/* Copyright (C) 2008, 2009, 2011, 2012 Free Software Foundation, Inc.
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/* Copyright (C) 2008, 2009, 2011, 2012 Free Software Foundation, Inc.
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Contributed by Richard Henderson <rth@redhat.com>.
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Contributed by Richard Henderson <rth@redhat.com>.
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This file is part of the GNU Transactional Memory Library (libitm).
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This file is part of the GNU Transactional Memory Library (libitm).
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Libitm is free software; you can redistribute it and/or modify it
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Libitm is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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(at your option) any later version.
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Libitm is distributed in the hope that it will be useful, but WITHOUT ANY
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Libitm is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details.
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more details.
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Under Section 7 of GPL version 3, you are granted additional
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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<http://www.gnu.org/licenses/>. */
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#include "libitm_i.h"
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#include "libitm_i.h"
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#include <pthread.h>
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#include <pthread.h>
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using namespace GTM;
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using namespace GTM;
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#if !defined(HAVE_ARCH_GTM_THREAD) || !defined(HAVE_ARCH_GTM_THREAD_DISP)
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#if !defined(HAVE_ARCH_GTM_THREAD) || !defined(HAVE_ARCH_GTM_THREAD_DISP)
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extern __thread gtm_thread_tls _gtm_thr_tls;
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extern __thread gtm_thread_tls _gtm_thr_tls;
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#endif
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#endif
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gtm_rwlock GTM::gtm_thread::serial_lock;
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gtm_rwlock GTM::gtm_thread::serial_lock;
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gtm_thread *GTM::gtm_thread::list_of_threads = 0;
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gtm_thread *GTM::gtm_thread::list_of_threads = 0;
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unsigned GTM::gtm_thread::number_of_threads = 0;
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unsigned GTM::gtm_thread::number_of_threads = 0;
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gtm_stmlock GTM::gtm_stmlock_array[LOCK_ARRAY_SIZE];
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gtm_stmlock GTM::gtm_stmlock_array[LOCK_ARRAY_SIZE];
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atomic<gtm_version> GTM::gtm_clock;
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atomic<gtm_version> GTM::gtm_clock;
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/* ??? Move elsewhere when we figure out library initialization. */
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/* ??? Move elsewhere when we figure out library initialization. */
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uint64_t GTM::gtm_spin_count_var = 1000;
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uint64_t GTM::gtm_spin_count_var = 1000;
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#ifdef HAVE_64BIT_SYNC_BUILTINS
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#ifdef HAVE_64BIT_SYNC_BUILTINS
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static atomic<_ITM_transactionId_t> global_tid;
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static atomic<_ITM_transactionId_t> global_tid;
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#else
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#else
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static _ITM_transactionId_t global_tid;
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static _ITM_transactionId_t global_tid;
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static pthread_mutex_t global_tid_lock = PTHREAD_MUTEX_INITIALIZER;
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static pthread_mutex_t global_tid_lock = PTHREAD_MUTEX_INITIALIZER;
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#endif
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#endif
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// Provides a on-thread-exit callback used to release per-thread data.
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// Provides a on-thread-exit callback used to release per-thread data.
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static pthread_key_t thr_release_key;
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static pthread_key_t thr_release_key;
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static pthread_once_t thr_release_once = PTHREAD_ONCE_INIT;
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static pthread_once_t thr_release_once = PTHREAD_ONCE_INIT;
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/* Allocate a transaction structure. */
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/* Allocate a transaction structure. */
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void *
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void *
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GTM::gtm_thread::operator new (size_t s)
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GTM::gtm_thread::operator new (size_t s)
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{
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{
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void *tx;
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void *tx;
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assert(s == sizeof(gtm_thread));
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assert(s == sizeof(gtm_thread));
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tx = xmalloc (sizeof (gtm_thread), true);
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tx = xmalloc (sizeof (gtm_thread), true);
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memset (tx, 0, sizeof (gtm_thread));
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memset (tx, 0, sizeof (gtm_thread));
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return tx;
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return tx;
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}
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}
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/* Free the given transaction. Raises an error if the transaction is still
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/* Free the given transaction. Raises an error if the transaction is still
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in use. */
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in use. */
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void
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void
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GTM::gtm_thread::operator delete(void *tx)
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GTM::gtm_thread::operator delete(void *tx)
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{
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{
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free(tx);
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free(tx);
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}
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}
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static void
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static void
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thread_exit_handler(void *)
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thread_exit_handler(void *)
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{
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{
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gtm_thread *thr = gtm_thr();
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gtm_thread *thr = gtm_thr();
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if (thr)
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if (thr)
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delete thr;
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delete thr;
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set_gtm_thr(0);
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set_gtm_thr(0);
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}
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}
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static void
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static void
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thread_exit_init()
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thread_exit_init()
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{
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{
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if (pthread_key_create(&thr_release_key, thread_exit_handler))
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if (pthread_key_create(&thr_release_key, thread_exit_handler))
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GTM_fatal("Creating thread release TLS key failed.");
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GTM_fatal("Creating thread release TLS key failed.");
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}
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}
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GTM::gtm_thread::~gtm_thread()
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GTM::gtm_thread::~gtm_thread()
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{
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{
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if (nesting > 0)
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if (nesting > 0)
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GTM_fatal("Thread exit while a transaction is still active.");
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GTM_fatal("Thread exit while a transaction is still active.");
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// Deregister this transaction.
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// Deregister this transaction.
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serial_lock.write_lock ();
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serial_lock.write_lock ();
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gtm_thread **prev = &list_of_threads;
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gtm_thread **prev = &list_of_threads;
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for (; *prev; prev = &(*prev)->next_thread)
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for (; *prev; prev = &(*prev)->next_thread)
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{
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{
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if (*prev == this)
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if (*prev == this)
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{
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{
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*prev = (*prev)->next_thread;
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*prev = (*prev)->next_thread;
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break;
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break;
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}
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}
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}
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}
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number_of_threads--;
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number_of_threads--;
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number_of_threads_changed(number_of_threads + 1, number_of_threads);
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number_of_threads_changed(number_of_threads + 1, number_of_threads);
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serial_lock.write_unlock ();
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serial_lock.write_unlock ();
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}
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}
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GTM::gtm_thread::gtm_thread ()
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GTM::gtm_thread::gtm_thread ()
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{
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{
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// This object's memory has been set to zero by operator new, so no need
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// This object's memory has been set to zero by operator new, so no need
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// to initialize any of the other primitive-type members that do not have
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// to initialize any of the other primitive-type members that do not have
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// constructors.
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// constructors.
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shared_state.store(-1, memory_order_relaxed);
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shared_state.store(-1, memory_order_relaxed);
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// Register this transaction with the list of all threads' transactions.
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// Register this transaction with the list of all threads' transactions.
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serial_lock.write_lock ();
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serial_lock.write_lock ();
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next_thread = list_of_threads;
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next_thread = list_of_threads;
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list_of_threads = this;
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list_of_threads = this;
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number_of_threads++;
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number_of_threads++;
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number_of_threads_changed(number_of_threads - 1, number_of_threads);
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number_of_threads_changed(number_of_threads - 1, number_of_threads);
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serial_lock.write_unlock ();
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serial_lock.write_unlock ();
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if (pthread_once(&thr_release_once, thread_exit_init))
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if (pthread_once(&thr_release_once, thread_exit_init))
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GTM_fatal("Initializing thread release TLS key failed.");
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GTM_fatal("Initializing thread release TLS key failed.");
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// Any non-null value is sufficient to trigger destruction of this
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// Any non-null value is sufficient to trigger destruction of this
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// transaction when the current thread terminates.
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// transaction when the current thread terminates.
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if (pthread_setspecific(thr_release_key, this))
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if (pthread_setspecific(thr_release_key, this))
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GTM_fatal("Setting thread release TLS key failed.");
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GTM_fatal("Setting thread release TLS key failed.");
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}
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}
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static inline uint32_t
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static inline uint32_t
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choose_code_path(uint32_t prop, abi_dispatch *disp)
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choose_code_path(uint32_t prop, abi_dispatch *disp)
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{
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{
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if ((prop & pr_uninstrumentedCode) && disp->can_run_uninstrumented_code())
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if ((prop & pr_uninstrumentedCode) && disp->can_run_uninstrumented_code())
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return a_runUninstrumentedCode;
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return a_runUninstrumentedCode;
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else
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else
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return a_runInstrumentedCode;
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return a_runInstrumentedCode;
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}
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}
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uint32_t
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uint32_t
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GTM::gtm_thread::begin_transaction (uint32_t prop, const gtm_jmpbuf *jb)
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GTM::gtm_thread::begin_transaction (uint32_t prop, const gtm_jmpbuf *jb)
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{
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{
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static const _ITM_transactionId_t tid_block_size = 1 << 16;
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static const _ITM_transactionId_t tid_block_size = 1 << 16;
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gtm_thread *tx;
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gtm_thread *tx;
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abi_dispatch *disp;
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abi_dispatch *disp;
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uint32_t ret;
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uint32_t ret;
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// ??? pr_undoLogCode is not properly defined in the ABI. Are barriers
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// ??? pr_undoLogCode is not properly defined in the ABI. Are barriers
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// omitted because they are not necessary (e.g., a transaction on thread-
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// omitted because they are not necessary (e.g., a transaction on thread-
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// local data) or because the compiler thinks that some kind of global
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// local data) or because the compiler thinks that some kind of global
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// synchronization might perform better?
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// synchronization might perform better?
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if (unlikely(prop & pr_undoLogCode))
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if (unlikely(prop & pr_undoLogCode))
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GTM_fatal("pr_undoLogCode not supported");
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GTM_fatal("pr_undoLogCode not supported");
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tx = gtm_thr();
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tx = gtm_thr();
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if (unlikely(tx == NULL))
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if (unlikely(tx == NULL))
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{
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{
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// Create the thread object. The constructor will also set up automatic
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// Create the thread object. The constructor will also set up automatic
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// deletion on thread termination.
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// deletion on thread termination.
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tx = new gtm_thread();
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tx = new gtm_thread();
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set_gtm_thr(tx);
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set_gtm_thr(tx);
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}
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}
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if (tx->nesting > 0)
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if (tx->nesting > 0)
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{
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{
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// This is a nested transaction.
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// This is a nested transaction.
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// Check prop compatibility:
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// Check prop compatibility:
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// The ABI requires pr_hasNoFloatUpdate, pr_hasNoVectorUpdate,
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// The ABI requires pr_hasNoFloatUpdate, pr_hasNoVectorUpdate,
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// pr_hasNoIrrevocable, pr_aWBarriersOmitted, pr_RaRBarriersOmitted, and
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// pr_hasNoIrrevocable, pr_aWBarriersOmitted, pr_RaRBarriersOmitted, and
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// pr_hasNoSimpleReads to hold for the full dynamic scope of a
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// pr_hasNoSimpleReads to hold for the full dynamic scope of a
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// transaction. We could check that these are set for the nested
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// transaction. We could check that these are set for the nested
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// transaction if they are also set for the parent transaction, but the
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// transaction if they are also set for the parent transaction, but the
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// ABI does not require these flags to be set if they could be set,
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// ABI does not require these flags to be set if they could be set,
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// so the check could be too strict.
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// so the check could be too strict.
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// ??? For pr_readOnly, lexical or dynamic scope is unspecified.
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// ??? For pr_readOnly, lexical or dynamic scope is unspecified.
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if (prop & pr_hasNoAbort)
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if (prop & pr_hasNoAbort)
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{
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{
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// We can use flat nesting, so elide this transaction.
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// We can use flat nesting, so elide this transaction.
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if (!(prop & pr_instrumentedCode))
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if (!(prop & pr_instrumentedCode))
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{
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{
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if (!(tx->state & STATE_SERIAL) ||
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if (!(tx->state & STATE_SERIAL) ||
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!(tx->state & STATE_IRREVOCABLE))
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!(tx->state & STATE_IRREVOCABLE))
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tx->serialirr_mode();
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tx->serialirr_mode();
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}
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}
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// Increment nesting level after checking that we have a method that
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// Increment nesting level after checking that we have a method that
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// allows us to continue.
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// allows us to continue.
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tx->nesting++;
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tx->nesting++;
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return choose_code_path(prop, abi_disp());
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return choose_code_path(prop, abi_disp());
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}
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}
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// The transaction might abort, so use closed nesting if possible.
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// The transaction might abort, so use closed nesting if possible.
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// pr_hasNoAbort has lexical scope, so the compiler should really have
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// pr_hasNoAbort has lexical scope, so the compiler should really have
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// generated an instrumented code path.
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// generated an instrumented code path.
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assert(prop & pr_instrumentedCode);
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assert(prop & pr_instrumentedCode);
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// Create a checkpoint of the current transaction.
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// Create a checkpoint of the current transaction.
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gtm_transaction_cp *cp = tx->parent_txns.push();
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gtm_transaction_cp *cp = tx->parent_txns.push();
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cp->save(tx);
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cp->save(tx);
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new (&tx->alloc_actions) aa_tree<uintptr_t, gtm_alloc_action>();
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new (&tx->alloc_actions) aa_tree<uintptr_t, gtm_alloc_action>();
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// Check whether the current method actually supports closed nesting.
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// Check whether the current method actually supports closed nesting.
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// If we can switch to another one, do so.
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// If we can switch to another one, do so.
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// If not, we assume that actual aborts are infrequent, and rather
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// If not, we assume that actual aborts are infrequent, and rather
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// restart in _ITM_abortTransaction when we really have to.
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// restart in _ITM_abortTransaction when we really have to.
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disp = abi_disp();
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disp = abi_disp();
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if (!disp->closed_nesting())
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if (!disp->closed_nesting())
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{
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{
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// ??? Should we elide the transaction if there is no alternative
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// ??? Should we elide the transaction if there is no alternative
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// method that supports closed nesting? If we do, we need to set
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// method that supports closed nesting? If we do, we need to set
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// some flag to prevent _ITM_abortTransaction from aborting the
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// some flag to prevent _ITM_abortTransaction from aborting the
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// wrong transaction (i.e., some parent transaction).
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// wrong transaction (i.e., some parent transaction).
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abi_dispatch *cn_disp = disp->closed_nesting_alternative();
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abi_dispatch *cn_disp = disp->closed_nesting_alternative();
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if (cn_disp)
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if (cn_disp)
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{
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{
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disp = cn_disp;
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disp = cn_disp;
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set_abi_disp(disp);
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set_abi_disp(disp);
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}
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}
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}
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}
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}
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}
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else
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else
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{
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{
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// Outermost transaction
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// Outermost transaction
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disp = tx->decide_begin_dispatch (prop);
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disp = tx->decide_begin_dispatch (prop);
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set_abi_disp (disp);
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set_abi_disp (disp);
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}
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}
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// Initialization that is common for outermost and nested transactions.
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// Initialization that is common for outermost and nested transactions.
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tx->prop = prop;
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tx->prop = prop;
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tx->nesting++;
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tx->nesting++;
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tx->jb = *jb;
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tx->jb = *jb;
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// As long as we have not exhausted a previously allocated block of TIDs,
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// As long as we have not exhausted a previously allocated block of TIDs,
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// we can avoid an atomic operation on a shared cacheline.
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// we can avoid an atomic operation on a shared cacheline.
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if (tx->local_tid & (tid_block_size - 1))
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if (tx->local_tid & (tid_block_size - 1))
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tx->id = tx->local_tid++;
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tx->id = tx->local_tid++;
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else
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else
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{
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{
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#ifdef HAVE_64BIT_SYNC_BUILTINS
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#ifdef HAVE_64BIT_SYNC_BUILTINS
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// We don't really care which block of TIDs we get but only that we
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// We don't really care which block of TIDs we get but only that we
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// acquire one atomically; therefore, relaxed memory order is
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// acquire one atomically; therefore, relaxed memory order is
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// sufficient.
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// sufficient.
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tx->id = global_tid.fetch_add(tid_block_size, memory_order_relaxed);
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tx->id = global_tid.fetch_add(tid_block_size, memory_order_relaxed);
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tx->local_tid = tx->id + 1;
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tx->local_tid = tx->id + 1;
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#else
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#else
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pthread_mutex_lock (&global_tid_lock);
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pthread_mutex_lock (&global_tid_lock);
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global_tid += tid_block_size;
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global_tid += tid_block_size;
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tx->id = global_tid;
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tx->id = global_tid;
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tx->local_tid = tx->id + 1;
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tx->local_tid = tx->id + 1;
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pthread_mutex_unlock (&global_tid_lock);
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pthread_mutex_unlock (&global_tid_lock);
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#endif
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#endif
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}
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}
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// Run dispatch-specific restart code. Retry until we succeed.
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// Run dispatch-specific restart code. Retry until we succeed.
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GTM::gtm_restart_reason rr;
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GTM::gtm_restart_reason rr;
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while ((rr = disp->begin_or_restart()) != NO_RESTART)
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while ((rr = disp->begin_or_restart()) != NO_RESTART)
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{
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{
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tx->decide_retry_strategy(rr);
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tx->decide_retry_strategy(rr);
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disp = abi_disp();
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disp = abi_disp();
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}
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}
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// Determine the code path to run. Only irrevocable transactions cannot be
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// Determine the code path to run. Only irrevocable transactions cannot be
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// restarted, so all other transactions need to save live variables.
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// restarted, so all other transactions need to save live variables.
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ret = choose_code_path(prop, disp);
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ret = choose_code_path(prop, disp);
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if (!(tx->state & STATE_IRREVOCABLE))
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if (!(tx->state & STATE_IRREVOCABLE))
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ret |= a_saveLiveVariables;
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ret |= a_saveLiveVariables;
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return ret;
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return ret;
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}
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}
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void
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void
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GTM::gtm_transaction_cp::save(gtm_thread* tx)
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GTM::gtm_transaction_cp::save(gtm_thread* tx)
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{
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{
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// Save everything that we might have to restore on restarts or aborts.
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// Save everything that we might have to restore on restarts or aborts.
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jb = tx->jb;
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jb = tx->jb;
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undolog_size = tx->undolog.size();
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undolog_size = tx->undolog.size();
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memcpy(&alloc_actions, &tx->alloc_actions, sizeof(alloc_actions));
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memcpy(&alloc_actions, &tx->alloc_actions, sizeof(alloc_actions));
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user_actions_size = tx->user_actions.size();
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user_actions_size = tx->user_actions.size();
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id = tx->id;
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id = tx->id;
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prop = tx->prop;
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prop = tx->prop;
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cxa_catch_count = tx->cxa_catch_count;
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cxa_catch_count = tx->cxa_catch_count;
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cxa_unthrown = tx->cxa_unthrown;
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cxa_unthrown = tx->cxa_unthrown;
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disp = abi_disp();
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disp = abi_disp();
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nesting = tx->nesting;
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nesting = tx->nesting;
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}
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}
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void
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void
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GTM::gtm_transaction_cp::commit(gtm_thread* tx)
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GTM::gtm_transaction_cp::commit(gtm_thread* tx)
|
{
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{
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// Restore state that is not persistent across commits. Exception handling,
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// Restore state that is not persistent across commits. Exception handling,
|
// information, nesting level, and any logs do not need to be restored on
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// information, nesting level, and any logs do not need to be restored on
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// commits of nested transactions. Allocation actions must be committed
|
// commits of nested transactions. Allocation actions must be committed
|
// before committing the snapshot.
|
// before committing the snapshot.
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tx->jb = jb;
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tx->jb = jb;
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memcpy(&tx->alloc_actions, &alloc_actions, sizeof(alloc_actions));
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memcpy(&tx->alloc_actions, &alloc_actions, sizeof(alloc_actions));
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tx->id = id;
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tx->id = id;
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tx->prop = prop;
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tx->prop = prop;
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}
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}
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void
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void
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GTM::gtm_thread::rollback (gtm_transaction_cp *cp, bool aborting)
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GTM::gtm_thread::rollback (gtm_transaction_cp *cp, bool aborting)
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{
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{
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// The undo log is special in that it used for both thread-local and shared
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// The undo log is special in that it used for both thread-local and shared
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// data. Because of the latter, we have to roll it back before any
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// data. Because of the latter, we have to roll it back before any
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// dispatch-specific rollback (which handles synchronization with other
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// dispatch-specific rollback (which handles synchronization with other
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// transactions).
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// transactions).
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undolog.rollback (this, cp ? cp->undolog_size : 0);
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undolog.rollback (this, cp ? cp->undolog_size : 0);
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|
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// Perform dispatch-specific rollback.
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// Perform dispatch-specific rollback.
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abi_disp()->rollback (cp);
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abi_disp()->rollback (cp);
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|
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// Roll back all actions that are supposed to happen around the transaction.
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// Roll back all actions that are supposed to happen around the transaction.
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rollback_user_actions (cp ? cp->user_actions_size : 0);
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rollback_user_actions (cp ? cp->user_actions_size : 0);
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commit_allocations (true, (cp ? &cp->alloc_actions : 0));
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commit_allocations (true, (cp ? &cp->alloc_actions : 0));
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revert_cpp_exceptions (cp);
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revert_cpp_exceptions (cp);
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|
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if (cp)
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if (cp)
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{
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{
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// We do not yet handle restarts of nested transactions. To do that, we
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// We do not yet handle restarts of nested transactions. To do that, we
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// would have to restore some state (jb, id, prop, nesting) not to the
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// would have to restore some state (jb, id, prop, nesting) not to the
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// checkpoint but to the transaction that was started from this
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// checkpoint but to the transaction that was started from this
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// checkpoint (e.g., nesting = cp->nesting + 1);
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// checkpoint (e.g., nesting = cp->nesting + 1);
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assert(aborting);
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assert(aborting);
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// Roll back the rest of the state to the checkpoint.
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// Roll back the rest of the state to the checkpoint.
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jb = cp->jb;
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jb = cp->jb;
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id = cp->id;
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id = cp->id;
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prop = cp->prop;
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prop = cp->prop;
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if (cp->disp != abi_disp())
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if (cp->disp != abi_disp())
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set_abi_disp(cp->disp);
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set_abi_disp(cp->disp);
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memcpy(&alloc_actions, &cp->alloc_actions, sizeof(alloc_actions));
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memcpy(&alloc_actions, &cp->alloc_actions, sizeof(alloc_actions));
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nesting = cp->nesting;
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nesting = cp->nesting;
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}
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}
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else
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else
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{
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{
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// Roll back to the outermost transaction.
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// Roll back to the outermost transaction.
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// Restore the jump buffer and transaction properties, which we will
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// Restore the jump buffer and transaction properties, which we will
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// need for the longjmp used to restart or abort the transaction.
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// need for the longjmp used to restart or abort the transaction.
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if (parent_txns.size() > 0)
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if (parent_txns.size() > 0)
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{
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{
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jb = parent_txns[0].jb;
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jb = parent_txns[0].jb;
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id = parent_txns[0].id;
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id = parent_txns[0].id;
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prop = parent_txns[0].prop;
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prop = parent_txns[0].prop;
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}
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}
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// Reset the transaction. Do not reset this->state, which is handled by
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// Reset the transaction. Do not reset this->state, which is handled by
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// the callers. Note that if we are not aborting, we reset the
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// the callers. Note that if we are not aborting, we reset the
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// transaction to the point after having executed begin_transaction
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// transaction to the point after having executed begin_transaction
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// (we will return from it), so the nesting level must be one, not zero.
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// (we will return from it), so the nesting level must be one, not zero.
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nesting = (aborting ? 0 : 1);
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nesting = (aborting ? 0 : 1);
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parent_txns.clear();
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parent_txns.clear();
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}
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}
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|
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if (this->eh_in_flight)
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if (this->eh_in_flight)
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{
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{
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_Unwind_DeleteException ((_Unwind_Exception *) this->eh_in_flight);
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_Unwind_DeleteException ((_Unwind_Exception *) this->eh_in_flight);
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this->eh_in_flight = NULL;
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this->eh_in_flight = NULL;
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}
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}
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}
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}
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|
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void ITM_REGPARM
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void ITM_REGPARM
|
_ITM_abortTransaction (_ITM_abortReason reason)
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_ITM_abortTransaction (_ITM_abortReason reason)
|
{
|
{
|
gtm_thread *tx = gtm_thr();
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gtm_thread *tx = gtm_thr();
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|
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assert (reason == userAbort || reason == (userAbort | outerAbort));
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assert (reason == userAbort || reason == (userAbort | outerAbort));
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assert ((tx->prop & pr_hasNoAbort) == 0);
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assert ((tx->prop & pr_hasNoAbort) == 0);
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|
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if (tx->state & gtm_thread::STATE_IRREVOCABLE)
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if (tx->state & gtm_thread::STATE_IRREVOCABLE)
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abort ();
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abort ();
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|
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// Roll back to innermost transaction.
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// Roll back to innermost transaction.
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if (tx->parent_txns.size() > 0 && !(reason & outerAbort))
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if (tx->parent_txns.size() > 0 && !(reason & outerAbort))
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{
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{
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// If the current method does not support closed nesting but we are
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// If the current method does not support closed nesting but we are
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// nested and must only roll back the innermost transaction, then
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// nested and must only roll back the innermost transaction, then
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// restart with a method that supports closed nesting.
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// restart with a method that supports closed nesting.
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abi_dispatch *disp = abi_disp();
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abi_dispatch *disp = abi_disp();
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if (!disp->closed_nesting())
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if (!disp->closed_nesting())
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tx->restart(RESTART_CLOSED_NESTING);
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tx->restart(RESTART_CLOSED_NESTING);
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|
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// The innermost transaction is a closed nested transaction.
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// The innermost transaction is a closed nested transaction.
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gtm_transaction_cp *cp = tx->parent_txns.pop();
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gtm_transaction_cp *cp = tx->parent_txns.pop();
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uint32_t longjmp_prop = tx->prop;
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uint32_t longjmp_prop = tx->prop;
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gtm_jmpbuf longjmp_jb = tx->jb;
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gtm_jmpbuf longjmp_jb = tx->jb;
|
|
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tx->rollback (cp, true);
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tx->rollback (cp, true);
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|
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// Jump to nested transaction (use the saved jump buffer).
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// Jump to nested transaction (use the saved jump buffer).
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GTM_longjmp (a_abortTransaction | a_restoreLiveVariables,
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GTM_longjmp (a_abortTransaction | a_restoreLiveVariables,
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&longjmp_jb, longjmp_prop);
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&longjmp_jb, longjmp_prop);
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}
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}
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else
|
else
|
{
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{
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// There is no nested transaction or an abort of the outermost
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// There is no nested transaction or an abort of the outermost
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// transaction was requested, so roll back to the outermost transaction.
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// transaction was requested, so roll back to the outermost transaction.
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tx->rollback (0, true);
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tx->rollback (0, true);
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|
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// Aborting an outermost transaction finishes execution of the whole
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// Aborting an outermost transaction finishes execution of the whole
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// transaction. Therefore, reset transaction state.
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// transaction. Therefore, reset transaction state.
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if (tx->state & gtm_thread::STATE_SERIAL)
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if (tx->state & gtm_thread::STATE_SERIAL)
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gtm_thread::serial_lock.write_unlock ();
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gtm_thread::serial_lock.write_unlock ();
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else
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else
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gtm_thread::serial_lock.read_unlock (tx);
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gtm_thread::serial_lock.read_unlock (tx);
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tx->state = 0;
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tx->state = 0;
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|
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GTM_longjmp (a_abortTransaction | a_restoreLiveVariables,
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GTM_longjmp (a_abortTransaction | a_restoreLiveVariables,
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&tx->jb, tx->prop);
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&tx->jb, tx->prop);
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}
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}
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}
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}
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|
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bool
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bool
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GTM::gtm_thread::trycommit ()
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GTM::gtm_thread::trycommit ()
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{
|
{
|
nesting--;
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nesting--;
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|
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// Skip any real commit for elided transactions.
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// Skip any real commit for elided transactions.
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if (nesting > 0 && (parent_txns.size() == 0 ||
|
if (nesting > 0 && (parent_txns.size() == 0 ||
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nesting > parent_txns[parent_txns.size() - 1].nesting))
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nesting > parent_txns[parent_txns.size() - 1].nesting))
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return true;
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return true;
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|
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if (nesting > 0)
|
if (nesting > 0)
|
{
|
{
|
// Commit of a closed-nested transaction. Remove one checkpoint and add
|
// Commit of a closed-nested transaction. Remove one checkpoint and add
|
// any effects of this transaction to the parent transaction.
|
// any effects of this transaction to the parent transaction.
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gtm_transaction_cp *cp = parent_txns.pop();
|
gtm_transaction_cp *cp = parent_txns.pop();
|
commit_allocations(false, &cp->alloc_actions);
|
commit_allocations(false, &cp->alloc_actions);
|
cp->commit(this);
|
cp->commit(this);
|
return true;
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return true;
|
}
|
}
|
|
|
// Commit of an outermost transaction.
|
// Commit of an outermost transaction.
|
gtm_word priv_time = 0;
|
gtm_word priv_time = 0;
|
if (abi_disp()->trycommit (priv_time))
|
if (abi_disp()->trycommit (priv_time))
|
{
|
{
|
// The transaction is now inactive. Everything that we still have to do
|
// The transaction is now inactive. Everything that we still have to do
|
// will not synchronize with other transactions anymore.
|
// will not synchronize with other transactions anymore.
|
if (state & gtm_thread::STATE_SERIAL)
|
if (state & gtm_thread::STATE_SERIAL)
|
{
|
{
|
gtm_thread::serial_lock.write_unlock ();
|
gtm_thread::serial_lock.write_unlock ();
|
// There are no other active transactions, so there's no need to
|
// There are no other active transactions, so there's no need to
|
// enforce privatization safety.
|
// enforce privatization safety.
|
priv_time = 0;
|
priv_time = 0;
|
}
|
}
|
else
|
else
|
gtm_thread::serial_lock.read_unlock (this);
|
gtm_thread::serial_lock.read_unlock (this);
|
state = 0;
|
state = 0;
|
|
|
// We can commit the undo log after dispatch-specific commit and after
|
// We can commit the undo log after dispatch-specific commit and after
|
// making the transaction inactive because we only have to reset
|
// making the transaction inactive because we only have to reset
|
// gtm_thread state.
|
// gtm_thread state.
|
undolog.commit ();
|
undolog.commit ();
|
// Reset further transaction state.
|
// Reset further transaction state.
|
cxa_catch_count = 0;
|
cxa_catch_count = 0;
|
cxa_unthrown = NULL;
|
cxa_unthrown = NULL;
|
restart_total = 0;
|
restart_total = 0;
|
|
|
// Ensure privatization safety, if necessary.
|
// Ensure privatization safety, if necessary.
|
if (priv_time)
|
if (priv_time)
|
{
|
{
|
// There must be a seq_cst fence between the following loads of the
|
// There must be a seq_cst fence between the following loads of the
|
// other transactions' shared_state and the dispatch-specific stores
|
// other transactions' shared_state and the dispatch-specific stores
|
// that signal updates by this transaction (e.g., lock
|
// that signal updates by this transaction (e.g., lock
|
// acquisitions). This ensures that if we read prior to other
|
// acquisitions). This ensures that if we read prior to other
|
// reader transactions setting their shared_state to 0, then those
|
// reader transactions setting their shared_state to 0, then those
|
// readers will observe our updates. We can reuse the seq_cst fence
|
// readers will observe our updates. We can reuse the seq_cst fence
|
// in serial_lock.read_unlock() however, so we don't need another
|
// in serial_lock.read_unlock() however, so we don't need another
|
// one here.
|
// one here.
|
// TODO Don't just spin but also block using cond vars / futexes
|
// TODO Don't just spin but also block using cond vars / futexes
|
// here. Should probably be integrated with the serial lock code.
|
// here. Should probably be integrated with the serial lock code.
|
for (gtm_thread *it = gtm_thread::list_of_threads; it != 0;
|
for (gtm_thread *it = gtm_thread::list_of_threads; it != 0;
|
it = it->next_thread)
|
it = it->next_thread)
|
{
|
{
|
if (it == this) continue;
|
if (it == this) continue;
|
// We need to load other threads' shared_state using acquire
|
// We need to load other threads' shared_state using acquire
|
// semantics (matching the release semantics of the respective
|
// semantics (matching the release semantics of the respective
|
// updates). This is necessary to ensure that the other
|
// updates). This is necessary to ensure that the other
|
// threads' memory accesses happen before our actions that
|
// threads' memory accesses happen before our actions that
|
// assume privatization safety.
|
// assume privatization safety.
|
// TODO Are there any platform-specific optimizations (e.g.,
|
// TODO Are there any platform-specific optimizations (e.g.,
|
// merging barriers)?
|
// merging barriers)?
|
while (it->shared_state.load(memory_order_acquire) < priv_time)
|
while (it->shared_state.load(memory_order_acquire) < priv_time)
|
cpu_relax();
|
cpu_relax();
|
}
|
}
|
}
|
}
|
|
|
// After ensuring privatization safety, we execute potentially
|
// After ensuring privatization safety, we execute potentially
|
// privatizing actions (e.g., calling free()). User actions are first.
|
// privatizing actions (e.g., calling free()). User actions are first.
|
commit_user_actions ();
|
commit_user_actions ();
|
commit_allocations (false, 0);
|
commit_allocations (false, 0);
|
|
|
return true;
|
return true;
|
}
|
}
|
return false;
|
return false;
|
}
|
}
|
|
|
void ITM_NORETURN
|
void ITM_NORETURN
|
GTM::gtm_thread::restart (gtm_restart_reason r, bool finish_serial_upgrade)
|
GTM::gtm_thread::restart (gtm_restart_reason r, bool finish_serial_upgrade)
|
{
|
{
|
// Roll back to outermost transaction. Do not reset transaction state because
|
// Roll back to outermost transaction. Do not reset transaction state because
|
// we will continue executing this transaction.
|
// we will continue executing this transaction.
|
rollback ();
|
rollback ();
|
|
|
// If we have to restart while an upgrade of the serial lock is happening,
|
// If we have to restart while an upgrade of the serial lock is happening,
|
// we need to finish this here, after rollback (to ensure privatization
|
// we need to finish this here, after rollback (to ensure privatization
|
// safety despite undo writes) and before deciding about the retry strategy
|
// safety despite undo writes) and before deciding about the retry strategy
|
// (which could switch to/from serial mode).
|
// (which could switch to/from serial mode).
|
if (finish_serial_upgrade)
|
if (finish_serial_upgrade)
|
gtm_thread::serial_lock.write_upgrade_finish(this);
|
gtm_thread::serial_lock.write_upgrade_finish(this);
|
|
|
decide_retry_strategy (r);
|
decide_retry_strategy (r);
|
|
|
// Run dispatch-specific restart code. Retry until we succeed.
|
// Run dispatch-specific restart code. Retry until we succeed.
|
abi_dispatch* disp = abi_disp();
|
abi_dispatch* disp = abi_disp();
|
GTM::gtm_restart_reason rr;
|
GTM::gtm_restart_reason rr;
|
while ((rr = disp->begin_or_restart()) != NO_RESTART)
|
while ((rr = disp->begin_or_restart()) != NO_RESTART)
|
{
|
{
|
decide_retry_strategy(rr);
|
decide_retry_strategy(rr);
|
disp = abi_disp();
|
disp = abi_disp();
|
}
|
}
|
|
|
GTM_longjmp (choose_code_path(prop, disp) | a_restoreLiveVariables,
|
GTM_longjmp (choose_code_path(prop, disp) | a_restoreLiveVariables,
|
&jb, prop);
|
&jb, prop);
|
}
|
}
|
|
|
void ITM_REGPARM
|
void ITM_REGPARM
|
_ITM_commitTransaction(void)
|
_ITM_commitTransaction(void)
|
{
|
{
|
gtm_thread *tx = gtm_thr();
|
gtm_thread *tx = gtm_thr();
|
if (!tx->trycommit ())
|
if (!tx->trycommit ())
|
tx->restart (RESTART_VALIDATE_COMMIT);
|
tx->restart (RESTART_VALIDATE_COMMIT);
|
}
|
}
|
|
|
void ITM_REGPARM
|
void ITM_REGPARM
|
_ITM_commitTransactionEH(void *exc_ptr)
|
_ITM_commitTransactionEH(void *exc_ptr)
|
{
|
{
|
gtm_thread *tx = gtm_thr();
|
gtm_thread *tx = gtm_thr();
|
if (!tx->trycommit ())
|
if (!tx->trycommit ())
|
{
|
{
|
tx->eh_in_flight = exc_ptr;
|
tx->eh_in_flight = exc_ptr;
|
tx->restart (RESTART_VALIDATE_COMMIT);
|
tx->restart (RESTART_VALIDATE_COMMIT);
|
}
|
}
|
}
|
}
|
|
|
