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=-8.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_NEOMUTT 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 879F5C46470 for ; Thu, 9 May 2019 14:31:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 58CBE2173C for ; Thu, 9 May 2019 14:31:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="qOlNtK75" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726821AbfEIOb5 (ORCPT ); Thu, 9 May 2019 10:31:57 -0400 Received: from mail-ed1-f66.google.com ([209.85.208.66]:41969 "EHLO mail-ed1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726704AbfEIOb4 (ORCPT ); Thu, 9 May 2019 10:31:56 -0400 Received: by mail-ed1-f66.google.com with SMTP id m4so2221541edd.8; Thu, 09 May 2019 07:31:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:reply-to:references:mime-version :content-disposition:in-reply-to:user-agent; bh=28M3/Gt0muyIKgyfcpD9ysscEUSK1ZnFipvrQH7okoo=; b=qOlNtK752XXn4kkfsFMWyY7kRPfrZUsTtqBPdR/hrsY1mJM2tbu2nhsutSmVVSM1WW nXRASbDxRAmYKoGMORG1Srq+QfFSesIFDMzjzchm3j4kE/sLGsIywSyqVlu3Yz91d/8r FlEQUB4qvWSHM4vKfCBekEvL6H1BeRT6mMgSjN/ZfvQ7xjppTiRrhRzhd0DiONdD3rHG 8+F+D+pkIWAxOZxeIGT+39UvOnSIMPWvX3z65R9GJNUd8yqfL58nMe8pY6Q7GvVCzYIM 6GCvJUep1xdo/Z8mF1dvC94zMfD6T5hlTY7VkMhVkudMpY654rvkzmeZxmnK6kPTSOvF yY0g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:reply-to :references:mime-version:content-disposition:in-reply-to:user-agent; bh=28M3/Gt0muyIKgyfcpD9ysscEUSK1ZnFipvrQH7okoo=; b=jed3anqXrvbj4ZZvMcgvnz2hOSjNy3GlKDIkndxem5pg6xUhbMGp3DiRnlt/60D/Fk Nlbqyk3kvsw5x5NNqNL02gvzh9nW04qPjtRpZ+jO7Dgzq6mbG3ThT1PPv8X3oj9vvk/W OMK93AhtoT7mXqO/l3WoH01bVYsfoeY9NBwtKv86IT2pYmybAp30GHGvAwi6pSNWU6oY GXzSbR3Hc8CCDpT34neVeyM2AMAQhpVLcuo6A40bfsVXQGMfTMVUO6XYUYUFSZy2lEmp qigou5nhe2KQQCZQjwm79BXY9V9JeBEf+x11vniURnLwIltSOAp45KB2wogDLdka78WF rGcA== X-Gm-Message-State: APjAAAWhrKkU7a4KxYYR7kMJH3IGts2oxo9gKjXZjrkhOiYntjm9cdEt yhy0jtvkuEDm1nuMcMbNUVQ= X-Google-Smtp-Source: APXvYqzkJhS5L8NnWGrt01x6w71u7E8s0GHuJykWEj8KfZGhfTtKpBAzu9nFzSqSe/2NArkKjIgUMw== X-Received: by 2002:a50:be48:: with SMTP id b8mr4401819edi.284.1557412313899; Thu, 09 May 2019 07:31:53 -0700 (PDT) Received: from localhost ([185.92.221.13]) by smtp.gmail.com with ESMTPSA id d11sm623679eda.45.2019.05.09.07.31.52 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 09 May 2019 07:31:52 -0700 (PDT) Date: Thu, 9 May 2019 14:31:51 +0000 From: Wei Yang To: David Hildenbrand Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, akpm@linux-foundation.org, Dan Williams , Greg Kroah-Hartman , "Rafael J. Wysocki" , "mike.travis@hpe.com" , Ingo Molnar , Andrew Banman , Oscar Salvador , Michal Hocko , Pavel Tatashin , Qian Cai , Wei Yang , Arun KS , Mathieu Malaterre Subject: Re: [PATCH v2 4/8] mm/memory_hotplug: Create memory block devices after arch_add_memory() Message-ID: <20190509143151.zexjmwu3ikkmye7i@master> Reply-To: Wei Yang References: <20190507183804.5512-1-david@redhat.com> <20190507183804.5512-5-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190507183804.5512-5-david@redhat.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 07, 2019 at 08:38:00PM +0200, David Hildenbrand wrote: >Only memory to be added to the buddy and to be onlined/offlined by >user space using memory block devices needs (and should have!) memory >block devices. > >Factor out creation of memory block devices Create all devices after >arch_add_memory() succeeded. We can later drop the want_memblock parameter, >because it is now effectively stale. > >Only after memory block devices have been added, memory can be onlined >by user space. This implies, that memory is not visible to user space at >all before arch_add_memory() succeeded. > >Cc: Greg Kroah-Hartman >Cc: "Rafael J. Wysocki" >Cc: David Hildenbrand >Cc: "mike.travis@hpe.com" >Cc: Andrew Morton >Cc: Ingo Molnar >Cc: Andrew Banman >Cc: Oscar Salvador >Cc: Michal Hocko >Cc: Pavel Tatashin >Cc: Qian Cai >Cc: Wei Yang >Cc: Arun KS >Cc: Mathieu Malaterre >Signed-off-by: David Hildenbrand >--- > drivers/base/memory.c | 70 ++++++++++++++++++++++++++---------------- > include/linux/memory.h | 2 +- > mm/memory_hotplug.c | 15 ++++----- > 3 files changed, 53 insertions(+), 34 deletions(-) > >diff --git a/drivers/base/memory.c b/drivers/base/memory.c >index 6e0cb4fda179..862c202a18ca 100644 >--- a/drivers/base/memory.c >+++ b/drivers/base/memory.c >@@ -701,44 +701,62 @@ static int add_memory_block(int base_section_nr) > return 0; > } > >+static void unregister_memory(struct memory_block *memory) >+{ >+ BUG_ON(memory->dev.bus != &memory_subsys); >+ >+ /* drop the ref. we got via find_memory_block() */ >+ put_device(&memory->dev); >+ device_unregister(&memory->dev); >+} >+ > /* >- * need an interface for the VM to add new memory regions, >- * but without onlining it. >+ * Create memory block devices for the given memory area. Start and size >+ * have to be aligned to memory block granularity. Memory block devices >+ * will be initialized as offline. > */ >-int hotplug_memory_register(int nid, struct mem_section *section) >+int hotplug_memory_register(unsigned long start, unsigned long size) One trivial suggestion about the function name. For memory_block device, sometimes we use the full name find_memory_block init_memory_block add_memory_block But sometimes we use *nick* name hotplug_memory_register register_memory unregister_memory This is a little bit confusion. Can we use one name convention here? [...] > /* >@@ -1106,6 +1100,13 @@ int __ref add_memory_resource(int nid, struct resource *res) > if (ret < 0) > goto error; > >+ /* create memory block devices after memory was added */ >+ ret = hotplug_memory_register(start, size); >+ if (ret) { >+ arch_remove_memory(nid, start, size, NULL); Functionally, it works I think. But arch_remove_memory() would remove pages from zone. At this point, we just allocate section/mmap for pages, the zones are empty and pages are not connected to zone. Function zone = page_zone(page); always gets zone #0, since pages->flags is 0 at this point. This is not exact. Would we add some comment to mention this? Or we need to clean up arch_remove_memory() to take out __remove_zone()? >+ goto error; >+ } >+ > if (new_node) { > /* If sysfs file of new node can't be created, cpu on the node > * can't be hot-added. There is no rollback way now. >-- >2.20.1 -- Wei Yang Help you, Help me