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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0CE7CC001B0 for ; Mon, 7 Aug 2023 12:41:40 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 952686B0080; Mon, 7 Aug 2023 08:41:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 904C38D0003; Mon, 7 Aug 2023 08:41:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7CA1E8D0002; Mon, 7 Aug 2023 08:41:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 6A8B06B0080 for ; Mon, 7 Aug 2023 08:41:39 -0400 (EDT) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 321BE1A0AB1 for ; Mon, 7 Aug 2023 12:41:39 +0000 (UTC) X-FDA: 81097269918.29.7695C62 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf06.hostedemail.com (Postfix) with ESMTP id F1DC9180019 for ; Mon, 7 Aug 2023 12:41:36 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=i0B08zjT; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf06.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1691412097; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Cffoe/mIarGWdUJhKqIOqLkz4ISA+A/ue3hIKcjnEoo=; b=kJsupWg3THQgLRsTMjbLJs5NC5i+OUl93vEuCBK/YjbOvTZnKq3QRFzoFoP1aITMokeIoa Z/YOjiglAY55WjIL6xKfN4xSftd5imnqfqSkBtZuiOFWageiKiudobaYvcb7NDtDk5IY3x xdXiqBBNzVHV0+tXTXOpFvtoyU//5OQ= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=i0B08zjT; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf06.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1691412097; a=rsa-sha256; cv=none; b=Vty9V+LoWrlQUEjzLWVs5F9dkYXSvCcq9Qcq/HKOLwnOHBQioZgxs+j4MOgztPDWen8xyv ul/Q9Wd975Hg3N9+Xfr8Vj119uu+Rdb+z+cfOxak8Er7W+RE+zA2fIAbG8UV5/ISh1Qqhm PzlncTjZyZvJDZYpDNHf8QU+Db0vOSM= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1691412096; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Cffoe/mIarGWdUJhKqIOqLkz4ISA+A/ue3hIKcjnEoo=; b=i0B08zjTpfs/suCOeJtMtS5T1y6c3sFFTOpKjXEwJKVFhzl89RxeeslhjOPYqFyWPkarH8 ZT7cfrcgaU0EkkkFu5xMG6/xYZyP8nU1JWW75lp0lONlh+N9YD3w8c/xzdad0MSA5S4iLu VVBpm3w+bAmY0KXKQh6ap1WAPlJNsQ8= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-447-XVqhEw9jNLOJbSFx8kJEsQ-1; Mon, 07 Aug 2023 08:41:34 -0400 X-MC-Unique: XVqhEw9jNLOJbSFx8kJEsQ-1 Received: by mail-wr1-f72.google.com with SMTP id ffacd0b85a97d-317c8fbbd4fso2141258f8f.3 for ; Mon, 07 Aug 2023 05:41:34 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691412093; x=1692016893; h=content-transfer-encoding:in-reply-to:subject:organization:from :references:cc:to:content-language:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=Cffoe/mIarGWdUJhKqIOqLkz4ISA+A/ue3hIKcjnEoo=; b=RPs4qCOJ6YmfQusGdKJCHPuXmRf8Dt8QOqurDL7XsnQ+YxDpgirNuyh5kZ3zDO3E9B K7Fdg8mG9/rdvg5BNezPnFe0zrhJa4zk0OtHvV69gzfzqAPn+qLwuVHq20lGHbyclfIP iHBQWu7HF1MrIueJQS3sTt8E2KRqbUNuELjuNBKv9ijWF0EGe8krWjjh2MKrdN/yupAj n5VDHFq9RBJuXdGHZ9frMrovx2wStXHDhQUL+K6aGMdatX9y8GyQs6lC83DF0Kw/TmBj SGAkNiJRGgTBBSpBNQQVbsd6dbwchfbyOw7uFNhCugd9FHcJ0JQ4mIvBZRXIYBgOb8WX KAyQ== X-Gm-Message-State: AOJu0YwMUkzXQExfRtxDdHVKpzc/kHs7+FwjX1StjX2ZNMiNAbosRwZ7 pwiwrsrS4yJH+HtVG0N/tTW8bmqe9s/C5/Cc9pUBbZ44O7PaVNpicgC0EM6vUwMVjsRWvShDVKP ydZBNu2g+NGQ= X-Received: by 2002:a05:6000:1205:b0:315:ad00:e628 with SMTP id e5-20020a056000120500b00315ad00e628mr7239867wrx.47.1691412093684; Mon, 07 Aug 2023 05:41:33 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFDdRlXQUfwJmmCSmWVUdhLU/0/E0iUB5FelqLUa9sMAlRtLKUYqcW7NQqfcuZwQOMZknYAOg== X-Received: by 2002:a05:6000:1205:b0:315:ad00:e628 with SMTP id e5-20020a056000120500b00315ad00e628mr7239854wrx.47.1691412093271; Mon, 07 Aug 2023 05:41:33 -0700 (PDT) Received: from ?IPV6:2003:cb:c740:5d00:5143:1cd2:a300:ceff? (p200300cbc7405d0051431cd2a300ceff.dip0.t-ipconnect.de. [2003:cb:c740:5d00:5143:1cd2:a300:ceff]) by smtp.gmail.com with ESMTPSA id m15-20020a056000008f00b0031417b0d338sm10543620wrx.87.2023.08.07.05.41.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 07 Aug 2023 05:41:32 -0700 (PDT) Message-ID: Date: Mon, 7 Aug 2023 14:41:31 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 To: Michal Hocko , Aneesh Kumar K V Cc: linux-mm@kvack.org, akpm@linux-foundation.org, mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org, npiggin@gmail.com, christophe.leroy@csgroup.eu, Oscar Salvador , Vishal Verma References: <31305ab7-1e65-80aa-ee91-9190c8f67430@redhat.com> <1c6a74f0-85e9-5299-1520-9068e842b1a5@redhat.com> From: David Hildenbrand Organization: Red Hat Subject: Re: [PATCH v7 7/7] mm/memory_hotplug: Enable runtime update of memmap_on_memory parameter In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: F1DC9180019 X-Stat-Signature: 5ytmribqh7ttbeozys5fqffjset4y7ok X-Rspam-User: X-HE-Tag: 1691412096-211763 X-HE-Meta: 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 ZV93aQdd 5SwyEJKiL3eYt3+39rX8+q1Q7dVKlPkAxxHLZgkE5y8lSiK86ZKW0qi1tZ2RkAUTmgXq9lr/m0xyCfzliifNkBNycJOB191C9Ka8CQ56rDH1nmx/ch00joVisCr53xz/l4nLqDSim0642nHTG3ppuDLbj0ANSzfTMeRVoftrCRNaGoyf3yX/RXjYWJKAjJ4NPwge7ZUjQRi+g6V0yjx2c07thVi2CRNz7rSMrujFTNvuXPbNUxci7e+rcfmVEXsTZVKw+RhyyPC4UqIgDIMBDzSwrfEDA/07MFT586K0zPotXezlChFz1pnNOUuyZCxX45UhQXb0fxqityCGKb2T3cUO5OkmErOd+JbPbSsGPN0K9SV0ErjXWr9jVvvbNvIs2P07J7r6ngGfiQ59h6jXwMFrnsTvEkPeslyxit2UR8PSwzxk= 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 07.08.23 14:27, Michal Hocko wrote: > On Sat 05-08-23 19:54:23, Aneesh Kumar K V wrote: > [...] >> Do you see a need for firmware-managed memory to be hotplugged in with >> different memory block sizes? > > In short. Yes. Slightly longer, a fixed size memory block semantic is > just standing in the way and I would even argue it is actively harmful. > Just have a look at ridicously small memory blocks on ppc. I do > understand that it makes some sense to be aligned to the memory model > (so sparsmem section aligned). In an ideal world, memory hotplug v2 > interface (if we ever go that path) should be physical memory range based. Yes, we discussed that a couple of times already (and so far nobody cared to implement any of that). Small memory block sizes are very beneficial for use cases like PPC dlar, virtio-mem, hyperv-balloon, ... essentially in most virtual environments where you might want to add/remove memory in very small granularity. I don't see that changing any time soon. Rather the opposite. Small memory block sizes are suboptimal for large machines where you might never end up removing such memory (boot memory), or when dealing with devices that can only be removed in one piece (DIMM/kmem). We already have memory groups in place to model that. For the latter it might be beneficial to have memory blocks of larger size that correspond to the physical memory ranges. That might also make a memmap (re-)configuration easier. Not sure if that is standing in any way or is harmful, though. -- Cheers, David / dhildenb