sched/debug: Add a new sched_trace_*() helper functions

The new functions allow modules to access internal data structures of
unexported struct cfs_rq and struct rq to extract important information
from the tracepoints to be introduced in later patches.

While at it fix alphabetical order of struct declarations in sched.h

Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pavankumar Kondeti <pkondeti@codeaurora.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Perret <quentin.perret@arm.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Uwe Kleine-Konig <u.kleine-koenig@pengutronix.de>
Link: https://lkml.kernel.org/r/20190604111459.2862-3-qais.yousef@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

include/linux/sched.h

@@ -35,6 +35,7 @@ struct audit_context;
 struct backing_dev_info;
 struct bio_list;
 struct blk_plug;
+struct capture_control;
 struct cfs_rq;
 struct fs_struct;
 struct futex_pi_state;
@@ -47,8 +48,9 @@ struct pid_namespace;
 struct pipe_inode_info;
 struct rcu_node;
 struct reclaim_state;
-struct capture_control;
 struct robust_list_head;
+struct root_domain;
+struct rq;
 struct sched_attr;
 struct sched_param;
 struct seq_file;
@@ -1920,4 +1922,16 @@ static inline void rseq_syscall(struct pt_regs *regs)
 
 #endif
 
+const struct sched_avg *sched_trace_cfs_rq_avg(struct cfs_rq *cfs_rq);
+char *sched_trace_cfs_rq_path(struct cfs_rq *cfs_rq, char *str, int len);
+int sched_trace_cfs_rq_cpu(struct cfs_rq *cfs_rq);
+
+const struct sched_avg *sched_trace_rq_avg_rt(struct rq *rq);
+const struct sched_avg *sched_trace_rq_avg_dl(struct rq *rq);
+const struct sched_avg *sched_trace_rq_avg_irq(struct rq *rq);
+
+int sched_trace_rq_cpu(struct rq *rq);
+
+const struct cpumask *sched_trace_rd_span(struct root_domain *rd);
+
 #endif

kernel/sched/fair.c

@@ -275,6 +275,19 @@ static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
 	return grp->my_q;
 }
 
+static inline void cfs_rq_tg_path(struct cfs_rq *cfs_rq, char *path, int len)
+{
+	if (!path)
+		return;
+
+	if (cfs_rq && task_group_is_autogroup(cfs_rq->tg))
+		autogroup_path(cfs_rq->tg, path, len);
+	else if (cfs_rq && cfs_rq->tg->css.cgroup)
+		cgroup_path(cfs_rq->tg->css.cgroup, path, len);
+	else
+		strlcpy(path, "(null)", len);
+}
+
 static inline bool list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
 {
 	struct rq *rq = rq_of(cfs_rq);
@@ -449,6 +462,12 @@ static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
 	return NULL;
 }
 
+static inline void cfs_rq_tg_path(struct cfs_rq *cfs_rq, char *path, int len)
+{
+	if (path)
+		strlcpy(path, "(null)", len);
+}
+
 static inline bool list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
 {
 	return true;
@@ -10408,3 +10427,83 @@ __init void init_sched_fair_class(void)
 #endif /* SMP */
 
 }
+
+/*
+ * Helper functions to facilitate extracting info from tracepoints.
+ */
+
+const struct sched_avg *sched_trace_cfs_rq_avg(struct cfs_rq *cfs_rq)
+{
+#ifdef CONFIG_SMP
+	return cfs_rq ? &cfs_rq->avg : NULL;
+#else
+	return NULL;
+#endif
+}
+EXPORT_SYMBOL_GPL(sched_trace_cfs_rq_avg);
+
+char *sched_trace_cfs_rq_path(struct cfs_rq *cfs_rq, char *str, int len)
+{
+	if (!cfs_rq) {
+		if (str)
+			strlcpy(str, "(null)", len);
+		else
+			return NULL;
+	}
+
+	cfs_rq_tg_path(cfs_rq, str, len);
+	return str;
+}
+EXPORT_SYMBOL_GPL(sched_trace_cfs_rq_path);
+
+int sched_trace_cfs_rq_cpu(struct cfs_rq *cfs_rq)
+{
+	return cfs_rq ? cpu_of(rq_of(cfs_rq)) : -1;
+}
+EXPORT_SYMBOL_GPL(sched_trace_cfs_rq_cpu);
+
+const struct sched_avg *sched_trace_rq_avg_rt(struct rq *rq)
+{
+#ifdef CONFIG_SMP
+	return rq ? &rq->avg_rt : NULL;
+#else
+	return NULL;
+#endif
+}
+EXPORT_SYMBOL_GPL(sched_trace_rq_avg_rt);
+
+const struct sched_avg *sched_trace_rq_avg_dl(struct rq *rq)
+{
+#ifdef CONFIG_SMP
+	return rq ? &rq->avg_dl : NULL;
+#else
+	return NULL;
+#endif
+}
+EXPORT_SYMBOL_GPL(sched_trace_rq_avg_dl);
+
+const struct sched_avg *sched_trace_rq_avg_irq(struct rq *rq)
+{
+#if defined(CONFIG_SMP) && defined(CONFIG_HAVE_SCHED_AVG_IRQ)
+	return rq ? &rq->avg_irq : NULL;
+#else
+	return NULL;
+#endif
+}
+EXPORT_SYMBOL_GPL(sched_trace_rq_avg_irq);
+
+int sched_trace_rq_cpu(struct rq *rq)
+{
+	return rq ? cpu_of(rq) : -1;
+}
+EXPORT_SYMBOL_GPL(sched_trace_rq_cpu);
+
+const struct cpumask *sched_trace_rd_span(struct root_domain *rd)
+{
+#ifdef CONFIG_SMP
+	return rd ? rd->span : NULL;
+#else
+	return NULL;
+#endif
+}
+EXPORT_SYMBOL_GPL(sched_trace_rd_span);