From cbed6a607d6b42b0cb264d2bee1bd784c8504d60 Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Fri, 9 Nov 2007 09:09:07 +0000 Subject: [BZ #5240] * sysdeps/unix/sysv/linux/lowlevellock.c (__lll_timedlock_wait): If we time out, try one last time to lock the futex to avoid losing a wakeup signal. * sysdeps/unix/sysv/linux/i386/i486/lowlevellock.S: Likewise. * sysdeps/unix/sysv/linux/x86_64/lowlevellock.S: Likewise. --- .../unix/sysv/linux/i386/i486/lowlevellock.S | 6 +++++- nptl/sysdeps/unix/sysv/linux/lowlevellock.c | 23 ++++++++++++---------- nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S | 6 ++++-- 3 files changed, 22 insertions(+), 13 deletions(-) (limited to 'nptl/sysdeps/unix/sysv/linux') diff --git a/nptl/sysdeps/unix/sysv/linux/i386/i486/lowlevellock.S b/nptl/sysdeps/unix/sysv/linux/i386/i486/lowlevellock.S index 745ab91239..6d3943b0eb 100644 --- a/nptl/sysdeps/unix/sysv/linux/i386/i486/lowlevellock.S +++ b/nptl/sysdeps/unix/sysv/linux/i386/i486/lowlevellock.S @@ -203,7 +203,7 @@ __lll_timedlock_wait: addl $1000000000, %edx subl $1, %ecx 4: testl %ecx, %ecx - js 5f /* Time is already up. */ + js 9f /* Time is already up. */ /* Store relative timeout. */ movl %ecx, (%esp) @@ -271,6 +271,10 @@ __lll_timedlock_wait: 5: movl $ETIMEDOUT, %eax jmp 6b + +9: movl $-ETIMEDOUT, %ecx + movl $2, %edx + jmp 8b cfi_endproc .size __lll_timedlock_wait,.-__lll_timedlock_wait #endif diff --git a/nptl/sysdeps/unix/sysv/linux/lowlevellock.c b/nptl/sysdeps/unix/sysv/linux/lowlevellock.c index f0e42957c2..c2cdf3a1e4 100644 --- a/nptl/sysdeps/unix/sysv/linux/lowlevellock.c +++ b/nptl/sysdeps/unix/sysv/linux/lowlevellock.c @@ -59,10 +59,10 @@ __lll_timedlock_wait (int *futex, const struct timespec *abstime, int private) if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) return EINVAL; + struct timespec rt; do { struct timeval tv; - struct timespec rt; /* Get the current time. */ (void) __gettimeofday (&tv, NULL); @@ -76,18 +76,21 @@ __lll_timedlock_wait (int *futex, const struct timespec *abstime, int private) --rt.tv_sec; } - /* Already timed out? */ - if (rt.tv_sec < 0) - return ETIMEDOUT; + /* If timed out do not go to sleep. */ + if (__builtin_expect (rt.tv_sec >= 0, 1)) + { + /* Wait. */ + int oldval = atomic_compare_and_exchange_val_acq (futex, 2, 1); + if (oldval != 0) + lll_futex_timed_wait (futex, 2, &rt, private); + } - /* Wait. */ - int oldval = atomic_compare_and_exchange_val_acq (futex, 2, 1); - if (oldval != 0) - lll_futex_timed_wait (futex, 2, &rt, private); + if (atomic_compare_and_exchange_bool_acq (futex, 2, 0) == 0) + return 0; } - while (atomic_compare_and_exchange_bool_acq (futex, 2, 0) != 0); + while (rt.tv_sec >= 0); - return 0; + return ETIMEDOUT; } diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S b/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S index 7065cfac32..a5ad88c199 100644 --- a/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S +++ b/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S @@ -199,14 +199,16 @@ __lll_timedlock_wait: addq $1000000000, %rsi decq %rdi 4: testq %rdi, %rdi - js 5f /* Time is already up. */ + movq $-ETIMEDOUT, %rcx + movl $2, %edx + js 8f /* Time is already up. */ /* Futex call. */ movq %rdi, (%rsp) /* Store relative timeout. */ movq %rsi, 8(%rsp) movl $1, %eax - movl $2, %edx + /* NB: $edx has been loaded early. */ LOCK cmpxchgl %edx, (%r12) -- cgit 1.4.1