generic-library/bionic
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Provide writer preference option in rwlock.

Browse Source 
Previous implementation of rwlock contains four atomic variables, which
is hard to maintain and change. So I make following changes in this CL:

1. Add pending flags in rwlock.state, so we don't need to synchronize
between different atomic variables. Using compare_and_swap operations
on rwlock.state is enough for all state change.

2. Add pending_lock to protect readers/writers waiting and wake up
operations. As waiting/wakeup is not performance critical, using a
lock is easier to maintain.

3. Add writer preference option.

4. Add unit tests for rwlock.

Bug: 19109156

Change-Id: Idcaa58d695ea401d64445610b465ac5cff23ec7c
This commit is contained in:
Yabin Cui
2015-03-17 14:22:09 -07:00
parent 4bd8f9637d
commit 76615dae93
4 changed files with 532 additions and 158 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
libc/include/pthread.h
View File

@@ -85,6 +85,11 @@ typedef long pthread_rwlockattr_t;
#define PTHREAD_RWLOCK_INITIALIZER { { 0 } }
enum {
PTHREAD_RWLOCK_PREFER_READER_NP = 0,
PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP = 1,
};
typedef int pthread_key_t;
typedef int pthread_once_t;
@@ -178,10 +183,12 @@ int pthread_mutex_unlock(pthread_mutex_t*) __nonnull((1));
int pthread_once(pthread_once_t*, void (*)(void)) __nonnull((1, 2));
int pthread_rwlockattr_init(pthread_rwlockattr_t*) __nonnull((1));
int pthread_rwlockattr_destroy(pthread_rwlockattr_t*) __nonnull((1));
int pthread_rwlockattr_getpshared(const pthread_rwlockattr_t*, int*) __nonnull((1, 2));
int pthread_rwlockattr_init(pthread_rwlockattr_t*) __nonnull((1));
int pthread_rwlockattr_setpshared(pthread_rwlockattr_t*, int) __nonnull((1));
int pthread_rwlockattr_getkind_np(const pthread_rwlockattr_t*, int*) __nonnull((1, 2));
int pthread_rwlockattr_setkind_np(pthread_rwlockattr_t*, int) __nonnull((1));
int pthread_rwlock_destroy(pthread_rwlock_t*) __nonnull((1));
int pthread_rwlock_init(pthread_rwlock_t*, const pthread_rwlockattr_t*) __nonnull((1));