From patchwork Mon Feb 1 18:13:46 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 12059653 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=-18.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,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 2033AC433E0 for ; Mon, 1 Feb 2021 18:14:11 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B7BE464EA1 for ; Mon, 1 Feb 2021 18:14:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B7BE464EA1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 55E056B0006; Mon, 1 Feb 2021 13:14:10 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 5332A6B0072; Mon, 1 Feb 2021 13:14:10 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3FB036B0073; Mon, 1 Feb 2021 13:14:10 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0003.hostedemail.com [216.40.44.3]) by kanga.kvack.org (Postfix) with ESMTP id 2BADF6B0006 for ; Mon, 1 Feb 2021 13:14:10 -0500 (EST) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id E099A181AEF10 for ; Mon, 1 Feb 2021 18:14:09 +0000 (UTC) X-FDA: 77770498218.02.crack46_04135ac275c4 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin02.hostedemail.com (Postfix) with ESMTP id B6E4910097AA1 for ; Mon, 1 Feb 2021 18:14:09 +0000 (UTC) X-HE-Tag: crack46_04135ac275c4 X-Filterd-Recvd-Size: 10172 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [63.128.21.124]) by imf42.hostedemail.com (Postfix) with ESMTP for ; Mon, 1 Feb 2021 18:14:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612203248; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dAX7GueyVaG6m75iPVmdP5d6g/SwNUAfhVVHI21U71M=; b=hnNJs8B9JAmQrnLzHM1aeXoGsxLkAPRPA8VW11UHscX9/KNs3WJyO9clKwXn6E4GoUER8H 1h9+seqi0uxRqScg5O9xVj1e0BTycRxTcXfbB3+qU/WOSPAj1IyV3EgL4+jcbrxVIu9jEL escVOSTXvnAo63bHG9WL9EHROWv+LRQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-248-BLBQQZBENLurE5KnNIZZPA-1; Mon, 01 Feb 2021 13:14:04 -0500 X-MC-Unique: BLBQQZBENLurE5KnNIZZPA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9BEDE106F8F7; Mon, 1 Feb 2021 18:13:57 +0000 (UTC) Received: from t480s.redhat.com (ovpn-115-24.ams2.redhat.com [10.36.115.24]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0ADFB18219; Mon, 1 Feb 2021 18:13:53 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, David Hildenbrand , Michal Hocko , Andrew Morton , Dave Hansen , Oscar Salvador , Greg Kroah-Hartman , Gerald Schaefer , Jonathan Corbet , "Rafael J. Wysocki" , Mauro Carvalho Chehab , Ilya Dryomov , Vaibhav Jain , Tom Rix , Geert Uytterhoeven , linux-doc@vger.kernel.org Subject: [PATCH v2 1/2] drivers/base/memory: don't store phys_device in memory blocks Date: Mon, 1 Feb 2021 19:13:46 +0100 Message-Id: <20210201181347.13262-2-david@redhat.com> In-Reply-To: <20210201181347.13262-1-david@redhat.com> References: <20210201181347.13262-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 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: No need to store the value for each and every memory block, as we can easily query the value at runtime. Reshuffle the members to optimize the memory layout. Also, let's clarify what the interface once was used for and why it's legacy nowadays. "phys_device" was used on s390x in older versions of lsmem[2]/chmem[3], back when they were still part of s390x-tools. They were later replaced by the variants in linux-utils. For example, RHEL6 and RHEL7 contain lsmem/chmem from s390-utils. RHEL8 switched to versions from util-linux on s390x [4]. "phys_device" was added with sysfs support for memory hotplug in commit 3947be1969a9 ("[PATCH] memory hotplug: sysfs and add/remove functions") in 2005. It always returned 0. s390x started returning something != 0 on some setups (if sclp.rzm is set by HW) in 2010 via commit 57b552ba0b2f ("memory hotplug/s390: set phys_device"). For s390x, it allowed for identifying which memory block devices belong to the same storage increment (RZM). Only if all memory block devices comprising a single storage increment were offline, the memory could actually be removed in the hypervisor. Since commit e5d709bb5fb7 ("s390/memory hotplug: provide memory_block_size_bytes() function") in 2013 a memory block device spans at least one storage increment - which is why the interface isn't really helpful/used anymore (except by old lsmem/chmem tools). There were once RFC patches to make use of "phys_device" in ACPI context; however, the underlying problem could be solved using different interfaces [1]. [1] https://patchwork.kernel.org/patch/2163871/ [2] https://github.com/ibm-s390-tools/s390-tools/blob/v2.1.0/zconf/lsmem [3] https://github.com/ibm-s390-tools/s390-tools/blob/v2.1.0/zconf/chmem [4] https://bugzilla.redhat.com/show_bug.cgi?id=1504134 Acked-by: Michal Hocko Cc: Andrew Morton Cc: Dave Hansen Cc: Michal Hocko Cc: Oscar Salvador Cc: Greg Kroah-Hartman Cc: Gerald Schaefer Cc: Jonathan Corbet Cc: "Rafael J. Wysocki" Cc: Mauro Carvalho Chehab Cc: Ilya Dryomov Cc: Vaibhav Jain Cc: Tom Rix Cc: Geert Uytterhoeven Cc: linux-doc@vger.kernel.org Signed-off-by: David Hildenbrand Reviewed-by: Oscar Salvador --- .../ABI/testing/sysfs-devices-memory | 5 ++-- .../admin-guide/mm/memory-hotplug.rst | 4 +-- drivers/base/memory.c | 25 +++++++------------ include/linux/memory.h | 3 +-- 4 files changed, 15 insertions(+), 22 deletions(-) diff --git a/Documentation/ABI/testing/sysfs-devices-memory b/Documentation/ABI/testing/sysfs-devices-memory index 246a45b96d22..58dbc592bc57 100644 --- a/Documentation/ABI/testing/sysfs-devices-memory +++ b/Documentation/ABI/testing/sysfs-devices-memory @@ -26,8 +26,9 @@ Date: September 2008 Contact: Badari Pulavarty Description: The file /sys/devices/system/memory/memoryX/phys_device - is read-only and is designed to show the name of physical - memory device. Implementation is currently incomplete. + is read-only; it is a legacy interface only ever used on s390x + to expose the covered storage increment. +Users: Legacy s390-tools lsmem/chmem What: /sys/devices/system/memory/memoryX/phys_index Date: September 2008 diff --git a/Documentation/admin-guide/mm/memory-hotplug.rst b/Documentation/admin-guide/mm/memory-hotplug.rst index 5c4432c96c4b..245739f55ac7 100644 --- a/Documentation/admin-guide/mm/memory-hotplug.rst +++ b/Documentation/admin-guide/mm/memory-hotplug.rst @@ -160,8 +160,8 @@ Under each memory block, you can see 5 files: "online_movable", "online", "offline" command which will be performed on all sections in the block. -``phys_device`` read-only: designed to show the name of physical memory - device. This is not well implemented now. +``phys_device`` read-only: legacy interface only ever used on s390x to + expose the covered storage increment. ``removable`` read-only: contains an integer value indicating whether the memory block is removable or not removable. A value of 1 indicates that the memory diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 901e379676be..f35298425575 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -290,20 +290,20 @@ static ssize_t state_store(struct device *dev, struct device_attribute *attr, } /* - * phys_device is a bad name for this. What I really want - * is a way to differentiate between memory ranges that - * are part of physical devices that constitute - * a complete removable unit or fru. - * i.e. do these ranges belong to the same physical device, - * s.t. if I offline all of these sections I can then - * remove the physical device? + * Legacy interface that we cannot remove: s390x exposes the storage increment + * covered by a memory block, allowing for identifying which memory blocks + * comprise a storage increment. Since a memory block spans complete + * storage increments nowadays, this interface is basically unused. Other + * archs never exposed != 0. */ static ssize_t phys_device_show(struct device *dev, struct device_attribute *attr, char *buf) { struct memory_block *mem = to_memory_block(dev); + unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr); - return sysfs_emit(buf, "%d\n", mem->phys_device); + return sysfs_emit(buf, "%d\n", + arch_get_memory_phys_device(start_pfn)); } #ifdef CONFIG_MEMORY_HOTREMOVE @@ -488,11 +488,7 @@ static DEVICE_ATTR_WO(soft_offline_page); static DEVICE_ATTR_WO(hard_offline_page); #endif -/* - * Note that phys_device is optional. It is here to allow for - * differentiation between which *physical* devices each - * section belongs to... - */ +/* See phys_device_show(). */ int __weak arch_get_memory_phys_device(unsigned long start_pfn) { return 0; @@ -574,7 +570,6 @@ int register_memory(struct memory_block *memory) static int init_memory_block(unsigned long block_id, unsigned long state) { struct memory_block *mem; - unsigned long start_pfn; int ret = 0; mem = find_memory_block_by_id(block_id); @@ -588,8 +583,6 @@ static int init_memory_block(unsigned long block_id, unsigned long state) mem->start_section_nr = block_id * sections_per_block; mem->state = state; - start_pfn = section_nr_to_pfn(mem->start_section_nr); - mem->phys_device = arch_get_memory_phys_device(start_pfn); mem->nid = NUMA_NO_NODE; ret = register_memory(mem); diff --git a/include/linux/memory.h b/include/linux/memory.h index 439a89e758d8..4da95e684e20 100644 --- a/include/linux/memory.h +++ b/include/linux/memory.h @@ -27,9 +27,8 @@ struct memory_block { unsigned long start_section_nr; unsigned long state; /* serialized by the dev->lock */ int online_type; /* for passing data to online routine */ - int phys_device; /* to which fru does this belong? */ - struct device dev; int nid; /* NID for this memory block */ + struct device dev; }; int arch_get_memory_phys_device(unsigned long start_pfn); From patchwork Mon Feb 1 18:13:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 12059655 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=-13.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 A5D58C433DB for ; Mon, 1 Feb 2021 18:14:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4BA3764EA3 for ; Mon, 1 Feb 2021 18:14:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4BA3764EA3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 840116B0072; Mon, 1 Feb 2021 13:14:11 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 7F1916B0073; Mon, 1 Feb 2021 13:14:11 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 694A46B0074; Mon, 1 Feb 2021 13:14:11 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0143.hostedemail.com [216.40.44.143]) by kanga.kvack.org (Postfix) with ESMTP id 53D306B0072 for ; Mon, 1 Feb 2021 13:14:11 -0500 (EST) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 1B35D1EE6 for ; Mon, 1 Feb 2021 18:14:11 +0000 (UTC) X-FDA: 77770498302.19.boats99_2109229275c4 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin19.hostedemail.com (Postfix) with ESMTP id DBB0B1AD1B0 for ; Mon, 1 Feb 2021 18:14:10 +0000 (UTC) X-HE-Tag: boats99_2109229275c4 X-Filterd-Recvd-Size: 9232 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [63.128.21.124]) by imf20.hostedemail.com (Postfix) with ESMTP for ; Mon, 1 Feb 2021 18:14:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612203249; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Hw/bbefHCDlpt7rxB9SfB7fxyTWhrX+xQPiAEBdtMcc=; b=YeEVxGVSptJXN5YQmdMWCv3FRw3G7E2oXyewJANvdxm5T8CDl1Wf7dosgfS9PHsJA6H+Gu MXWZ5mSXlmIsXYX3FUJVs9xYxfgOkUpOizuB7N8/QwlOrA7LUX71o7NvIjOUIsd3htBLoC eaZ6qW6BZ0Oc47+QWAlV9XIp9cs3W8A= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-514-UMcO-sFEP7mPMII8WaFClA-1; Mon, 01 Feb 2021 13:14:07 -0500 X-MC-Unique: UMcO-sFEP7mPMII8WaFClA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E70701060B70; Mon, 1 Feb 2021 18:14:00 +0000 (UTC) Received: from t480s.redhat.com (ovpn-115-24.ams2.redhat.com [10.36.115.24]) by smtp.corp.redhat.com (Postfix) with ESMTP id EB0C85C8A7; Mon, 1 Feb 2021 18:13:57 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, David Hildenbrand , Michal Hocko , Andrew Morton , Dave Hansen , Oscar Salvador , Jonathan Corbet , Greg Kroah-Hartman , Jonathan Cameron , Ilya Dryomov , Mauro Carvalho Chehab , Geert Uytterhoeven , linux-doc@vger.kernel.org Subject: [PATCH v2 2/2] Documentation: sysfs/memory: clarify some memory block device properties Date: Mon, 1 Feb 2021 19:13:47 +0100 Message-Id: <20210201181347.13262-3-david@redhat.com> In-Reply-To: <20210201181347.13262-1-david@redhat.com> References: <20210201181347.13262-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 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: In commit 53cdc1cb29e8 ("drivers/base/memory.c: indicate all memory blocks as removable") we changed the output of the "removable" property of memory devices to return "1" if and only if the kernel supports memory offlining. Let's update documentation, stating that the interface is legacy. Also update documentation of the "state" property and "valid_zones" properties. Acked-by: Michal Hocko Cc: Andrew Morton Cc: Dave Hansen Cc: Michal Hocko Cc: Oscar Salvador Cc: Jonathan Corbet Cc: David Hildenbrand Cc: Greg Kroah-Hartman Cc: Jonathan Cameron Cc: Ilya Dryomov Cc: Mauro Carvalho Chehab Cc: Geert Uytterhoeven Cc: linux-doc@vger.kernel.org Signed-off-by: David Hildenbrand Reviewed-by: Oscar Salvador --- .../ABI/testing/sysfs-devices-memory | 53 ++++++++++++------- .../admin-guide/mm/memory-hotplug.rst | 16 +++--- 2 files changed, 41 insertions(+), 28 deletions(-) diff --git a/Documentation/ABI/testing/sysfs-devices-memory b/Documentation/ABI/testing/sysfs-devices-memory index 58dbc592bc57..d8b0f80b9e33 100644 --- a/Documentation/ABI/testing/sysfs-devices-memory +++ b/Documentation/ABI/testing/sysfs-devices-memory @@ -13,13 +13,13 @@ What: /sys/devices/system/memory/memoryX/removable Date: June 2008 Contact: Badari Pulavarty Description: - The file /sys/devices/system/memory/memoryX/removable - indicates whether this memory block is removable or not. - This is useful for a user-level agent to determine - identify removable sections of the memory before attempting - potentially expensive hot-remove memory operation + The file /sys/devices/system/memory/memoryX/removable is a + legacy interface used to indicated whether a memory block is + likely to be offlineable or not. Newer kernel versions return + "1" if and only if the kernel supports memory offlining. Users: hotplug memory remove tools http://www.ibm.com/developerworks/wikis/display/LinuxP/powerpc-utils + lsmem/chmem part of util-linux What: /sys/devices/system/memory/memoryX/phys_device Date: September 2008 @@ -44,23 +44,25 @@ Date: September 2008 Contact: Badari Pulavarty Description: The file /sys/devices/system/memory/memoryX/state - is read-write. When read, its contents show the - online/offline state of the memory section. When written, - root can toggle the the online/offline state of a removable - memory section (see removable file description above) - using the following commands:: + is read-write. When read, it returns the online/offline + state of the memory block. When written, root can toggle + the online/offline state of a memory block using the following + commands:: # echo online > /sys/devices/system/memory/memoryX/state # echo offline > /sys/devices/system/memory/memoryX/state - For example, if /sys/devices/system/memory/memory22/removable - contains a value of 1 and - /sys/devices/system/memory/memory22/state contains the - string "online" the following command can be executed by - by root to offline that section:: - - # echo offline > /sys/devices/system/memory/memory22/state - + On newer kernel versions, advanced states can be specified + when onlining to select a target zone: "online_movable" + selects the movable zone. "online_kernel" selects the + applicable kernel zone (DMA, DMA32, or Normal). However, + after successfully setting one of the advanced states, + reading the file will return "online"; the zone information + can be obtained via "valid_zones" instead. + + While onlining is unlikely to fail, there are no guarantees + that offlining will succeed. Offlining is more likely to + succeed if "valid_zones" indicates "Movable". Users: hotplug memory remove tools http://www.ibm.com/developerworks/wikis/display/LinuxP/powerpc-utils @@ -70,8 +72,19 @@ Date: July 2014 Contact: Zhang Zhen Description: The file /sys/devices/system/memory/memoryX/valid_zones is - read-only and is designed to show which zone this memory - block can be onlined to. + read-only. + + For online memory blocks, it returns in which zone memory + provided by a memory block is managed. If multiple zones + apply (not applicable for hotplugged memory), "None" is returned + and the memory block cannot be offlined. + + For offline memory blocks, it returns by which zone memory + provided by a memory block can be managed when onlining. + The first returned zone ("default") will be used when setting + the state of an offline memory block to "online". Only one of + the kernel zones (DMA, DMA32, Normal) is applicable for a single + memory block. What: /sys/devices/system/memoryX/nodeY Date: October 2009 diff --git a/Documentation/admin-guide/mm/memory-hotplug.rst b/Documentation/admin-guide/mm/memory-hotplug.rst index 245739f55ac7..5307f90738aa 100644 --- a/Documentation/admin-guide/mm/memory-hotplug.rst +++ b/Documentation/admin-guide/mm/memory-hotplug.rst @@ -162,14 +162,14 @@ Under each memory block, you can see 5 files: which will be performed on all sections in the block. ``phys_device`` read-only: legacy interface only ever used on s390x to expose the covered storage increment. -``removable`` read-only: contains an integer value indicating - whether the memory block is removable or not - removable. A value of 1 indicates that the memory - block is removable and a value of 0 indicates that - it is not removable. A memory block is removable only if - every section in the block is removable. -``valid_zones`` read-only: designed to show which zones this memory block - can be onlined to. +``removable`` read-only: legacy interface that indicated whether a memory + block was likely to be offlineable or not. Newer kernel + versions return "1" if and only if the kernel supports + memory offlining. +``valid_zones`` read-only: designed to show by which zone memory provided by + a memory block is managed, and to show by which zone memory + provided by an offline memory block could be managed when + onlining. The first column shows it`s default zone.