ANDROID: vendor_hooks: add hooks in rwsem

these hooks are required by the following features:
1.For rwsem readers, currently only the latest reader will be
recorded in sem->owner. We add hooks to record all readers which
have acquired the lock, once there are UX threads blocked in the
rwsem waiting list, these read_owners will be given high
priority in scheduling.
2.For rwsem writer, when a writer acquires the lock, we check
whether there are UX threads blocked in the rwsem wait list. If
so, we give this writer a high priority in scheduling so that it
can release the lock as soon as possible.

Both of these features can optimize the priority inversion
problem caused by rwsem and improve system responsiveness and
performance.

Bug: 335408185
Change-Id: I82a6fbb6acd2ce05d049e686b61e34e4d3b39a5e
Signed-off-by: zhujingpeng <zhujingpeng@vivo.com>
[jstultz: Rebased and resolved minor conflict]
Signed-off-by: John Stultz <jstultz@google.com>
(cherry picked from commit 188c41744ddcccef6daf6dcd4d6a444dabdc2f94)

drivers/android/vendor_hooks.c

@@ -491,3 +491,7 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_hibernate_save_cmp_len);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_percpu_rwsem_down_read);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_percpu_rwsem_up_write);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_percpu_rwsem_wait_complete);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_record_rwsem_reader_owned);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_clear_rwsem_reader_owned);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_record_rwsem_writer_owned);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_clear_rwsem_writer_owned);

include/trace/hooks/rwsem.h

@@ -31,6 +31,19 @@ DECLARE_HOOK(android_vh_rwsem_downgrade_wake_finish,
 DECLARE_HOOK(android_vh_rwsem_wake_finish,
 	TP_PROTO(struct rw_semaphore *sem),
 	TP_ARGS(sem));
+DECLARE_HOOK(android_vh_record_rwsem_reader_owned,
+	TP_PROTO(struct rw_semaphore *sem,
+		 struct list_head *wlist),
+	TP_ARGS(sem, wlist));
+DECLARE_HOOK(android_vh_clear_rwsem_reader_owned,
+	TP_PROTO(struct rw_semaphore *sem),
+	TP_ARGS(sem));
+DECLARE_HOOK(android_vh_record_rwsem_writer_owned,
+	TP_PROTO(struct rw_semaphore *sem),
+	TP_ARGS(sem));
+DECLARE_HOOK(android_vh_clear_rwsem_writer_owned,
+	TP_PROTO(struct rw_semaphore *sem),
+	TP_ARGS(sem));
 #endif /* _TRACE_HOOK_RWSEM_H */
 /* This part must be outside protection */
 #include <trace/define_trace.h>

kernel/locking/rwsem.c

@@ -143,12 +143,14 @@ static inline void rwsem_set_owner(struct rw_semaphore *sem)
 {
 	lockdep_assert_preemption_disabled();
 	atomic_long_set(&sem->owner, (long)current);
+	trace_android_vh_record_rwsem_writer_owned(sem);
 }
 
 static inline void rwsem_clear_owner(struct rw_semaphore *sem)
 {
 	lockdep_assert_preemption_disabled();
 	atomic_long_set(&sem->owner, 0);
+	trace_android_vh_clear_rwsem_writer_owned(sem);
 }
 
 /*
@@ -181,6 +183,7 @@ static inline void __rwsem_set_reader_owned(struct rw_semaphore *sem,
 static inline void rwsem_set_reader_owned(struct rw_semaphore *sem)
 {
 	__rwsem_set_reader_owned(sem, current);
+	trace_android_vh_record_rwsem_reader_owned(sem, NULL);
 }
 
 #ifdef CONFIG_DEBUG_RWSEMS
@@ -218,6 +221,7 @@ static inline void rwsem_clear_reader_owned(struct rw_semaphore *sem)
 {
 	unsigned long val = atomic_long_read(&sem->owner);
 
+	trace_android_vh_clear_rwsem_reader_owned(sem);
 	while ((val & ~RWSEM_OWNER_FLAGS_MASK) == (unsigned long)current) {
 		if (atomic_long_try_cmpxchg(&sem->owner, &val,
 					    val & RWSEM_OWNER_FLAGS_MASK))
@@ -227,6 +231,7 @@ static inline void rwsem_clear_reader_owned(struct rw_semaphore *sem)
 #else
 static inline void rwsem_clear_reader_owned(struct rw_semaphore *sem)
 {
+	trace_android_vh_clear_rwsem_reader_owned(sem);
 }
 #endif
 
@@ -547,6 +552,7 @@ static void rwsem_mark_wake(struct rw_semaphore *sem,
 
 	if (adjustment)
 		atomic_long_add(adjustment, &sem->count);
+	trace_android_vh_record_rwsem_reader_owned(sem, &wlist);
 
 	/* 2nd pass */
 	list_for_each_entry_safe(waiter, tmp, &wlist, list) {