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=?utf-8?B?ZVRzdGRDN0RIMEVzMWJETFNVZDMrMExCRzdRRCtMSUxrQzhaZ0pZTXd4RHlH?= =?utf-8?Q?IO0JHUm49wl7SuBo=3D?= X-Exchange-RoutingPolicyChecked: ItXSTFOgyJ/YEsSJ2WTBI5gw3faDiR2KbvapCHA+0/guIY3nNDgD6I2/8Sx6e1730+xn1vR7ir1kzfGjXxI8yUN6T8E90duXfOjaUwxsRkEOtXx3thNY8Ju306QHfTTFbRlcEKJ7bYXEedc7ncXVhYgsMWH/RVGI2251DRVCNRiSWqjwOnfhWBsLKwkgs81bbDcpFSZmebcin2XF/gOYLmzt7LmAcYPKupVtXEG71GQqD6Z6BkPUYCuGW/R3AgwmlMPe4Mlgm+NawTETuMzESg1h6GfnuPn+y/T1B+XiLWFlWiO8jpWHe2CUDYyylLYhz2unaEDxckmjPHSgo35I2w== X-MS-Exchange-CrossTenant-Network-Message-Id: 0b5a5120-2574-49e0-d485-08deabaec309 X-MS-Exchange-CrossTenant-AuthSource: SJ2PR11MB7573.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 May 2026 20:33:42.2596 (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: whHS6VOQpgC2n2l0o9YZ3Dhg2Vx8nXpYLgywCrgTwDFe/L6FGA5XQlPs7SBGCkRT+l9EiAx1Lst2u/SvlnKJAGPFx5vPQJMkF9e8ymktQyk= X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR11MB7261 X-OriginatorOrg: intel.com Hi Tony, On 5/6/26 1:02 PM, Luck, Tony wrote: > Question? > >> + if (!is_percpu_thread()) { >> + list_for_each_entry(d, &r->mon_domains, hdr.list) { >> + if (d->mbm_work_cpu == nr_cpu_ids) >> + mbm_setup_overflow_handler(d, MBM_OVERFLOW_INTERVAL, RESCTRL_PICK_ANY_CPU); > > Should that "MBM_OVERFLOW_INTERVAL" be "0"? This worker is presumably > already slightly late because of the offline CPU overhead and time to > be picked up by another CPU. Maybe it should run right away on whatever > new CPU in the domain is picked? The delay is intentionally _not_ zero and there should probably be a comment to make that clear. My module experiment demonstrated that when the work associated with the work_struct is already running then no matter which CPU is provided as parameter to schedule_delayed_work_on() the workqueue handling will schedule the work on the same CPU as the currently executing work. Second time around is_percpu_thread() will still be false but this time mbm_work_cpu will be set to CPU it should have been scheduled to and work will exit without re-arming the worker and the associated domain loses its worker. By setting the delay to MBM_OVERFLOW_INTERVAL it guarantees that the current executing worker will be done by the time the newly scheduled worker should run and thus be scheduled on correct CPU. I assume you are hinting that if the memory bandwidth is under pressure there may thus be a risk that an overflow occurred? Perhaps MBM_OVERFLOW_INTERVAL is too big - the delay only needs to be big enough to ensure that current worker is done before new worker is scheduled. Do you have suggestions? Reinette