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,USER_AGENT_NEOMUTT 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 02AE0C04AB3 for ; Thu, 9 May 2019 21:50:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC0CD217D7 for ; Thu, 9 May 2019 21:50:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="NGl7wg2c" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726974AbfEIVuj (ORCPT ); Thu, 9 May 2019 17:50:39 -0400 Received: from mail-ed1-f67.google.com ([209.85.208.67]:33840 "EHLO mail-ed1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726754AbfEIVuj (ORCPT ); Thu, 9 May 2019 17:50:39 -0400 Received: by mail-ed1-f67.google.com with SMTP id p27so3381267eda.1; Thu, 09 May 2019 14:50:37 -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=BMlSqCqK74ztHAZfTWbqmYSf5DVD6ofjZO6Gjzp7WWI=; b=NGl7wg2cGVpKyD9cpJHljZftn+LLkSh0SgfYuUD7pOjyCs9Ci6mgnsJnI/5YX2u2sA N00ub+BHjZPR67iWK7zGrSKdc2FIKgprC22Vnd+8DssY7k0hLeRClyrdM+litkTcYs5z wn30Qa8o0THNaD/XsPLrjqCpWhF62kj/AuENHYy+QRCEAH6uviiC55pbVSOOb7LbHdGw b43TyiAMIlgHR0fXTDmkpRK1aekheRqQsoO5nwvkE4LFcuDJ1jZjKz5V1h8l0HDavI8L LGaLQ402+MxxhMuG/j6qecZBHC9qJ7cHkd3zoNCrkpuydFRs/uCvLnQVkbwD/RSUNA0G Zriw== 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=BMlSqCqK74ztHAZfTWbqmYSf5DVD6ofjZO6Gjzp7WWI=; b=I+W5WEYUud8UU38P30M4kThIuoKLltm0GAxZ0GTIOxpgZtL4zcY5zIbY9DtxotcF6g rwNgApDExsO7svkXg0MhR0Oh4PlJnA2u83fL5I5hBUEymrR7pqdX/zvx5ZzxjyBgqOLF fwXZTBwevD9idFvaP7tPuCL8uDIXLtLheu8UrOaNRmwgyp7Tymevg/XP8wg9Yuc9oi6p SU/HrvamTJqN5OhKzRWULMnFm2EsSm4fE5M7V2AXrMGNlY3jRi+Ixa9AGrGERMMTuI5u WgIQMkmAs0zqYY7A/hi10jkv21BowhLphsn70heMfJbG0fwk/ad0VHwvTL7d/naSmobw BLig== X-Gm-Message-State: APjAAAVPfVkkTRyCNFT3NdCUdS7C+f8uwUETTG6NRorJij8KjOwYL2rC utXtsY4A6sSu+/OYK4Yq010= X-Google-Smtp-Source: APXvYqymBHLkj8Y+oaiwW9YuwNj6GLPLzc74NUHJXE/g8FqI3LUNlHjOkXv2ihOrqJ30gkhHPU8rNA== X-Received: by 2002:a17:906:45c3:: with SMTP id z3mr5444210ejq.134.1557438636558; Thu, 09 May 2019 14:50:36 -0700 (PDT) Received: from localhost ([185.92.221.13]) by smtp.gmail.com with ESMTPSA id v35sm890246edc.4.2019.05.09.14.50.35 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 09 May 2019 14:50:35 -0700 (PDT) Date: Thu, 9 May 2019 21:50:34 +0000 From: Wei Yang To: David Hildenbrand Cc: Wei Yang , 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 , Arun KS , Mathieu Malaterre Subject: Re: [PATCH v2 4/8] mm/memory_hotplug: Create memory block devices after arch_add_memory() Message-ID: <20190509215034.jl2qejw3pzqtbu5d@master> Reply-To: Wei Yang References: <20190507183804.5512-1-david@redhat.com> <20190507183804.5512-5-david@redhat.com> <20190509143151.zexjmwu3ikkmye7i@master> <28071389-372c-14eb-1209-02464726b4f0@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <28071389-372c-14eb-1209-02464726b4f0@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 Thu, May 09, 2019 at 04:58:56PM +0200, David Hildenbrand wrote: >On 09.05.19 16:31, Wei Yang wrote: >> 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? > >We can just go for > >crate_memory_blocks() and free_memory_blocks(). Or do >you have better suggestions? s/crate/create/ Looks good to me. > >(I would actually even prefer "memory_block_devices", because memory >blocks have different meanins) > Agree with you, this comes to my mind sometime ago :-) >> >> [...] >> >>> /* >>> @@ -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()? > >That is precisely what is on my list next (see cover letter).This is >already broken when memory that was never onlined is removed again. >So I am planning to fix that independently. > Sounds great :-) Hope you would cc me in the following series. > >-- > >Thanks, > >David / dhildenb -- Wei Yang Help you, Help me