[RFC 10/14] dept: Add proc knobs to show stats and dependency graph

[Byungchul Park <byungchul.park@lge.com>]

It'd be useful to show Dept internal stats and dependency graph on
runtime via proc for better information. Introduced the knobs.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
---
 kernel/dependency/Makefile        |  1 +
 kernel/dependency/dept.c          | 24 ++++------
 kernel/dependency/dept_internal.h | 26 +++++++++++
 kernel/dependency/dept_proc.c     | 97 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 133 insertions(+), 15 deletions(-)
 create mode 100644 kernel/dependency/dept_internal.h
 create mode 100644 kernel/dependency/dept_proc.c

diff --git a/kernel/dependency/Makefile b/kernel/dependency/Makefile
index 9f7778e..49152ad 100644
--- a/kernel/dependency/Makefile
+++ b/kernel/dependency/Makefile
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_DEPT) += dept.o
+obj-$(CONFIG_DEPT) += dept_proc.o
 
diff --git a/kernel/dependency/dept.c b/kernel/dependency/dept.c
index 64287894..b682bf9 100644
--- a/kernel/dependency/dept.c
+++ b/kernel/dependency/dept.c
@@ -90,6 +90,7 @@
 #include <linux/hash.h>
 #include <linux/dept.h>
 #include <linux/utsname.h>
+#include "dept_internal.h"
 
 static int dept_stop;
 static int dept_per_cpu_ready;
@@ -241,20 +242,13 @@ static inline struct dept_task *dept_task(void)
  *       have been freed will be placed.
  */
 
-enum object_t {
-#define OBJECT(id, nr) OBJECT_##id,
-	#include "dept_object.h"
-#undef  OBJECT
-	OBJECT_NR,
-};
-
 #define OBJECT(id, nr)							\
 static struct dept_##id spool_##id[nr];					\
 static DEFINE_PER_CPU(struct llist_head, lpool_##id);
 	#include "dept_object.h"
 #undef  OBJECT
 
-static struct dept_pool pool[OBJECT_NR] = {
+struct dept_pool dept_pool[OBJECT_NR] = {
 #define OBJECT(id, nr) {						\
 	.name = #id,							\
 	.obj_sz = sizeof(struct dept_##id),				\
@@ -283,7 +277,7 @@ static void *from_pool(enum object_t t)
 	if (DEPT_WARN_ON(!irqs_disabled()))
 		return NULL;
 
-	p = &pool[t];
+	p = &dept_pool[t];
 
 	/*
 	 * Try local pool first.
@@ -312,7 +306,7 @@ static void *from_pool(enum object_t t)
 
 static void to_pool(void *o, enum object_t t)
 {
-	struct dept_pool *p = &pool[t];
+	struct dept_pool *p = &dept_pool[t];
 	struct llist_head *h;
 
 	preempt_disable();
@@ -1986,7 +1980,7 @@ void dept_map_nocheck(struct dept_map *m)
 }
 EXPORT_SYMBOL_GPL(dept_map_nocheck);
 
-static LIST_HEAD(classes);
+LIST_HEAD(dept_classes);
 
 static inline bool within(const void *addr, void *start, unsigned long size)
 {
@@ -2031,7 +2025,7 @@ void dept_free_range(void *start, unsigned int sz)
 	 */
 	free_staleie_staleiw_range(start, sz);
 
-	list_for_each_entry_safe(c, n, &classes, all_node) {
+	list_for_each_entry_safe(c, n, &dept_classes, all_node) {
 		if (!within((void *)c->key, start, sz) &&
 		    !within(c->name, start, sz))
 			continue;
@@ -2100,7 +2094,7 @@ static struct dept_class *check_new_class(struct dept_key *local,
 	c->sub = sub;
 	c->key = (unsigned long)(k->subkeys + sub);
 	hash_add_class(c);
-	list_add(&c->all_node, &classes);
+	list_add(&c->all_node, &dept_classes);
 unlock:
 	dept_unlock();
 caching:
@@ -2429,8 +2423,8 @@ static void migrate_per_cpu_pool(void)
 		struct llist_head *from;
 		struct llist_head *to;
 
-		from = &pool[i].boot_pool;
-		to = per_cpu_ptr(pool[i].lpool, boot_cpu);
+		from = &dept_pool[i].boot_pool;
+		to = per_cpu_ptr(dept_pool[i].lpool, boot_cpu);
 		move_llist(to, from);
 	}
 }
diff --git a/kernel/dependency/dept_internal.h b/kernel/dependency/dept_internal.h
new file mode 100644
index 0000000..007c1ee
--- /dev/null
+++ b/kernel/dependency/dept_internal.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Dept(DEPendency Tracker) - runtime dependency tracker internal header
+ *
+ * Started by Byungchul Park <max.byungchul.park@gmail.com>:
+ *
+ *  Copyright (c) 2020 LG Electronics, Inc., Byungchul Park
+ */
+
+#ifndef __DEPT_INTERNAL_H
+#define __DEPT_INTERNAL_H
+
+#ifdef CONFIG_DEPT
+
+enum object_t {
+#define OBJECT(id, nr) OBJECT_##id,
+	#include "dept_object.h"
+#undef  OBJECT
+	OBJECT_NR,
+};
+
+extern struct list_head dept_classes;
+extern struct dept_pool dept_pool[];
+
+#endif
+#endif /* __DEPT_INTERNAL_H */
diff --git a/kernel/dependency/dept_proc.c b/kernel/dependency/dept_proc.c
new file mode 100644
index 0000000..5e5afa3
--- /dev/null
+++ b/kernel/dependency/dept_proc.c
@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * kernel/dependency/dept_proc.c
+ *
+ * Runtime dependency tracker
+ *
+ * Started by Byungchul Park <max.byungchul.park@gmail.com>:
+ *
+ *  Copyright (C) 2021 LG Electronics, Inc. , Byungchul Park
+ *
+ * Code for /proc/dept_*:
+ *
+ */
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/dept.h>
+#include "dept_internal.h"
+
+static void *l_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	/*
+	 * XXX: Serialize list traversal if needed. The following might
+	 * give a wrong information on contention.
+	 */
+	return seq_list_next(v, &dept_classes, pos);
+}
+
+static void *l_start(struct seq_file *m, loff_t *pos)
+{
+	/*
+	 * XXX: Serialize list traversal if needed. The following might
+	 * give a wrong information on contention.
+	 */
+	return seq_list_start_head(&dept_classes, *pos);
+}
+
+static void l_stop(struct seq_file *m, void *v)
+{
+}
+
+static int l_show(struct seq_file *m, void *v)
+{
+	struct dept_class *fc = list_entry(v, struct dept_class, all_node);
+	struct dept_dep *d;
+
+	if (v == &dept_classes) {
+		seq_printf(m, "All classes:\n\n");
+		return 0;
+	}
+
+	seq_printf(m, "[%p] %s\n", (void *)fc->key, fc->name);
+
+	/*
+	 * XXX: Serialize list traversal if needed. The following might
+	 * give a wrong information on contention.
+	 */
+	list_for_each_entry(d, &fc->dep_head, dep_node) {
+		struct dept_class *tc = d->wait->class;
+		seq_printf(m, " -> [%p] %s\n", (void *)tc->key, tc->name);
+	}
+	seq_puts(m, "\n");
+
+	return 0;
+}
+
+static const struct seq_operations dept_deps_ops = {
+	.start	= l_start,
+	.next	= l_next,
+	.stop	= l_stop,
+	.show	= l_show,
+};
+
+static int dept_stats_show(struct seq_file *m, void *v)
+{
+	int r;
+
+	seq_printf(m, "Availablity in the static pools:\n\n");
+#define OBJECT(id, nr)							\
+	r = atomic_read(&dept_pool[OBJECT_##id].obj_nr);		\
+	if (r < 0)							\
+		r = 0;							\
+	seq_printf(m, "%s\t%d/%d(%d%%)\n", #id, r, nr, (r * 100) / (nr));
+	#include "dept_object.h"
+#undef  OBJECT
+
+	return 0;
+}
+
+static int __init dept_proc_init(void)
+{
+	proc_create_seq("dept_deps", S_IRUSR, NULL, &dept_deps_ops);
+	proc_create_single("dept_stats", S_IRUSR, NULL, dept_stats_show);
+	return 0;
+}
+
+__initcall(dept_proc_init);
+
-- 
1.9.1