Mercurial > hg > truffle
view src/os_cpu/linux_sparc/vm/thread_linux_sparc.cpp @ 453:c96030fff130
6684579: SoftReference processing can be made more efficient
Summary: For current soft-ref clearing policies, we can decide at marking time if a soft-reference will definitely not be cleared, postponing the decision of whether it will definitely be cleared to the final reference processing phase. This can be especially beneficial in the case of concurrent collectors where the marking is usually concurrent but reference processing is usually not.
Reviewed-by: jmasa
author | ysr |
---|---|
date | Thu, 20 Nov 2008 16:56:09 -0800 |
parents | d1605aabd0a1 |
children | c18cbe5936b8 |
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/* * Copyright 2003-2008 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, * CA 95054 USA or visit www.sun.com if you need additional information or * have any questions. * */ #include "incls/_precompiled.incl" #include "incls/_thread_linux_sparc.cpp.incl" // For Forte Analyzer AsyncGetCallTrace profiling support - thread is // currently interrupted by SIGPROF bool JavaThread::pd_get_top_frame_for_signal_handler(frame* fr_addr, void* ucontext, bool isInJava) { assert(Thread::current() == this, "caller must be current thread"); assert(this->is_Java_thread(), "must be JavaThread"); JavaThread* jt = (JavaThread *)this; if (!isInJava) { // make_walkable flushes register windows and grabs last_Java_pc // which can not be done if the ucontext sp matches last_Java_sp // stack walking utilities assume last_Java_pc set if marked flushed jt->frame_anchor()->make_walkable(jt); } // If we have a walkable last_Java_frame, then we should use it // even if isInJava == true. It should be more reliable than // ucontext info. if (jt->has_last_Java_frame() && jt->frame_anchor()->walkable()) { *fr_addr = jt->pd_last_frame(); return true; } ucontext_t* uc = (ucontext_t*) ucontext; // At this point, we don't have a walkable last_Java_frame, so // we try to glean some information out of the ucontext. intptr_t* ret_sp; ExtendedPC addr = os::fetch_frame_from_context(uc, &ret_sp, NULL /* ret_fp only used on X86 */); if (addr.pc() == NULL || ret_sp == NULL) { // ucontext wasn't useful return false; } // we were running Java code when SIGPROF came in if (isInJava) { // If we have a last_Java_sp, then the SIGPROF signal caught us // right when we were transitioning from _thread_in_Java to a new // JavaThreadState. We use last_Java_sp instead of the sp from // the ucontext since it should be more reliable. if (jt->has_last_Java_frame()) { ret_sp = jt->last_Java_sp(); } // Implied else: we don't have a last_Java_sp so we use what we // got from the ucontext. frame ret_frame(ret_sp, frame::unpatchable, addr.pc()); if (!ret_frame.safe_for_sender(jt)) { // nothing else to try if the frame isn't good return false; } *fr_addr = ret_frame; return true; } // At this point, we know we weren't running Java code. We might // have a last_Java_sp, but we don't have a walkable frame. // However, we might still be able to construct something useful // if the thread was running native code. if (jt->has_last_Java_frame()) { assert(!jt->frame_anchor()->walkable(), "case covered above"); if (jt->thread_state() == _thread_in_native) { frame ret_frame(jt->last_Java_sp(), frame::unpatchable, addr.pc()); if (!ret_frame.safe_for_sender(jt)) { // nothing else to try if the frame isn't good return false; } *fr_addr = ret_frame; return true; } } // nothing else to try return false; }