inital procfs support

kernel/sched/pb.c

+#include <linux/seq_file.h>
+#include <linux/proc_fs.h>
 #include "perf_error_detection.h"
 #include <linux/syscalls.h>
 
@@ -251,3 +253,106 @@ const struct sched_class pb_sched_class = {
 EXPORT_SYMBOL(pb_sched_class);
 
 
+///////////////////// ProcFS Ausgabe ///////////////////////////////////
+
+static int show_pbsched(struct seq_file *seq, void *v)
+{
+    int cpu;
+
+	if (v == (void *)1) {
+		seq_printf(seq, "cpuid mode curr_entry curr_pb_cycles curr_admin_cycles\n");
+	} else {
+        char mode;
+		struct rq *rq;
+		struct pb_rq *pb;
+
+		cpu = (unsigned long)(v - 2);
+		rq = cpu_rq(cpu);
+        pb = &(rq->pb);
+
+        switch(pb->mode) {
+	        case PB_DISABLED_MODE: mode='D'; break;
+	        case PB_EXEC_MODE: mode='E'; break;
+	        case PB_ADMIN_MODE: mode='A'; break;
+	        default: mode='U'; break;
+        }
+
+
+		/* runqueue-specific stats */
+		seq_printf(seq,
+		    "cpu%d %c %u %llu %llu\n",
+		    cpu,
+		    mode,
+            pb->c_entry,
+            pb->count_pb_cycles,
+            pb->count_admin_cycles
+        );
+	}
+	return 0;
+}
+
+/*
+ * This itererator needs some explanation.
+ * It returns 1 for the header position.
+ * This means 2 is cpu 0.
+ * In a hotplugged system some cpus, including cpu 0, may be missing so we have
+ * to use cpumask_* to iterate over the cpus.
+ */
+static void *pbsched_start(struct seq_file *file, loff_t *offset)
+{
+    unsigned long n = *offset;
+
+	if (n == 0)
+		return (void *) 1;
+
+	n--;
+
+	if (n > 0)
+		n = cpumask_next(n - 1, cpu_online_mask);
+	else
+		n = cpumask_first(cpu_online_mask);
+
+	*offset = n + 1;
+
+	if (n < nr_cpu_ids)
+		return (void *)(unsigned long)(n + 2);
+	return NULL;
+}
+
+static void *pbsched_next(struct seq_file *file, void *data, loff_t *offset)
+{
+    (*offset)++;
+	return pbsched_start(file, offset);
+}
+
+static void pbsched_stop(struct seq_file *file, void *data)
+{
+    // NOP
+}
+
+static const struct seq_operations pbsched_sops = {
+	.start = pbsched_start,
+	.next  = pbsched_next,
+	.stop  = pbsched_stop,
+	.show  = show_pbsched,
+};
+
+static int pbsched_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &pbsched_sops);
+}
+
+static const struct file_operations proc_pbsched_operations = {
+	.open    = pbsched_open,
+	.read    = seq_read,
+	.llseek  = seq_lseek,
+	.release = seq_release,
+};
+
+static int __init proc_pbsched_init(void)
+{
+	proc_create("pbsched", 0, NULL, &proc_pbsched_operations);
+	return 0;
+}
+subsys_initcall(proc_pbsched_init);
+