[1/7] nptl: Add clockid parameter to futex timed wait calls
Commit Message
In preparation for adding POSIX clockwait variants of timedwait functions,
add a clockid_t parameter to futex_abstimed_wait functions and pass
CLOCK_REALTIME from all callers for the time being.
Replace lll_futex_timed_wait_bitset with lll_futex_clock_wait_bitset which
takes a clockid_t parameter rather than the magic clockbit.
* sysdeps/nptl/lowlevellock-futex.h,
sysdeps/unix/sysv/linux/lowlevellock-futex.h: Replace
lll_futex_timed_wait_bitset with lll_futex_clock_wait_bitset that takes a
clockid rather than a special clockbit.
* sysdeps/nptl/lowlevellock-futex.h: Add lll_futex_supported_clockid so
that client functions can check whether their clockid parameter is valid
even if they don't ultimately end up calling lll_futex_clock_wait_bitset.
* sysdeps/nptl/futex-internal.h, sysdeps/unix/sysv/linux/futex-internal.h
(futex_abstimed_wait, futex_abstimed_wait_cancelable): Add clockid_t
parameter to indicate which clock the absolute time passed should be
measured against. Pass that clockid onto lll_futex_clock_wait_bitset.
Add invalid clock as reason for returning -EINVAL.
* sysdeps/nptl/futex-internal.h, sysdeps/unix/sysv/linux/futex-internal.h:
Introduce futex_abstimed_supported_clockid so that client functions can
check whether their clockid parameter is valid even if they don't
ultimately end up calling futex_abstimed_wait.
* nptl/pthread_cond_wait.c (__pthread_cond_wait_common),
nptl/pthread_rwlock_common (__pthread_rwlock_rdlock_full,
__pthread_wrlock_full), nptl/sem_waitcommon (do_futex_wait): Pass
additional CLOCK_REALTIME to futex_abstimed_wait_cancelable.
* nptl/pthread_mutex_timedlock.c (__pthread_mutex_timedlock): Switch to
lll_futex_clock_wait_bitset and pass CLOCK_REALTIME
---
nptl/pthread_cond_wait.c | 2 +-
nptl/pthread_mutex_timedlock.c | 8 +++---
nptl/pthread_rwlock_common.c | 8 +++---
nptl/sem_waitcommon.c | 6 ++--
sysdeps/nptl/futex-internal.h | 7 +++++-
sysdeps/nptl/lowlevellock-futex.h | 14 ++++++----
sysdeps/unix/sysv/linux/futex-internal.h | 26 +++++++++++++------
sysdeps/unix/sysv/linux/lowlevellock-futex.h | 29 ++++++++++++++++-----
8 files changed, 71 insertions(+), 29 deletions(-)
Comments
On 27/02/2019 15:23, Mike Crowe wrote:
> In preparation for adding POSIX clockwait variants of timedwait functions,
> add a clockid_t parameter to futex_abstimed_wait functions and pass
> CLOCK_REALTIME from all callers for the time being.
>
> Replace lll_futex_timed_wait_bitset with lll_futex_clock_wait_bitset which
> takes a clockid_t parameter rather than the magic clockbit.
>
> * sysdeps/nptl/lowlevellock-futex.h,
> sysdeps/unix/sysv/linux/lowlevellock-futex.h: Replace
> lll_futex_timed_wait_bitset with lll_futex_clock_wait_bitset that takes a
> clockid rather than a special clockbit.
>
> * sysdeps/nptl/lowlevellock-futex.h: Add lll_futex_supported_clockid so
> that client functions can check whether their clockid parameter is valid
> even if they don't ultimately end up calling lll_futex_clock_wait_bitset.
>
> * sysdeps/nptl/futex-internal.h, sysdeps/unix/sysv/linux/futex-internal.h
> (futex_abstimed_wait, futex_abstimed_wait_cancelable): Add clockid_t
> parameter to indicate which clock the absolute time passed should be
> measured against. Pass that clockid onto lll_futex_clock_wait_bitset.
> Add invalid clock as reason for returning -EINVAL.
>
> * sysdeps/nptl/futex-internal.h, sysdeps/unix/sysv/linux/futex-internal.h:
> Introduce futex_abstimed_supported_clockid so that client functions can
> check whether their clockid parameter is valid even if they don't
> ultimately end up calling futex_abstimed_wait.
>
> * nptl/pthread_cond_wait.c (__pthread_cond_wait_common),
> nptl/pthread_rwlock_common (__pthread_rwlock_rdlock_full,
> __pthread_wrlock_full), nptl/sem_waitcommon (do_futex_wait): Pass
> additional CLOCK_REALTIME to futex_abstimed_wait_cancelable.
>
> * nptl/pthread_mutex_timedlock.c (__pthread_mutex_timedlock): Switch to
> lll_futex_clock_wait_bitset and pass CLOCK_REALTIME
> ---
> nptl/pthread_cond_wait.c | 2 +-
> nptl/pthread_mutex_timedlock.c | 8 +++---
> nptl/pthread_rwlock_common.c | 8 +++---
> nptl/sem_waitcommon.c | 6 ++--
> sysdeps/nptl/futex-internal.h | 7 +++++-
> sysdeps/nptl/lowlevellock-futex.h | 14 ++++++----
> sysdeps/unix/sysv/linux/futex-internal.h | 26 +++++++++++++------
> sysdeps/unix/sysv/linux/lowlevellock-futex.h | 29 ++++++++++++++++-----
> 8 files changed, 71 insertions(+), 29 deletions(-)
>
> diff --git a/nptl/pthread_cond_wait.c b/nptl/pthread_cond_wait.c
> index 9a0f29e..daa4e25 100644
> --- a/nptl/pthread_cond_wait.c
> +++ b/nptl/pthread_cond_wait.c
> @@ -537,7 +537,7 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex,
> {
> /* Use CLOCK_REALTIME. */
> err = futex_abstimed_wait_cancelable
> - (cond->__data.__g_signals + g, 0, abstime, private);
> + (cond->__data.__g_signals + g, 0, CLOCK_REALTIME, abstime, private);
> }
> }
>
Since we still assume that an architecture might not support futex
with CLOCK_REALTIME, this part should check for __ASSUME_FUTEX_CLOCK_REALTIME
as other parts.
I proposed recently to just assume __ASSUME_FUTEX_CLOCK_REALTIME
support [1], which simplifies this patch.
[1] https://sourceware.org/ml/libc-alpha/2019-02/msg00667.html
> diff --git a/nptl/pthread_mutex_timedlock.c b/nptl/pthread_mutex_timedlock.c
> index 2f61a7d..c145a65 100644
> --- a/nptl/pthread_mutex_timedlock.c
> +++ b/nptl/pthread_mutex_timedlock.c
> @@ -241,7 +241,7 @@ __pthread_mutex_timedlock (pthread_mutex_t *mutex,
> if (__glibc_unlikely (abstime->tv_sec < 0))
> return ETIMEDOUT;
> #if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
> - || !defined lll_futex_timed_wait_bitset)
> + || !defined lll_futex_clock_wait_bitset)
> struct timeval tv;
> struct timespec rt;
>
> @@ -288,12 +288,12 @@ __pthread_mutex_timedlock (pthread_mutex_t *mutex,
>
> /* Block using the futex. */
> #if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
> - || !defined lll_futex_timed_wait_bitset)
> + || !defined lll_futex_clock_wait_bitset)
> lll_futex_timed_wait (&mutex->__data.__lock, oldval,
> &rt, PTHREAD_ROBUST_MUTEX_PSHARED (mutex));
> #else
> - int err = lll_futex_timed_wait_bitset (&mutex->__data.__lock,
> - oldval, abstime, FUTEX_CLOCK_REALTIME,
> + int err = lll_futex_clock_wait_bitset (&mutex->__data.__lock,
> + oldval, CLOCK_REALTIME, abstime,
> PTHREAD_ROBUST_MUTEX_PSHARED (mutex));
> /* The futex call timed out. */
> if (err == -ETIMEDOUT)
> diff --git a/nptl/pthread_rwlock_common.c b/nptl/pthread_rwlock_common.c
> index 2560734..89ba21a 100644
> --- a/nptl/pthread_rwlock_common.c
> +++ b/nptl/pthread_rwlock_common.c
> @@ -319,7 +319,7 @@ __pthread_rwlock_rdlock_full (pthread_rwlock_t *rwlock,
> {
> int private = __pthread_rwlock_get_private (rwlock);
> int err = futex_abstimed_wait (&rwlock->__data.__readers,
> - r, abstime, private);
> + r, CLOCK_REALTIME, abstime, private);
> /* We ignore EAGAIN and EINTR. On time-outs, we can just
> return because we don't need to clean up anything. */
> if (err == ETIMEDOUT)
> @@ -447,7 +447,7 @@ __pthread_rwlock_rdlock_full (pthread_rwlock_t *rwlock,
> continue;
> int err = futex_abstimed_wait (&rwlock->__data.__wrphase_futex,
> 1 | PTHREAD_RWLOCK_FUTEX_USED,
> - abstime, private);
> + CLOCK_REALTIME, abstime, private);
> if (err == ETIMEDOUT)
> {
> /* If we timed out, we need to unregister. If no read phase
> @@ -707,7 +707,7 @@ __pthread_rwlock_wrlock_full (pthread_rwlock_t *rwlock,
> may_share_futex_used_flag = true;
> int err = futex_abstimed_wait (&rwlock->__data.__writers_futex,
> 1 | PTHREAD_RWLOCK_FUTEX_USED,
> - abstime, private);
> + CLOCK_REALTIME, abstime, private);
> if (err == ETIMEDOUT)
> {
> if (prefer_writer)
> @@ -806,7 +806,7 @@ __pthread_rwlock_wrlock_full (pthread_rwlock_t *rwlock,
> continue;
> int err = futex_abstimed_wait (&rwlock->__data.__wrphase_futex,
> PTHREAD_RWLOCK_FUTEX_USED,
> - abstime, private);
> + CLOCK_REALTIME, abstime, private);
> if (err == ETIMEDOUT)
> {
> if (rwlock->__data.__flags != PTHREAD_RWLOCK_PREFER_READER_NP)
> diff --git a/nptl/sem_waitcommon.c b/nptl/sem_waitcommon.c
> index 5646bea..425d040 100644
> --- a/nptl/sem_waitcommon.c
> +++ b/nptl/sem_waitcommon.c
> @@ -109,11 +109,13 @@ do_futex_wait (struct new_sem *sem, const struct timespec *abstime)
>
> #if __HAVE_64B_ATOMICS
> err = futex_abstimed_wait_cancelable (
> - (unsigned int *) &sem->data + SEM_VALUE_OFFSET, 0, abstime,
> + (unsigned int *) &sem->data + SEM_VALUE_OFFSET, 0,
> + CLOCK_REALTIME, abstime,
> sem->private);
> #else
> err = futex_abstimed_wait_cancelable (&sem->value, SEM_NWAITERS_MASK,
> - abstime, sem->private);
> + CLOCK_REALTIME, abstime,
> + sem->private);
> #endif
>
> return err;
> diff --git a/sysdeps/nptl/futex-internal.h b/sysdeps/nptl/futex-internal.h
> index 86a0818..54b7319 100644
> --- a/sysdeps/nptl/futex-internal.h
> +++ b/sysdeps/nptl/futex-internal.h
> @@ -159,16 +159,23 @@ futex_reltimed_wait_cancelable (unsigned int* futex_word,
> unsigned int expected,
> const struct timespec* reltime, int private);
>
> +/* Check whether the specified clockid is supported by
> + futex_abstimed_wait and futex_abstimed_wait_cancelable. */
> +static __always_inline int
> +futex_abstimed_supported_clockid (clockid_t clockid);
> +
> /* Like futex_reltimed_wait, but the provided timeout (ABSTIME) is an
> absolute point in time; a call will time out after this point in time. */
> static __always_inline int
> futex_abstimed_wait (unsigned int* futex_word, unsigned int expected,
> + clockid_t clockid,
> const struct timespec* abstime, int private);
>
> /* Like futex_reltimed_wait but is a POSIX cancellation point. */
> static __always_inline int
> futex_abstimed_wait_cancelable (unsigned int* futex_word,
> unsigned int expected,
> + clockid_t clockid,
> const struct timespec* abstime, int private);
>
> /* Atomically wrt other futex operations on the same futex, this unblocks the
> diff --git a/sysdeps/nptl/lowlevellock-futex.h b/sysdeps/nptl/lowlevellock-futex.h
> index bb8effe..35fcfbb 100644
> --- a/sysdeps/nptl/lowlevellock-futex.h
> +++ b/sysdeps/nptl/lowlevellock-futex.h
> @@ -43,11 +43,15 @@
> #define lll_futex_timed_wait(futexp, val, timeout, private) \
> -ENOSYS
>
> -/* This macro should be defined only if FUTEX_CLOCK_REALTIME is also defined.
> - If CLOCKBIT is zero, this is identical to lll_futex_timed_wait.
> - If CLOCKBIT has FUTEX_CLOCK_REALTIME set, then it's the same but
> - TIMEOUT is counted by CLOCK_REALTIME rather than CLOCK_MONOTONIC. */
> -#define lll_futex_timed_wait_bitset(futexp, val, timeout, clockbit, private) \
> +/* Verify whether the supplied clockid is supported by
> + lll_futex_clock_wait_bitset */
> +#define lll_futex_supported_clockid(clockid) \
> + (0)
> +
> +/* Wait until a lll_futex_wake call on FUTEXP, or the absolute TIMEOUT
> + measured against CLOCKID elapses. CLOCKID may be CLOCK_REALTIME or
> + CLOCK_MONOTONIC. */
> +#define lll_futex_clock_wait_bitset(futexp, val, clockid, timeout, private) \
> -ENOSYS
>
> /* Wake up up to NR waiters on FUTEXP. */
> diff --git a/sysdeps/unix/sysv/linux/futex-internal.h b/sysdeps/unix/sysv/linux/futex-internal.h
> index 55f0fab..68bfe7e 100644
> --- a/sysdeps/unix/sysv/linux/futex-internal.h
> +++ b/sysdeps/unix/sysv/linux/futex-internal.h
> @@ -162,15 +162,24 @@ futex_reltimed_wait_cancelable (unsigned int *futex_word,
>
> /* See sysdeps/nptl/futex-internal.h for details. */
> static __always_inline int
> +futex_abstimed_supported_clockid (clockid_t clockid)
> +{
> + return lll_futex_supported_clockid (clockid);
> +}
> +
> +/* See sysdeps/nptl/futex-internal.h for details. */
> +static __always_inline int
> futex_abstimed_wait (unsigned int *futex_word, unsigned int expected,
> + clockid_t clockid,
> const struct timespec *abstime, int private)
> {
> /* Work around the fact that the kernel rejects negative timeout values
> despite them being valid. */
> if (__glibc_unlikely ((abstime != NULL) && (abstime->tv_sec < 0)))
> return ETIMEDOUT;
> - int err = lll_futex_timed_wait_bitset (futex_word, expected, abstime,
> - FUTEX_CLOCK_REALTIME, private);
> + int err = lll_futex_clock_wait_bitset (futex_word, expected,
> + clockid, abstime,
> + private);
> switch (err)
> {
> case 0:
> @@ -180,9 +189,10 @@ futex_abstimed_wait (unsigned int *futex_word, unsigned int expected,
> return -err;
>
> case -EFAULT: /* Must have been caused by a glibc or application bug. */
> - case -EINVAL: /* Either due to wrong alignment or due to the timeout not
> - being normalized. Must have been caused by a glibc or
> - application bug. */
> + case -EINVAL: /* Either due to wrong alignment, unsupported
> + clockid or due to the timeout not being
> + normalized. Must have been caused by a glibc or
> + application bug. */
> case -ENOSYS: /* Must have been caused by a glibc bug. */
> /* No other errors are documented at this time. */
> default:
> @@ -194,6 +204,7 @@ futex_abstimed_wait (unsigned int *futex_word, unsigned int expected,
> static __always_inline int
> futex_abstimed_wait_cancelable (unsigned int *futex_word,
> unsigned int expected,
> + clockid_t clockid,
> const struct timespec *abstime, int private)
> {
> /* Work around the fact that the kernel rejects negative timeout values
> @@ -202,8 +213,9 @@ futex_abstimed_wait_cancelable (unsigned int *futex_word,
> return ETIMEDOUT;
> int oldtype;
> oldtype = __pthread_enable_asynccancel ();
> - int err = lll_futex_timed_wait_bitset (futex_word, expected, abstime,
> - FUTEX_CLOCK_REALTIME, private);
> + int err = lll_futex_clock_wait_bitset (futex_word, expected,
> + clockid, abstime,
> + private);
> __pthread_disable_asynccancel (oldtype);
> switch (err)
> {
> diff --git a/sysdeps/unix/sysv/linux/lowlevellock-futex.h b/sysdeps/unix/sysv/linux/lowlevellock-futex.h
> index 6f060b1..c3e7152 100644
> --- a/sysdeps/unix/sysv/linux/lowlevellock-futex.h
> +++ b/sysdeps/unix/sysv/linux/lowlevellock-futex.h
> @@ -82,12 +82,29 @@
> __lll_private_flag (FUTEX_WAIT, private), \
> val, timeout)
>
> -#define lll_futex_timed_wait_bitset(futexp, val, timeout, clockbit, private) \
> - lll_futex_syscall (6, futexp, \
> - __lll_private_flag (FUTEX_WAIT_BITSET | (clockbit), \
> - private), \
> - val, timeout, NULL /* Unused. */, \
> - FUTEX_BITSET_MATCH_ANY)
> +/* Verify whether the supplied clockid is supported by
> + lll_futex_clock_wait_bitset */
> +#define lll_futex_supported_clockid(clockid) \
> + (clockid == CLOCK_REALTIME || clockid == CLOCK_MONOTONIC)
I think we need evaluate clockid with parentesis to avoid some macro
evaluation issues.
> +
> +/* The kernel currently only supports CLOCK_MONOTONIC or
> + * CLOCK_REALTIME timeouts for FUTEX_WAIT_BITSET. We could attempt to
> + * convert others here but currently do not.
> + */
> +#define lll_futex_clock_wait_bitset(futexp, val, clockid, timeout, private) \
> + ({ \
> + long int __ret; \
> + if (lll_futex_supported_clockid (clockid)) { \
I think even for macro definitions we need to use GNU style for brackets
(which means break in a subsequent line).
> + const unsigned int clockbit = (clockid == CLOCK_REALTIME) ? FUTEX_CLOCK_REALTIME : 0; \
> + __ret = lll_futex_syscall (6, futexp, \
> + __lll_private_flag (FUTEX_WAIT_BITSET | clockbit, \
> + private), \
> + val, timeout, NULL /* Unused. */, \
> + FUTEX_BITSET_MATCH_ANY); \
> + } else \
> + __ret = -EINVAL; \
> + __ret; \
> + })
>
> #define lll_futex_wake(futexp, nr, private) \
> lll_futex_syscall (4, futexp, \
>
On Tuesday 05 March 2019 at 09:39:58 -0300, Adhemerval Zanella wrote:
> > diff --git a/nptl/pthread_cond_wait.c b/nptl/pthread_cond_wait.c
> > index 9a0f29e..daa4e25 100644
> > --- a/nptl/pthread_cond_wait.c
> > +++ b/nptl/pthread_cond_wait.c
> > @@ -537,7 +537,7 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex,
> > {
> > /* Use CLOCK_REALTIME. */
> > err = futex_abstimed_wait_cancelable
> > - (cond->__data.__g_signals + g, 0, abstime, private);
> > + (cond->__data.__g_signals + g, 0, CLOCK_REALTIME, abstime, private);
> > }
> > }
> >
>
> Since we still assume that an architecture might not support futex
> with CLOCK_REALTIME, this part should check for __ASSUME_FUTEX_CLOCK_REALTIME
> as other parts.
>
> I proposed recently to just assume __ASSUME_FUTEX_CLOCK_REALTIME
> support [1], which simplifies this patch.
Whilst trying to implement pthread_mutex_clockclock offline yesterday, I
decided to propose the same thing. It looks like I don't need to. :)
> [1] https://sourceware.org/ml/libc-alpha/2019-02/msg00667.html
It would certainly make my life easier if that patch was merged.
Thanks.
Mike.
On 10/03/2019 05:59, Mike Crowe wrote:
> On Tuesday 05 March 2019 at 09:39:58 -0300, Adhemerval Zanella wrote:
>>> diff --git a/nptl/pthread_cond_wait.c b/nptl/pthread_cond_wait.c
>>> index 9a0f29e..daa4e25 100644
>>> --- a/nptl/pthread_cond_wait.c
>>> +++ b/nptl/pthread_cond_wait.c
>>> @@ -537,7 +537,7 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex,
>>> {
>>> /* Use CLOCK_REALTIME. */
>>> err = futex_abstimed_wait_cancelable
>>> - (cond->__data.__g_signals + g, 0, abstime, private);
>>> + (cond->__data.__g_signals + g, 0, CLOCK_REALTIME, abstime, private);
>>> }
>>> }
>>>
>>
>> Since we still assume that an architecture might not support futex
>> with CLOCK_REALTIME, this part should check for __ASSUME_FUTEX_CLOCK_REALTIME
>> as other parts.
>>
>> I proposed recently to just assume __ASSUME_FUTEX_CLOCK_REALTIME
>> support [1], which simplifies this patch.
>
> Whilst trying to implement pthread_mutex_clockclock offline yesterday, I
> decided to propose the same thing. It looks like I don't need to. :)
>
>> [1] https://sourceware.org/ml/libc-alpha/2019-02/msg00667.html
>
> It would certainly make my life easier if that patch was merged.
>
> Thanks.
It is already merged.
@@ -537,7 +537,7 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex,
{
/* Use CLOCK_REALTIME. */
err = futex_abstimed_wait_cancelable
- (cond->__data.__g_signals + g, 0, abstime, private);
+ (cond->__data.__g_signals + g, 0, CLOCK_REALTIME, abstime, private);
}
}
@@ -241,7 +241,7 @@ __pthread_mutex_timedlock (pthread_mutex_t *mutex,
if (__glibc_unlikely (abstime->tv_sec < 0))
return ETIMEDOUT;
#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
- || !defined lll_futex_timed_wait_bitset)
+ || !defined lll_futex_clock_wait_bitset)
struct timeval tv;
struct timespec rt;
@@ -288,12 +288,12 @@ __pthread_mutex_timedlock (pthread_mutex_t *mutex,
/* Block using the futex. */
#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
- || !defined lll_futex_timed_wait_bitset)
+ || !defined lll_futex_clock_wait_bitset)
lll_futex_timed_wait (&mutex->__data.__lock, oldval,
&rt, PTHREAD_ROBUST_MUTEX_PSHARED (mutex));
#else
- int err = lll_futex_timed_wait_bitset (&mutex->__data.__lock,
- oldval, abstime, FUTEX_CLOCK_REALTIME,
+ int err = lll_futex_clock_wait_bitset (&mutex->__data.__lock,
+ oldval, CLOCK_REALTIME, abstime,
PTHREAD_ROBUST_MUTEX_PSHARED (mutex));
/* The futex call timed out. */
if (err == -ETIMEDOUT)
@@ -319,7 +319,7 @@ __pthread_rwlock_rdlock_full (pthread_rwlock_t *rwlock,
{
int private = __pthread_rwlock_get_private (rwlock);
int err = futex_abstimed_wait (&rwlock->__data.__readers,
- r, abstime, private);
+ r, CLOCK_REALTIME, abstime, private);
/* We ignore EAGAIN and EINTR. On time-outs, we can just
return because we don't need to clean up anything. */
if (err == ETIMEDOUT)
@@ -447,7 +447,7 @@ __pthread_rwlock_rdlock_full (pthread_rwlock_t *rwlock,
continue;
int err = futex_abstimed_wait (&rwlock->__data.__wrphase_futex,
1 | PTHREAD_RWLOCK_FUTEX_USED,
- abstime, private);
+ CLOCK_REALTIME, abstime, private);
if (err == ETIMEDOUT)
{
/* If we timed out, we need to unregister. If no read phase
@@ -707,7 +707,7 @@ __pthread_rwlock_wrlock_full (pthread_rwlock_t *rwlock,
may_share_futex_used_flag = true;
int err = futex_abstimed_wait (&rwlock->__data.__writers_futex,
1 | PTHREAD_RWLOCK_FUTEX_USED,
- abstime, private);
+ CLOCK_REALTIME, abstime, private);
if (err == ETIMEDOUT)
{
if (prefer_writer)
@@ -806,7 +806,7 @@ __pthread_rwlock_wrlock_full (pthread_rwlock_t *rwlock,
continue;
int err = futex_abstimed_wait (&rwlock->__data.__wrphase_futex,
PTHREAD_RWLOCK_FUTEX_USED,
- abstime, private);
+ CLOCK_REALTIME, abstime, private);
if (err == ETIMEDOUT)
{
if (rwlock->__data.__flags != PTHREAD_RWLOCK_PREFER_READER_NP)
@@ -109,11 +109,13 @@ do_futex_wait (struct new_sem *sem, const struct timespec *abstime)
#if __HAVE_64B_ATOMICS
err = futex_abstimed_wait_cancelable (
- (unsigned int *) &sem->data + SEM_VALUE_OFFSET, 0, abstime,
+ (unsigned int *) &sem->data + SEM_VALUE_OFFSET, 0,
+ CLOCK_REALTIME, abstime,
sem->private);
#else
err = futex_abstimed_wait_cancelable (&sem->value, SEM_NWAITERS_MASK,
- abstime, sem->private);
+ CLOCK_REALTIME, abstime,
+ sem->private);
#endif
return err;
@@ -159,16 +159,23 @@ futex_reltimed_wait_cancelable (unsigned int* futex_word,
unsigned int expected,
const struct timespec* reltime, int private);
+/* Check whether the specified clockid is supported by
+ futex_abstimed_wait and futex_abstimed_wait_cancelable. */
+static __always_inline int
+futex_abstimed_supported_clockid (clockid_t clockid);
+
/* Like futex_reltimed_wait, but the provided timeout (ABSTIME) is an
absolute point in time; a call will time out after this point in time. */
static __always_inline int
futex_abstimed_wait (unsigned int* futex_word, unsigned int expected,
+ clockid_t clockid,
const struct timespec* abstime, int private);
/* Like futex_reltimed_wait but is a POSIX cancellation point. */
static __always_inline int
futex_abstimed_wait_cancelable (unsigned int* futex_word,
unsigned int expected,
+ clockid_t clockid,
const struct timespec* abstime, int private);
/* Atomically wrt other futex operations on the same futex, this unblocks the
@@ -43,11 +43,15 @@
#define lll_futex_timed_wait(futexp, val, timeout, private) \
-ENOSYS
-/* This macro should be defined only if FUTEX_CLOCK_REALTIME is also defined.
- If CLOCKBIT is zero, this is identical to lll_futex_timed_wait.
- If CLOCKBIT has FUTEX_CLOCK_REALTIME set, then it's the same but
- TIMEOUT is counted by CLOCK_REALTIME rather than CLOCK_MONOTONIC. */
-#define lll_futex_timed_wait_bitset(futexp, val, timeout, clockbit, private) \
+/* Verify whether the supplied clockid is supported by
+ lll_futex_clock_wait_bitset */
+#define lll_futex_supported_clockid(clockid) \
+ (0)
+
+/* Wait until a lll_futex_wake call on FUTEXP, or the absolute TIMEOUT
+ measured against CLOCKID elapses. CLOCKID may be CLOCK_REALTIME or
+ CLOCK_MONOTONIC. */
+#define lll_futex_clock_wait_bitset(futexp, val, clockid, timeout, private) \
-ENOSYS
/* Wake up up to NR waiters on FUTEXP. */
@@ -162,15 +162,24 @@ futex_reltimed_wait_cancelable (unsigned int *futex_word,
/* See sysdeps/nptl/futex-internal.h for details. */
static __always_inline int
+futex_abstimed_supported_clockid (clockid_t clockid)
+{
+ return lll_futex_supported_clockid (clockid);
+}
+
+/* See sysdeps/nptl/futex-internal.h for details. */
+static __always_inline int
futex_abstimed_wait (unsigned int *futex_word, unsigned int expected,
+ clockid_t clockid,
const struct timespec *abstime, int private)
{
/* Work around the fact that the kernel rejects negative timeout values
despite them being valid. */
if (__glibc_unlikely ((abstime != NULL) && (abstime->tv_sec < 0)))
return ETIMEDOUT;
- int err = lll_futex_timed_wait_bitset (futex_word, expected, abstime,
- FUTEX_CLOCK_REALTIME, private);
+ int err = lll_futex_clock_wait_bitset (futex_word, expected,
+ clockid, abstime,
+ private);
switch (err)
{
case 0:
@@ -180,9 +189,10 @@ futex_abstimed_wait (unsigned int *futex_word, unsigned int expected,
return -err;
case -EFAULT: /* Must have been caused by a glibc or application bug. */
- case -EINVAL: /* Either due to wrong alignment or due to the timeout not
- being normalized. Must have been caused by a glibc or
- application bug. */
+ case -EINVAL: /* Either due to wrong alignment, unsupported
+ clockid or due to the timeout not being
+ normalized. Must have been caused by a glibc or
+ application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
@@ -194,6 +204,7 @@ futex_abstimed_wait (unsigned int *futex_word, unsigned int expected,
static __always_inline int
futex_abstimed_wait_cancelable (unsigned int *futex_word,
unsigned int expected,
+ clockid_t clockid,
const struct timespec *abstime, int private)
{
/* Work around the fact that the kernel rejects negative timeout values
@@ -202,8 +213,9 @@ futex_abstimed_wait_cancelable (unsigned int *futex_word,
return ETIMEDOUT;
int oldtype;
oldtype = __pthread_enable_asynccancel ();
- int err = lll_futex_timed_wait_bitset (futex_word, expected, abstime,
- FUTEX_CLOCK_REALTIME, private);
+ int err = lll_futex_clock_wait_bitset (futex_word, expected,
+ clockid, abstime,
+ private);
__pthread_disable_asynccancel (oldtype);
switch (err)
{
@@ -82,12 +82,29 @@
__lll_private_flag (FUTEX_WAIT, private), \
val, timeout)
-#define lll_futex_timed_wait_bitset(futexp, val, timeout, clockbit, private) \
- lll_futex_syscall (6, futexp, \
- __lll_private_flag (FUTEX_WAIT_BITSET | (clockbit), \
- private), \
- val, timeout, NULL /* Unused. */, \
- FUTEX_BITSET_MATCH_ANY)
+/* Verify whether the supplied clockid is supported by
+ lll_futex_clock_wait_bitset */
+#define lll_futex_supported_clockid(clockid) \
+ (clockid == CLOCK_REALTIME || clockid == CLOCK_MONOTONIC)
+
+/* The kernel currently only supports CLOCK_MONOTONIC or
+ * CLOCK_REALTIME timeouts for FUTEX_WAIT_BITSET. We could attempt to
+ * convert others here but currently do not.
+ */
+#define lll_futex_clock_wait_bitset(futexp, val, clockid, timeout, private) \
+ ({ \
+ long int __ret; \
+ if (lll_futex_supported_clockid (clockid)) { \
+ const unsigned int clockbit = (clockid == CLOCK_REALTIME) ? FUTEX_CLOCK_REALTIME : 0; \
+ __ret = lll_futex_syscall (6, futexp, \
+ __lll_private_flag (FUTEX_WAIT_BITSET | clockbit, \
+ private), \
+ val, timeout, NULL /* Unused. */, \
+ FUTEX_BITSET_MATCH_ANY); \
+ } else \
+ __ret = -EINVAL; \
+ __ret; \
+ })
#define lll_futex_wake(futexp, nr, private) \
lll_futex_syscall (4, futexp, \