8221540: ZGC: Reduce width of zForwardingEntry::from_index field
Reviewed-by: stefank, eosterlund
/*
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* 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.
*
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*/
#ifndef SHARE_GC_Z_ZALLOCATIONFLAGS_HPP
#define SHARE_GC_Z_ZALLOCATIONFLAGS_HPP
#include "gc/z/zBitField.hpp"
#include "memory/allocation.hpp"
//
// Allocation flags layout
// -----------------------
//
// 7 3 2 1 0
// +----+-+-+-+-+
// |0000|1|1|1|1|
// +----+-+-+-+-+
// | | | | |
// | | | | * 0-0 Worker Thread Flag (1-bit)
// | | | |
// | | | * 1-1 Non-Blocking Flag (1-bit)
// | | |
// | | * 2-2 Relocation Flag (1-bit)
// | |
// | * 3-3 No Reserve Flag (1-bit)
// |
// * 7-4 Unused (4-bits)
//
class ZAllocationFlags {
private:
typedef ZBitField<uint8_t, bool, 0, 1> field_worker_thread;
typedef ZBitField<uint8_t, bool, 1, 1> field_non_blocking;
typedef ZBitField<uint8_t, bool, 2, 1> field_relocation;
typedef ZBitField<uint8_t, bool, 3, 1> field_no_reserve;
uint8_t _flags;
public:
ZAllocationFlags() :
_flags(0) {}
void set_worker_thread() {
_flags |= field_worker_thread::encode(true);
}
void set_non_blocking() {
_flags |= field_non_blocking::encode(true);
}
void set_relocation() {
_flags |= field_relocation::encode(true);
}
void set_no_reserve() {
_flags |= field_no_reserve::encode(true);
}
bool worker_thread() const {
return field_worker_thread::decode(_flags);
}
bool non_blocking() const {
return field_non_blocking::decode(_flags);
}
bool relocation() const {
return field_relocation::decode(_flags);
}
bool no_reserve() const {
return field_no_reserve::decode(_flags);
}
};
#endif // SHARE_GC_Z_ZALLOCATIONFLAGS_HPP