diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/i386/lowlevellock.h')
| -rw-r--r-- | sysdeps/unix/sysv/linux/i386/lowlevellock.h | 42 |
1 files changed, 20 insertions, 22 deletions
diff --git a/sysdeps/unix/sysv/linux/i386/lowlevellock.h b/sysdeps/unix/sysv/linux/i386/lowlevellock.h index 6fef23d16d..63d58aef00 100644 --- a/sysdeps/unix/sysv/linux/i386/lowlevellock.h +++ b/sysdeps/unix/sysv/linux/i386/lowlevellock.h @@ -221,32 +221,30 @@ extern int __lll_timedlock_elision (int *futex, short *adapt_count, #define lll_islocked(futex) \ (futex != LLL_LOCK_INITIALIZER) +extern int __lll_timedwait_tid (int *tid, const struct timespec *abstime) + __attribute__ ((regparm (2))) attribute_hidden; + /* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex wake-up when the clone terminates. The memory location contains the thread ID while the clone is running and is reset to zero by the kernel afterwards. The kernel up to version 3.16.3 does not use the private futex - operations for futex wake-up when the clone terminates. */ -#define lll_wait_tid(tid) \ - do { \ - __typeof (tid) __tid; \ - while ((__tid = (tid)) != 0) \ - lll_futex_wait (&(tid), __tid, LLL_SHARED);\ - } while (0) - -extern int __lll_timedwait_tid (int *tid, const struct timespec *abstime) - __attribute__ ((regparm (2))) attribute_hidden; - -/* As lll_wait_tid, but with a timeout. If the timeout occurs then return - ETIMEDOUT. If ABSTIME is invalid, return EINVAL. - XXX Note that this differs from the generic version in that we do the - error checking here and not in __lll_timedwait_tid. */ -#define lll_timedwait_tid(tid, abstime) \ - ({ \ - int __result = 0; \ - if ((tid) != 0) \ - __result = __lll_timedwait_tid (&(tid), (abstime)); \ - __result; }) - + operations for futex wake-up when the clone terminates. + If ABSTIME is not NULL, is used a timeout for futex call. If the timeout + occurs then return ETIMEOUT, if ABSTIME is invalid, return EINVAL. + The futex operation are issues with cancellable versions. */ +#define lll_wait_tid(tid, abstime) \ + ({ \ + int __res = 0; \ + __typeof (tid) __tid; \ + if (abstime != NULL) \ + __res = __lll_timedwait_tid (&(tid), (abstime)); \ + else \ + /* We need acquire MO here so that we synchronize with the \ + kernel's store to 0 when the clone terminates. (see above) */ \ + while ((__tid = atomic_load_acquire (&(tid))) != 0) \ + lll_futex_wait_cancel (&(tid), __tid, LLL_SHARED); \ + __res; \ + }) extern int __lll_lock_elision (int *futex, short *adapt_count, int private) attribute_hidden; |