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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 821F5F5A8AA for ; Mon, 20 Apr 2026 19:03:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E54536B0088; Mon, 20 Apr 2026 15:03:12 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E055A6B0089; Mon, 20 Apr 2026 15:03:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D1AE46B008A; Mon, 20 Apr 2026 15:03:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id C2F766B0088 for ; Mon, 20 Apr 2026 15:03:12 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 28A731409C8 for ; Mon, 20 Apr 2026 19:03:12 +0000 (UTC) X-FDA: 84679857024.08.214B561 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf04.hostedemail.com (Postfix) with ESMTP id 628AB40012 for ; Mon, 20 Apr 2026 19:03:10 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=UTxb0bxf; spf=pass (imf04.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1776711790; 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=oZXTmsrU0/pJ1tebX4gelHJDs4GiWytOzVRnEm7LrNQ=; b=ENQuDSX6AbOAnlqoK5oPTQ3DAthhy9J9GC8mOnEHJdwNOcD2PtTfYI7c9NjZe4sNFSsg18 Ipql8lVC5N2iSCpHMK5eH6u03NHhuRDgOkev41TCApZmzaHSqtcmVqTUp64+JcxeA9V2G0 FSzrDo2tSyFpo3VAmP0FLS2iTncqaJ0= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=UTxb0bxf; spf=pass (imf04.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1776711790; a=rsa-sha256; cv=none; b=JRzlVXVJMJ1ZxuSmBBwdfzEoMpoNnu8D0igN63xJILVLRjvSOpOAU/ePrOgKoLBcwTweKw 5ThpoOOZQFLU4/oAZrPFf0BzTNUCM7dhVNsfBFMyTVzBXwPLekg2zBRLEVNO1QoW1E/FPJ A4nkGkZsf+4cwnG1UeQvoog3hMSB3Sw= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id CB50D600AD; Mon, 20 Apr 2026 19:03:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7FE27C19425; Mon, 20 Apr 2026 19:03:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776711789; bh=HCf8DsqrqtUoC3kEuRnRvbL+Njp65zOlbz2OuhLRP1E=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=UTxb0bxf0p9SPGEz9c3QpVnszUtxBZp8b1Ewfcg5N9lAntzEIcDLXzN7AJts++4yy T4Zqs912LANKgvHFYt2K2Cp4dmiB4jWbjLdg2CP3iSJMLvosJc2dpCsUTqIbCW3Ap8 SykFg4rNgwuL9fA3KwKuxGeiGJNOc6wcS2DR3dpCp7+2mphDlupSbw2QXo4NOZ7qCM 3V4MIhpkKrYSNDNKlHKq0DZHZB4HVyf0HInlsg8aTte2nZyh+ePBBs1sHMbcihbUBO YTLzFYBgoE63K/l55t22vG6PY6Xvso7AMEPv1bY9x3voVlYzYkt8EWuwmxHUkYkbox tqGCfkEPFY+eQ== Message-ID: <5bebc75d-19e7-4d06-a5c1-d3f0bb5f4e05@kernel.org> Date: Mon, 20 Apr 2026 21:03:04 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH -next] mm: make sure freeram is smaller than totalram To: Yang Yingliang , akpm@linux-foundation.org, ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, hucool.lihua@huawei.com References: <20260413115736.1237680-1-yangyingliang@huawei.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20260413115736.1237680-1-yangyingliang@huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 628AB40012 X-Stat-Signature: fehd9iicrmtonrq99ymrgncfsowg61po X-Rspam-User: X-HE-Tag: 1776711790-719114 X-HE-Meta: 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 8m4LEkqe ZIKanRWpRouqOSCI6Knv7QGX8gYCIl2ByEtAmfS2J54++ixKs9ZRjHUOLT0ce5LHUDOn0R+RzEfxxUjRVeYE5aq+8Fe+RARjnLP5gv7aC+sGSv1tIrtqbuUANps8OSUMOEEdXGXd8tiu/j1i//s5cqBkLWqqGxfSKeCCYiEh9HV3sm9lMbGDYXNMoKIV27kaS4OaQwMDxvrflsTeU4iR/+EcDyfBDp46itN6cK+P+nVBvHj51ObhhhyZHhlyqd1Sg229h Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/13/26 13:57, Yang Yingliang wrote: > The memory stat is not done in real time, it have some gap with > real value. In CPU-less NUMA node, the values of MemTotal and > MemFree can be nearly equal, the gap may cause MemFree bigger > than MemTotal, it leads MemUsed is negative which print as a large > positive number. How does this interact with CPU-less NUMA node? Some concurrent memory hotunplug, or how could be possible get MemFree that is larger than MemTotal? > > cat /sys/devices/system/node/node17/meminfo > Node 17 MemTotal: 4194304 kB > Node 17 MemFree: 4195552 kB > Node 17 MemUsed: 18446744073709550368 kB > Node 17 Active: 52 kB > Node 17 Inactive: 320 kB > Node 17 Active(anon): 0 kB > Node 17 Inactive(anon): 0 kB > Node 17 Active(file): 52 kB > Node 17 Inactive(file): 320 kB > Node 17 Unevictable: 0 kB > Node 17 Mlocked: 0 kB > Node 17 Dirty: 0 kB > Node 17 Writeback: 0 kB > Node 17 FilePages: 372 kB > Node 17 Mapped: 320 kB > Node 17 AnonPages: 0 kB > Node 17 Shmem: 0 kB > Node 17 KernelStack: 0 kB > Node 17 PageTables: 0 kB > Node 17 NFS_Unstable: 0 kB > Node 17 Bounce: 0 kB > Node 17 WritebackTmp: 0 kB > Node 17 KReclaimable: 0 kB > Node 17 Slab: 0 kB > Node 17 SReclaimable: 0 kB > Node 17 SUnreclaim: 0 kB > Node 17 AnonHugePages: 79872 kB > Node 17 ShmemHugePages: 0 kB > Node 17 ShmemPmdMapped: 0 kB > Node 17 FileHugePages: 0 kB > Node 17 FilePmdMapped: 0 kB > Node 17 HugePages_Total: 0 > Node 17 HugePages_Free: 0 > Node 17 HugePages_Surp: 0 > > To avoid this exception by refreshing vm_stat, when MemFree > is bigger than MemTotal. > -- Cheers, David