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view src/share/vm/gc_implementation/parallelScavenge/adjoiningVirtualSpaces.hpp @ 12301:2c022e432e10
8024974: Incorrect use of GC_locker::is_active()
Summary: SymbolTable and StringTable can make calls to GC_locker::is_active() outside a safepoint. This isn't safe because the GC_locker active state (lock count) is only updated at a safepoint and only remains valid as long as _needs_gc is true. However, outside a safepoint_needs_gc can change to false at any time, which makes it impossible to do a correct call to is_active() in that context. In this case these calls can just be removed since the input argument to basic_add() should never be on the heap and so there's no need to check the GC_locker state. This change also adjusts the assert() in is_active() to makes sure all calls to this function are always done under a safepoint.
Reviewed-by: brutisso, dcubed
Contributed-by: per.liden@oracle.com
author | stefank |
---|---|
date | Fri, 20 Sep 2013 10:53:28 +0200 |
parents | f95d63e2154a |
children |
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/* * Copyright (c) 2003, 2010, 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. * */ #ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_ADJOININGVIRTUALSPACES_HPP #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_ADJOININGVIRTUALSPACES_HPP #include "gc_implementation/parallelScavenge/psVirtualspace.hpp" // Contains two virtual spaces that each can individually span // most of the reserved region but committed parts of which // cannot overlap. // // +-------+ <--- high_boundary for H // | | // | H | // | | // | | // | | // --------- <--- low for H // | | // ========= <--- low_boundary for H, high_boundary for L // | | // | | // | | // --------- <--- high for L // | | // | L | // | | // | | // | | // +-------+ <--- low_boundary for L // // Each virtual space in the AdjoiningVirtualSpaces grows and shrink // within its reserved region (between the low_boundary and the // boundary) independently. If L want to grow above its high_boundary, // then the high_boundary of L and the low_boundary of H must be // moved up consistently. AdjoiningVirtualSpaces provide the // interfaces for moving the this boundary. class AdjoiningVirtualSpaces { // space at the high end and the low end, respectively PSVirtualSpace* _high; PSVirtualSpace* _low; // The reserved space spanned by the two spaces. ReservedSpace _reserved_space; // The minimum byte size for the low space. It will not // be shrunk below this value. size_t _min_low_byte_size; // Same for the high space size_t _min_high_byte_size; const size_t _alignment; public: // Allocates two virtual spaces that will be located at the // high and low ends. Does no initialization. AdjoiningVirtualSpaces(ReservedSpace rs, size_t min_low_byte_size, size_t min_high_byte_size, size_t alignment); // accessors PSVirtualSpace* high() { return _high; } PSVirtualSpace* low() { return _low; } ReservedSpace reserved_space() { return _reserved_space; } size_t min_low_byte_size() { return _min_low_byte_size; } size_t min_high_byte_size() { return _min_high_byte_size; } size_t alignment() const { return _alignment; } // move boundary between the two spaces up bool adjust_boundary_up(size_t size_in_bytes); // and down bool adjust_boundary_down(size_t size_in_bytes); // Maximum byte size for the high space. size_t high_byte_size_limit() { return _reserved_space.size() - _min_low_byte_size; } // Maximum byte size for the low space. size_t low_byte_size_limit() { return _reserved_space.size() - _min_high_byte_size; } // Sets the boundaries for the virtual spaces and commits and // initial size; void initialize(size_t max_low_byte_size, size_t init_low_byte_size, size_t init_high_byte_size); }; #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_ADJOININGVIRTUALSPACES_HPP