Mercurial > hg > truffle
diff src/share/vm/gc_implementation/shared/spaceDecorator.cpp @ 269:850fdf70db2b
Merge
author | jmasa |
---|---|
date | Mon, 28 Jul 2008 15:30:23 -0700 |
parents | 12eea04c8b06 |
children | 818a18cd69a8 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/gc_implementation/shared/spaceDecorator.cpp Mon Jul 28 15:30:23 2008 -0700 @@ -0,0 +1,140 @@ +/* + * Copyright 2002-2005 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/_spaceDecorator.cpp.incl" + +// Catch-all file for utility classes + +#ifndef PRODUCT + +// Returns true is the location q matches the mangling +// pattern. +bool SpaceMangler::is_mangled(HeapWord* q) { + // This test loses precision but is good enough + return badHeapWord == (max_juint & (uintptr_t) q->value()); +} + + +void SpaceMangler::set_top_for_allocations(HeapWord* v) { + if (v < end()) { + assert(is_mangled(v), "The high water mark is not mangled"); + } + _top_for_allocations = v; +} + +// Mangle only the unused space that has not previously +// been mangled and that has not been allocated since being +// mangled. +void SpaceMangler::mangle_unused_area() { + assert(ZapUnusedHeapArea, "Mangling should not be in use"); + // Mangle between top and the high water mark. Safeguard + // against the space changing since top_for_allocations was + // set. + HeapWord* mangled_end = MIN2(top_for_allocations(), end()); + if (top() < mangled_end) { + MemRegion mangle_mr(top(), mangled_end); + SpaceMangler::mangle_region(mangle_mr); + // Light weight check of mangling. + check_mangled_unused_area(end()); + } + // Complete check of unused area which is functional when + // DEBUG_MANGLING is defined. + check_mangled_unused_area_complete(); +} + +// A complete mangle is expected in the +// exceptional case where top_for_allocations is not +// properly tracking the high water mark for mangling. +// This can be the case when to-space is being used for +// scratch space during a mark-sweep-compact. See +// contribute_scratch() and PSMarkSweep::allocate_stacks(). +void SpaceMangler::mangle_unused_area_complete() { + assert(ZapUnusedHeapArea, "Mangling should not be in use"); + MemRegion mangle_mr(top(), end()); + SpaceMangler::mangle_region(mangle_mr); +} + +// Simply mangle the MemRegion mr. +void SpaceMangler::mangle_region(MemRegion mr) { + assert(ZapUnusedHeapArea, "Mangling should not be in use"); +#ifdef ASSERT + if(TraceZapUnusedHeapArea) { + gclog_or_tty->print("Mangling [0x%x to 0x%x)", mr.start(), mr.end()); + } + Copy::fill_to_words(mr.start(), mr.word_size(), badHeapWord); + if(TraceZapUnusedHeapArea) { + gclog_or_tty->print_cr(" done"); + } +#endif +} + +// Check that top, top_for_allocations and the last +// word of the space are mangled. In a tight memory +// situation even this light weight mangling could +// cause paging by touching the end of the space. +void SpaceMangler::check_mangled_unused_area(HeapWord* limit) { + if (CheckZapUnusedHeapArea) { + // This method can be called while the spaces are + // being reshaped so skip the test if the end of the + // space is beyond the specified limit; + if (end() > limit) return; + + assert(top() == end() || + (is_mangled(top())), "Top not mangled"); + assert((top_for_allocations() < top()) || + (top_for_allocations() >= end()) || + (is_mangled(top_for_allocations())), + "Older unused not mangled"); + assert(top() == end() || + (is_mangled(end() - 1)), "End not properly mangled"); + // Only does checking when DEBUG_MANGLING is defined. + check_mangled_unused_area_complete(); + } +} + +#undef DEBUG_MANGLING +// This should only be used while debugging the mangling +// because of the high cost of checking the completeness. +void SpaceMangler::check_mangled_unused_area_complete() { + if (CheckZapUnusedHeapArea) { + assert(ZapUnusedHeapArea, "Not mangling unused area"); +#ifdef DEBUG_MANGLING + HeapWord* q = top(); + HeapWord* limit = end(); + + bool passed = true; + while (q < limit) { + if (!is_mangled(q)) { + passed = false; + break; + } + q++; + } + assert(passed, "Mangling is not complete"); +#endif + } +} +#undef DEBUG_MANGLING +#endif // not PRODUCT