From: Mike Crowe <mac@mcrowe.com>
To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org
Cc: Mike Crowe <mac@mcrowe.com>
Subject: [PATCH 10/11] libstdc++ timed_mutex: Ensure that try_lock_for waits for long enough
Date: Sat, 28 Sep 2019 08:48:00 -0000 [thread overview]
Message-ID: <bfc5aa5bb099c28f73d366af396d8c2e253c195c.1569660153.git-series.mac@mcrowe.com> (raw)
In-Reply-To: <cover.401206917148c9c806e008aa7336564a639de964.1569660153.git-series.mac@mcrowe.com>
The user-defined clock used with shared_mutex::try_lock_for and
shared_mutex::try_lock_shared_for may have higher precision than
__clock_t. We may need to round the duration up to ensure that the timeout
is long enough. (See __timed_mutex_impl::_M_try_lock_for)
* include/std/shared_mutex: (try_lock_for) Round up wait duration
if necessary. (try_lock_shared_for) Likewise.
---
libstdc++-v3/include/std/shared_mutex | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/libstdc++-v3/include/std/shared_mutex b/libstdc++-v3/include/std/shared_mutex
index b637bdc..6e67324 100644
--- a/libstdc++-v3/include/std/shared_mutex
+++ b/libstdc++-v3/include/std/shared_mutex
@@ -471,9 +471,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Rep, typename _Period>
bool
- try_lock_for(const chrono::duration<_Rep, _Period>& __rel_time)
+ try_lock_for(const chrono::duration<_Rep, _Period>& __rtime)
{
- return try_lock_until(__clock_t::now() + __rel_time);
+ auto __rt = chrono::duration_cast<__clock_t::duration>(__rtime);
+ if (ratio_greater<__clock_t::period, _Period>())
+ ++__rt;
+ return try_lock_until(__clock_t::now() + __rt);
}
// Shared ownership
@@ -484,9 +487,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Rep, typename _Period>
bool
- try_lock_shared_for(const chrono::duration<_Rep, _Period>& __rel_time)
+ try_lock_shared_for(const chrono::duration<_Rep, _Period>& __rtime)
{
- return try_lock_shared_until(__clock_t::now() + __rel_time);
+ auto __rt = chrono::duration_cast<__clock_t::duration>(__rtime);
+ if (ratio_greater<__clock_t::period, _Period>())
+ ++__rt;
+ return try_lock_shared_until(__clock_t::now() + __rt);
}
#if _GLIBCXX_USE_PTHREAD_RWLOCK_T && _GTHREAD_USE_MUTEX_TIMEDLOCK
--
git-series 0.9.1
next prev parent reply other threads:[~2019-09-28 8:48 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-28 8:45 [PATCH 00/11] timed_mutex, shared_timed_mutex: Add full steady clock support Mike Crowe
2019-09-28 8:45 ` [PATCH 05/11] PR libstdc++/78237 Add full steady_clock support to timed_mutex Mike Crowe
2019-09-28 8:45 ` [PATCH 09/11] libstdc++ shared_mutex: Add full steady_clock support to shared_timed_mutex Mike Crowe
2019-09-28 8:45 ` [PATCH 03/11] libstdc++ testsuite: Also test timed_mutex with steady_clock Mike Crowe
2019-09-28 8:45 ` [PATCH 07/11] PR libstdc++/91906 Fix timed_mutex::try_lock_until on arbitrary clock Mike Crowe
2019-09-28 8:45 ` [PATCH 01/11] libstdc++ testsuite: Check return value from timed_mutex::try_lock_until Mike Crowe
2019-09-28 8:48 ` [PATCH 06/11] libstdc++ testsuite: Move slow_clock to its own header Mike Crowe
2019-09-28 8:48 ` Mike Crowe [this message]
2019-09-28 8:48 ` [PATCH 04/11] libstdc++ testsuite: Also test unique_lock::try_lock_until with steady_clock Mike Crowe
2019-09-28 8:48 ` [PATCH 08/11] libstdc++ testsuite: Also test shared_timed_mutex " Mike Crowe
2019-09-28 8:48 ` [PATCH 11/11] shared_mutex: Fix try_lock_until and try_lock_shared_until on arbitrary clock Mike Crowe
2019-09-28 8:48 ` [PATCH 02/11] libstdc++ testsuite: Add timed_mutex::try_lock_until test Mike Crowe
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