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nptl: Add clockid parameter to futex timed wait calls

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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): Remove
	code to calculate relative timeout for
	__PTHREAD_COND_CLOCK_MONOTONIC_MASK and just pass CLOCK_MONOTONIC
	or CLOCK_REALTIME as required to futex_abstimed_wait_cancelable.
	* 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

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This commit is contained in:
Mike Crowe 2019-06-21 14:53:40 +00:00 committed by Adhemerval Zanella
parent a008c76b56
commit 99d01ffcc3
9 changed files with 110 additions and 51 deletions
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33
ChangeLog
View File

@ -1,3 +1,36 @@
2019-07-12 Mike Crowe <mac@mcrowe.com>
nptl: Add clockid parameter to futex timed wait calls
* 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): Remove
code to calculate relative timeout for
__PTHREAD_COND_CLOCK_MONOTONIC_MASK and just pass CLOCK_MONOTONIC
or CLOCK_REALTIME as required to futex_abstimed_wait_cancelable.
* 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
2019-07-10 Adhemerval Zanella <adhemerval.zanella@linaro.org>
[BZ #24699]

32
nptl/pthread_cond_wait.c
View File

@ -509,35 +509,15 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex,
values despite them being valid. */
if (__glibc_unlikely (abstime->tv_sec < 0))
err = ETIMEDOUT;
else if ((flags & __PTHREAD_COND_CLOCK_MONOTONIC_MASK) != 0)
{
/* CLOCK_MONOTONIC is requested. */
struct timespec rt;
if (__clock_gettime (CLOCK_MONOTONIC, &rt) != 0)
__libc_fatal ("clock_gettime does not support "
"CLOCK_MONOTONIC\n");
/* Convert the absolute timeout value to a relative
timeout. */
rt.tv_sec = abstime->tv_sec - rt.tv_sec;
rt.tv_nsec = abstime->tv_nsec - rt.tv_nsec;
if (rt.tv_nsec < 0)
{
rt.tv_nsec += 1000000000;
--rt.tv_sec;
}
/* Did we already time out? */
if (__glibc_unlikely (rt.tv_sec < 0))
err = ETIMEDOUT;
else
err = futex_reltimed_wait_cancelable
(cond->__data.__g_signals + g, 0, &rt, private);
}
else
{
/* Use CLOCK_REALTIME. */
const clockid_t clockid =
((flags & __PTHREAD_COND_CLOCK_MONOTONIC_MASK) != 0) ?
CLOCK_MONOTONIC : CLOCK_REALTIME;
err = futex_abstimed_wait_cancelable
(cond->__data.__g_signals + g, 0, abstime, private);
(cond->__data.__g_signals + g, 0, clockid, abstime,
private);
}
}

4
nptl/pthread_mutex_timedlock.c
View File

@ -266,8 +266,8 @@ __pthread_mutex_timedlock (pthread_mutex_t *mutex,
assume_other_futex_waiters |= FUTEX_WAITERS;
/* Block using the futex. */
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)

8
nptl/pthread_rwlock_common.c
View File

@ -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)

6
nptl/sem_waitcommon.c
View File

@ -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;

9
sysdeps/nptl/futex-internal.h
View File

@ -49,7 +49,7 @@
futex word.
Both absolute and relative timeouts can be used. An absolute timeout
expires when the given specific point in time on the CLOCK_REALTIME clock
expires when the given specific point in time on the specified clock
passes, or when it already has passed. A relative timeout expires when
the given duration of time on the CLOCK_MONOTONIC clock passes. Relative
timeouts may be imprecise (see futex_supports_exact_relative_timeouts).
@ -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

13
sysdeps/nptl/lowlevellock-futex.h
View File

@ -43,10 +43,15 @@
#define lll_futex_timed_wait(futexp, val, timeout, private) \
-ENOSYS
/* 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. */

24
sysdeps/unix/sysv/linux/futex-internal.h
View File

@ -160,17 +160,26 @@ 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:
@ -180,8 +189,9 @@ 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
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. */
@ -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)
{

32
sysdeps/unix/sysv/linux/lowlevellock-futex.h
View File

@ -82,12 +82,32 @@
__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; \
const int op = \
__lll_private_flag (FUTEX_WAIT_BITSET | clockbit, private); \
\
__ret = lll_futex_syscall (6, futexp, op, val, \
timeout, NULL /* Unused. */, \
FUTEX_BITSET_MATCH_ANY); \
} \
else \
__ret = -EINVAL; \
__ret; \
})
#define lll_futex_wake(futexp, nr, private) \
lll_futex_syscall (4, futexp, \