From 3265ef0b670180b0b946d73ee9825d6d91e98a08 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sat, 5 Sep 2026 06:09:55 -1000 Subject: [PATCH] sched_ext: Rename sch to root_sch in dispatch_one() dispatch_one() uses the root scheduler for everything it does, including the two decisions to keep running @prev, which are wrong when @prev belongs to a sub-scheduler. The function has to deal with @prev's scheduler too. Rename the root's local from sch to root_sch for clarity and to make room for it. No functional change. Signed-off-by: Tejun Heo Reviewed-by: Andrea Righi --- kernel/sched/ext/ext.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c index 7e414a7c53fc..120540cdda74 100644 --- a/kernel/sched/ext/ext.c +++ b/kernel/sched/ext/ext.c @@ -2919,7 +2919,7 @@ static inline void maybe_queue_balance_callback(struct rq *rq) static enum scx_dsp_verdict dispatch_one(struct rq *rq, struct task_struct *prev) { - struct scx_sched *sch = scx_root_protected_live(); + struct scx_sched *root_sch = scx_root_protected_live(); enum scx_dsp_verdict verdict; s32 cpu = cpu_of(rq); @@ -2928,7 +2928,7 @@ static enum scx_dsp_verdict dispatch_one(struct rq *rq, struct task_struct *prev scx_process_sync_ecaps(rq, prev); - if ((sch->ops.flags & SCX_OPS_HAS_CPU_PREEMPT) && + if ((root_sch->ops.flags & SCX_OPS_HAS_CPU_PREEMPT) && unlikely(rq->scx.cpu_released)) { /* * If the previous sched_class for the current CPU was not SCX, @@ -2936,8 +2936,8 @@ static enum scx_dsp_verdict dispatch_one(struct rq *rq, struct task_struct *prev * core. This callback complements ->cpu_release(), which is * emitted in switch_class(). */ - if (sch->ops.cpu_acquire) - SCX_CALL_OP(sch, cpu_acquire, rq, cpu, NULL); + if (root_sch->ops.cpu_acquire) + SCX_CALL_OP(root_sch, cpu_acquire, rq, cpu, NULL); rq->scx.cpu_released = false; } @@ -2955,7 +2955,7 @@ static enum scx_dsp_verdict dispatch_one(struct rq *rq, struct task_struct *prev * test. */ if ((prev->scx.flags & SCX_TASK_QUEUED) && prev->scx.slice && - !scx_bypassing(sch, cpu)) { + !scx_bypassing(root_sch, cpu)) { verdict = SCX_DSP_PREV; goto has_tasks; } @@ -2967,7 +2967,7 @@ static enum scx_dsp_verdict dispatch_one(struct rq *rq, struct task_struct *prev goto has_tasks; } - verdict = scx_dispatch_sched(sch, rq, prev, false); + verdict = scx_dispatch_sched(root_sch, rq, prev, false); if (verdict != SCX_DSP_NONE) goto has_tasks; @@ -2976,9 +2976,9 @@ static enum scx_dsp_verdict dispatch_one(struct rq *rq, struct task_struct *prev * %SCX_OPS_ENQ_LAST is in effect. */ if ((prev->scx.flags & SCX_TASK_QUEUED) && - (!(sch->ops.flags & SCX_OPS_ENQ_LAST) || scx_bypassing(sch, cpu)) && + (!(root_sch->ops.flags & SCX_OPS_ENQ_LAST) || scx_bypassing(root_sch, cpu)) && scx_task_can_stay_on_cpu(rq, prev)) { - __scx_add_event(sch, SCX_EV_DISPATCH_KEEP_LAST, 1); + __scx_add_event(root_sch, SCX_EV_DISPATCH_KEEP_LAST, 1); verdict = SCX_DSP_PREV; goto has_tasks; }