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Thu, 11 Sep 2025 17:56:38 +0000 Date: Thu, 11 Sep 2025 10:56:36 -0700 From: "Luck, Tony" To: David Hildenbrand CC: Kyle Meyer , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: Re: [PATCH] mm/memory-failure: Disable soft offline for HugeTLB pages by default Message-ID: References: <749511a8-7c57-4f97-9e49-8ebe8befe9aa@redhat.com> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <749511a8-7c57-4f97-9e49-8ebe8befe9aa@redhat.com> X-ClientProxiedBy: SJ0PR03CA0014.namprd03.prod.outlook.com (2603:10b6:a03:33a::19) To SJ1PR11MB6083.namprd11.prod.outlook.com (2603:10b6:a03:48a::9) Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SJ1PR11MB6083:EE_|IA0PR11MB7356:EE_ X-MS-Office365-Filtering-Correlation-Id: c8cb49a0-edb7-4ba6-d60b-08ddf15c8e7e X-LD-Processed: 46c98d88-e344-4ed4-8496-4ed7712e255d,ExtAddr X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|1800799024|7416014|376014; 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But that is only one of several places in the kernel that feed into the page offline code. This patch was motivated by the GHES path where BIOS indicates a corrected error threshold was exceeded. There's also the drivers/ras/cec.c path where Linux does it's own threshold counting. > > If your read about MADV_SOFT_OFFLINE in the man page it clearly says: > > "This feature is intended for testing of memory error-handling code; it is > available only if the kernel was configured with CONFIG_MEMORY_FAILURE." Agreed that this all depends on CONFIG_MEMORY_FAILURE ... so if any part of the flow is compiled in when that is "=n" then some changes are needed to fix that. > > So I'm sorry to say: I miss why we should add all this complexity to make a > feature used for testing soft-offlining work differently for hugetlb folios > -- with a testing interface. > > -- > Cheers > > David / dhildenb -Tony