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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?Dfzs2suEurWpb/mTjM4jaLnOVArFxgoIxPTjK8W7WhlA7oGCS+PIeoKiE9So?= =?us-ascii?Q?zXwMhJVzGtmeca5CaNK5ugI4hHsaicJGz6xH2B1ub0xxlB47oTWagV5eopDR?= =?us-ascii?Q?Ujmn76lyceIKSruZ01lyyGqBzhuVUoBLEhuzceApGd+RTRBNaT9Y7ugPKyyN?= =?us-ascii?Q?N5k7+m7I6PkWZUlb9U5jOynWjH4Q6YxcuJB9d/pNwCWKx35w36fLnPWbmnhF?= =?us-ascii?Q?gGBuvr0NOlIFga9Bh0K8aT/cp3zliwo+bzVY37hB7Av4QkhGFikCEBx18lP2?= =?us-ascii?Q?UzPK9gxVt0WRfNQ4lsv0zHry6NLdc0oxqd5CNO7gaPk4OIVfeBBbf7GnY0tF?= =?us-ascii?Q?/xb1ASO6HpzoTXDWez2vnQyTHM7sOfZ4qoVKgg++wVIay844/ehNaEHGmOXJ?= =?us-ascii?Q?cQlt1ljK4COsP9e+9xbMIgMVTlHu0zrBezjjXNKAdFRmALatS2oUmwEjT0sO?= =?us-ascii?Q?JvY0BGA41FX8eOBDcPAORs91wdGJsWZL6J/bbgb59P0mMY1v0O8ByeseO/BU?= =?us-ascii?Q?pXl5qzmN9tFiECegsr5F6N9m7c7sNU7DcBguBp6VPol7YlXo2Un6mXEkhZeP?= =?us-ascii?Q?2Jhn/8WVyuZ5weiJNO9JnTjgr3tcsMrOwXgQuSR18QStUszqrl09BOHXKz3e?= =?us-ascii?Q?1h29S61gLDg2quzeRnoPWshkal7rCoS5P0mO6GU9SERe92U5zghfDAGsfZbo?= =?us-ascii?Q?DHYnhIDVF5fbJM7YtPPQMwsFZ41V+6lDCfkyxQRVCVMBpIpeY1PuycM6g1SW?= =?us-ascii?Q?aqM1INxea+nofHTCdys14l04P23D3WQYBo39iaNf22P90bbaPnujf8qziI10?= =?us-ascii?Q?FfEtQ+jyOv2pG+3KT5sQLYp0v0EjWnGJ5iawdF94EDz7+l59vHLFK3ETf9+T?= =?us-ascii?Q?v/YtSUKc1NH9toMdUtoa99APSMngxlmhhlil3FWK/msCjm+eIxdlOwt618mS?= =?us-ascii?Q?upqi+VX2Pd7kGg54B4RU/xkFHYlPEWHt31rgTvfD0lL/cux2//l587Kf6qpP?= =?us-ascii?Q?HDXiqDTAdNEQRk8IpP4Su8kruNIp3WkoJtoaj1f3yY5wImBUTkYWfi6e96jB?= =?us-ascii?Q?/lf+wrdx4YFTWMv2f2rIhNxPzQT8Y1gyFurxohDTw07f5yVYaaYumeW3DUoF?= =?us-ascii?Q?LotuHXuSpyxCpzsAyP9HJakeKPysBEsE+R3NN7P2taYQzaEyQgr6R5+KUgFD?= =?us-ascii?Q?1cFlr5eAfzhrjg4o5oHPi8B2KNOF8BzCZIDIgnFDdLLfVD6EDqM8sT1s/JGr?= =?us-ascii?Q?fb9ZTSyIbcWHfAndCIWzSmPyNVDjlJjSTwbWpgRqyDhZ1TPLPgidXMXwAm0O?= =?us-ascii?Q?DQm/09w71+993JbSCmOO56ExqBu18gZAZ/+0Dc4cWsyr2EeMa29K3ahvHKs8?= =?us-ascii?Q?26HGacd2i+4qEs1znXCrk+hFvHQN20OhfhQDz2bVFNv2wwcGM9x4BzrAzQiO?= =?us-ascii?Q?8hm122W07xiHkzG8+w4kpxg6Vv461HVNJWGwIB774lWUcVMO6si5lkHO+6JG?= =?us-ascii?Q?cgHvsXgPCY2BIdurCB6+FKYbGMeE+4YnI7HPdnI2n6cE4yDC832SaX1Tn2by?= =?us-ascii?Q?pjclD/sASFEy33XyqnTWBXmPFW1O4fuErCqncjki+VVclFkYsqilOT3doaiz?= =?us-ascii?Q?NnzZb/PV1qwwDxpnvifiBAEEpYHXOGy5rqFpVGTwLuuYXl3gB6M2Phm0Zdr5?= =?us-ascii?Q?N+LRgMuUWDIhtu7vQTzEbWiOo/mTomhFTFMMD4/xA3zDbkuSa4dbAYmc31jd?= =?us-ascii?Q?8UGEFpB/wA=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 03226296-7400-404a-9702-08de41863d39 X-MS-Exchange-CrossTenant-AuthSource: LV8PR12MB9620.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Dec 2025 18:16:34.3491 (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: kwWi6owYqQj+x/a3mHo69lHaioo6yjt9TrF1sxRn9j/ROudqgxiW9wWPaS9vmzTHM+EO9BjnIniXjlJ6lSMPVg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA1PR12MB8162 On Mon, Dec 22, 2025 at 07:53:17PM +0800, Zqiang wrote: > For the PREEMPT_RT kernels, the scx_bypass_lb_timerfn() running in the > preemptible per-CPU ktimer kthread context, this means that the following > scenarios will occur(for x86 platform): > > cpu1 cpu2 > ktimer kthread: > ->scx_bypass_lb_timerfn > ->bypass_lb_node > ->for_each_cpu(cpu, resched_mask) > > migration/1: by preempt by migration/2: > multi_cpu_stop() multi_cpu_stop() > ->take_cpu_down() > ->__cpu_disable() > ->set cpu1 offline > > ->rq1 = cpu_rq(cpu1) > ->resched_curr(rq1) > ->smp_send_reschedule(cpu1) > ->native_smp_send_reschedule(cpu1) > ->if(unlikely(cpu_is_offline(cpu))) { > WARN(1, "sched: Unexpected > reschedule of offline CPU#%d!\n", cpu); > return; > } > > This commit therefore use the resched_cpu() to replace resched_curr() > in the bypass_lb_node() to avoid send-ipi to offline CPUs. > > Signed-off-by: Zqiang Good catch, resched_cpu() checks for online CPUs, so makes sense to me. Reviewed-by: Andrea Righi Thanks, -Andrea > --- > kernel/sched/ext.c | 9 ++------- > 1 file changed, 2 insertions(+), 7 deletions(-) > > diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c > index 5ebf8a740847..8f6d8d7f895c 100644 > --- a/kernel/sched/ext.c > +++ b/kernel/sched/ext.c > @@ -3956,13 +3956,8 @@ static void bypass_lb_node(struct scx_sched *sch, int node) > nr_donor_target, nr_target); > } > > - for_each_cpu(cpu, resched_mask) { > - struct rq *rq = cpu_rq(cpu); > - > - raw_spin_rq_lock_irq(rq); > - resched_curr(rq); > - raw_spin_rq_unlock_irq(rq); > - } > + for_each_cpu(cpu, resched_mask) > + resched_cpu(cpu); > > for_each_cpu_and(cpu, cpu_online_mask, node_mask) { > u32 nr = READ_ONCE(cpu_rq(cpu)->scx.bypass_dsq.nr); > -- > 2.17.1 >