Received-SPF: pass (google.com: domain of linux-kernel+bounces-32515-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
Message-ID: <9d9b39fc-82db-4320-9935-f760ee723064@amperemail.onmicrosoft.com>
Date: Mon, 22 Jan 2024 16:27:58 +0800
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH] NUMA: Early use of cpu_to_node() returns 0 instead of the
 correct node id
To: Mike Rapoport <rppt@kernel.org>
Cc: Yury Norov <yury.norov@gmail.com>,
 Huang Shijie <shijie@os.amperecomputing.com>, gregkh@linuxfoundation.org,
 patches@amperecomputing.com, rafael@kernel.org, paul.walmsley@sifive.com,
 palmer@dabbelt.com, aou@eecs.berkeley.edu, kuba@kernel.org,
 vschneid@redhat.com, mingo@kernel.org, akpm@linux-foundation.org,
 vbabka@suse.cz, tglx@linutronix.de, jpoimboe@kernel.org,
 ndesaulniers@google.com, mikelley@microsoft.com, mhiramat@kernel.org,
 arnd@arndb.de, linux-kernel@vger.kernel.org,
 linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org,
 catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com,
 mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org, chenhuacai@kernel.org,
 jiaxun.yang@flygoat.com, linux-mips@vger.kernel.org,
 cl@os.amperecomputing.com
References: <20240119033227.14113-1-shijie@os.amperecomputing.com>
 <Zan9sb0vtSvVvQeA@yury-ThinkPad>
 <1cd078fd-c345-4d85-a92f-04c806c20efa@amperemail.onmicrosoft.com>
 <Zao13I4Bb0tur0fZ@kernel.org>
 <b8786c38-d6c4-4fea-a918-ac6a45682dba@amperemail.onmicrosoft.com>
 <Za4cNBQBLZujlAlP@kernel.org>
From: Shijie Huang <shijie@amperemail.onmicrosoft.com>
In-Reply-To: <Za4cNBQBLZujlAlP@kernel.org>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Precedence: bulk
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0:
	=?utf-8?B?SEw0UjFlZUVFVTh3OUFHVjZGK0docW1WelhrY2RXTXhPZUR5U2xnL0NadUo5?=
 =?utf-8?B?dkJsMGJ5QWVvdXYxRXNxb3F0V2FJaVNhSVRjejdtTWJSckNVblM5TnNvSG0y?=
 =?utf-8?B?Q2liKzhOQ05GNE9ySEY3VFFDdmZtR2V0VXhYeFJWQXNrWGkrWTEzeElCelZr?=
 =?utf-8?B?NnNTeEt2U200RVlvM21VcllsWlpnTWs2ZVhaQ2o4VXBMb1hPcy9QSmF3dmRk?=
 =?utf-8?B?dFhSbkZ0Yldaem5kVWF1UDFVcHorQkZVdjliOWNOajF1TjN4cVF4TUx6NUcw?=
 =?utf-8?B?L3lqYmN1WWhMZi9rbDFDQytSWlFaQStDYXZWVDlaY0RDR2RWTWIvcnEram5v?=
 =?utf-8?B?SW8rU3RIblJGNGV4cm1KcnZEdkJRZTJuMkl3K1NISUZIQ25IZVZyZWNMb0xm?=
 =?utf-8?B?eFh4SzB3YWsyRXVBbkhtbGpnNXRJMlZTZlg1aW85V3NyWk9UUHJmTEtiTHNt?=
 =?utf-8?B?WllBcDZMam15MnR6alNPZWNVV0tYZEwzRXltYVlTNWVvaWdGdmkzUUQrclZL?=
 =?utf-8?B?ZEh6anhnREZ2RWlaWEUrQVYvZlRzZjN2WjlHd2JQa3hpeGxTMDd5YTF1dGRG?=
 =?utf-8?B?UE4vdnBjZFg5S0JNelNCV1VCc0I5Qkd4cVh4R2MrYitZSEM1ZzFIYzVnQnc2?=
 =?utf-8?B?aFF2eWhWLzgzQTRUdXZabGZaQzNkdDg1YmszY2xpNndaR3o5R2NjNDNtZFhZ?=
 =?utf-8?B?bFp0bnRFcno3V1hBTFRDbHJGMktaWlhkYVM2SlpjQkdaMlRmR1JvRmF2dm1R?=
 =?utf-8?B?cXlYb3BCRHlUZ3ZFU2JQYkhJY0IzY01PV29HN3pTY1h0SG44cWZyZXMxQkEw?=
 =?utf-8?B?cXQ0aW5MWXBOYkkzN1dLNmY0UDNUNmwzUlh6WW9WUW9sUUJ3cmhEUjRwZWNt?=
 =?utf-8?B?VGh0YmhsTDhWK2RrN0tFTnFNb1p0YWlCcTRwem02Zk5sZEJERnBlQldnZmtS?=
 =?utf-8?B?U1ZjQ0VWL01vSWZHeE54b1dmS3V1SDBOZDJjd2gyM3VLaVY5K3pDSVp3Qkx2?=
 =?utf-8?B?S0xVM2hkU09SdDdNVFRzdjQ2aHZDZTc4UmxIYW9YSStYT25oaGZZZGhLODVl?=
 =?utf-8?B?Rk1LVUE3MWJlb1YzRHkxMXFiYU9Ga0U0bG5KU2xSdnZSTFA1UER2M2NpQW1M?=
 =?utf-8?B?UnNjNCtrOGlhaE5vc2JPQzQxTE12WUNlOTF0N2pXckZWOVQrNitndW5PNkdu?=
 =?utf-8?B?NDg4cE1pMWtEa1FhT3IvRlZvdC9Rc0Zjalk2cFJ3MnY3M3pVZnpsN2YzOStu?=
 =?utf-8?B?WG9yRTNnREZwMnZ6R25ST0xYY2xwTmh2RS9WME42MzYxVEZUT0loZnhsM3Bu?=
 =?utf-8?B?bGxnc0FtUmUxSDJhdlRtdGJaTzFuV1NvMU0zZGVXZFV5V1JvRFVUNEJWTjhv?=
 =?utf-8?B?Skd2YjdKc1dsVVR1NkxQNG9ibTNRSGE4ZlZTaVJUSUs2QmVUNlFTVUlIOGNy?=
 =?utf-8?B?TFk2RjlnNzEwbWVZOTkwb0loYlhGa2NnT2grVStLRFZyMGx0VG5tNC9Pc21Q?=
 =?utf-8?B?ZkhiZ3NKamI1S3kycENweVpMRlREWXJYbEsxVFcvSVRiOU1Tenh3eDJHTkxF?=
 =?utf-8?B?OXFlckpYV05qbzRYd2t0cW4vS1JLdy94Q283NU5HMjB3NjRoYXBvcGlpRW82?=
 =?utf-8?B?Q1ZBSWZyMWlkaTFUUS96VHNnNWRROTJNbGtCT3oxUVk5cE4vNjNneS93R2dB?=
 =?utf-8?B?WDBuV1hmZEtYTXBoaHJIVGE0L2NPbXdiUlI1OEdOUnZVSVRPamxlZWtOOXhn?=
 =?utf-8?B?eVR2elI3eHd1R3FZaWZUVlNDVEtWMFI3eEE2aEZlZnI1YzhBZmRUWTY2SjI2?=
 =?utf-8?B?N00yT3NGQnhQek13RUZzdEJoYVprR3NKeUtSN0RuemFzMFJoOEZDRmZtaTVo?=
 =?utf-8?B?cEpkaHFCRlNvUThwcDZiV2hvR1hnVUphbHVBYjhrWkV6ckZmN2h2Vk5EeXJt?=
 =?utf-8?B?ZTVUSlg3Zk1QYzJ5Y21sa0JUL0M1RW1Gd2dsSEdYZzhCR3YzQVhrSDJLMGRa?=
 =?utf-8?B?T3VNcDd0bjR4VlVsSm94UlVEb05QTkQwYlBnV2Rzb2RkZUR1cDREalZlZ2wz?=
 =?utf-8?B?bFFBQ0FGNjM4bVM0UytCbEUrZ1hkNTRMN09QMGJQa3JBZEFiN3F1UURoNHpv?=
 =?utf-8?B?Q2RObHlNQWN1WE02ZGIrR25LMVpUcCtNZWtGanIweHhxbktGbDhkc08yOE9M?=
 =?utf-8?Q?75qimKA5MLosMzfaujCi8JE=3D?=
X-OriginatorOrg: amperemail.onmicrosoft.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 4636f5cc-2fc9-458f-b000-08dc1b2413cd
X-MS-Exchange-CrossTenant-AuthSource: PH0PR01MB7975.prod.exchangelabs.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Jan 2024 08:28:14.6559
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 3bc2b170-fd94-476d-b0ce-4229bdc904a7
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: Mns27POmZo2tUMhwRvOVd5bbbz4iztUoNj1TqB9I7OLAgLJ3z8x3KYm4LaF9U4BDX0R/3C5I4coNgEZIbZtIpDCTNwvYUm9qY6gPCM//DH0RH/oby4N+7+uWd/+M/BLJ
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR01MB6603


在 2024/1/22 15:41, Mike Rapoport 写道:
> On Fri, Jan 19, 2024 at 04:50:53PM +0800, Shijie Huang wrote:
>> 在 2024/1/19 16:42, Mike Rapoport 写道:
>>> Is there a fundamental reason to have early_cpu_to_node() at all?
>> The early_cpu_to_node does not work on some ARCHs (which support the NUMA),
>> such as  SPARC, MIPS and S390.
> My question was why we need early_cpu_to_node() at all and why can't we use
> cpu_to_node() early on arches that do have it

As you see, some ARCHs use cpu_to_node() all the time, such as 
SPARC,mips and S390.

They do not use early_cpu_to_node() at all.


In some ARCHs(arm64, powerpc riscv), the cpu_to_node() is ready at:

     start_kernel --> arch_call_rest_init() --> rest_init()
                            --> kernel_init() --> kernel_init_freeable()
                            --> smp_prepare_cpus()


The cpu_to_node() is initialized too late.


I am not sure if we can move "cpu_to_node initialization" to an early place.

Move "cpu_to_node() initization" to an early place is more complicated, 
I guess.


Thanks

Huang Shijie