--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/g1/g1PageBasedVirtualSpace.hpp Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,154 @@
+/*
+ * Copyright (c) 2014, 2015, 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_G1_G1PAGEBASEDVIRTUALSPACE_HPP
+#define SHARE_VM_GC_G1_G1PAGEBASEDVIRTUALSPACE_HPP
+
+#include "memory/allocation.hpp"
+#include "memory/memRegion.hpp"
+#include "memory/virtualspace.hpp"
+#include "utilities/align.hpp"
+#include "utilities/bitMap.hpp"
+
+class WorkGang;
+
+// Virtual space management helper for a virtual space with an OS page allocation
+// granularity.
+// (De-)Allocation requests are always OS page aligned by passing a page index
+// and multiples of pages.
+// For systems that only commits of memory in a given size (always greater than
+// page size) the base address is required to be aligned to that page size.
+// The actual size requested need not be aligned to that page size, but the size
+// of the reservation passed may be rounded up to this page size. Any fragment
+// (less than the page size) of the actual size at the tail of the request will
+// be committed using OS small pages.
+// The implementation gives an error when trying to commit or uncommit pages that
+// have already been committed or uncommitted.
+class G1PageBasedVirtualSpace VALUE_OBJ_CLASS_SPEC {
+ friend class VMStructs;
+ private:
+ // Reserved area addresses.
+ char* _low_boundary;
+ char* _high_boundary;
+
+ // The size of the tail in bytes of the handled space that needs to be committed
+ // using small pages.
+ size_t _tail_size;
+
+ // The preferred page size used for commit/uncommit in bytes.
+ size_t _page_size;
+
+ // Bitmap used for verification of commit/uncommit operations.
+ CHeapBitMap _committed;
+
+ // Bitmap used to keep track of which pages are dirty or not for _special
+ // spaces. This is needed because for those spaces the underlying memory
+ // will only be zero filled the first time it is committed. Calls to commit
+ // will use this bitmap and return whether or not the memory is zero filled.
+ CHeapBitMap _dirty;
+
+ // Indicates that the entire space has been committed and pinned in memory,
+ // os::commit_memory() or os::uncommit_memory() have no function.
+ bool _special;
+
+ // Indicates whether the committed space should be executable.
+ bool _executable;
+
+ // Helper function for committing memory. Commit the given memory range by using
+ // _page_size pages as much as possible and the remainder with small sized pages.
+ void commit_internal(size_t start_page, size_t end_page);
+ // Commit num_pages pages of _page_size size starting from start. All argument
+ // checking has been performed.
+ void commit_preferred_pages(size_t start_page, size_t end_page);
+ // Commit space at the high end of the space that needs to be committed with small
+ // sized pages.
+ void commit_tail();
+
+ // Uncommit the given memory range.
+ void uncommit_internal(size_t start_page, size_t end_page);
+
+ // Pretouch the given memory range.
+ void pretouch_internal(size_t start_page, size_t end_page);
+
+ // Returns the index of the page which contains the given address.
+ uintptr_t addr_to_page_index(char* addr) const;
+ // Returns the address of the given page index.
+ char* page_start(size_t index) const;
+
+ // Is the given page index the last page?
+ bool is_last_page(size_t index) const { return index == (_committed.size() - 1); }
+ // Is the given page index the first after last page?
+ bool is_after_last_page(size_t index) const;
+ // Is the last page only partially covered by this space?
+ bool is_last_page_partial() const { return !is_aligned(_high_boundary, _page_size); }
+ // Returns the end address of the given page bounded by the reserved space.
+ char* bounded_end_addr(size_t end_page) const;
+
+ // Returns true if the entire area is backed by committed memory.
+ bool is_area_committed(size_t start_page, size_t size_in_pages) const;
+ // Returns true if the entire area is not backed by committed memory.
+ bool is_area_uncommitted(size_t start_page, size_t size_in_pages) const;
+
+ void initialize_with_page_size(ReservedSpace rs, size_t used_size, size_t page_size);
+ public:
+
+ // Commit the given area of pages starting at start being size_in_pages large.
+ // Returns true if the given area is zero filled upon completion.
+ bool commit(size_t start_page, size_t size_in_pages);
+
+ // Uncommit the given area of pages starting at start being size_in_pages large.
+ void uncommit(size_t start_page, size_t size_in_pages);
+
+ void pretouch(size_t start_page, size_t size_in_pages, WorkGang* pretouch_gang = NULL);
+
+ // Initialize the given reserved space with the given base address and the size
+ // actually used.
+ // Prefer to commit in page_size chunks.
+ G1PageBasedVirtualSpace(ReservedSpace rs, size_t used_size, size_t page_size);
+
+ // Destruction
+ ~G1PageBasedVirtualSpace();
+
+ // Amount of reserved memory.
+ size_t reserved_size() const;
+ // Memory used 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;
+
+ MemRegion reserved() {
+ MemRegion x((HeapWord*)_low_boundary, reserved_size() / HeapWordSize);
+ return x;
+ }
+
+ void check_for_contiguity() PRODUCT_RETURN;
+
+ // Debugging
+ void print_on(outputStream* out) PRODUCT_RETURN;
+ void print();
+};
+
+#endif // SHARE_VM_GC_G1_G1PAGEBASEDVIRTUALSPACE_HPP