Merge pull request #1272 from multics69/lavd-opt-preemption3

scx_lavd: Don't try preemption for greedy tasks
sched-ext · Jan 30, 2025 · ffcd3f0 · ffcd3f0
2 parents c7ba8f2 + 8028349
commit ffcd3f0
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Showing 2 changed files with 8 additions and 1 deletion.
diff --git a/scheds/rust/scx_lavd/src/bpf/main.bpf.c b/scheds/rust/scx_lavd/src/bpf/main.bpf.c
@@ -1068,7 +1068,8 @@ bool can_direct_dispatch(struct task_struct *p, struct task_ctx *taskc,
 		if (!scx_bpf_dsq_nr_queued(SCX_DSQ_LOCAL_ON | cpu_id))
 			return true;
 
-		if (can_task1_kick_cpu2(taskc, cpuc_task, now)) {
+		if (is_eligible(taskc) &&
+		    can_task1_kick_cpu2(taskc, cpuc_task, now)) {
 			*enq_flags |= SCX_ENQ_PREEMPT;
 			return true;
 		}

diff --git a/scheds/rust/scx_lavd/src/bpf/preempt.bpf.c b/scheds/rust/scx_lavd/src/bpf/preempt.bpf.c
@@ -277,6 +277,12 @@ static bool try_find_and_kick_victim_cpu(struct task_struct *p,
 	struct cpu_ctx *victim_cpuc;
 	bool ret = false;
 
+	/*
+	 * Don't even try to perform expensive preemption for greedy tasks.
+	 */
+	if (!is_eligible(taskc))
+		return false;
+
 	/*
 	 * Prepare a cpumak so we find a victim in @p's compute domain.
 	 */