From 477174ac35c510d0ed3043f5bd4fba25546a21ce Mon Sep 17 00:00:00 2001 From: David Carlier Date: Tue, 24 Feb 2026 05:56:37 +0000 Subject: sched_ext: Optimize sched_ext_entity layout for cache locality Reorder struct sched_ext_entity to place ops_state, ddsp_dsq_id, and ddsp_enq_flags immediately after dsq. These fields are accessed together in the do_enqueue_task() and finish_dispatch() hot paths but were previously spread across three different cache lines. Grouping them on the same cache line reduces cache misses on every enqueue and dispatch operation. Signed-off-by: David Carlier Signed-off-by: Tejun Heo --- include/linux/sched/ext.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/sched/ext.h b/include/linux/sched/ext.h index 4601e5ecb43c..0150b3fe6230 100644 --- a/include/linux/sched/ext.h +++ b/include/linux/sched/ext.h @@ -163,6 +163,9 @@ struct scx_dsq_list_node { */ struct sched_ext_entity { struct scx_dispatch_q *dsq; + atomic_long_t ops_state; + u64 ddsp_dsq_id; + u64 ddsp_enq_flags; struct scx_dsq_list_node dsq_list; /* dispatch order */ struct rb_node dsq_priq; /* p->scx.dsq_vtime order */ u32 dsq_seq; @@ -174,7 +177,6 @@ struct sched_ext_entity { s32 selected_cpu; u32 kf_mask; /* see scx_kf_mask above */ struct task_struct *kf_tasks[2]; /* see SCX_CALL_OP_TASK() */ - atomic_long_t ops_state; struct list_head runnable_node; /* rq->scx.runnable_list */ unsigned long runnable_at; @@ -182,8 +184,6 @@ struct sched_ext_entity { #ifdef CONFIG_SCHED_CORE u64 core_sched_at; /* see scx_prio_less() */ #endif - u64 ddsp_dsq_id; - u64 ddsp_enq_flags; /* BPF scheduler modifiable fields */ -- cgit v1.2.3