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 /*

  * 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

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  */

 #include "precompiled.hpp"

 #include "gc_implementation/g1/g1PageBasedVirtualSpace.hpp"

 #include "oops/markOop.hpp"

 #include "oops/oop.inline.hpp"

 #include "services/memTracker.hpp"

 #ifdef TARGET_OS_FAMILY_linux

 # include "os_linux.inline.hpp"

 #endif

 #ifdef TARGET_OS_FAMILY_solaris

 # include "os_solaris.inline.hpp"

 #endif

 #ifdef TARGET_OS_FAMILY_windows

 # include "os_windows.inline.hpp"

 #endif

 #ifdef TARGET_OS_FAMILY_aix

 # include "os_aix.inline.hpp"

 #endif

 #ifdef TARGET_OS_FAMILY_bsd

 # include "os_bsd.inline.hpp"

 #endif

 #include "utilities/bitMap.inline.hpp"

 G1PageBasedVirtualSpace::G1PageBasedVirtualSpace(ReservedSpace rs, size_t used_size, size_t page_size) :

   _low_boundary(NULL), _high_boundary(NULL), _committed(), _page_size(0), _special(false),

   _dirty(), _executable(false) {

   initialize_with_page_size(rs, used_size, page_size);

 }

 void G1PageBasedVirtualSpace::initialize_with_page_size(ReservedSpace rs, size_t used_size, size_t page_size) {

   guarantee(rs.is_reserved(), "Given reserved space must have been reserved already.");

   assert(_low_boundary == NULL, "VirtualSpace already initialized");

   assert(page_size > 0, "Page size must be non-zero.");

   guarantee(is_ptr_aligned(rs.base(), page_size),

             err_msg("Reserved space base " PTR_FORMAT " is not aligned to requested page size " SIZE_FORMAT, p2i(rs.base()), page_size));

   guarantee(is_size_aligned(used_size, os::vm_page_size()),

             err_msg("Given used reserved space size needs to be OS page size aligned (%d bytes) but is " SIZE_FORMAT, os::vm_page_size(), used_size));

   guarantee(used_size <= rs.size(),

             err_msg("Used size of reserved space " SIZE_FORMAT " bytes is smaller than reservation at " SIZE_FORMAT " bytes", used_size, rs.size()));

   guarantee(is_size_aligned(rs.size(), page_size),

             err_msg("Expected that the virtual space is size aligned, but " SIZE_FORMAT " is not aligned to page size " SIZE_FORMAT, rs.size(), page_size));

   _low_boundary  = rs.base();

   _high_boundary = _low_boundary + used_size;

   _special = rs.special();

   _executable = rs.executable();

   _page_size = page_size;

   assert(_committed.size() == 0, "virtual space initialized more than once");

   BitMap::idx_t size_in_pages = rs.size() / page_size;

   _committed.resize(size_in_pages, /* in_resource_area */ false);

   if (_special) {

     _dirty.resize(size_in_pages, /* in_resource_area */ false);

   }

   _tail_size = used_size % _page_size;

 }

 G1PageBasedVirtualSpace::~G1PageBasedVirtualSpace() {

   release();

 }

 void G1PageBasedVirtualSpace::release() {

   // This does not release memory it never reserved.

   // Caller must release via rs.release();

   _low_boundary           = NULL;

   _high_boundary          = NULL;

   _special                = false;

   _executable             = false;

   _page_size              = 0;

   _tail_size              = 0;

   _committed.resize(0, false);

   _dirty.resize(0, false);

 }

 size_t G1PageBasedVirtualSpace::committed_size() const {

   size_t result = _committed.count_one_bits() * _page_size;

   // The last page might not be in full.

   if (is_last_page_partial() && _committed.at(_committed.size() - 1)) {

     result -= _page_size - _tail_size;

   }

   return result;

 }

 size_t G1PageBasedVirtualSpace::reserved_size() const {

   return pointer_delta(_high_boundary, _low_boundary, sizeof(char));

 }

 size_t G1PageBasedVirtualSpace::uncommitted_size()  const {

   return reserved_size() - committed_size();

 }

 size_t G1PageBasedVirtualSpace::addr_to_page_index(char* addr) const {

   return (addr - _low_boundary) / _page_size;

 }

 bool G1PageBasedVirtualSpace::is_area_committed(size_t start_page, size_t size_in_pages) const {

   size_t end_page = start_page + size_in_pages;

   return _committed.get_next_zero_offset(start_page, end_page) >= end_page;

 }

 bool G1PageBasedVirtualSpace::is_area_uncommitted(size_t start_page, size_t size_in_pages) const {

   size_t end_page = start_page + size_in_pages;

   return _committed.get_next_one_offset(start_page, end_page) >= end_page;

 }

 char* G1PageBasedVirtualSpace::page_start(size_t index) const {

   return _low_boundary + index * _page_size;

 }

 bool G1PageBasedVirtualSpace::is_after_last_page(size_t index) const {

   guarantee(index <= _committed.size(),

             err_msg("Given boundary page " SIZE_FORMAT " is beyond managed page count " SIZE_FORMAT, index, _committed.size()));

   return index == _committed.size();

 }

 void G1PageBasedVirtualSpace::commit_preferred_pages(size_t start, size_t num_pages) {

   assert(num_pages > 0, "No full pages to commit");

   assert(start + num_pages <= _committed.size(),

            err_msg("Tried to commit area from page " SIZE_FORMAT " to page " SIZE_FORMAT " "

                    "that is outside of managed space of " SIZE_FORMAT " pages",

                    start, start + num_pages, _committed.size()));

   char* start_addr = page_start(start);

   size_t size = num_pages * _page_size;

   os::commit_memory_or_exit(start_addr, size, _page_size, _executable,

                             err_msg("Failed to commit area from " PTR_FORMAT " to " PTR_FORMAT " of length " SIZE_FORMAT ".",

                                     p2i(start_addr), p2i(start_addr + size), size));

 }

 void G1PageBasedVirtualSpace::commit_tail() {

   assert(_tail_size > 0, "The size of the tail area must be > 0 when reaching here");

   char* const aligned_end_address = (char*)align_ptr_down(_high_boundary, _page_size);

   os::commit_memory_or_exit(aligned_end_address, _tail_size, os::vm_page_size(), _executable,

                             err_msg("Failed to commit tail area from " PTR_FORMAT " to " PTR_FORMAT " of length " SIZE_FORMAT ".",

                                     p2i(aligned_end_address), p2i(_high_boundary), _tail_size));

 }

 void G1PageBasedVirtualSpace::commit_internal(size_t start_page, size_t end_page) {

   guarantee(start_page < end_page,

             err_msg("Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page));

   guarantee(end_page <= _committed.size(),

             err_msg("Given end page " SIZE_FORMAT " is beyond end of managed page amount of " SIZE_FORMAT, end_page, _committed.size()));

   size_t pages = end_page - start_page;

   bool need_to_commit_tail = is_after_last_page(end_page) && is_last_page_partial();

   // If we have to commit some (partial) tail area, decrease the amount of pages to avoid

   // committing that in the full-page commit code.

   if (need_to_commit_tail) {

     pages--;

   }

   if (pages > 0) {

     commit_preferred_pages(start_page, pages);

   }

   if (need_to_commit_tail) {

     commit_tail();

   }

 }

 char* G1PageBasedVirtualSpace::bounded_end_addr(size_t end_page) const {

   return MIN2(_high_boundary, page_start(end_page));

 }

 void G1PageBasedVirtualSpace::pretouch_internal(size_t start_page, size_t end_page) {

   guarantee(start_page < end_page,

             err_msg("Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page));

   os::pretouch_memory(page_start(start_page), bounded_end_addr(end_page));

 }

 bool G1PageBasedVirtualSpace::commit(size_t start_page, size_t size_in_pages) {

   // We need to make sure to commit all pages covered by the given area.

   guarantee(is_area_uncommitted(start_page, size_in_pages), "Specified area is not uncommitted");

   bool zero_filled = true;

   size_t end_page = start_page + size_in_pages;

   if (_special) {

     // Check for dirty pages and update zero_filled if any found.

     if (_dirty.get_next_one_offset(start_page, end_page) < end_page) {

       zero_filled = false;

       _dirty.clear_range(start_page, end_page);

     }

   } else {

     commit_internal(start_page, end_page);

   }

   _committed.set_range(start_page, end_page);

   if (AlwaysPreTouch) {

     pretouch_internal(start_page, end_page);

   }

   return zero_filled;

 }

 void G1PageBasedVirtualSpace::uncommit_internal(size_t start_page, size_t end_page) {

   guarantee(start_page < end_page,

             err_msg("Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page));

   char* start_addr = page_start(start_page);

   os::uncommit_memory(start_addr, pointer_delta(bounded_end_addr(end_page), start_addr, sizeof(char)));

 }

 void G1PageBasedVirtualSpace::uncommit(size_t start_page, size_t size_in_pages) {

   guarantee(is_area_committed(start_page, size_in_pages), "checking");

   size_t end_page = start_page + size_in_pages;

   if (_special) {

     // Mark that memory is dirty. If committed again the memory might

     // need to be cleared explicitly.

     _dirty.set_range(start_page, end_page);

   } else {

     uncommit_internal(start_page, end_page);

   }

   _committed.clear_range(start_page, end_page);

 }

 bool G1PageBasedVirtualSpace::contains(const void* p) const {

   return _low_boundary <= (const char*) p && (const char*) p < _high_boundary;

 }

 #ifndef PRODUCT

 void G1PageBasedVirtualSpace::print_on(outputStream* out) {

   out->print   ("Virtual space:");

   if (_special) out->print(" (pinned in memory)");

   out->cr();

   out->print_cr(" - committed: " SIZE_FORMAT, committed_size());

   out->print_cr(" - reserved:  " SIZE_FORMAT, reserved_size());

   out->print_cr(" - preferred page size: " SIZE_FORMAT, _page_size);

   out->print_cr(" - [low_b, high_b]: [" PTR_FORMAT ", " PTR_FORMAT "]",  p2i(_low_boundary), p2i(_high_boundary));

 }

 void G1PageBasedVirtualSpace::print() {

   print_on(tty);

 }

 #endif