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From: Tejun Heo <tj@kernel.org>
To: linux-kernel@vger.kernel.org, sched-ext@lists.linux.dev
Cc: void@manifault.com, arighi@nvidia.com, changwoo@igalia.com,
	emil@etsalapatis.com, hannes@cmpxchg.org, mkoutny@suse.com,
	cgroups@vger.kernel.org, Tejun Heo <tj@kernel.org>
Subject: [PATCH 14/34] sched_ext: Make scx_prio_less() handle multiple schedulers
Date: Tue, 24 Feb 2026 19:01:32 -1000	[thread overview]
Message-ID: <20260225050152.1070601-15-tj@kernel.org> (raw)
In-Reply-To: <20260225050152.1070601-1-tj@kernel.org>

Call ops.core_sched_before() iff both tasks belong to the same scx_sched.
Otherwise, use timestamp based ordering.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
 kernel/sched/ext.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 5d13b9b93249..3d46e6e125c7 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -2805,16 +2805,17 @@ void ext_server_init(struct rq *rq)
 bool scx_prio_less(const struct task_struct *a, const struct task_struct *b,
 		   bool in_fi)
 {
-	struct scx_sched *sch = scx_root;
+	struct scx_sched *sch_a = scx_task_sched(a);
+	struct scx_sched *sch_b = scx_task_sched(b);
 
 	/*
 	 * The const qualifiers are dropped from task_struct pointers when
 	 * calling ops.core_sched_before(). Accesses are controlled by the
 	 * verifier.
 	 */
-	if (SCX_HAS_OP(sch, core_sched_before) &&
+	if (sch_a == sch_b && SCX_HAS_OP(sch_a, core_sched_before) &&
 	    !scx_rq_bypassing(task_rq(a)))
-		return SCX_CALL_OP_2TASKS_RET(sch, SCX_KF_REST, core_sched_before,
+		return SCX_CALL_OP_2TASKS_RET(sch_a, SCX_KF_REST, core_sched_before,
 					      NULL,
 					      (struct task_struct *)a,
 					      (struct task_struct *)b);
-- 
2.53.0


  parent reply	other threads:[~2026-02-25  5:02 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-25  5:01 [PATCHSET v2 sched_ext/for-7.1] sched_ext: Implement cgroup sub-scheduler support Tejun Heo
2026-02-25  5:01 ` [PATCH 01/34] sched_ext: Implement cgroup subtree iteration for scx_task_iter Tejun Heo
2026-02-25  5:01 ` [PATCH 02/34] sched_ext: Add @kargs to scx_fork() Tejun Heo
2026-02-25  5:01 ` [PATCH 03/34] sched/core: Swap the order between sched_post_fork() and cgroup_post_fork() Tejun Heo
2026-02-25  5:01 ` [PATCH 04/34] cgroup: Expose some cgroup helpers Tejun Heo
2026-02-25  5:01 ` [PATCH 05/34] sched_ext: Update p->scx.disallow warning in scx_init_task() Tejun Heo
2026-02-25  5:01 ` [PATCH 06/34] sched_ext: Reorganize enable/disable path for multi-scheduler support Tejun Heo
2026-02-25  5:01 ` [PATCH 07/34] sched_ext: Introduce cgroup sub-sched support Tejun Heo
2026-02-25  5:01 ` [PATCH 08/34] sched_ext: Introduce scx_task_sched[_rcu]() Tejun Heo
2026-02-25  5:01 ` [PATCH 09/34] sched_ext: Introduce scx_prog_sched() Tejun Heo
2026-02-25  5:01 ` [PATCH 10/34] sched_ext: Enforce scheduling authority in dispatch and select_cpu operations Tejun Heo
2026-02-25  5:01 ` [PATCH 11/34] sched_ext: Enforce scheduler ownership when updating slice and dsq_vtime Tejun Heo
2026-02-25  5:01 ` [PATCH 12/34] sched_ext: scx_dsq_move() should validate the task belongs to the right scheduler Tejun Heo
2026-02-25  5:01 ` [PATCH 13/34] sched_ext: Refactor task init/exit helpers Tejun Heo
2026-02-25  5:01 ` Tejun Heo [this message]
2026-02-25  5:01 ` [PATCH 15/34] sched_ext: Move default slice to per-scheduler field Tejun Heo
2026-02-25  5:01 ` [PATCH 16/34] sched_ext: Move aborting flag " Tejun Heo
2026-02-25  5:01 ` [PATCH 17/34] sched_ext: Move bypass_dsq into scx_sched_pcpu Tejun Heo
2026-02-25  5:01 ` [PATCH 18/34] sched_ext: Move bypass state into scx_sched Tejun Heo
2026-02-25  5:01 ` [PATCH 19/34] sched_ext: Prepare bypass mode for hierarchical operation Tejun Heo
2026-02-25  5:01 ` [PATCH 20/34] sched_ext: Factor out scx_dispatch_sched() Tejun Heo
2026-02-25  5:01 ` [PATCH 21/34] sched_ext: When calling ops.dispatch() @prev must be on the same scx_sched Tejun Heo
2026-02-25  5:01 ` [PATCH 22/34] sched_ext: Separate bypass dispatch enabling from bypass depth tracking Tejun Heo
2026-02-25  5:01 ` [PATCH 23/34] sched_ext: Implement hierarchical bypass mode Tejun Heo
2026-02-25  5:01 ` [PATCH 24/34] sched_ext: Dispatch from all scx_sched instances Tejun Heo
2026-02-25  5:01 ` [PATCH 25/34] sched_ext: Move scx_dsp_ctx and scx_dsp_max_batch into scx_sched Tejun Heo
2026-02-25  5:01 ` [PATCH 26/34] sched_ext: Make watchdog sub-sched aware Tejun Heo
2026-02-25  5:01 ` [PATCH 27/34] sched_ext: Convert scx_dump_state() spinlock to raw spinlock Tejun Heo
2026-02-25  5:01 ` [PATCH 28/34] sched_ext: Support dumping multiple schedulers and add scheduler identification Tejun Heo
2026-02-25  5:01 ` [PATCH 29/34] sched_ext: Implement cgroup sub-sched enabling and disabling Tejun Heo
2026-02-25  5:01 ` [PATCH 30/34] sched_ext: Add scx_sched back pointer to scx_sched_pcpu Tejun Heo
2026-02-25  5:01 ` [PATCH 31/34] sched_ext: Make scx_bpf_reenqueue_local() sub-sched aware Tejun Heo
2026-02-25  5:01 ` [PATCH 32/34] sched_ext: Factor out scx_link_sched() and scx_unlink_sched() Tejun Heo
2026-02-25  5:01 ` [PATCH 33/34] sched_ext: Add rhashtable lookup for sub-schedulers Tejun Heo
2026-02-25  5:01 ` [PATCH 34/34] sched_ext: Add basic building blocks for nested sub-scheduler dispatching Tejun Heo
2026-02-25  5:18 ` [PATCHSET v2 sched_ext/for-7.1] sched_ext: Implement cgroup sub-scheduler support Tejun Heo
  -- strict thread matches above, loose matches on Subject: below --
2026-03-04 22:00 [PATCHSET v3 " Tejun Heo
2026-03-04 22:00 ` [PATCH 14/34] sched_ext: Make scx_prio_less() handle multiple schedulers Tejun Heo
2026-02-25  5:00 [PATCHSET v2 sched_ext/for-7.1] sched_ext: Implement cgroup sub-scheduler support Tejun Heo
2026-02-25  5:00 ` [PATCH 14/34] sched_ext: Make scx_prio_less() handle multiple schedulers Tejun Heo
2026-01-21 23:11 [PATCHSET v1 sched_ext/for-6.20] sched_ext: Implement cgroup sub-scheduler support Tejun Heo
2026-01-21 23:11 ` [PATCH 14/34] sched_ext: Make scx_prio_less() handle multiple schedulers Tejun Heo

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