From ec381af90208a5675183202cf05078eac208edfb Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Tue, 2 Aug 2011 21:11:36 -0400 Subject: [PATCH] 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. --- src/internal/futex.h | 3 ++ src/internal/pthread_impl.h | 3 +- src/thread/__timedwait.c | 53 ++++++++++++++++++------- src/thread/__timedwait_cp.c | 23 ----------- src/thread/pthread_cond_timedwait.c | 7 ++-- src/thread/pthread_join.c | 6 ++- src/thread/pthread_mutex_timedlock.c | 2 +- src/thread/pthread_rwlock_timedrdlock.c | 2 +- src/thread/pthread_rwlock_timedwrlock.c | 2 +- src/thread/sem_timedwait.c | 8 +--- 10 files changed, 56 insertions(+), 53 deletions(-) delete mode 100644 src/thread/__timedwait_cp.c diff --git a/src/internal/futex.h b/src/internal/futex.h index c0453822..d7bf2b7d 100644 --- 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 03af4c12..c11840d6 100644 --- 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 b1d3af23..931675eb 100644 --- a/src/thread/__timedwait.c +++ b/src/thread/__timedwait.c @@ -1,23 +1,48 @@ +#include #include #include #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 index c2890985..00000000 --- a/src/thread/__timedwait_cp.c +++ /dev/null @@ -1,23 +0,0 @@ -#include -#include -#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 13728282..ee874a36 100644 --- 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 ba7bb7d5..664abda9 100644 --- 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 ae1e2c31..44bd4bbe 100644 --- 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 1e76a8e1..a6f61b05 100644 --- 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 96827749..484808e8 100644 --- 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 1d4b3e2c..4e12389c 100644 --- 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; -- 2.25.1