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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?sG+jFjGK3IQWsEFJnHZdx8TCsFTGhry+wN2lqCXJGHHpNwmv7SaFgWSNWmCm?= =?us-ascii?Q?ZSIdfR01IJIgOKOUgUW0zuv08mVIcwHIRha03l2IH2ItQgdFZWbuhzi7noRI?= =?us-ascii?Q?c17BMfzVhpLdlIMCKlr9Pp4VQpj1BaO8Q7ouBsXSXw2Ntf0GwSTJXpC/Xnjv?= =?us-ascii?Q?YidpH4ajz6u3mnViZn6llFkD/QfrcDBNJe2NmxWzrFKPmEOz3dKQVPGxyiVh?= =?us-ascii?Q?Em94Q4XBWfEyt0sDZ73AQ7XHrSw1b6pfKenawN/DI3c0g3SCWMR8d6E0GI7D?= =?us-ascii?Q?IzoENwYCC1aQMIQZlywWtSMPRHqF9ouuclpNDpPmWNFkqjPTq2zg+Sf6hb7j?= =?us-ascii?Q?nTFcY8uqt4Q+jUHoTEqjc80XDYRgNRpTmQwhsywSLaygJ7b1npW2M/7g8vjY?= =?us-ascii?Q?pT7SpTnOvKN/4ajC2JapBfwSoI6G7/vSxudGSoCYVqdcAPxpsVOSbRGGiEcz?= =?us-ascii?Q?u59NCgQ8NWUoOJDR6oCo7CbDLUlWdnWcwG/ITUhO0MUZXZu4sw32FRb84qp1?= =?us-ascii?Q?qZ5XZ+tBpoeA4EidxzWAAklk0uwOs6lNYcq6HXWwLshYA2HZR1GRwQTyostO?= =?us-ascii?Q?7aGCM3I9MM4+zMrE+TDPtNVZkWUODCamOIptlOrbQsfTtVJPDmPbsOqykWiU?= =?us-ascii?Q?0d/ygMCrAYSp+C57ysxH5yII6D3UWM5K0w7CkFqKLs6bLtXFmFwDJ1Nyxp0B?= =?us-ascii?Q?Z655oPWCimbxUtrlmyNPQMMv/1uPV/rucuVCwx+7PuCyorL8ltq+RywhTU2X?= =?us-ascii?Q?CtRnKZUMr2811L0iL1cJ88VeTndGpRCi5f4kUNgciPcS6mdqLww5YXmduV29?= =?us-ascii?Q?OYxkVraK2Bkra3SmmPtbekGkULiTJ3JTcR7CwfgY/Jt8wwg4WXYJM8uTbaoR?= =?us-ascii?Q?dVcPaoUVjGFuP20ynWh8nXOzWYJG3MrYdSP82W1QpEjtm1v4zGxfbbSk+Xxz?= =?us-ascii?Q?uXNHbP+d9/K95lLsP/0xVW53GkoZ1WVj0hjT7WT5E2ByePcuKB5ZC7Fe8fqD?= =?us-ascii?Q?ppIsslF9/OiYgdmxz9d79HsVdkivKZcZ+2X+HqhIJqjn59AhB0gwMZN81MCc?= =?us-ascii?Q?3bzKFc9oERIUfRXSR+TlzrQXPiXvwxJtI+t3uPZE9PKmuTB7ZZs29gOr9Qfl?= =?us-ascii?Q?47Iw1jR5f91uODOOLFxkmZdbrcPgTp5H5OVeL6yhOngigjLA4+7g5lZcZVfF?= =?us-ascii?Q?jGgd0PPEcIDmjA4QFLJioVrVC71rqSIHUCXZlFvFcFMRNkIrhMoxVrMgNIRV?= =?us-ascii?Q?p/rnDrdcyh7dcRHVCwtTkrgZOWSVhBAsZd7oBk8afcRaLAwfd6O9/iaHLAMO?= =?us-ascii?Q?PBZFA+jy3by61L3tbSlyd3Nwp6is3k3bNp81eIU9w6Nc6T9+L+QkjcfxCPHG?= =?us-ascii?Q?mEp5eRUR5t5bd7vuG+Wda1e6l/adopRGbuJtWNs77bR/Wp+n2fh96VDixC2B?= =?us-ascii?Q?MX2V7OmA9URyOhRZ4+4UnGREOYmElVVrLf19D3lbyJxDROhxStukxf9xKsZb?= =?us-ascii?Q?jMVpRQFXwCfxz6j7TW8km42lkS3dcoDbvTwkoZa1M+LYRQda9SJ2ZsHw8LJ+?= =?us-ascii?Q?cw3hMOlfuyPsRX88m6XQrjrFktGqW0wk7b+pL1mf?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 65c5af4a-aed3-4800-2542-08ddeafe04d8 X-MS-Exchange-CrossTenant-AuthSource: LV8PR12MB9620.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 03 Sep 2025 15:24:48.2659 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: R1Wh3iSnkAY+W+n3zw3bs9mJ8sDvOZlEQfBdg1CzwOydIIJQxAyz66Frt9fOWoLsU6gBNL4inXgkZ6H+31FOlg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH2PR12MB4200 On Wed, Sep 03, 2025 at 05:15:18PM +0200, Juri Lelli wrote: > On 03/09/25 17:10, Andrea Righi wrote: > > On Wed, Sep 03, 2025 at 04:53:59PM +0200, Juri Lelli wrote: > > > Hi, > > > > > > On 03/09/25 11:33, Andrea Righi wrote: > > > > From: Joel Fernandes > > > > > > > > Hotplugged CPUs coming online do an enqueue but are not a part of any > > > > root domain containing cpu_active() CPUs. So in this case, don't mess > > > > with accounting and we can retry later. Without this patch, we see > > > > crashes with sched_ext selftest's hotplug test due to divide by zero. > > > > > > > > Signed-off-by: Joel Fernandes > > > > --- > > > > kernel/sched/deadline.c | 7 ++++++- > > > > 1 file changed, 6 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > > > > index 3c478a1b2890d..753e50b1e86fc 100644 > > > > --- a/kernel/sched/deadline.c > > > > +++ b/kernel/sched/deadline.c > > > > @@ -1689,7 +1689,12 @@ int dl_server_apply_params(struct sched_dl_entity *dl_se, u64 runtime, u64 perio > > > > cpus = dl_bw_cpus(cpu); > > > > cap = dl_bw_capacity(cpu); > > > > > > > > - if (__dl_overflow(dl_b, cap, old_bw, new_bw)) > > > > + /* > > > > + * Hotplugged CPUs coming online do an enqueue but are not a part of any > > > > + * root domain containing cpu_active() CPUs. So in this case, don't mess > > > > + * with accounting and we can retry later. > > > > + */ > > > > + if (!cpus || __dl_overflow(dl_b, cap, old_bw, new_bw)) > > > > return -EBUSY; > > > > > > > > if (init) { > > > > > > Yuri is proposing to ignore dl-servers bandwidth contribution from > > > admission control (as they essentially operate on the remaining > > > bandwidth portion not available to RT/DEADLINE tasks): > > > > > > https://lore.kernel.org/lkml/20250903114448.664452-1-yurand2000@gmail.com/ > > > > > > His patch should make this patch not required. Would you be able and > > > willing to test this assumption? > > > > I'll run some tests with Yuri's patch applied and dropping this one (and we > > may also need to drop "[PATCH 10/16] sched/deadline: Account ext server > > bandwidth"). > > Please mind that Yuri's change is still under discussion! :)) > > I just wanted to mention it here as it might change how we account for > dl-servers if we decide to go that way. That's fine, I've already done a quick test. :) It seems to work (more or less), meaning that in case of RT/sched_ext contention the sched_ext tasks seem to get the right amount of CPU bandwidth (5%), but the total_bw kselftest is quite broken and it's always reporting a bw value of 0... in any case, even if we go this way there's no major disruption apparently. -Andrea