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[209.132.183.28]) by mx.google.com with ESMTPS id n31si1432870qtb.300.2019.05.09.07.05.49 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 09 May 2019 07:05:49 -0700 (PDT) Received-SPF: pass (google.com: domain of david@redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; Authentication-Results: mx.google.com; spf=pass (google.com: domain of david@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 258DAC075D75; Thu, 9 May 2019 14:05:38 +0000 (UTC) Received: from [10.36.117.56] (ovpn-117-56.ams2.redhat.com [10.36.117.56]) by smtp.corp.redhat.com (Postfix) with ESMTP id 73DB110027C1; Thu, 9 May 2019 14:05:30 +0000 (UTC) Subject: Re: [PATCH v2 4/8] mm/memory_hotplug: Create memory block devices after arch_add_memory() To: Wei Yang 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 , Arun KS , Mathieu Malaterre References: <20190507183804.5512-1-david@redhat.com> <20190507183804.5512-5-david@redhat.com> <20190509135533.6xok3v7rxxaohc77@master> From: David Hildenbrand Openpgp: preference=signencrypt Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwX4EEwECACgFAljj9eoCGwMFCQlmAYAGCwkI BwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEE3eEPcA/4Na5IIP/3T/FIQMxIfNzZshIq687qgG 8UbspuE/YSUDdv7r5szYTK6KPTlqN8NAcSfheywbuYD9A4ZeSBWD3/NAVUdrCaRP2IvFyELj xoMvfJccbq45BxzgEspg/bVahNbyuBpLBVjVWwRtFCUEXkyazksSv8pdTMAs9IucChvFmmq3 jJ2vlaz9lYt/lxN246fIVceckPMiUveimngvXZw21VOAhfQ+/sofXF8JCFv2mFcBDoa7eYob s0FLpmqFaeNRHAlzMWgSsP80qx5nWWEvRLdKWi533N2vC/EyunN3HcBwVrXH4hxRBMco3jvM m8VKLKao9wKj82qSivUnkPIwsAGNPdFoPbgghCQiBjBe6A75Z2xHFrzo7t1jg7nQfIyNC7ez MZBJ59sqA9EDMEJPlLNIeJmqslXPjmMFnE7Mby/+335WJYDulsRybN+W5rLT5aMvhC6x6POK z55fMNKrMASCzBJum2Fwjf/VnuGRYkhKCqqZ8gJ3OvmR50tInDV2jZ1DQgc3i550T5JDpToh dPBxZocIhzg+MBSRDXcJmHOx/7nQm3iQ6iLuwmXsRC6f5FbFefk9EjuTKcLMvBsEx+2DEx0E UnmJ4hVg7u1PQ+2Oy+Lh/opK/BDiqlQ8Pz2jiXv5xkECvr/3Sv59hlOCZMOaiLTTjtOIU7Tq 7ut6OL64oAq+zsFNBFXLn5EBEADn1959INH2cwYJv0tsxf5MUCghCj/CA/lc/LMthqQ773ga uB9mN+F1rE9cyyXb6jyOGn+GUjMbnq1o121Vm0+neKHUCBtHyseBfDXHA6m4B3mUTWo13nid 0e4AM71r0DS8+KYh6zvweLX/LL5kQS9GQeT+QNroXcC1NzWbitts6TZ+IrPOwT1hfB4WNC+X 2n4AzDqp3+ILiVST2DT4VBc11Gz6jijpC/KI5Al8ZDhRwG47LUiuQmt3yqrmN63V9wzaPhC+ xbwIsNZlLUvuRnmBPkTJwwrFRZvwu5GPHNndBjVpAfaSTOfppyKBTccu2AXJXWAE1Xjh6GOC 8mlFjZwLxWFqdPHR1n2aPVgoiTLk34LR/bXO+e0GpzFXT7enwyvFFFyAS0Nk1q/7EChPcbRb hJqEBpRNZemxmg55zC3GLvgLKd5A09MOM2BrMea+l0FUR+PuTenh2YmnmLRTro6eZ/qYwWkC u8FFIw4pT0OUDMyLgi+GI1aMpVogTZJ70FgV0pUAlpmrzk/bLbRkF3TwgucpyPtcpmQtTkWS gDS50QG9DR/1As3LLLcNkwJBZzBG6PWbvcOyrwMQUF1nl4SSPV0LLH63+BrrHasfJzxKXzqg rW28CTAE2x8qi7e/6M/+XXhrsMYG+uaViM7n2je3qKe7ofum3s4vq7oFCPsOgwARAQABwsFl BBgBAgAPBQJVy5+RAhsMBQkJZgGAAAoJEE3eEPcA/4NagOsP/jPoIBb/iXVbM+fmSHOjEshl KMwEl/m5iLj3iHnHPVLBUWrXPdS7iQijJA/VLxjnFknhaS60hkUNWexDMxVVP/6lbOrs4bDZ NEWDMktAeqJaFtxackPszlcpRVkAs6Msn9tu8hlvB517pyUgvuD7ZS9gGOMmYwFQDyytpepo YApVV00P0u3AaE0Cj/o71STqGJKZxcVhPaZ+LR+UCBZOyKfEyq+ZN311VpOJZ1IvTExf+S/5 lqnciDtbO3I4Wq0ArLX1gs1q1XlXLaVaA3yVqeC8E7kOchDNinD3hJS4OX0e1gdsx/e6COvy qNg5aL5n0Kl4fcVqM0LdIhsubVs4eiNCa5XMSYpXmVi3HAuFyg9dN+x8thSwI836FoMASwOl C7tHsTjnSGufB+D7F7ZBT61BffNBBIm1KdMxcxqLUVXpBQHHlGkbwI+3Ye+nE6HmZH7IwLwV W+Ajl7oYF+jeKaH4DZFtgLYGLtZ1LDwKPjX7VAsa4Yx7S5+EBAaZGxK510MjIx6SGrZWBrrV TEvdV00F2MnQoeXKzD7O4WFbL55hhyGgfWTHwZ457iN9SgYi1JLPqWkZB0JRXIEtjd4JEQcx +8Umfre0Xt4713VxMygW0PnQt5aSQdMD58jHFxTk092mU+yIHj5LeYgvwSgZN4airXk5yRXl SE+xAvmumFBY Organization: Red Hat GmbH Message-ID: Date: Thu, 9 May 2019 16:05:29 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190509135533.6xok3v7rxxaohc77@master> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Thu, 09 May 2019 14:05:48 +0000 (UTC) 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: On 09.05.19 15:55, 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) >> { >> - int ret = 0; >> + unsigned long block_nr_pages = memory_block_size_bytes() >> PAGE_SHIFT; >> + unsigned long start_pfn = PFN_DOWN(start); >> + unsigned long end_pfn = start_pfn + (size >> PAGE_SHIFT); >> + unsigned long pfn; >> struct memory_block *mem; >> + int ret = 0; >> >> - mutex_lock(&mem_sysfs_mutex); >> + BUG_ON(!IS_ALIGNED(start, memory_block_size_bytes())); >> + BUG_ON(!IS_ALIGNED(size, memory_block_size_bytes())); >> >> - mem = find_memory_block(section); >> - if (mem) { >> - mem->section_count++; >> - put_device(&mem->dev); >> - } else { >> - ret = init_memory_block(&mem, section, MEM_OFFLINE); >> + mutex_lock(&mem_sysfs_mutex); >> + for (pfn = start_pfn; pfn != end_pfn; pfn += block_nr_pages) { >> + mem = find_memory_block(__pfn_to_section(pfn)); >> + if (mem) { >> + WARN_ON_ONCE(false); > > One question here, the purpose of WARN_ON_ONCE(false) is? Would we trigger > this? Would happen if something goes terribly wrong. We might want to remove this once we are sure this will not happen. I replaced it in the meantime by a if (WARN_ON_ONCE(mem)) { put_device(&mem->dev); ret = -EEXIST; break; } > >> + put_device(&mem->dev); >> + continue; >> + } >> + ret = init_memory_block(&mem, __pfn_to_section(pfn), >> + MEM_OFFLINE); >> if (ret) >> - goto out; >> - mem->section_count++; >> + break; >> + mem->section_count = memory_block_size_bytes() / >> + MIN_MEMORY_BLOCK_SIZE; > > Maybe we can leverage sections_per_block variable. Most certainly if it does what I think it does :) thanks! -- Thanks, David / dhildenb