unify and overhaul timed futex waits

new features:

- FUTEX_WAIT_BITSET op will be used for timed waits if available. this
  saves a call to clock_gettime.

- error checking for the timespec struct is now inside __timedwait so
  it doesn't need to be duplicated everywhere. cond_timedwait still
  needs to duplicate it to avoid unlocking the mutex, though.

- pushing and popping the cancellation handler is delegated to
  __timedwait, and cancellable/non-cancellable waits are unified.

diff --git a/src/internal/futex.h b/src/internal/futex.h
index c045382..d7bf2b7 100644 (file)
--- a/src/internal/futex.h
+++ b/src/internal/futex.h
@@ -10,6 +10,9 @@
 #define FUTEX_LOCK_PI          6
 #define FUTEX_UNLOCK_PI                7
 #define FUTEX_TRYLOCK_PI       8
+#define FUTEX_WAIT_BITSET      9
+
+#define FUTEX_CLOCK_REALTIME 256
 
 int __futex(volatile int *, int, int, void *);
 

diff --git a/src/internal/pthread_impl.h b/src/internal/pthread_impl.h
index 03af4c1..c11840d 100644 (file)
--- a/src/internal/pthread_impl.h
+++ b/src/internal/pthread_impl.h
@@ -95,8 +95,7 @@ int __libc_sigprocmask(int, const sigset_t *, sigset_t *);
 void __lock(volatile int *);
 void __unmapself(void *, size_t);
 
-int __timedwait(volatile int *, int, clockid_t, const struct timespec *, int);
-int __timedwait_cp(volatile int *, int, clockid_t, const struct timespec *, int);
+int __timedwait(volatile int *, int, clockid_t, const struct timespec *, void (*)(void *), void *, int);
 void __wait(volatile int *, volatile int *, int, int);
 void __wake(volatile int *, int, int);
 

diff --git a/src/thread/__timedwait.c b/src/thread/__timedwait.c
index b1d3af2..931675e 100644 (file)
--- a/src/thread/__timedwait.c
+++ b/src/thread/__timedwait.c
@@ -1,23 +1,48 @@
+#include <pthread.h>
 #include <time.h>
 #include <errno.h>
 #include "futex.h"
 #include "syscall.h"
 
-int __timedwait(volatile int *addr, int val, clockid_t clk, const struct timespec *at, int priv)
+static int do_wait(volatile int *addr, int val, clockid_t clk, const struct timespec *at, int cp, int priv)
 {
-       int r;
-       struct timespec to;
-       if (at) {
-               clock_gettime(clk, &to);
-               to.tv_sec = at->tv_sec - to.tv_sec;
-               if ((to.tv_nsec = at->tv_nsec - to.tv_nsec) < 0) {
-                       to.tv_sec--;
-                       to.tv_nsec += 1000000000;
-               }
-               if (to.tv_sec < 0) return ETIMEDOUT;
+       int r, flag = 0;
+       struct timespec to, *top=0;
+
+       if (!at) goto notimeout;
+       if (at->tv_nsec >= 1000000000UL)
+               return EINVAL;
+       if (clk == CLOCK_REALTIME || clk == CLOCK_MONOTONIC) {
+               if (clk == CLOCK_REALTIME) flag = FUTEX_CLOCK_REALTIME;
+               if (cp) r = -__syscall_cp(SYS_futex, addr, FUTEX_WAIT_BITSET|flag, val, at, 0, -1);
+               else r = -__syscall(SYS_futex, addr, FUTEX_WAIT_BITSET|flag, val, at, 0, -1);
+               if (r != ENOSYS) goto done;
        }
-       if (priv) priv = 128; priv=0;
-       r = -__syscall(SYS_futex, (long)addr, FUTEX_WAIT | priv, val, at ? (long)&to : 0);
-       if (r == ETIMEDOUT || r == EINTR) return r;
+       if (clock_gettime(clk, &to)) return EINVAL;
+       to.tv_sec = at->tv_sec - to.tv_sec;
+       if ((to.tv_nsec = at->tv_nsec - to.tv_nsec) < 0) {
+               to.tv_sec--;
+               to.tv_nsec += 1000000000;
+       }
+       if (to.tv_sec < 0) return ETIMEDOUT;
+       top = &to;
+notimeout:
+       if (cp) r = -__syscall_cp(SYS_futex, addr, FUTEX_WAIT, val, top);
+       else r = -__syscall(SYS_futex, addr, FUTEX_WAIT, val, top);
+done:
+       if (r == EINTR || r == EINVAL || r == ETIMEDOUT) return r;
        return 0;
 }
+
+int __timedwait(volatile int *addr, int val, clockid_t clk, const struct timespec *at, void (*cleanup)(void *), void *arg, int priv)
+{
+       int r;
+       if (cleanup) {
+               pthread_cleanup_push(cleanup, arg);
+               r = do_wait(addr, val, clk, at, 1, priv);
+               pthread_cleanup_pop(0);
+       } else {
+               r = do_wait(addr, val, clk, at, 0, priv);
+       }
+       return r;
+}

diff --git a/src/thread/__timedwait_cp.c b/src/thread/__timedwait_cp.c
deleted file mode 100644 (file)
index c289098..0000000
--- a/src/thread/__timedwait_cp.c
+++ /dev/null
@@ -1,23 +0,0 @@
-#include <time.h>
-#include <errno.h>
-#include "futex.h"
-#include "syscall.h"
-
-int __timedwait_cp(volatile int *addr, int val, clockid_t clk, const struct timespec *at, int priv)
-{
-       int r;
-       struct timespec to;
-       if (at) {
-               clock_gettime(clk, &to);
-               to.tv_sec = at->tv_sec - to.tv_sec;
-               if ((to.tv_nsec = at->tv_nsec - to.tv_nsec) < 0) {
-                       to.tv_sec--;
-                       to.tv_nsec += 1000000000;
-               }
-               if (to.tv_sec < 0) return ETIMEDOUT;
-       }
-       if (priv) priv = 128; priv=0;
-       r = -__syscall_cp(SYS_futex, (long)addr, FUTEX_WAIT | priv, val, at ? (long)&to : 0);
-       if (r == ETIMEDOUT || r == EINTR) return r;
-       return 0;
-}

diff --git a/src/thread/pthread_cond_timedwait.c b/src/thread/pthread_cond_timedwait.c
index 1372828..ee874a3 100644 (file)
--- a/src/thread/pthread_cond_timedwait.c
+++ b/src/thread/pthread_cond_timedwait.c
@@ -9,16 +9,17 @@ int pthread_cond_timedwait(pthread_cond_t *c, pthread_mutex_t *m, const struct t
 {
        int r, e=0;
 
+       if (ts && ts->tv_nsec >= 1000000000UL)
+               return EINVAL;
+
        pthread_testcancel();
 
-       pthread_cleanup_push(relock, m);
        c->_c_block = 1;
        if ((r=pthread_mutex_unlock(m))) return r;
 
-       do e = __timedwait_cp(&c->_c_block, 1, c->_c_clock, ts, 0);
+       do e = __timedwait(&c->_c_block, 1, c->_c_clock, ts, relock, m, 0);
        while (e == EINTR);
 
-       pthread_cleanup_pop(0);
        if ((r=pthread_mutex_lock(m))) return r;
 
        pthread_testcancel();

diff --git a/src/thread/pthread_join.c b/src/thread/pthread_join.c
index ba7bb7d..664abda 100644 (file)
--- a/src/thread/pthread_join.c
+++ b/src/thread/pthread_join.c
@@ -1,9 +1,13 @@
 #include "pthread_impl.h"
 
+static void dummy(void *p)
+{
+}
+
 int pthread_join(pthread_t t, void **res)
 {
        int tmp = t->tid;
-       if (tmp) __timedwait_cp(&t->tid, tmp, 0, 0, 1);
+       if (tmp) __timedwait(&t->tid, tmp, 0, 0, dummy, 0, 1);
        if (res) *res = t->result;
        if (t->map_base) munmap(t->map_base, t->map_size);
        return 0;

diff --git a/src/thread/pthread_mutex_timedlock.c b/src/thread/pthread_mutex_timedlock.c
index ae1e2c3..44bd4bb 100644 (file)
--- a/src/thread/pthread_mutex_timedlock.c
+++ b/src/thread/pthread_mutex_timedlock.c
@@ -16,7 +16,7 @@ int pthread_mutex_timedlock(pthread_mutex_t *m, const struct timespec *at)
                a_inc(&m->_m_waiters);
                t = r | 0x80000000;
                a_cas(&m->_m_lock, r, t);
-               r = __timedwait(&m->_m_lock, t, CLOCK_REALTIME, at, 0);
+               r = __timedwait(&m->_m_lock, t, CLOCK_REALTIME, at, 0, 0, 0);
                a_dec(&m->_m_waiters);
                if (r && r != EINTR) break;
        }

diff --git a/src/thread/pthread_rwlock_timedrdlock.c b/src/thread/pthread_rwlock_timedrdlock.c
index 1e76a8e..a6f61b0 100644 (file)
--- a/src/thread/pthread_rwlock_timedrdlock.c
+++ b/src/thread/pthread_rwlock_timedrdlock.c
@@ -5,7 +5,7 @@ int pthread_rwlock_timedrdlock(pthread_rwlock_t *rw, const struct timespec *at)
        int w=0;
        while (pthread_rwlock_tryrdlock(rw)) {
                if (!w) a_inc(&rw->_rw_waiters), w++;
-               if (__timedwait(&rw->_rw_wrlock, 1, CLOCK_REALTIME, at, 0)==ETIMEDOUT) {
+               if (__timedwait(&rw->_rw_wrlock, 1, CLOCK_REALTIME, at, 0, 0, 0)==ETIMEDOUT) {
                        if (w) a_dec(&rw->_rw_waiters);
                        return ETIMEDOUT;
                }

diff --git a/src/thread/pthread_rwlock_timedwrlock.c b/src/thread/pthread_rwlock_timedwrlock.c
index 9682774..484808e 100644 (file)
--- a/src/thread/pthread_rwlock_timedwrlock.c
+++ b/src/thread/pthread_rwlock_timedwrlock.c
@@ -7,7 +7,7 @@ int pthread_rwlock_timedwrlock(pthread_rwlock_t *rw, const struct timespec *at)
                if (!w) a_inc(&rw->_rw_waiters), w++;
                if ((nr=rw->_rw_readers)) p = &rw->_rw_readers;
                else nr=1, p = &rw->_rw_wrlock;
-               if (__timedwait(p, nr, CLOCK_REALTIME, at, 0)==ETIMEDOUT) {
+               if (__timedwait(p, nr, CLOCK_REALTIME, at, 0, 0, 0)==ETIMEDOUT) {
                        if (w) a_dec(&rw->_rw_waiters);
                        return ETIMEDOUT;
                }

diff --git a/src/thread/sem_timedwait.c b/src/thread/sem_timedwait.c
index 1d4b3e2..4e12389 100644 (file)
--- a/src/thread/sem_timedwait.c
+++ b/src/thread/sem_timedwait.c
@@ -10,15 +10,9 @@ int sem_timedwait(sem_t *sem, const struct timespec *at)
 {
        while (sem_trywait(sem)) {
                int r;
-               if (at && at->tv_nsec >= 1000000000UL) {
-                       errno = EINVAL;
-                       return -1;
-               }
                a_inc(sem->__val+1);
                a_cas(sem->__val, 0, -1);
-               pthread_cleanup_push(cleanup, sem->__val+1);
-               r = __timedwait_cp(sem->__val, -1, CLOCK_REALTIME, at, 0);
-               pthread_cleanup_pop(1);
+               r = __timedwait(sem->__val, -1, CLOCK_REALTIME, at, cleanup, sem->__val+1, 0);
                if (r) {
                        errno = r;
                        return -1;