Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Byungchul Park <byungchul.park@lge.com>
To:     torvalds@linux-foundation.org
Cc:     damien.lemoal@opensource.wdc.com, linux-ide@vger.kernel.org,
        adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org,
        mingo@redhat.com, linux-kernel@vger.kernel.org,
        peterz@infradead.org, will@kernel.org, tglx@linutronix.de,
        rostedt@goodmis.org, joel@joelfernandes.org, sashal@kernel.org,
        daniel.vetter@ffwll.ch, chris@chris-wilson.co.uk,
        duyuyang@gmail.com, johannes.berg@intel.com, tj@kernel.org,
        tytso@mit.edu, willy@infradead.org, david@fromorbit.com,
        amir73il@gmail.com, bfields@fieldses.org,
        gregkh@linuxfoundation.org, kernel-team@lge.com,
        linux-mm@kvack.org, akpm@linux-foundation.org, mhocko@kernel.org,
        minchan@kernel.org, hannes@cmpxchg.org, vdavydov.dev@gmail.com,
        sj@kernel.org, jglisse@redhat.com, dennis@kernel.org, cl@linux.com,
        penberg@kernel.org, rientjes@google.com, vbabka@suse.cz,
        ngupta@vflare.org, linux-block@vger.kernel.org,
        paolo.valente@linaro.org, josef@toxicpanda.com,
        linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk,
        jack@suse.cz, jack@suse.com, jlayton@kernel.org,
        dan.j.williams@intel.com, hch@infradead.org, djwong@kernel.org,
        dri-devel@lists.freedesktop.org, airlied@linux.ie,
        rodrigosiqueiramelo@gmail.com, melissa.srw@gmail.com,
        hamohammed.sa@gmail.com
Subject: [PATCH RFC v5 10/21] dept: Add proc knobs to show stats and dependency graph
Date:   Wed, 16 Mar 2022 11:26:22 +0900
Message-Id: <1647397593-16747-11-git-send-email-byungchul.park@lge.com>
In-Reply-To: <1647397593-16747-1-git-send-email-byungchul.park@lge.com>
References: <1647397593-16747-1-git-send-email-byungchul.park@lge.com>
Precedence: bulk

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     | 92 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 128 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 b5cfb8a..92f1654 100644
--- a/kernel/dependency/Makefile
+++ b/kernel/dependency/Makefile
@@ -1,3 +1,4 @@
 # 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 cfd8735..b810939 100644
--- a/kernel/dependency/dept.c
+++ b/kernel/dependency/dept.c
@@ -73,6 +73,7 @@
 #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;
@@ -233,20 +234,13 @@ 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),				\
@@ -276,7 +270,7 @@ 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.
@@ -306,7 +300,7 @@ 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();
@@ -1997,7 +1991,7 @@ 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)
 {
@@ -2024,7 +2018,7 @@ void dept_free_range(void *start, unsigned int sz)
 	while (unlikely(!dept_lock()))
 		cpu_relax();
 
-	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;
@@ -2093,7 +2087,7 @@ 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:
@@ -2570,8 +2564,8 @@ 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..c069354
--- /dev/null
+++ b/kernel/dependency/dept_proc.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Procfs knobs for Dept(DEPendency Tracker)
+ *
+ * Started by Byungchul Park <max.byungchul.park@gmail.com>:
+ *
+ *  Copyright (C) 2021 LG Electronics, Inc. , Byungchul Park
+ */
+#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_puts(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_puts(m, "Availability 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