tools/sched_ext: Add error logging for dsq creation failures in remaining schedulers

Add scx_bpf_error() calls when scx_bpf_create_dsq() fails in the remaining
schedulers to improve debuggability:

- scx_simple.bpf.c: simple_init()
- scx_sdt.bpf.c: sdt_init()
- scx_cpu0.bpf.c: cpu0_init()
- scx_flatcg.bpf.c: fcg_init()

This follows the same pattern established in commit 2f8d489
("sched_ext: Add error logging for dsq creation failures") for other
schedulers and ensures consistent error reporting across all schedulers.

Signed-off-by: zhidao su <suzhidao@xiaomi.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Author: soolaugust

tools/sched_ext/scx_cpu0.bpf.c

@@ -71,7 +71,15 @@ void BPF_STRUCT_OPS(cpu0_dispatch, s32 cpu, struct task_struct *prev)
 
 s32 BPF_STRUCT_OPS_SLEEPABLE(cpu0_init)
 {
-	return scx_bpf_create_dsq(DSQ_CPU0, -1);
+	int ret;
+
+	ret = scx_bpf_create_dsq(DSQ_CPU0, -1);
+	if (ret) {
+		scx_bpf_error("failed to create DSQ %d (%d)", DSQ_CPU0, ret);
+		return ret;
+	}
+
+	return 0;
 }
 
 void BPF_STRUCT_OPS(cpu0_exit, struct scx_exit_info *ei)

tools/sched_ext/scx_flatcg.bpf.c

@@ -929,7 +929,15 @@ void BPF_STRUCT_OPS(fcg_cgroup_move, struct task_struct *p,
 
 s32 BPF_STRUCT_OPS_SLEEPABLE(fcg_init)
 {
-	return scx_bpf_create_dsq(FALLBACK_DSQ, -1);
+	int ret;
+
+	ret = scx_bpf_create_dsq(FALLBACK_DSQ, -1);
+	if (ret) {
+		scx_bpf_error("failed to create DSQ %d (%d)", FALLBACK_DSQ, ret);
+		return ret;
+	}
+
+	return 0;
 }
 
 void BPF_STRUCT_OPS(fcg_exit, struct scx_exit_info *ei)

tools/sched_ext/scx_sdt.bpf.c

@@ -691,7 +691,13 @@ s32 BPF_STRUCT_OPS_SLEEPABLE(sdt_init)
 		return ret;
 	}
 
-	return scx_bpf_create_dsq(SHARED_DSQ, -1);
+	ret = scx_bpf_create_dsq(SHARED_DSQ, -1);
+	if (ret) {
+		scx_bpf_error("failed to create DSQ %d (%d)", SHARED_DSQ, ret);
+		return ret;
+	}
+
+	return 0;
 }
 
 void BPF_STRUCT_OPS(sdt_exit, struct scx_exit_info *ei)

tools/sched_ext/scx_simple.bpf.c

@@ -131,7 +131,15 @@ void BPF_STRUCT_OPS(simple_enable, struct task_struct *p)
 
 s32 BPF_STRUCT_OPS_SLEEPABLE(simple_init)
 {
-	return scx_bpf_create_dsq(SHARED_DSQ, -1);
+	int ret;
+
+	ret = scx_bpf_create_dsq(SHARED_DSQ, -1);
+	if (ret) {
+		scx_bpf_error("failed to create DSQ %d (%d)", SHARED_DSQ, ret);
+		return ret;
+	}
+
+	return 0;
 }
 
 void BPF_STRUCT_OPS(simple_exit, struct scx_exit_info *ei)