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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4B169CDB474 for ; Fri, 20 Oct 2023 07:36:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376424AbjJTHg4 (ORCPT ); Fri, 20 Oct 2023 03:36:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35236 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376317AbjJTHgz (ORCPT ); Fri, 20 Oct 2023 03:36:55 -0400 Received: from mail-ot1-x32b.google.com (mail-ot1-x32b.google.com [IPv6:2607:f8b0:4864:20::32b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 263DC93 for ; Fri, 20 Oct 2023 00:36:31 -0700 (PDT) Received: by mail-ot1-x32b.google.com with SMTP id 46e09a7af769-6c6591642f2so122757a34.1 for ; Fri, 20 Oct 2023 00:36:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1697787390; x=1698392190; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=WCNi48seP9TxdPwmbtccian/XwAwjZ/WgugH0G6tpfw=; b=Z766HoxbZlvjcQPaAl5vuXGKN6cDHrHjtvfS82d2gChFYHrPa3lXylNlPuvaL6XTD7 yq8ZwTMiXMkGMQofbM5WlNqlMGEhxlOFAqC2M+Aw6p8godYegNn9KYIZHx1MNrgaV5i2 d2l+BDwqpAhae20shig7QyZ/hrPt1UFLaPLTxH4NAz/ZnVHjTci4z1IPCeH+zsAtHpF1 NLTTUaqVWynch4J5I5GJu8R5w1Q9sT9BMRJcx/fzwftsjdUX1UWrNG+oC488TDAGCOxq cA6/Snp3y3DF76rNM/gpjiZUbLugYQSfyzeyWcCUXulyX1qIiMfnmn/VS3rjYZ9rMC1y cxcw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697787390; x=1698392190; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=WCNi48seP9TxdPwmbtccian/XwAwjZ/WgugH0G6tpfw=; b=EZNNxPbCBgCU+j/3Ea2J0VkukPiV78uWQGodSMubcQes70y9Wuc5yOlUYclpdS35eS kRS1B+acJMQN2qt9NlGgccMJQE3zg5TLF65EerjeOnA8sjM5/aEyrpFDlF+B2qTYDyE5 c9ojvCRywcvKf3s8IRboWmY6c4xsfzkNqI6X4va5HOP1NBPBAYRfiwyJrNg2m7PKSO1d TJtBKte0g/5MaUKJ0Nb10AtU4PusSo0GDKBq5aFyt01We3xjCFkyV5AKq4bJrM/eBsLN A+tqwIT9lNVBVwYOjSLPI/4CgRbiJF/ZpCacLmxqP8OL7fsu41kMgFrqBvtIXc2odync fJeg== X-Gm-Message-State: AOJu0Yw9wKotfg/S6jxeUkT8U26S5NJR5qEK7pM5/4abilE6UEvLXFRg e1956kQvWP8+qjgfRYY0yQQN9w== X-Google-Smtp-Source: AGHT+IEExtAcncpE853r0NUUBr+n8rNCzGqX9LGHQB21UvbaftQszULEGnMqBXLMrtQpZsXXiAAEUQ== X-Received: by 2002:a05:6808:3197:b0:3b2:ec66:d863 with SMTP id cd23-20020a056808319700b003b2ec66d863mr1078555oib.3.1697787390443; Fri, 20 Oct 2023 00:36:30 -0700 (PDT) Received: from [10.84.155.153] ([203.208.167.147]) by smtp.gmail.com with ESMTPSA id n9-20020aa79849000000b00682868714fdsm938225pfq.95.2023.10.20.00.36.25 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 20 Oct 2023 00:36:29 -0700 (PDT) Message-ID: <4bfa007c-a20f-9e68-4a9f-935dacf43222@bytedance.com> Date: Fri, 20 Oct 2023 15:35:08 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.15.1 Subject: Re: [PATCH v3 2/2] mm: memory_hotplug: drop memoryless node from fallback lists Content-Language: en-US To: "Huang, Ying" Cc: akpm@linux-foundation.org, rppt@kernel.org, david@redhat.com, vbabka@suse.cz, mhocko@suse.com, willy@infradead.org, mgorman@techsingularity.net, mingo@kernel.org, aneesh.kumar@linux.ibm.com, hannes@cmpxchg.org, osalvador@suse.de, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <9f1dbe7ee1301c7163b2770e32954ff5e3ecf2c4.1697711415.git.zhengqi.arch@bytedance.com> <87bkctg4f4.fsf@yhuang6-desk2.ccr.corp.intel.com> From: Qi Zheng In-Reply-To: <87bkctg4f4.fsf@yhuang6-desk2.ccr.corp.intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Ying, On 2023/10/20 15:05, Huang, Ying wrote: > Qi Zheng writes: > >> In offline_pages(), if a node becomes memoryless, we >> will clear its N_MEMORY state by calling node_states_clear_node(). >> But we do this after rebuilding the zonelists by calling >> build_all_zonelists(), which will cause this memoryless node to >> still be in the fallback list of other nodes. > > For fallback list, do you mean pgdat->node_zonelists[]? If so, in > > build_all_zonelists > __build_all_zonelists > build_zonelists > build_zonelists_in_node_order > build_zonerefs_node > > populated_zone() will be checked before adding zone into zonelist. > > So, IIUC, we will not try to allocate from the memory less node. Normally yes, but if it is the weird topology mentioned in [1], it's possible to allocate memory from it, it is a memoryless node, but it also has memory. In addition to the above case, I think it's reasonable to remove memory less node from node_order[] in advance. In this way it will not to be traversed in build_zonelists_in_node_order(). [1]. https://lore.kernel.org/all/20230212110305.93670-1-zhengqi.arch@bytedance.com/ Thanks, Qi > > -- > Best Regards, > Huang, Ying > > >> This will incur >> some runtime overhead. >> >> To drop memoryless node from fallback lists in this case, just >> call node_states_clear_node() before calling build_all_zonelists(). >> >> Signed-off-by: Qi Zheng >> Acked-by: David Hildenbrand > > [snip] > > -- > Best Regards, > Huang, Ying