System RAM. Leave ..._BUSY clear + * so that add_memory() can add a child resource. Do not + * inherit flags from the parent since it may set new flags + * unknown to us that will break add_memory() below. + */ + new_res->flags = IORESOURCE_SYSTEM_RAM; + new_res->name = dev_name(dev); + + rc = add_memory(numa_node, new_res->start, resource_size(new_res)); + if (rc) + return rc; + + return 0; +} + +static int dev_dax_kmem_remove(struct device *dev) +{ + /* + * Purposely leak the request_mem_region() for the device-dax + * range and return '0' to ->remove() attempts. The removal of + * the device from the driver always succeeds, but the region + * is permanently pinned as reserved by the unreleased + * request_mem_region(). + */ + return -EBUSY; +} + +static struct dax_device_driver device_dax_kmem_driver = { + .drv = { + .probe = dev_dax_kmem_probe, + .remove = dev_dax_kmem_remove, + }, +}; + +static int __init dax_kmem_init(void) +{ + return dax_driver_register(&device_dax_kmem_driver); +} + +static void __exit dax_kmem_exit(void) +{ + dax_driver_unregister(&device_dax_kmem_driver); +} + +MODULE_AUTHOR("Intel Corporation"); +MODULE_LICENSE("GPL v2"); +module_init(dax_kmem_init); +module_exit(dax_kmem_exit); +MODULE_ALIAS_DAX_DEVICE(0); diff -puN drivers/dax/Makefile~dax-kmem-try-4 drivers/dax/Makefile --- a/drivers/dax/Makefile~dax-kmem-try-4 2019-01-24 15:13:15.990199535 -0800 +++ b/drivers/dax/Makefile 2019-01-24 15:13:15.994199535 -0800 @@ -1,6 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_DAX) += dax.o obj-$(CONFIG_DEV_DAX) += device_dax.o +obj-$(CONFIG_DEV_DAX_KMEM) += kmem.o dax-y := super.o dax-y += bus.o