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Use native rwlock.

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This commit is contained in:
David Xu 2008-04-22 06:44:11 +00:00
parent cf7285f2db
commit fb2641d9b1
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=178413
1 changed files with 20 additions and 54 deletions
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74
lib/libthr/thread/thr_rtld.c
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@ -40,8 +40,6 @@
extern int errno;
#define CACHE_LINE_SIZE 64
#define WAFLAG 0x1
#define RC_INCR 0x2
static int _thr_rtld_clr_flag(int);
static void *_thr_rtld_lock_create(void);
@ -52,11 +50,7 @@ static int _thr_rtld_set_flag(int);
static void _thr_rtld_wlock_acquire(void *);
struct rtld_lock {
volatile int lock;
volatile int rd_waiters;
volatile int wr_waiters;
volatile long rd_cv;
volatile long wr_cv;
struct urwlock lock;
void *base;
};
@ -67,19 +61,22 @@ _thr_rtld_lock_create(void)
char *p;
uintptr_t r;
struct rtld_lock *l;
size_t size;
THR_ASSERT(sizeof(struct rtld_lock) <= CACHE_LINE_SIZE,
"rtld_lock too large");
base = calloc(1, CACHE_LINE_SIZE);
size = CACHE_LINE_SIZE;
while (size < sizeof(struct rtld_lock))
size <<= 1;
base = calloc(1, size);
p = (char *)base;
if ((uintptr_t)p % CACHE_LINE_SIZE != 0) {
free(base);
base = calloc(1, 2 * CACHE_LINE_SIZE);
base = calloc(1, size + CACHE_LINE_SIZE);
p = (char *)base;
if ((r = (uintptr_t)p % CACHE_LINE_SIZE) != 0)
p += CACHE_LINE_SIZE - r;
}
l = (struct rtld_lock *)p;
l->lock.rw_flags = URWLOCK_PREFER_READER;
l->base = base;
return (l);
}
@ -110,7 +107,6 @@ _thr_rtld_rlock_acquire(void *lock)
{
struct pthread *curthread;
struct rtld_lock *l;
long v;
int errsave;
curthread = _get_curthread();
@ -118,18 +114,8 @@ _thr_rtld_rlock_acquire(void *lock)
l = (struct rtld_lock *)lock;
THR_CRITICAL_ENTER(curthread);
atomic_add_acq_int(&l->lock, RC_INCR);
if (!(l->lock & WAFLAG)) {
RESTORE_ERRNO();
return;
}
v = l->rd_cv;
atomic_add_int(&l->rd_waiters, 1);
while (l->lock & WAFLAG) {
_thr_umtx_wait(&l->rd_cv, v, NULL);
v = l->rd_cv;
}
atomic_add_int(&l->rd_waiters, -1);
while (_thr_rwlock_rdlock(&l->lock, 0, NULL) != 0)
;
RESTORE_ERRNO();
}
@ -138,7 +124,6 @@ _thr_rtld_wlock_acquire(void *lock)
{
struct pthread *curthread;
struct rtld_lock *l;
long v;
int errsave;
curthread = _get_curthread();
@ -146,19 +131,9 @@ _thr_rtld_wlock_acquire(void *lock)
l = (struct rtld_lock *)lock;
_thr_signal_block(curthread);
for (;;) {
if (atomic_cmpset_acq_int(&l->lock, 0, WAFLAG)) {
RESTORE_ERRNO();
return;
}
v = l->wr_cv;
atomic_add_int(&l->wr_waiters, 1);
while (l->lock != 0) {
_thr_umtx_wait(&l->wr_cv, v, NULL);
v = l->wr_cv;
}
atomic_add_int(&l->wr_waiters, -1);
}
while (_thr_rwlock_wrlock(&l->lock, NULL) != 0)
;
RESTORE_ERRNO();
}
static void
@ -166,29 +141,20 @@ _thr_rtld_lock_release(void *lock)
{
struct pthread *curthread;
struct rtld_lock *l;
int32_t state;
int errsave;
curthread = _get_curthread();
SAVE_ERRNO();
l = (struct rtld_lock *)lock;
if ((l->lock & WAFLAG) == 0) {
atomic_add_rel_int(&l->lock, -RC_INCR);
if (l->lock == 0 && l->wr_waiters) {
atomic_add_long(&l->wr_cv, 1);
_thr_umtx_wake(&l->wr_cv, l->wr_waiters);
state = l->lock.rw_state;
if (_thr_rwlock_unlock(&l->lock) == 0) {
if ((state & URWLOCK_WRITE_OWNER) == 0) {
THR_CRITICAL_LEAVE(curthread);
} else {
_thr_signal_unblock(curthread);
}
THR_CRITICAL_LEAVE(curthread);
} else {
atomic_add_rel_int(&l->lock, -WAFLAG);
if (l->lock == 0 && l->wr_waiters) {
atomic_add_long(&l->wr_cv, 1);
_thr_umtx_wake(&l->wr_cv, l->wr_waiters);
} else if (l->rd_waiters) {
atomic_add_long(&l->rd_cv, 1);
_thr_umtx_wake(&l->rd_cv, l->rd_waiters);
}
_thr_signal_unblock(curthread);
}
RESTORE_ERRNO();
}