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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?vYtbMHlnAuE7xLDVLJBMJBMl6Xfbvhk7NsQNPo6D0WEq7dkek1nkGqg9TqCu?= =?us-ascii?Q?11lcIypmlQMVxFW29/9y08iZlUQbG3BT194olmcQ5E+8FCTQEUf4j5PSFRqH?= =?us-ascii?Q?pDsrFVhc0u1OQ9Pbf2ZWIGontFXxDLU8mjYIY3DB8CeG3XGv0IAf6GGp3vRB?= =?us-ascii?Q?3H8aKRELyGOP/yWpc9G167gESFpMVcHPgthv51+5iOAq9hEIlhcKg6YazkuV?= =?us-ascii?Q?l6IF1nZLTB8jMcUOO7onOA4ysIkPtx+kj3lp8nPuh9mLWzledExTQuCbxkXs?= =?us-ascii?Q?7Fp7ZJvKIrw/lDIhhACLKCRuG4Klxip6cos4T7H8e5R6iz8ikIeyLDKXAY9e?= =?us-ascii?Q?Is1SogkoPnJbgKe8p10++19eoYBw5W2IeM5oDD/cerdmzwt3xyDgizMcvXds?= =?us-ascii?Q?XaYNAtSLM6Dl6BmUo4ig5iV2pjC6HRwACtfXicwtbn87//PLu8TLFBL8NA47?= =?us-ascii?Q?hCuYM0qGQ6xTE7E3msgMi15+REznQhtU8eFV3hd3iM6eIMjbIBbnXwU0mSe4?= =?us-ascii?Q?pvbqFY2MvIYFwybnpOLBQV6I641bDYjBfjceKQlUPdVsSImc/9XnnOQTMP12?= =?us-ascii?Q?s7OmEOP0g9QUoFpJq6+SexbYGHtORvJ6DN9+fJkjWQ+IJ5BnfCWlvh8lwMHb?= =?us-ascii?Q?NN4xrqXntsTtxw0Bman/NMhuIij5vFJV8yWJSgi4F0hhKtbG6q9mcx8tMsQE?= =?us-ascii?Q?kFGDuvpn9sFnbPGtgheZDb/rhmhR3VxnC3HAjs1rb/AVz4tnbwLn2ggdHRdS?= =?us-ascii?Q?rvVIAtw+w6lP89m6MmBp7bVobEzOPuyvAF8GXqvkRzlD+POHt62wW7pTWm/L?= =?us-ascii?Q?J0KZ8G/1TVMdNWsGPMmTXs4X9B7pjnQsrp9+oJABkC6dau1b0i+0J3xT5I9S?= =?us-ascii?Q?CC1gVblNWgfJETT6fympinnW/Ay0KpXnf0rFBXoO43UCgT0ODuRc70k6gkRw?= =?us-ascii?Q?BP8NiTuiAK75Z6VZofDpQl40GakyiK5SYcKIFEz0YRPHZxCm2HaHy6WuWo0+?= =?us-ascii?Q?q/y+bAI+vT+GB6uZoVHixnEqdkE1fr5Pgp/z1w2y9+oCN24LDtrz14hm/wsv?= =?us-ascii?Q?XT+w7O5mxbgyNQU49ZsY0P+fiex2lr6kfZ9C02Ntn6BiEe850b173/94gWKi?= =?us-ascii?Q?givOi7LTChl2ovXVJFhvEhPiIaq0cD9j+5VTYuWD9ZQKRD0mKH33WKlQPSA3?= =?us-ascii?Q?bOKewFulazlQGISeog8q7g0SKrdZ/Zp0XHZA+zekUTQYd8+dGP7mx2lB4aEG?= =?us-ascii?Q?6WcrHVDtnoEUGMyfffFDRsSxMfLHLglqi1reA/ChN4T4w29SzG2mJevXi9FE?= =?us-ascii?Q?dEgRfTnz/swWX0WI3jE2p3EOK2tzbXG20Ku/Z5gdRKsc+wX10zpCrtJRN/Lk?= =?us-ascii?Q?b/TZiXDZKfVdZxDr+jBpfTS6KDFK/OC8cblfyIFnvxhBmmxhznFEt8aLOPaA?= =?us-ascii?Q?bfBAGuZXHoik1iUIzYAiE3843rlQef0VLif6k7xOOB4HRK8taqNtRa6VudbD?= =?us-ascii?Q?ndZN4V3+3PIU8+cDcSKdNtFd6xqKIwsacexC4G+wtOfImt1hUszDHbR1fmdQ?= =?us-ascii?Q?8bUymLZVh9vRWG1tKZ8+ZEm9KbfavPKNz+hz3Qkr2Cfc5mNzjjsZl8h7MH/h?= =?us-ascii?Q?ag=3D=3D?= X-MS-Exchange-CrossTenant-Network-Message-Id: 8edcf568-ab9d-4a23-f124-08db47593de0 X-MS-Exchange-CrossTenant-AuthSource: PH8PR11MB8107.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Apr 2023 19:54:42.2853 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: qpTlAz9FaXXjghK5HIKlYtR7w4w6x1I+CEydMPyFGuaJEhgcL814Z20Rg2Xt8bsCIgIvqKbZ+T1UWemJB08lk6fbGODsk96DSHrT6qY0wR0= X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA1PR11MB6565 X-OriginatorOrg: intel.com Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org Alison Schofield wrote: > On Thu, Apr 27, 2023 at 09:35:02AM -0700, Dan Williams wrote: > > Davidlohr Bueso wrote: > > > On Wed, 26 Apr 2023, Alison Schofield wrote: > > > > > > >At the moment, I have 'trigger_scan_media' that results in a spew of > > > >scan media results to a trace file. I guess we'll chat more about > > > >presenting a _nocache, when I post for review. > > > > > > I'm not crazy about calling the interface scan media straight how just > > > because it's very unintuitive - albeit users that care will probably > > > don't care. > > > > > > > > > > >I'm concerned that a _nocache_ will lead user to believe they are > > > >getting 'fresher' results, and to over-use it with that mindset. > > > > > > Agreed. > > > > > > >Get Poison List gives accurate results and Scan Media is only necessary > > > >when the poison list has overflowed. OK...here I go opening the can of > > > >worms myself ;) > > > > > > trigger_poison_list_overflow? > > > > > > If triggered and the list hasn't overflowed yet, just be a nop? > > > > What about a "poison_overflow" policy? Defaults to "report", but you can > > write "scan" to have trigger_poison_list invocations fallback to > > scan_media on overflow. > > With a policy like that, the driver may automatically do scan media > in response to overflow reports. Sure that's what the policy enables. > For users that want to schedule those scans (policy set to 'report'), > they can do so my doing trigger_scan_media at their leisure. It's not clear that scan media matters so much in practice that the kernel needs to have separate controls for it. One of the observations of the overflow threshold is that the failing part is likely to be RMA'd before the poison list fills up. Scan Media was more relevant in the PMEM days [1] before List Poison was introduced in CXL that promised to always record poison on creation. If Scan Media is an operation that is rarely used, does the kernel need to carry a trigger_scan_media attribute? I.e. the kernel only needs one way to kick off a poison collection event and the depth of that collection is an optional policy setting. Whether that policy needs to be configurable is also an argument that needs evidence. > Would you expect the driver to retain overflow state, and warn those > users that they are issuing scan_media without prior overflow events? I don't follow the use of plural "users". Only the single platform owner cares about the health of the hardware. [1]: https://pmem.io/documents/IntelOptanePMem_DSM_Interface-V3.0.pdf