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[PATCH v4 12/12] nptl: Remove futex_supports_exact_relative_timeouts
The only implementation of futex_supports_exact_relative_timeouts always
returns true. Let's remove it and all its callers.
* nptl/pthread_cond_wait.c: (__pthread_cond_clockwait): Remove code that is
only useful if futex_supports_exact_relative_timeouts () returns false.
* nptl/pthread_condattr_setclock.c: (pthread_condattr_setclock): Likewise.
* sysdeps/nptl/futex-internal.h: Remove comment about relative timeouts
potentially being imprecise since it's no longer true. Remove declaration
of futex_supports_exact_relative_timeouts.
* sysdeps/unix/sysv/linux/futex-internal.h: Remove implementation of
futex_supports_exact_relative_timeouts.
---
ChangeLog | 13 +++++++++++++
nptl/pthread_cond_wait.c | 5 -----
nptl/pthread_condattr_setclock.c | 5 -----
sysdeps/nptl/futex-internal.h | 9 +--------
sysdeps/unix/sysv/linux/futex-internal.h | 8 --------
5 files changed, 14 insertions(+), 26 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 984275c..cf07e4d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2019-06-18 Mike Crowe <mac@mcrowe.com>
+
+ * nptl/pthread_cond_wait.c: (__pthread_cond_clockwait): Remove code
+ that is only useful if futex_supports_exact_relative_timeouts ()
+ returns false.
+ * nptl/pthread_condattr_setclock.c: (pthread_condattr_setclock):
+ Likewise.
+ * sysdeps/nptl/futex-internal.h: Remove comment about relative
+ timeouts potentially being imprecise since it's no longer true.
+ Remove declaration of futex_supports_exact_relative_timeouts.
+ * sysdeps/unix/sysv/linux/futex-internal.h: Remove implementation
+ of futex_supports_exact_relative_timeouts.
+
2019-05-27 Mike Crowe <mac@mcrowe.com>
* NEWS: Mention recently-added pthread_cond_clockwait,
diff --git a/nptl/pthread_cond_wait.c b/nptl/pthread_cond_wait.c
index 558f930..cd98f50 100644
--- a/nptl/pthread_cond_wait.c
+++ b/nptl/pthread_cond_wait.c
@@ -670,11 +670,6 @@ __pthread_cond_clockwait (pthread_cond_t *cond, pthread_mutex_t *mutex,
if (!futex_abstimed_supported_clockid (clockid))
return EINVAL;
- /* If we do not support waiting using CLOCK_MONOTONIC, return an error. */
- if (clockid == CLOCK_MONOTONIC
- && !futex_supports_exact_relative_timeouts ())
- return EINVAL;
-
return __pthread_cond_wait_common (cond, mutex, clockid, abstime);
}
diff --git a/nptl/pthread_condattr_setclock.c b/nptl/pthread_condattr_setclock.c
index 641a041..ac91923 100644
--- a/nptl/pthread_condattr_setclock.c
+++ b/nptl/pthread_condattr_setclock.c
@@ -33,11 +33,6 @@ pthread_condattr_setclock (pthread_condattr_t *attr, clockid_t clock_id)
in the pthread_cond_t structure needs to be adjusted. */
return EINVAL;
- /* If we do not support waiting using CLOCK_MONOTONIC, return an error. */
- if (clock_id == CLOCK_MONOTONIC
- && !futex_supports_exact_relative_timeouts())
- return ENOTSUP;
-
/* Make sure the value fits in the bits we reserved. */
assert (clock_id < (1 << COND_CLOCK_BITS));
diff --git a/sysdeps/nptl/futex-internal.h b/sysdeps/nptl/futex-internal.h
index bc29bdb..9baae38 100644
--- a/sysdeps/nptl/futex-internal.h
+++ b/sysdeps/nptl/futex-internal.h
@@ -51,8 +51,7 @@
Both absolute and relative timeouts can be used. An absolute timeout
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).
+ the given duration of time on the CLOCK_MONOTONIC clock passes.
Due to POSIX requirements on when synchronization data structures such
as mutexes or semaphores can be destroyed and due to the futex design
@@ -81,12 +80,6 @@
static __always_inline int
futex_supports_pshared (int pshared);
-/* Returns true if relative timeouts are robust to concurrent changes to the
- system clock. If this returns false, relative timeouts can still be used
- but might be effectively longer or shorter than requested. */
-static __always_inline bool
-futex_supports_exact_relative_timeouts (void);
-
/* Atomically wrt other futex operations on the same futex, this blocks iff
the value *FUTEX_WORD matches the expected value. This is
semantically equivalent to:
diff --git a/sysdeps/unix/sysv/linux/futex-internal.h b/sysdeps/unix/sysv/linux/futex-internal.h
index 03312d6..30707e7 100644
--- a/sysdeps/unix/sysv/linux/futex-internal.h
+++ b/sysdeps/unix/sysv/linux/futex-internal.h
@@ -46,14 +46,6 @@ futex_supports_pshared (int pshared)
return EINVAL;
}
-/* The Linux kernel supports relative timeouts measured against the
- CLOCK_MONOTONIC clock. */
-static __always_inline bool
-futex_supports_exact_relative_timeouts (void)
-{
- return true;
-}
-
/* See sysdeps/nptl/futex-internal.h for details. */
static __always_inline int
futex_wait (unsigned int *futex_word, unsigned int expected, int private)
--
git-series 0.9.1