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/*
* Copyright (c) 1997, 2021, 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_MEMORY_VIRTUALSPACE_HPP
#define SHARE_MEMORY_VIRTUALSPACE_HPP
#include "memory/memRegion.hpp"
#include "utilities/globalDefinitions.hpp"
class outputStream;
// ReservedSpace is a data structure for reserving a contiguous address range.
class ReservedSpace {
friend class VMStructs;
protected:
char* _base;
size_t _size;
size_t _noaccess_prefix;
size_t _alignment;
size_t _page_size;
bool _special;
int _fd_for_heap;
private:
bool _executable;
// ReservedSpace
ReservedSpace(char* base, size_t size, size_t alignment,
size_t page_size, bool special, bool executable);
protected:
// Helpers to clear and set members during initialization. Two members
// require special treatment:
// * _fd_for_heap - The fd is set once and should not be cleared
// even if the reservation has to be retried.
// * _noaccess_prefix - Used for compressed heaps and updated after
// the reservation is initialized. Always set to
// 0 during initialization.
void clear_members();
void initialize_members(char* base, size_t size, size_t alignment,
size_t page_size, bool special, bool executable);
void initialize(size_t size, size_t alignment, size_t page_size,
char* requested_address, bool executable);
void reserve(size_t size, size_t alignment, size_t page_size,
char* requested_address, bool executable);
public:
// Constructor
ReservedSpace();
// Initialize the reserved space with the given size. Depending on the size
// a suitable page size and alignment will be used.
explicit ReservedSpace(size_t size);
// Initialize the reserved space with the given size. The preferred_page_size
// is used as the minimum page size/alignment. This may waste some space if
// the given size is not aligned to that value, as the reservation will be
// aligned up to the final alignment in this case.
ReservedSpace(size_t size, size_t preferred_page_size);
ReservedSpace(size_t size, size_t alignment, size_t page_size,
char* requested_address = NULL);
// Accessors
char* base() const { return _base; }
size_t size() const { return _size; }
char* end() const { return _base + _size; }
size_t alignment() const { return _alignment; }
size_t page_size() const { return _page_size; }
bool special() const { return _special; }
bool executable() const { return _executable; }
size_t noaccess_prefix() const { return _noaccess_prefix; }
bool is_reserved() const { return _base != NULL; }
void release();
// Splitting
// This splits the space into two spaces, the first part of which will be returned.
ReservedSpace first_part(size_t partition_size, size_t alignment);
ReservedSpace last_part (size_t partition_size, size_t alignment);
// These simply call the above using the default alignment.
inline ReservedSpace first_part(size_t partition_size);
inline ReservedSpace last_part (size_t partition_size);
// Alignment
static size_t page_align_size_up(size_t size);
static size_t page_align_size_down(size_t size);
static size_t allocation_align_size_up(size_t size);
bool contains(const void* p) const {
return (base() <= ((char*)p)) && (((char*)p) < (base() + size()));
}
};
ReservedSpace
ReservedSpace::first_part(size_t partition_size)
{
return first_part(partition_size, alignment());
}
ReservedSpace ReservedSpace::last_part(size_t partition_size)
{
return last_part(partition_size, alignment());
}
// Class encapsulating behavior specific of memory space reserved for Java heap.
class ReservedHeapSpace : public ReservedSpace {
private:
void try_reserve_heap(size_t size, size_t alignment, size_t page_size,
char *requested_address);
void try_reserve_range(char *highest_start, char *lowest_start,
size_t attach_point_alignment, char *aligned_HBMA,
char *upper_bound, size_t size, size_t alignment, size_t page_size);
void initialize_compressed_heap(const size_t size, size_t alignment, size_t page_size);
// Create protection page at the beginning of the space.
void establish_noaccess_prefix();
public:
// Constructor. Tries to find a heap that is good for compressed oops.
// heap_allocation_directory is the path to the backing memory for Java heap. When set, Java heap will be allocated
// on the device which is managed by the file system where the directory resides.
ReservedHeapSpace(size_t size, size_t forced_base_alignment, size_t page_size, const char* heap_allocation_directory = NULL);
// Returns the base to be used for compression, i.e. so that null can be
// encoded safely and implicit null checks can work.
char *compressed_oop_base() const { return _base - _noaccess_prefix; }
MemRegion region() const;
};
// Class encapsulating behavior specific memory space for Code
class ReservedCodeSpace : public ReservedSpace {
public:
// Constructor
ReservedCodeSpace(size_t r_size, size_t rs_align, size_t page_size);
};
// VirtualSpace is data structure for committing a previously reserved address range in smaller chunks.
class VirtualSpace {
friend class VMStructs;
private:
// Reserved area
char* _low_boundary;
char* _high_boundary;
// Committed area
char* _low;
char* _high;
// The entire space has been committed and pinned in memory, no
// os::commit_memory() or os::uncommit_memory().
bool _special;
// Need to know if commit should be executable.
bool _executable;
// MPSS Support
// Each virtualspace region has a lower, middle, and upper region.
// Each region has an end boundary and a high pointer which is the
// high water mark for the last allocated byte.
// The lower and upper unaligned to LargePageSizeInBytes uses default page.
// size. The middle region uses large page size.
char* _lower_high;
char* _middle_high;
char* _upper_high;
char* _lower_high_boundary;
char* _middle_high_boundary;
char* _upper_high_boundary;
size_t _lower_alignment;
size_t _middle_alignment;
size_t _upper_alignment;
// MPSS Accessors
char* lower_high() const { return _lower_high; }
char* middle_high() const { return _middle_high; }
char* upper_high() const { return _upper_high; }
char* lower_high_boundary() const { return _lower_high_boundary; }
char* middle_high_boundary() const { return _middle_high_boundary; }
char* upper_high_boundary() const { return _upper_high_boundary; }
size_t lower_alignment() const { return _lower_alignment; }
size_t middle_alignment() const { return _middle_alignment; }
size_t upper_alignment() const { return _upper_alignment; }
public:
// Committed area
char* low() const { return _low; }
char* high() const { return _high; }
// Reserved area
char* low_boundary() const { return _low_boundary; }
char* high_boundary() const { return _high_boundary; }
bool special() const { return _special; }
public:
// Initialization
VirtualSpace();
bool initialize_with_granularity(ReservedSpace rs, size_t committed_byte_size, size_t max_commit_ganularity);
bool initialize(ReservedSpace rs, size_t committed_byte_size);
// Destruction
~VirtualSpace();
// Reserved memory
size_t reserved_size() const;
// Actually committed OS memory
size_t actual_committed_size() const;
// Memory used/expanded in this virtual space
size_t committed_size() const;
// Memory left to use/expand in this virtual space
size_t uncommitted_size() const;
bool contains(const void* p) const;
// Operations
// returns true on success, false otherwise
bool expand_by(size_t bytes, bool pre_touch = false);
void shrink_by(size_t bytes);
void release();
void check_for_contiguity() PRODUCT_RETURN;
// Debugging
void print_on(outputStream* out) const PRODUCT_RETURN;
void print() const;
};
#endif // SHARE_MEMORY_VIRTUALSPACE_HPP
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