diff options
Diffstat (limited to 'libitm/config/posix')
| -rw-r--r-- | libitm/config/posix/rwlock.h | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/libitm/config/posix/rwlock.h b/libitm/config/posix/rwlock.h index a1a6042e562..79f14296df6 100644 --- a/libitm/config/posix/rwlock.h +++ b/libitm/config/posix/rwlock.h @@ -1,4 +1,4 @@ -/* Copyright (C) 2009, 2011 Free Software Foundation, Inc. +/* Copyright (C) 2009, 2011, 2012 Free Software Foundation, Inc. Contributed by Richard Henderson <rth@redhat.com>. This file is part of the GNU Transactional Memory Library (libitm). @@ -74,6 +74,14 @@ class gtm_rwlock bool write_upgrade (gtm_thread *tx); void write_upgrade_finish (gtm_thread *tx); + // Returns true iff there is a concurrent active or waiting writer. + // This is primarily useful for simple HyTM approaches, and the value being + // checked is loaded with memory_order_relaxed. + bool is_write_locked() + { + return summary.load (memory_order_relaxed) & (a_writer | w_writer); + } + protected: bool write_lock_generic (gtm_thread *tx); }; |