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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 85E49C282CE for ; Tue, 4 Jun 2019 17:52:08 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3A4132075B for ; Tue, 4 Jun 2019 17:52:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3A4132075B 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 B31E16B0271; Tue, 4 Jun 2019 13:52:07 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AE1DE6B0273; Tue, 4 Jun 2019 13:52:07 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9AAAE6B0277; Tue, 4 Jun 2019 13:52:07 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-vs1-f70.google.com (mail-vs1-f70.google.com [209.85.217.70]) by kanga.kvack.org (Postfix) with ESMTP id 78A2A6B0271 for ; Tue, 4 Jun 2019 13:52:07 -0400 (EDT) Received: by mail-vs1-f70.google.com with SMTP id b70so87885vsd.19 for ; Tue, 04 Jun 2019 10:52:07 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:subject:to:cc :references:from:openpgp:autocrypt:organization:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=Mlnc1PENy6BubUC3qMTM4yUW1mdnZfFrWQ6xDaxH6ek=; b=MhXPn8EOBnnDJiNxMQDq5GMQ/Mg9/DpySU6Tj72WdUdxnYqT9s51AELxZBshOYom3R Dh5PiDFSjTimOYdqDUr6CoYR7Kd/Z1sapMNlEyhTs9GwVgqdyzya+cC4/zX/ddK+vMHj g6/F/h/EAfkixXvvcbomjuWnXbi5heUsgEq+riuNbJhZFM6b9kFbn1TfSKw3k9bvdP8I mZ47pb3/nJ8JVAJ/B7DC0G3m5ytQ/5tQ+eSZs+rP/jw9pkI3YAYHUZ4QZwKJxGlxd7f2 bOT5PyOXW8OFIdIy/N3IZPi+zblXNVq+jGqJ5vFqZgSPH+JKZXK2TEnjMZMim7pqtua6 ++MQ== X-Original-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 X-Gm-Message-State: APjAAAXGFZ3jqgEpKzhAdKf4/tkJTG+2Y1KKCzVIk2tEaEFfSZ2hy2Ym oEz8AetrkiK3On5HMiObecDcr7GsUegbcIfEjCBGPge2pPO3BgfpWb/fPIxDaSVLa2GnMfKxJbB 2JNXhCeAkGwCLSEXfDtkM7DRWXGWgv9fUzCVFdUDfG9UGR/c13v9aFTPnxk29uMetCw== X-Received: by 2002:a1f:56c3:: with SMTP id k186mr8310611vkb.24.1559670727120; Tue, 04 Jun 2019 10:52:07 -0700 (PDT) X-Google-Smtp-Source: APXvYqzkhAQFUCqSqRZv2k7M1biC+x+rbbSXB4uSoL7zRdoc9FRqnyZkPbiuPOV2u/IHL2lXiIJ+ X-Received: by 2002:a1f:56c3:: with SMTP id k186mr8310530vkb.24.1559670726095; Tue, 04 Jun 2019 10:52:06 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1559670726; cv=none; d=google.com; s=arc-20160816; b=Pgq2Xsig0FHW034hVv/cSZDE1h7VaEMAmL/szmKe7TYLesV5ZrYufYTgFBKIQVqWEb HJIPc4/Wj00rDUdhh7+dKhbvoVGTB4loR9XdtQtbL7lBU1DWM+hZEbmxeT9jiuUe9xSj f5qRmdAkzrUay2a0UHvlUm4ARLSjNlCI1HItpqIqRwa35gnqf5XYIdCqbfAElarjjoZR tJam8K6y9jnigl4P1o+b4ZphGwpq9aZXtlMbc4y3PQfmzPekimhA0DGWUnLH07V78VZT olX5cGYWDCHKUmY4uViXfrcx4nkIU1IVSYbeeqgyRY+BdmUJ2ODXa2PL7XA/+64G2rP8 K5AQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:organization:autocrypt:openpgp:from :references:cc:to:subject; bh=Mlnc1PENy6BubUC3qMTM4yUW1mdnZfFrWQ6xDaxH6ek=; b=ZHpXAfzKHQVAWNoraHRmU+HMRPGHQ/jZDkKFnD1vPc6JRC47CfHQyHYhytZUpzIO2x VKquAT4CNRNVOcMVoa3/P3/WuBcpOvdExFRTQ9hRp8GFBVAM1ASeLp0L22hUsO2sqytG dD+RcM1XHE5Fu7zyFYaUvmxXJkAgyyFxSm0jlSIDTgVw1IeRKALOnkMsPrTkZCJ9IhQ5 ipoUJcdbvl9kCl5ukUJda+IwNbXiC4+KJLcy8aLeRdAYbmbGnO0PA1WvIIg3o0oaT9I9 +RCVRJV7VikI0cl1+AYyBQNbIkTfxoCWkjA4DtvdQCm38QXgZSFi0TQ7jZdNa+KpRrSq ps4A== ARC-Authentication-Results: i=1; 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 mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id k11si3532313uaj.103.2019.06.04.10.52.05 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 04 Jun 2019 10:52:06 -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-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DC01AC04FFF1; Tue, 4 Jun 2019 17:51:59 +0000 (UTC) Received: from [10.36.116.79] (ovpn-116-79.ams2.redhat.com [10.36.116.79]) by smtp.corp.redhat.com (Postfix) with ESMTP id 735B9600CC; Tue, 4 Jun 2019 17:51:53 +0000 (UTC) Subject: Re: [PATCH v3 04/11] arm64/mm: Add temporary arch_remove_memory() implementation To: Robin Murphy , 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, linux-arm-kernel@lists.infradead.org, akpm@linux-foundation.org, Dan Williams , Igor Mammedov , Catalin Marinas , Will Deacon , Mark Rutland , Ard Biesheuvel , Chintan Pandya , Mike Rapoport , Jun Yao , Yu Zhao , Anshuman Khandual References: <20190527111152.16324-1-david@redhat.com> <20190527111152.16324-5-david@redhat.com> <20190603214139.mercn5hol2yyfl2s@master> <5059f68d-45d2-784e-0770-ee67060773c7@redhat.com> <7a5b8c8d-f1bb-9c7e-9809-405af374fecd@arm.com> 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: <4f2a87e9-7fd6-4b2b-892d-52482a330235@redhat.com> Date: Tue, 4 Jun 2019 19:51:52 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <7a5b8c8d-f1bb-9c7e-9809-405af374fecd@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Tue, 04 Jun 2019 17:52:00 +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 04.06.19 19:36, Robin Murphy wrote: > On 04/06/2019 07:56, David Hildenbrand wrote: >> On 03.06.19 23:41, Wei Yang wrote: >>> On Mon, May 27, 2019 at 01:11:45PM +0200, David Hildenbrand wrote: >>>> A proper arch_remove_memory() implementation is on its way, which also >>>> cleanly removes page tables in arch_add_memory() in case something goes >>>> wrong. >>> >>> Would this be better to understand? >>> >>> removes page tables created in arch_add_memory >> >> That's not what this sentence expresses. Have a look at >> arch_add_memory(), in case __add_pages() fails, the page tables are not >> removed. This will also be fixed by Anshuman in the same shot. >> >>> >>>> >>>> As we want to use arch_remove_memory() in case something goes wrong >>>> during memory hotplug after arch_add_memory() finished, let's add >>>> a temporary hack that is sufficient enough until we get a proper >>>> implementation that cleans up page table entries. >>>> >>>> We will remove CONFIG_MEMORY_HOTREMOVE around this code in follow up >>>> patches. >>>> >>>> Cc: Catalin Marinas >>>> Cc: Will Deacon >>>> Cc: Mark Rutland >>>> Cc: Andrew Morton >>>> Cc: Ard Biesheuvel >>>> Cc: Chintan Pandya >>>> Cc: Mike Rapoport >>>> Cc: Jun Yao >>>> Cc: Yu Zhao >>>> Cc: Robin Murphy >>>> Cc: Anshuman Khandual >>>> Signed-off-by: David Hildenbrand >>>> --- >>>> arch/arm64/mm/mmu.c | 19 +++++++++++++++++++ >>>> 1 file changed, 19 insertions(+) >>>> >>>> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c >>>> index a1bfc4413982..e569a543c384 100644 >>>> --- a/arch/arm64/mm/mmu.c >>>> +++ b/arch/arm64/mm/mmu.c >>>> @@ -1084,4 +1084,23 @@ int arch_add_memory(int nid, u64 start, u64 size, >>>> return __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, >>>> restrictions); >>>> } >>>> +#ifdef CONFIG_MEMORY_HOTREMOVE >>>> +void arch_remove_memory(int nid, u64 start, u64 size, >>>> + struct vmem_altmap *altmap) >>>> +{ >>>> + unsigned long start_pfn = start >> PAGE_SHIFT; >>>> + unsigned long nr_pages = size >> PAGE_SHIFT; >>>> + struct zone *zone; >>>> + >>>> + /* >>>> + * FIXME: Cleanup page tables (also in arch_add_memory() in case >>>> + * adding fails). Until then, this function should only be used >>>> + * during memory hotplug (adding memory), not for memory >>>> + * unplug. ARCH_ENABLE_MEMORY_HOTREMOVE must not be >>>> + * unlocked yet. >>>> + */ >>>> + zone = page_zone(pfn_to_page(start_pfn)); >>> >>> Compared with arch_remove_memory in x86. If altmap is not NULL, zone will be >>> retrieved from page related to altmap. Not sure why this is not the same? >> >> This is a minimal implementation, sufficient for this use case here. A >> full implementation is in the works. For now, this function will not be >> used with an altmap (ZONE_DEVICE is not esupported for arm64 yet). > > FWIW the other pieces of ZONE_DEVICE are now due to land in parallel, > but as long as we don't throw the ARCH_ENABLE_MEMORY_HOTREMOVE switch > then there should still be no issue. Besides, given that we should > consistently ignore the altmap everywhere at the moment, it may even > work out regardless. Thanks for the info. > > One thing stands out about the failure path thing, though - if > __add_pages() did fail, can it still be guaranteed to have initialised > the memmap such that page_zone() won't return nonsense? Last time I if __add_pages() fails, then arch_add_memory() fails and arch_remove_memory() will not be called in the context of this series. Only if it succeeded. > looked that was still a problem when removing memory which had been > successfully added, but never onlined (although I do know that > particular case was already being discussed at the time, and I've not > been paying the greatest attention since). Yes, that part is next on my list. It works but is ugly. The memory removal process should not care about zones at all. Slowly moving into the right direction :) > > Robin. > -- Thanks, David / dhildenb