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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: O6bnwluvpRuIp60APcKyv7yOb0jfGy2WuVX9tAu34IgBOntQgAjeLBIMyDBTBmGU1t30JyIcLcHpZFbce7F8hy8f4HwnxmLkYSVmWp3m7ObthR+/zPdMYb5iL7Do3gdmEw+47o9XDyUAlnfSaXXWNsSHWfmxFPenTM/xqRmslJw4Va8p64HS8J1YWgPeExDrtVmv7YZWZiqciK9UcVrj2Rii+0ukUBbTrrtJC+NB3NdBIwVfiCvJA4zeUQVaWQssenT+bav6Nh6pWycczBbHPkE5RLF5PN/FgQpLqMyKKeZkMt8FJ/d+VSXUbi2XP7m4DNjyE0t9/BVTrg2s8aL345aK3QCEkYdgiMXdyaja3eDy7+FwvmWT/x/M8MmfAEyZZ+3chav9tiRuWXT26/ykI8ptneQq6mCa91i3GFsT/nxO9hfzF4I7GpjHpDMqfuky X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Aug 2026 06:31:02.1271 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 4d4c2a6d-ceaf-4623-ddcd-08df033b9973 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[149.199.90.133];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: CH2PEPF0000014A.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR12MB6967 Delayed owner have a stable task_cpu() since they are ON_RQ_QUEUED. Move the donor to delayed owner's CPU and block the delayed owner completely if find_proxy_task() resolves to them similar to what pick would have done. This avoids needing to handle chain-wakeup for delayed tasks, simplifying the ttwu_runnable() handling in the subsequent commits. Signed-off-by: K Prateek Nayak --- kernel/sched/core.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 9d9db7ccf01f..b4a2771eb290 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6958,8 +6958,8 @@ find_proxy_task(struct rq *rq, struct task_struct *donor, struct rq_flags *rf) goto activate; } - if (!READ_ONCE(owner->on_rq) || owner->se.sched_delayed) { - /* XXX Don't handle blocked owners/delayed dequeue yet */ + if (!READ_ONCE(owner->on_rq)) { + /* XXX Don't handle blocked owners yet */ if (curr_in_chain) return proxy_resched_idle(rq); __clear_task_blocked_on(p, NULL); @@ -7025,6 +7025,18 @@ find_proxy_task(struct rq *rq, struct task_struct *donor, struct rq_flags *rf) */ return proxy_resched_idle(rq); } + + /* + * Delayed owner is on the same CPU and rq_lock is held. Treat this + * like pick resolving to the delayed owner and block the task + * completely before retrying the pick. + * + * This prevents the need to resolve "owner->blocked_head" chain for + * wakeup of delayed task and fast-path them. + */ + if (owner->se.sched_delayed) + goto block_delayed_owner; + /* * OK, now we're absolutely sure @owner is on this * rq, therefore holding @rq->lock is sufficient to @@ -7052,6 +7064,9 @@ find_proxy_task(struct rq *rq, struct task_struct *donor, struct rq_flags *rf) migrate_task: proxy_migrate_task(rq, rf, p, owner_cpu); return NULL; +block_delayed_owner: + dequeue_task(rq, owner, DEQUEUE_SLEEP | DEQUEUE_DELAYED); + return NULL; } #else /* SCHED_PROXY_EXEC */ static struct task_struct * -- 2.34.1