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 E0301CDB465 for ; Thu, 19 Oct 2023 08:18:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235102AbjJSISC (ORCPT ); Thu, 19 Oct 2023 04:18:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37666 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232850AbjJSISB (ORCPT ); Thu, 19 Oct 2023 04:18:01 -0400 Received: from mail-io1-xd29.google.com (mail-io1-xd29.google.com [IPv6:2607:f8b0:4864:20::d29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0F758121 for ; Thu, 19 Oct 2023 01:17:56 -0700 (PDT) Received: by mail-io1-xd29.google.com with SMTP id ca18e2360f4ac-79fab2caf70so66278539f.1 for ; Thu, 19 Oct 2023 01:17:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1697703475; x=1698308275; 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=NTRribnuit49G/y2EzbJW5y/2X4z+tHgfEKRHq2xxoY=; b=V8FC29OIeQwwHF4v/TSfZKmqCtCxTMd7eNtl7HeIlR9ao3ZoU2ZalSYG5qNt+R3VHQ jJldNqypw0zzsar9hEmjNiQ9gO+AfkWgAYVUfUXgcO/Cf1EBlIXCbIVo3bFejlUsLEs1 y3VJOEr9lmGEFLO0d9OXeIkx4tBQQbukg8MHDuELimjndtJbMCszgSmn09mPrcSg/j+D dZZafaKQDnRRbxD/xowGI4dvsHdLv8cCBx/w17otKfWvuwjqETUQyxyHgHN/G8+JXJsU AyupDY9gtYDHTmR53z7nuCCxmmJlJ4oTg2Yry8cuZcfIVAfyNkrN07vebeeKXzYRFsO/ wWaw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697703475; x=1698308275; 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=NTRribnuit49G/y2EzbJW5y/2X4z+tHgfEKRHq2xxoY=; b=i9Ft37JEfO0vKvz4rlw0JclxNF0NNnh8BRB3rKfte89fKZHmREHCbt9Lz+nPJ2D3VT tC4PaCjm5R3iAX6UWzWYdK31TM52O6Ndy4UnLLfteZHib/rPIYxQRkdIHLSg14inX1Kq WcdRsjeIH/PT60pr9t8eDRueU+EJet7lmaoY1UZ1hJJHFsOahI2czyU1hV5g7mV7R0X2 tYnJw67MReqzrCiG2IWRt078M+fRJpoCBHfbRgnHP8CpyTkt+AqSQ0eqQrkrk5SByOo4 kbZixZZ3PvDjPq4rrMGMrcd+twH7KF0FbxAipJUVHcQu75BFQ232oukTx7q3p3HVLxst zFmg== X-Gm-Message-State: AOJu0Yy34JFxtT5aQ2v2fTWFa+Yxr1o+0uHfxVJ3cauVysMK35ezGVWe EKjTnj1hv3SgFt25JPSC/os/4g== X-Google-Smtp-Source: AGHT+IGe5nKRw+md+BBt3ZQJSAmpr5vhEIgwOaeR5uUz3l+eZsLAGJRYdyyePTsbGWd80XvIo9t32A== X-Received: by 2002:a05:6e02:13c1:b0:350:f353:4017 with SMTP id v1-20020a056e0213c100b00350f3534017mr1585801ilj.0.1697703475324; Thu, 19 Oct 2023 01:17:55 -0700 (PDT) Received: from [10.84.155.153] ([203.208.167.147]) by smtp.gmail.com with ESMTPSA id a13-20020a65640d000000b005b458aa0541sm2500961pgv.15.2023.10.19.01.17.50 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 19 Oct 2023 01:17:54 -0700 (PDT) Message-ID: Date: Thu, 19 Oct 2023 16:17:48 +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 v2 0/2] handle memoryless nodes more appropriately Content-Language: en-US To: David Hildenbrand Cc: akpm@linux-foundation.org, rppt@kernel.org, vbabka@suse.cz, mhocko@suse.com, willy@infradead.org, mgorman@techsingularity.net, mingo@kernel.org, aneesh.kumar@linux.ibm.com, ying.huang@intel.com, hannes@cmpxchg.org, osalvador@suse.de, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <2a3bd858-5464-4569-be1e-2a1867d90c15@redhat.com> From: Qi Zheng In-Reply-To: <2a3bd858-5464-4569-be1e-2a1867d90c15@redhat.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 David, On 2023/10/19 15:56, David Hildenbrand wrote: > On 19.10.23 09:36, Qi Zheng wrote: >> Hi all, >> >> Currently, in the process of initialization or offline memory, memoryless >> nodes will still be built into the fallback list of itself or other >> nodes. >> >> This is not what we expected, so this patch series removes memoryless >> nodes from the fallback list entirely. > > What's the end result of this change -- IOW why do we care? Patch #1 > mentions "which will reduce runtime overhead." and patch #2 mentions > "This will incur some runtime overhead.". IIUC the comment in patch #1 > correctly, these changes don't fix anything, correct? Yes, after dropping the NODE_MIN_SIZE constrain in x86, the panic problem fixed by this patch no longer exists (Unless there are other architectures that have this constrain). The reason I am re-sending this patch is that I agree with Ingo's point of view: ``` While I agree with dropping the limitation, and I agree that 9391a3f9c7f1 should have provided more of a justification, I believe a core MM fix is in order as well, for it to not crash. ``` I also think that core MM should be safe (not crash) even in some weird topology. > > Did you look into showing a performance gain? > No, and I think the performance gain should be small, after all it just traverses one less node. ;) Thanks, Qi