Mercurial > hg > truffle
view src/share/vm/runtime/park.cpp @ 20256:b0b97602393a
8033923: Use BufferingOopClosure for G1 code root scanning
Reviewed-by: mgerdin, brutisso
author | stefank |
---|---|
date | Mon, 10 Feb 2014 12:58:09 +0100 |
parents | 0e6af9b390af |
children | 2c95095271e9 |
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/* * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #include "precompiled.hpp" #include "runtime/thread.hpp" // Lifecycle management for TSM ParkEvents. // ParkEvents are type-stable (TSM). // In our particular implementation they happen to be immortal. // // We manage concurrency on the FreeList with a CAS-based // detach-modify-reattach idiom that avoids the ABA problems // that would otherwise be present in a simple CAS-based // push-pop implementation. (push-one and pop-all) // // Caveat: Allocate() and Release() may be called from threads // other than the thread associated with the Event! // If we need to call Allocate() when running as the thread in // question then look for the PD calls to initialize native TLS. // Native TLS (Win32/Linux/Solaris) can only be initialized or // accessed by the associated thread. // See also pd_initialize(). // // Note that we could defer associating a ParkEvent with a thread // until the 1st time the thread calls park(). unpark() calls to // an unprovisioned thread would be ignored. The first park() call // for a thread would allocate and associate a ParkEvent and return // immediately. volatile int ParkEvent::ListLock = 0 ; ParkEvent * volatile ParkEvent::FreeList = NULL ; ParkEvent * ParkEvent::Allocate (Thread * t) { // In rare cases -- JVM_RawMonitor* operations -- we can find t == null. ParkEvent * ev ; // Start by trying to recycle an existing but unassociated // ParkEvent from the global free list. // Using a spin lock since we are part of the mutex impl. // 8028280: using concurrent free list without memory management can leak // pretty badly it turns out. Thread::SpinAcquire(&ListLock, "ParkEventFreeListAllocate"); { ev = FreeList; if (ev != NULL) { FreeList = ev->FreeNext; } } Thread::SpinRelease(&ListLock); if (ev != NULL) { guarantee (ev->AssociatedWith == NULL, "invariant") ; } else { // Do this the hard way -- materialize a new ParkEvent. ev = new ParkEvent () ; guarantee ((intptr_t(ev) & 0xFF) == 0, "invariant") ; } ev->reset() ; // courtesy to caller ev->AssociatedWith = t ; // Associate ev with t ev->FreeNext = NULL ; return ev ; } void ParkEvent::Release (ParkEvent * ev) { if (ev == NULL) return ; guarantee (ev->FreeNext == NULL , "invariant") ; ev->AssociatedWith = NULL ; // Note that if we didn't have the TSM/immortal constraint, then // when reattaching we could trim the list. Thread::SpinAcquire(&ListLock, "ParkEventFreeListRelease"); { ev->FreeNext = FreeList; FreeList = ev; } Thread::SpinRelease(&ListLock); } // Override operator new and delete so we can ensure that the // least significant byte of ParkEvent addresses is 0. // Beware that excessive address alignment is undesirable // as it can result in D$ index usage imbalance as // well as bank access imbalance on Niagara-like platforms, // although Niagara's hash function should help. void * ParkEvent::operator new (size_t sz) throw() { return (void *) ((intptr_t (AllocateHeap(sz + 256, mtInternal, CALLER_PC)) + 256) & -256) ; } void ParkEvent::operator delete (void * a) { // ParkEvents are type-stable and immortal ... ShouldNotReachHere(); } // 6399321 As a temporary measure we copied & modified the ParkEvent:: // allocate() and release() code for use by Parkers. The Parker:: forms // will eventually be removed as we consolide and shift over to ParkEvents // for both builtin synchronization and JSR166 operations. volatile int Parker::ListLock = 0 ; Parker * volatile Parker::FreeList = NULL ; Parker * Parker::Allocate (JavaThread * t) { guarantee (t != NULL, "invariant") ; Parker * p ; // Start by trying to recycle an existing but unassociated // Parker from the global free list. // 8028280: using concurrent free list without memory management can leak // pretty badly it turns out. Thread::SpinAcquire(&ListLock, "ParkerFreeListAllocate"); { p = FreeList; if (p != NULL) { FreeList = p->FreeNext; } } Thread::SpinRelease(&ListLock); if (p != NULL) { guarantee (p->AssociatedWith == NULL, "invariant") ; } else { // Do this the hard way -- materialize a new Parker.. p = new Parker() ; } p->AssociatedWith = t ; // Associate p with t p->FreeNext = NULL ; return p ; } void Parker::Release (Parker * p) { if (p == NULL) return ; guarantee (p->AssociatedWith != NULL, "invariant") ; guarantee (p->FreeNext == NULL , "invariant") ; p->AssociatedWith = NULL ; Thread::SpinAcquire(&ListLock, "ParkerFreeListRelease"); { p->FreeNext = FreeList; FreeList = p; } Thread::SpinRelease(&ListLock); }