Mercurial > hg > truffle
view src/os_cpu/solaris_sparc/vm/thread_solaris_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 |
line wrap: on
line source
/* * 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_solaris_sparc.cpp.incl" // For Forte Analyzer AsyncGetCallTrace profiling support - thread is // currently interrupted by SIGPROF // // NOTE: On Solaris, register windows are flushed in the signal handler // except for possibly the top frame. // 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::Solaris::fetch_frame_from_ucontext(this, uc, &ret_sp, NULL /* ret_fp only used on Solaris X86 */); if (addr.pc() == NULL || ret_sp == NULL) { // ucontext wasn't useful return false; } frame ret_frame(ret_sp, frame::unpatchable, addr.pc()); // we were running Java code when SIGPROF came in if (isInJava) { // If the frame we got is safe then it is most certainly valid if (ret_frame.safe_for_sender(jt)) { *fr_addr = ret_frame; return true; } // If it isn't safe then we can try several things to try and get // a good starting point. // // On sparc the frames are almost certainly walkable in the sense // of sp/fp linkages. However because of recycling of windows if // a piece of code does multiple save's where the initial save creates // a real frame with a return pc and the succeeding save's are used to // simply get free registers and have no real pc then the pc linkage on these // "inner" temporary frames will be bogus. // Since there is in general only a nesting level like // this one deep in general we'll try and unwind such an "inner" frame // here ourselves and see if it makes sense frame unwind_frame(ret_frame.fp(), frame::unpatchable, addr.pc()); if (unwind_frame.safe_for_sender(jt)) { *fr_addr = unwind_frame; return true; } // Well that didn't work. Most likely we're toast on this tick // The previous code would try this. I think it is dubious in light // of changes to safe_for_sender and the unwind trick above but // if it gets us a safe frame who wants to argue. // 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(); frame ret_frame2(ret_sp, frame::unpatchable, addr.pc()); if (ret_frame2.safe_for_sender(jt)) { *fr_addr = ret_frame2; return true; } } // This is the best we can do. We will only be able to decode the top frame *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"); frame ret_frame(jt->last_Java_sp(), frame::unpatchable, addr.pc()); *fr_addr = ret_frame; return true; } // nothing else to try but what we found initially *fr_addr = ret_frame; return true; }