[RFC,v7,03/23] dept: Add single event dependency tracker APIs

Commit Message

Byungchul Park Jan. 9, 2023, 3:33 a.m. UTC

Wrapped the base APIs for easier annotation on wait and event. Start
with supporting waiters on each single event. More general support for
multiple events is a future work. Do more when the need arises.

How to annotate (the simplest way):

1. Initaialize a map for the interesting wait.

   /*
    * Recommand to place along with the wait instance.
    */
   struct dept_map my_wait;

   /*
    * Recommand to place in the initialization code.
    */
   sdt_map_init(&my_wait);

2. Place the following at the wait code.

   sdt_wait(&my_wait);

3. Place the following at the event code.

   sdt_event(&my_wait);

That's it!

Signed-off-by: Byungchul Park <[e-mail]>
---
 include/linux/dept_sdt.h | 72 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100644 include/linux/dept_sdt.h

Comments

Thomas Gleixner Jan. 18, 2023, 1:01 p.m. UTC | #1

On Mon, Jan 09 2023 at 12:33, Byungchul Park wrote:
> +/*
> + * sdt_might_sleep() and its family will be committed in __schedule()
> + * when it actually gets to __schedule(). Both dept_request_event() and
> + * dept_wait() will be performed on the commit.
> + */
> +
> +/*
> + * Use the code location as the class key if an explicit map is not used.
> + */
> +#define sdt_might_sleep_strong(m)					\
> +	do {								\
> +		struct dept_map *__m = m;				\
> +		static struct dept_key __key;				\
> +		dept_stage_wait(__m, __m ? NULL : &__key, _THIS_IP_, __func__, true);\
> +	} while (0)
> +
> +/*
> + * Use the code location as the class key if an explicit map is not used.
> + */
> +#define sdt_might_sleep_weak(m)						\
> +	do {								\
> +		struct dept_map *__m = m;				\
> +		static struct dept_key __key;				\
> +		dept_stage_wait(__m, __m ? NULL : &__key, _THIS_IP_, __func__, false);\
> +	} while (0)
> +
> +#define sdt_might_sleep_finish()	dept_clean_stage()
> +
> +#define sdt_ecxt_enter(m)		dept_ecxt_enter(m, 1UL, _THIS_IP_, "start", "event", 0)
> +#define sdt_event(m)			dept_event(m, 1UL, _THIS_IP_, __func__)
> +#define sdt_ecxt_exit(m)		dept_ecxt_exit(m, 1UL, _THIS_IP_)

None of the above comes with a proper documentation of the various
macros/functions. How should anyone aside of you understand what this is
about and how this should be used?

Thanks,

        tglx

Patch

diff --git a/include/linux/dept_sdt.h b/include/linux/dept_sdt.h
new file mode 100644
index 00000000..2644e77
--- /dev/null
+++ b/include/linux/dept_sdt.h
@@ -0,0 +1,72 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Single-event Dependency Tracker
+ *
+ * Started by Byungchul Park <[e-mail]>:
+ *
+ *  Copyright (c) 2020 LG Electronics, Inc., Byungchul Park
+ */
+
+#ifndef __LINUX_DEPT_SDT_H
+#define __LINUX_DEPT_SDT_H
+
+#include <linux/dept.h>
+
+#ifdef CONFIG_DEPT
+#define sdt_map_init(m)							\
+	do {								\
+		static struct dept_key __key;				\
+		dept_map_init(m, &__key, 0, #m);			\
+	} while (0)
+
+#define sdt_map_init_key(m, k)		dept_map_init(m, k, 0, #m)
+
+#define sdt_wait(m)							\
+	do {								\
+		dept_request_event(m);					\
+		dept_wait(m, 1UL, _THIS_IP_, __func__, 0);		\
+	} while (0)
+
+/*
+ * sdt_might_sleep() and its family will be committed in __schedule()
+ * when it actually gets to __schedule(). Both dept_request_event() and
+ * dept_wait() will be performed on the commit.
+ */
+
+/*
+ * Use the code location as the class key if an explicit map is not used.
+ */
+#define sdt_might_sleep_strong(m)					\
+	do {								\
+		struct dept_map *__m = m;				\
+		static struct dept_key __key;				\
+		dept_stage_wait(__m, __m ? NULL : &__key, _THIS_IP_, __func__, true);\
+	} while (0)
+
+/*
+ * Use the code location as the class key if an explicit map is not used.
+ */
+#define sdt_might_sleep_weak(m)						\
+	do {								\
+		struct dept_map *__m = m;				\
+		static struct dept_key __key;				\
+		dept_stage_wait(__m, __m ? NULL : &__key, _THIS_IP_, __func__, false);\
+	} while (0)
+
+#define sdt_might_sleep_finish()	dept_clean_stage()
+
+#define sdt_ecxt_enter(m)		dept_ecxt_enter(m, 1UL, _THIS_IP_, "start", "event", 0)
+#define sdt_event(m)			dept_event(m, 1UL, _THIS_IP_, __func__)
+#define sdt_ecxt_exit(m)		dept_ecxt_exit(m, 1UL, _THIS_IP_)
+#else /* !CONFIG_DEPT */
+#define sdt_map_init(m)			do { } while (0)
+#define sdt_map_init_key(m, k)		do { (void)(k); } while (0)
+#define sdt_wait(m)			do { } while (0)
+#define sdt_might_sleep_strong(m)	do { } while (0)
+#define sdt_might_sleep_weak(m)		do { } while (0)
+#define sdt_might_sleep_finish()	do { } while (0)
+#define sdt_ecxt_enter(m)		do { } while (0)
+#define sdt_event(m)			do { } while (0)
+#define sdt_ecxt_exit(m)		do { } while (0)
+#endif
+#endif /* __LINUX_DEPT_SDT_H */