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 9B8C4C6FD1C for ; Wed, 22 Mar 2023 16:49:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230086AbjCVQtv (ORCPT ); Wed, 22 Mar 2023 12:49:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53926 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229941AbjCVQtv (ORCPT ); Wed, 22 Mar 2023 12:49:51 -0400 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8D32439BB5; Wed, 22 Mar 2023 09:49:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1679503790; x=1711039790; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=PmlDxcsDFapOGbfdlWh2GWhkkqitl+2PBEpJ4f3MM/Y=; b=aQrtXiaZV40d30HJtF8PITqUnrEyqWKf6bnSZTC7DlBsiUG7lb4bXehi svWmqgp0i5+AMBP+8nBuosYwwxJcGaaZvHjYx4v4ajetq+jeddsWQhIGe AEsCF+ukiXVRMtZ7bfNZy8RG0bneSJcI+cft52PTs9Qjjdabb8kds3fV2 lMsNk74Cg25XEtId4bQ4mltblwhTr1A/vQzBvg+aNOIGNdSRerjXcm9yf gA5cMx9xaMfPA7gzh9VyiSzbAeBZK9ZW9LXRszbL2lB9Up1pzQPF4VXb6 NiwSDJ8ZEjlYjMaTBIlr8GQPGeTRs9KaFszEtk5WyDiTS+xvq7jkGOUmN g==; X-IronPort-AV: E=McAfee;i="6600,9927,10657"; a="404159809" X-IronPort-AV: E=Sophos;i="5.98,282,1673942400"; d="scan'208";a="404159809" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Mar 2023 09:49:49 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10657"; a="1011437716" X-IronPort-AV: E=Sophos;i="5.98,282,1673942400"; d="scan'208";a="1011437716" Received: from mtfreder-mobl1.amr.corp.intel.com (HELO [10.209.35.23]) ([10.209.35.23]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Mar 2023 09:49:48 -0700 Message-ID: Date: Wed, 22 Mar 2023 09:49:48 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [PATCH] mm/slab: Fix undefined init_cache_node_node() for NUMA and !SMP Content-Language: en-US To: Matthew Wilcox Cc: Geert Uytterhoeven , Dave Hansen , Arnd Bergmann , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, John Paul Adrian Glaubitz , linux-mm@kvack.org, linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org, Randy Dunlap References: <67261c513706241d479b8b4cf46eb4e6fb0417ba.1679387262.git.geert+renesas@glider.be> <6320abf6-0898-361b-d5f6-bcc58306f55c@intel.com> From: Dave Hansen In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org On 3/22/23 09:46, Matthew Wilcox wrote: > On Wed, Mar 22, 2023 at 09:16:55AM -0700, Dave Hansen wrote: >> On 3/21/23 09:40, Matthew Wilcox wrote: >>> On Tue, Mar 21, 2023 at 09:30:59AM +0100, Geert Uytterhoeven wrote: >>>> -#if (defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)) || defined(CONFIG_SMP) >>>> +#if defined(CONFIG_NUMA) || defined(CONFIG_SMP) >>> I'm amused by the thought of CONFIG_NUMA without CONFIG_SMP. >>> Is it possible to have one node with memory and a single CPU, then >>> another node with memory and no CPU? >> It's _possible_ for sure, just unlikely. The most likely place these >> days is probably a teensy tiny VM that just happens to have some >> performance-differentiated memory exposed to it for some reason. Maybe >> it's got a slice of slow PMEM or fast High-Bandwidth memory for whatever >> reason. > Right, you can construct such a system, but do we support the CONFIG > options of NUMA enabled and SMP disabled? It seems so niche that we > shouldn't be spending time testing that combination. On x86 we don't: > config NUMA > bool "NUMA Memory Allocation and Scheduler Support" > depends on SMP > depends on X86_64 || (X86_32 && HIGHMEM64G && X86_BIGSMP) ... which I think is fine. I totally agree that NUMA without SMP is too niche to care about. Heck, !SMP is almost too niche to care about these days.