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@sk.com>
To:     linux-kernel@vger.kernel.org
Cc:     kernel_team@skhynix.com, torvalds@linux-foundation.org,
        damien.lemoal@opensource.wdc.com, linux-ide@vger.kernel.org,
        adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org,
        mingo@redhat.com, peterz@infradead.org, will@kernel.org,
        tglx@linutronix.de, rostedt@goodmis.org, joel@joelfernandes.org,
        sashal@kernel.org, daniel.vetter@ffwll.ch, duyuyang@gmail.com,
        johannes.berg@intel.com, tj@kernel.org, tytso@mit.edu,
        willy@infradead.org, david@fromorbit.com, amir73il@gmail.com,
        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,
        josef@toxicpanda.com, linux-fsdevel@vger.kernel.org,
        viro@zeniv.linux.org.uk, jack@suse.cz, jlayton@kernel.org,
        dan.j.williams@intel.com, hch@infradead.org, djwong@kernel.org,
        dri-devel@lists.freedesktop.org, rodrigosiqueiramelo@gmail.com,
        melissa.srw@gmail.com, hamohammed.sa@gmail.com,
        42.hyeyoo@gmail.com, chris.p.wilson@intel.com,
        gwan-gyeong.mun@intel.com, max.byungchul.park@gmail.com,
        boqun.feng@gmail.com, longman@redhat.com, hdanton@sina.com,
        her0gyugyu@gmail.com
Subject: [PATCH v10 rebased on v6.4 03/25] dept: Add single event dependency tracker APIs
Date:   Mon,  3 Jul 2023 18:47:30 +0900
Message-Id: <20230703094752.79269-4-byungchul@sk.com>
In-Reply-To: <20230703094752.79269-1-byungchul@sk.com>
References: <20230703094752.79269-1-byungchul@sk.com>
Precedence: bulk

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 <byungchul@sk.com>
---
 include/linux/dept_sdt.h | 62 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 include/linux/dept_sdt.h

diff --git a/include/linux/dept_sdt.h b/include/linux/dept_sdt.h
new file mode 100644
index 000000000000..12a793b90c7e
--- /dev/null
+++ b/include/linux/dept_sdt.h
@@ -0,0 +1,62 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Single-event Dependency Tracker
+ *
+ * Started by Byungchul Park <max.byungchul.park@gmail.com>:
+ *
+ *  Copyright (c) 2020 LG Electronics, Inc., Byungchul Park
+ */
+
+#ifndef __LINUX_DEPT_SDT_H
+#define __LINUX_DEPT_SDT_H
+
+#include <linux/kernel.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_start(m)					\
+	do {								\
+		struct dept_map *__m = m;				\
+		static struct dept_key __key;				\
+		dept_stage_wait(__m, __m ? NULL : &__key, _THIS_IP_, __func__);\
+	} while (0)
+
+#define sdt_might_sleep_end()		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_start(m)	do { } while (0)
+#define sdt_might_sleep_end()		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 */
-- 
2.17.1