| /* |
| * Copyright (c) 1997, 2012, 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. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "oops/markOop.hpp" |
| #include "oops/oop.inline.hpp" |
| #include "runtime/virtualspace.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_bsd |
| # include "os_bsd.inline.hpp" |
| #endif |
| |
| |
| // ReservedSpace |
| ReservedSpace::ReservedSpace(size_t size) { |
| initialize(size, 0, false, NULL, 0, false); |
| } |
| |
| ReservedSpace::ReservedSpace(size_t size, size_t alignment, |
| bool large, |
| char* requested_address, |
| const size_t noaccess_prefix) { |
| initialize(size+noaccess_prefix, alignment, large, requested_address, |
| noaccess_prefix, false); |
| } |
| |
| ReservedSpace::ReservedSpace(size_t size, size_t alignment, |
| bool large, |
| bool executable) { |
| initialize(size, alignment, large, NULL, 0, executable); |
| } |
| |
| char * |
| ReservedSpace::align_reserved_region(char* addr, const size_t len, |
| const size_t prefix_size, |
| const size_t prefix_align, |
| const size_t suffix_size, |
| const size_t suffix_align) |
| { |
| assert(addr != NULL, "sanity"); |
| const size_t required_size = prefix_size + suffix_size; |
| assert(len >= required_size, "len too small"); |
| |
| const size_t s = size_t(addr); |
| const size_t beg_ofs = (s + prefix_size) & (suffix_align - 1); |
| const size_t beg_delta = beg_ofs == 0 ? 0 : suffix_align - beg_ofs; |
| |
| if (len < beg_delta + required_size) { |
| return NULL; // Cannot do proper alignment. |
| } |
| const size_t end_delta = len - (beg_delta + required_size); |
| |
| if (beg_delta != 0) { |
| os::release_memory(addr, beg_delta); |
| } |
| |
| if (end_delta != 0) { |
| char* release_addr = (char*) (s + beg_delta + required_size); |
| os::release_memory(release_addr, end_delta); |
| } |
| |
| return (char*) (s + beg_delta); |
| } |
| |
| char* ReservedSpace::reserve_and_align(const size_t reserve_size, |
| const size_t prefix_size, |
| const size_t prefix_align, |
| const size_t suffix_size, |
| const size_t suffix_align) |
| { |
| assert(reserve_size > prefix_size + suffix_size, "should not be here"); |
| |
| char* raw_addr = os::reserve_memory(reserve_size, NULL, prefix_align); |
| if (raw_addr == NULL) return NULL; |
| |
| char* result = align_reserved_region(raw_addr, reserve_size, prefix_size, |
| prefix_align, suffix_size, |
| suffix_align); |
| if (result == NULL && !os::release_memory(raw_addr, reserve_size)) { |
| fatal("os::release_memory failed"); |
| } |
| |
| #ifdef ASSERT |
| if (result != NULL) { |
| const size_t raw = size_t(raw_addr); |
| const size_t res = size_t(result); |
| assert(res >= raw, "alignment decreased start addr"); |
| assert(res + prefix_size + suffix_size <= raw + reserve_size, |
| "alignment increased end addr"); |
| assert((res & (prefix_align - 1)) == 0, "bad alignment of prefix"); |
| assert(((res + prefix_size) & (suffix_align - 1)) == 0, |
| "bad alignment of suffix"); |
| } |
| #endif |
| |
| return result; |
| } |
| |
| // Helper method. |
| static bool failed_to_reserve_as_requested(char* base, char* requested_address, |
| const size_t size, bool special) |
| { |
| if (base == requested_address || requested_address == NULL) |
| return false; // did not fail |
| |
| if (base != NULL) { |
| // Different reserve address may be acceptable in other cases |
| // but for compressed oops heap should be at requested address. |
| assert(UseCompressedOops, "currently requested address used only for compressed oops"); |
| if (PrintCompressedOopsMode) { |
| tty->cr(); |
| tty->print_cr("Reserved memory not at requested address: " PTR_FORMAT " vs " PTR_FORMAT, base, requested_address); |
| } |
| // OS ignored requested address. Try different address. |
| if (special) { |
| if (!os::release_memory_special(base, size)) { |
| fatal("os::release_memory_special failed"); |
| } |
| } else { |
| if (!os::release_memory(base, size)) { |
| fatal("os::release_memory failed"); |
| } |
| } |
| } |
| return true; |
| } |
| |
| ReservedSpace::ReservedSpace(const size_t prefix_size, |
| const size_t prefix_align, |
| const size_t suffix_size, |
| const size_t suffix_align, |
| char* requested_address, |
| const size_t noaccess_prefix) |
| { |
| assert(prefix_size != 0, "sanity"); |
| assert(prefix_align != 0, "sanity"); |
| assert(suffix_size != 0, "sanity"); |
| assert(suffix_align != 0, "sanity"); |
| assert((prefix_size & (prefix_align - 1)) == 0, |
| "prefix_size not divisible by prefix_align"); |
| assert((suffix_size & (suffix_align - 1)) == 0, |
| "suffix_size not divisible by suffix_align"); |
| assert((suffix_align & (prefix_align - 1)) == 0, |
| "suffix_align not divisible by prefix_align"); |
| |
| // Assert that if noaccess_prefix is used, it is the same as prefix_align. |
| assert(noaccess_prefix == 0 || |
| noaccess_prefix == prefix_align, "noaccess prefix wrong"); |
| |
| // Add in noaccess_prefix to prefix_size; |
| const size_t adjusted_prefix_size = prefix_size + noaccess_prefix; |
| const size_t size = adjusted_prefix_size + suffix_size; |
| |
| // On systems where the entire region has to be reserved and committed up |
| // front, the compound alignment normally done by this method is unnecessary. |
| const bool try_reserve_special = UseLargePages && |
| prefix_align == os::large_page_size(); |
| if (!os::can_commit_large_page_memory() && try_reserve_special) { |
| initialize(size, prefix_align, true, requested_address, noaccess_prefix, |
| false); |
| return; |
| } |
| |
| _base = NULL; |
| _size = 0; |
| _alignment = 0; |
| _special = false; |
| _noaccess_prefix = 0; |
| _executable = false; |
| |
| // Optimistically try to reserve the exact size needed. |
| char* addr; |
| if (requested_address != 0) { |
| requested_address -= noaccess_prefix; // adjust address |
| assert(requested_address != NULL, "huge noaccess prefix?"); |
| addr = os::attempt_reserve_memory_at(size, requested_address); |
| if (failed_to_reserve_as_requested(addr, requested_address, size, false)) { |
| // OS ignored requested address. Try different address. |
| addr = NULL; |
| } |
| } else { |
| addr = os::reserve_memory(size, NULL, prefix_align); |
| } |
| if (addr == NULL) return; |
| |
| // Check whether the result has the needed alignment (unlikely unless |
| // prefix_align < suffix_align). |
| const size_t ofs = (size_t(addr) + adjusted_prefix_size) & (suffix_align - 1); |
| if (ofs != 0) { |
| // Wrong alignment. Release, allocate more space and do manual alignment. |
| // |
| // On most operating systems, another allocation with a somewhat larger size |
| // will return an address "close to" that of the previous allocation. The |
| // result is often the same address (if the kernel hands out virtual |
| // addresses from low to high), or an address that is offset by the increase |
| // in size. Exploit that to minimize the amount of extra space requested. |
| if (!os::release_memory(addr, size)) { |
| fatal("os::release_memory failed"); |
| } |
| |
| const size_t extra = MAX2(ofs, suffix_align - ofs); |
| addr = reserve_and_align(size + extra, adjusted_prefix_size, prefix_align, |
| suffix_size, suffix_align); |
| if (addr == NULL) { |
| // Try an even larger region. If this fails, address space is exhausted. |
| addr = reserve_and_align(size + suffix_align, adjusted_prefix_size, |
| prefix_align, suffix_size, suffix_align); |
| } |
| |
| if (requested_address != 0 && |
| failed_to_reserve_as_requested(addr, requested_address, size, false)) { |
| // As a result of the alignment constraints, the allocated addr differs |
| // from the requested address. Return back to the caller who can |
| // take remedial action (like try again without a requested address). |
| assert(_base == NULL, "should be"); |
| return; |
| } |
| } |
| |
| _base = addr; |
| _size = size; |
| _alignment = prefix_align; |
| _noaccess_prefix = noaccess_prefix; |
| } |
| |
| void ReservedSpace::initialize(size_t size, size_t alignment, bool large, |
| char* requested_address, |
| const size_t noaccess_prefix, |
| bool executable) { |
| const size_t granularity = os::vm_allocation_granularity(); |
| assert((size & (granularity - 1)) == 0, |
| "size not aligned to os::vm_allocation_granularity()"); |
| assert((alignment & (granularity - 1)) == 0, |
| "alignment not aligned to os::vm_allocation_granularity()"); |
| assert(alignment == 0 || is_power_of_2((intptr_t)alignment), |
| "not a power of 2"); |
| |
| alignment = MAX2(alignment, (size_t)os::vm_page_size()); |
| |
| // Assert that if noaccess_prefix is used, it is the same as alignment. |
| assert(noaccess_prefix == 0 || |
| noaccess_prefix == alignment, "noaccess prefix wrong"); |
| |
| _base = NULL; |
| _size = 0; |
| _special = false; |
| _executable = executable; |
| _alignment = 0; |
| _noaccess_prefix = 0; |
| if (size == 0) { |
| return; |
| } |
| |
| // If OS doesn't support demand paging for large page memory, we need |
| // to use reserve_memory_special() to reserve and pin the entire region. |
| bool special = large && !os::can_commit_large_page_memory(); |
| char* base = NULL; |
| |
| if (requested_address != 0) { |
| requested_address -= noaccess_prefix; // adjust requested address |
| assert(requested_address != NULL, "huge noaccess prefix?"); |
| } |
| |
| if (special) { |
| |
| base = os::reserve_memory_special(size, requested_address, executable); |
| |
| if (base != NULL) { |
| if (failed_to_reserve_as_requested(base, requested_address, size, true)) { |
| // OS ignored requested address. Try different address. |
| return; |
| } |
| // Check alignment constraints |
| assert((uintptr_t) base % alignment == 0, |
| "Large pages returned a non-aligned address"); |
| _special = true; |
| } else { |
| // failed; try to reserve regular memory below |
| if (UseLargePages && (!FLAG_IS_DEFAULT(UseLargePages) || |
| !FLAG_IS_DEFAULT(LargePageSizeInBytes))) { |
| if (PrintCompressedOopsMode) { |
| tty->cr(); |
| tty->print_cr("Reserve regular memory without large pages."); |
| } |
| } |
| } |
| } |
| |
| if (base == NULL) { |
| // Optimistically assume that the OSes returns an aligned base pointer. |
| // When reserving a large address range, most OSes seem to align to at |
| // least 64K. |
| |
| // If the memory was requested at a particular address, use |
| // os::attempt_reserve_memory_at() to avoid over mapping something |
| // important. If available space is not detected, return NULL. |
| |
| if (requested_address != 0) { |
| base = os::attempt_reserve_memory_at(size, requested_address); |
| if (failed_to_reserve_as_requested(base, requested_address, size, false)) { |
| // OS ignored requested address. Try different address. |
| base = NULL; |
| } |
| } else { |
| base = os::reserve_memory(size, NULL, alignment); |
| } |
| |
| if (base == NULL) return; |
| |
| // Check alignment constraints |
| if ((((size_t)base + noaccess_prefix) & (alignment - 1)) != 0) { |
| // Base not aligned, retry |
| if (!os::release_memory(base, size)) fatal("os::release_memory failed"); |
| // Reserve size large enough to do manual alignment and |
| // increase size to a multiple of the desired alignment |
| size = align_size_up(size, alignment); |
| size_t extra_size = size + alignment; |
| do { |
| char* extra_base = os::reserve_memory(extra_size, NULL, alignment); |
| if (extra_base == NULL) return; |
| // Do manual alignement |
| base = (char*) align_size_up((uintptr_t) extra_base, alignment); |
| assert(base >= extra_base, "just checking"); |
| // Re-reserve the region at the aligned base address. |
| os::release_memory(extra_base, extra_size); |
| base = os::reserve_memory(size, base); |
| } while (base == NULL); |
| |
| if (requested_address != 0 && |
| failed_to_reserve_as_requested(base, requested_address, size, false)) { |
| // As a result of the alignment constraints, the allocated base differs |
| // from the requested address. Return back to the caller who can |
| // take remedial action (like try again without a requested address). |
| assert(_base == NULL, "should be"); |
| return; |
| } |
| } |
| } |
| // Done |
| _base = base; |
| _size = size; |
| _alignment = alignment; |
| _noaccess_prefix = noaccess_prefix; |
| |
| // Assert that if noaccess_prefix is used, it is the same as alignment. |
| assert(noaccess_prefix == 0 || |
| noaccess_prefix == _alignment, "noaccess prefix wrong"); |
| |
| assert(markOopDesc::encode_pointer_as_mark(_base)->decode_pointer() == _base, |
| "area must be distinguisable from marks for mark-sweep"); |
| assert(markOopDesc::encode_pointer_as_mark(&_base[size])->decode_pointer() == &_base[size], |
| "area must be distinguisable from marks for mark-sweep"); |
| } |
| |
| |
| ReservedSpace::ReservedSpace(char* base, size_t size, size_t alignment, |
| bool special, bool executable) { |
| assert((size % os::vm_allocation_granularity()) == 0, |
| "size not allocation aligned"); |
| _base = base; |
| _size = size; |
| _alignment = alignment; |
| _noaccess_prefix = 0; |
| _special = special; |
| _executable = executable; |
| } |
| |
| |
| ReservedSpace ReservedSpace::first_part(size_t partition_size, size_t alignment, |
| bool split, bool realloc) { |
| assert(partition_size <= size(), "partition failed"); |
| if (split) { |
| os::split_reserved_memory(base(), size(), partition_size, realloc); |
| } |
| ReservedSpace result(base(), partition_size, alignment, special(), |
| executable()); |
| return result; |
| } |
| |
| |
| ReservedSpace |
| ReservedSpace::last_part(size_t partition_size, size_t alignment) { |
| assert(partition_size <= size(), "partition failed"); |
| ReservedSpace result(base() + partition_size, size() - partition_size, |
| alignment, special(), executable()); |
| return result; |
| } |
| |
| |
| size_t ReservedSpace::page_align_size_up(size_t size) { |
| return align_size_up(size, os::vm_page_size()); |
| } |
| |
| |
| size_t ReservedSpace::page_align_size_down(size_t size) { |
| return align_size_down(size, os::vm_page_size()); |
| } |
| |
| |
| size_t ReservedSpace::allocation_align_size_up(size_t size) { |
| return align_size_up(size, os::vm_allocation_granularity()); |
| } |
| |
| |
| size_t ReservedSpace::allocation_align_size_down(size_t size) { |
| return align_size_down(size, os::vm_allocation_granularity()); |
| } |
| |
| |
| void ReservedSpace::release() { |
| if (is_reserved()) { |
| char *real_base = _base - _noaccess_prefix; |
| const size_t real_size = _size + _noaccess_prefix; |
| if (special()) { |
| os::release_memory_special(real_base, real_size); |
| } else{ |
| os::release_memory(real_base, real_size); |
| } |
| _base = NULL; |
| _size = 0; |
| _noaccess_prefix = 0; |
| _special = false; |
| _executable = false; |
| } |
| } |
| |
| void ReservedSpace::protect_noaccess_prefix(const size_t size) { |
| assert( (_noaccess_prefix != 0) == (UseCompressedOops && _base != NULL && |
| (Universe::narrow_oop_base() != NULL) && |
| Universe::narrow_oop_use_implicit_null_checks()), |
| "noaccess_prefix should be used only with non zero based compressed oops"); |
| |
| // If there is no noaccess prefix, return. |
| if (_noaccess_prefix == 0) return; |
| |
| assert(_noaccess_prefix >= (size_t)os::vm_page_size(), |
| "must be at least page size big"); |
| |
| // Protect memory at the base of the allocated region. |
| // If special, the page was committed (only matters on windows) |
| if (!os::protect_memory(_base, _noaccess_prefix, os::MEM_PROT_NONE, |
| _special)) { |
| fatal("cannot protect protection page"); |
| } |
| if (PrintCompressedOopsMode) { |
| tty->cr(); |
| tty->print_cr("Protected page at the reserved heap base: " PTR_FORMAT " / " INTX_FORMAT " bytes", _base, _noaccess_prefix); |
| } |
| |
| _base += _noaccess_prefix; |
| _size -= _noaccess_prefix; |
| assert((size == _size) && ((uintptr_t)_base % _alignment == 0), |
| "must be exactly of required size and alignment"); |
| } |
| |
| ReservedHeapSpace::ReservedHeapSpace(size_t size, size_t alignment, |
| bool large, char* requested_address) : |
| ReservedSpace(size, alignment, large, |
| requested_address, |
| (UseCompressedOops && (Universe::narrow_oop_base() != NULL) && |
| Universe::narrow_oop_use_implicit_null_checks()) ? |
| lcm(os::vm_page_size(), alignment) : 0) { |
| // Only reserved space for the java heap should have a noaccess_prefix |
| // if using compressed oops. |
| protect_noaccess_prefix(size); |
| } |
| |
| ReservedHeapSpace::ReservedHeapSpace(const size_t prefix_size, |
| const size_t prefix_align, |
| const size_t suffix_size, |
| const size_t suffix_align, |
| char* requested_address) : |
| ReservedSpace(prefix_size, prefix_align, suffix_size, suffix_align, |
| requested_address, |
| (UseCompressedOops && (Universe::narrow_oop_base() != NULL) && |
| Universe::narrow_oop_use_implicit_null_checks()) ? |
| lcm(os::vm_page_size(), prefix_align) : 0) { |
| protect_noaccess_prefix(prefix_size+suffix_size); |
| } |
| |
| // Reserve space for code segment. Same as Java heap only we mark this as |
| // executable. |
| ReservedCodeSpace::ReservedCodeSpace(size_t r_size, |
| size_t rs_align, |
| bool large) : |
| ReservedSpace(r_size, rs_align, large, /*executable*/ true) { |
| } |
| |
| // VirtualSpace |
| |
| VirtualSpace::VirtualSpace() { |
| _low_boundary = NULL; |
| _high_boundary = NULL; |
| _low = NULL; |
| _high = NULL; |
| _lower_high = NULL; |
| _middle_high = NULL; |
| _upper_high = NULL; |
| _lower_high_boundary = NULL; |
| _middle_high_boundary = NULL; |
| _upper_high_boundary = NULL; |
| _lower_alignment = 0; |
| _middle_alignment = 0; |
| _upper_alignment = 0; |
| _special = false; |
| _executable = false; |
| } |
| |
| |
| bool VirtualSpace::initialize(ReservedSpace rs, size_t committed_size) { |
| if(!rs.is_reserved()) return false; // allocation failed. |
| assert(_low_boundary == NULL, "VirtualSpace already initialized"); |
| _low_boundary = rs.base(); |
| _high_boundary = low_boundary() + rs.size(); |
| |
| _low = low_boundary(); |
| _high = low(); |
| |
| _special = rs.special(); |
| _executable = rs.executable(); |
| |
| // When a VirtualSpace begins life at a large size, make all future expansion |
| // and shrinking occur aligned to a granularity of large pages. This avoids |
| // fragmentation of physical addresses that inhibits the use of large pages |
| // by the OS virtual memory system. Empirically, we see that with a 4MB |
| // page size, the only spaces that get handled this way are codecache and |
| // the heap itself, both of which provide a substantial performance |
| // boost in many benchmarks when covered by large pages. |
| // |
| // No attempt is made to force large page alignment at the very top and |
| // bottom of the space if they are not aligned so already. |
| _lower_alignment = os::vm_page_size(); |
| _middle_alignment = os::page_size_for_region(rs.size(), rs.size(), 1); |
| _upper_alignment = os::vm_page_size(); |
| |
| // End of each region |
| _lower_high_boundary = (char*) round_to((intptr_t) low_boundary(), middle_alignment()); |
| _middle_high_boundary = (char*) round_down((intptr_t) high_boundary(), middle_alignment()); |
| _upper_high_boundary = high_boundary(); |
| |
| // High address of each region |
| _lower_high = low_boundary(); |
| _middle_high = lower_high_boundary(); |
| _upper_high = middle_high_boundary(); |
| |
| // commit to initial size |
| if (committed_size > 0) { |
| if (!expand_by(committed_size)) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| |
| VirtualSpace::~VirtualSpace() { |
| release(); |
| } |
| |
| |
| void VirtualSpace::release() { |
| // This does not release memory it never reserved. |
| // Caller must release via rs.release(); |
| _low_boundary = NULL; |
| _high_boundary = NULL; |
| _low = NULL; |
| _high = NULL; |
| _lower_high = NULL; |
| _middle_high = NULL; |
| _upper_high = NULL; |
| _lower_high_boundary = NULL; |
| _middle_high_boundary = NULL; |
| _upper_high_boundary = NULL; |
| _lower_alignment = 0; |
| _middle_alignment = 0; |
| _upper_alignment = 0; |
| _special = false; |
| _executable = false; |
| } |
| |
| |
| size_t VirtualSpace::committed_size() const { |
| return pointer_delta(high(), low(), sizeof(char)); |
| } |
| |
| |
| size_t VirtualSpace::reserved_size() const { |
| return pointer_delta(high_boundary(), low_boundary(), sizeof(char)); |
| } |
| |
| |
| size_t VirtualSpace::uncommitted_size() const { |
| return reserved_size() - committed_size(); |
| } |
| |
| |
| bool VirtualSpace::contains(const void* p) const { |
| return low() <= (const char*) p && (const char*) p < high(); |
| } |
| |
| /* |
| First we need to determine if a particular virtual space is using large |
| pages. This is done at the initialize function and only virtual spaces |
| that are larger than LargePageSizeInBytes use large pages. Once we |
| have determined this, all expand_by and shrink_by calls must grow and |
| shrink by large page size chunks. If a particular request |
| is within the current large page, the call to commit and uncommit memory |
| can be ignored. In the case that the low and high boundaries of this |
| space is not large page aligned, the pages leading to the first large |
| page address and the pages after the last large page address must be |
| allocated with default pages. |
| */ |
| bool VirtualSpace::expand_by(size_t bytes, bool pre_touch) { |
| if (uncommitted_size() < bytes) return false; |
| |
| if (special()) { |
| // don't commit memory if the entire space is pinned in memory |
| _high += bytes; |
| return true; |
| } |
| |
| char* previous_high = high(); |
| char* unaligned_new_high = high() + bytes; |
| assert(unaligned_new_high <= high_boundary(), |
| "cannot expand by more than upper boundary"); |
| |
| // Calculate where the new high for each of the regions should be. If |
| // the low_boundary() and high_boundary() are LargePageSizeInBytes aligned |
| // then the unaligned lower and upper new highs would be the |
| // lower_high() and upper_high() respectively. |
| char* unaligned_lower_new_high = |
| MIN2(unaligned_new_high, lower_high_boundary()); |
| char* unaligned_middle_new_high = |
| MIN2(unaligned_new_high, middle_high_boundary()); |
| char* unaligned_upper_new_high = |
| MIN2(unaligned_new_high, upper_high_boundary()); |
| |
| // Align the new highs based on the regions alignment. lower and upper |
| // alignment will always be default page size. middle alignment will be |
| // LargePageSizeInBytes if the actual size of the virtual space is in |
| // fact larger than LargePageSizeInBytes. |
| char* aligned_lower_new_high = |
| (char*) round_to((intptr_t) unaligned_lower_new_high, lower_alignment()); |
| char* aligned_middle_new_high = |
| (char*) round_to((intptr_t) unaligned_middle_new_high, middle_alignment()); |
| char* aligned_upper_new_high = |
| (char*) round_to((intptr_t) unaligned_upper_new_high, upper_alignment()); |
| |
| // Determine which regions need to grow in this expand_by call. |
| // If you are growing in the lower region, high() must be in that |
| // region so calcuate the size based on high(). For the middle and |
| // upper regions, determine the starting point of growth based on the |
| // location of high(). By getting the MAX of the region's low address |
| // (or the prevoius region's high address) and high(), we can tell if it |
| // is an intra or inter region growth. |
| size_t lower_needs = 0; |
| if (aligned_lower_new_high > lower_high()) { |
| lower_needs = |
| pointer_delta(aligned_lower_new_high, lower_high(), sizeof(char)); |
| } |
| size_t middle_needs = 0; |
| if (aligned_middle_new_high > middle_high()) { |
| middle_needs = |
| pointer_delta(aligned_middle_new_high, middle_high(), sizeof(char)); |
| } |
| size_t upper_needs = 0; |
| if (aligned_upper_new_high > upper_high()) { |
| upper_needs = |
| pointer_delta(aligned_upper_new_high, upper_high(), sizeof(char)); |
| } |
| |
| // Check contiguity. |
| assert(low_boundary() <= lower_high() && |
| lower_high() <= lower_high_boundary(), |
| "high address must be contained within the region"); |
| assert(lower_high_boundary() <= middle_high() && |
| middle_high() <= middle_high_boundary(), |
| "high address must be contained within the region"); |
| assert(middle_high_boundary() <= upper_high() && |
| upper_high() <= upper_high_boundary(), |
| "high address must be contained within the region"); |
| |
| // Commit regions |
| if (lower_needs > 0) { |
| assert(low_boundary() <= lower_high() && |
| lower_high() + lower_needs <= lower_high_boundary(), |
| "must not expand beyond region"); |
| if (!os::commit_memory(lower_high(), lower_needs, _executable)) { |
| debug_only(warning("os::commit_memory failed")); |
| return false; |
| } else { |
| _lower_high += lower_needs; |
| } |
| } |
| if (middle_needs > 0) { |
| assert(lower_high_boundary() <= middle_high() && |
| middle_high() + middle_needs <= middle_high_boundary(), |
| "must not expand beyond region"); |
| if (!os::commit_memory(middle_high(), middle_needs, middle_alignment(), |
| _executable)) { |
| debug_only(warning("os::commit_memory failed")); |
| return false; |
| } |
| _middle_high += middle_needs; |
| } |
| if (upper_needs > 0) { |
| assert(middle_high_boundary() <= upper_high() && |
| upper_high() + upper_needs <= upper_high_boundary(), |
| "must not expand beyond region"); |
| if (!os::commit_memory(upper_high(), upper_needs, _executable)) { |
| debug_only(warning("os::commit_memory failed")); |
| return false; |
| } else { |
| _upper_high += upper_needs; |
| } |
| } |
| |
| if (pre_touch || AlwaysPreTouch) { |
| int vm_ps = os::vm_page_size(); |
| for (char* curr = previous_high; |
| curr < unaligned_new_high; |
| curr += vm_ps) { |
| // Note the use of a write here; originally we tried just a read, but |
| // since the value read was unused, the optimizer removed the read. |
| // If we ever have a concurrent touchahead thread, we'll want to use |
| // a read, to avoid the potential of overwriting data (if a mutator |
| // thread beats the touchahead thread to a page). There are various |
| // ways of making sure this read is not optimized away: for example, |
| // generating the code for a read procedure at runtime. |
| *curr = 0; |
| } |
| } |
| |
| _high += bytes; |
| return true; |
| } |
| |
| // A page is uncommitted if the contents of the entire page is deemed unusable. |
| // Continue to decrement the high() pointer until it reaches a page boundary |
| // in which case that particular page can now be uncommitted. |
| void VirtualSpace::shrink_by(size_t size) { |
| if (committed_size() < size) |
| fatal("Cannot shrink virtual space to negative size"); |
| |
| if (special()) { |
| // don't uncommit if the entire space is pinned in memory |
| _high -= size; |
| return; |
| } |
| |
| char* unaligned_new_high = high() - size; |
| assert(unaligned_new_high >= low_boundary(), "cannot shrink past lower boundary"); |
| |
| // Calculate new unaligned address |
| char* unaligned_upper_new_high = |
| MAX2(unaligned_new_high, middle_high_boundary()); |
| char* unaligned_middle_new_high = |
| MAX2(unaligned_new_high, lower_high_boundary()); |
| char* unaligned_lower_new_high = |
| MAX2(unaligned_new_high, low_boundary()); |
| |
| // Align address to region's alignment |
| char* aligned_upper_new_high = |
| (char*) round_to((intptr_t) unaligned_upper_new_high, upper_alignment()); |
| char* aligned_middle_new_high = |
| (char*) round_to((intptr_t) unaligned_middle_new_high, middle_alignment()); |
| char* aligned_lower_new_high = |
| (char*) round_to((intptr_t) unaligned_lower_new_high, lower_alignment()); |
| |
| // Determine which regions need to shrink |
| size_t upper_needs = 0; |
| if (aligned_upper_new_high < upper_high()) { |
| upper_needs = |
| pointer_delta(upper_high(), aligned_upper_new_high, sizeof(char)); |
| } |
| size_t middle_needs = 0; |
| if (aligned_middle_new_high < middle_high()) { |
| middle_needs = |
| pointer_delta(middle_high(), aligned_middle_new_high, sizeof(char)); |
| } |
| size_t lower_needs = 0; |
| if (aligned_lower_new_high < lower_high()) { |
| lower_needs = |
| pointer_delta(lower_high(), aligned_lower_new_high, sizeof(char)); |
| } |
| |
| // Check contiguity. |
| assert(middle_high_boundary() <= upper_high() && |
| upper_high() <= upper_high_boundary(), |
| "high address must be contained within the region"); |
| assert(lower_high_boundary() <= middle_high() && |
| middle_high() <= middle_high_boundary(), |
| "high address must be contained within the region"); |
| assert(low_boundary() <= lower_high() && |
| lower_high() <= lower_high_boundary(), |
| "high address must be contained within the region"); |
| |
| // Uncommit |
| if (upper_needs > 0) { |
| assert(middle_high_boundary() <= aligned_upper_new_high && |
| aligned_upper_new_high + upper_needs <= upper_high_boundary(), |
| "must not shrink beyond region"); |
| if (!os::uncommit_memory(aligned_upper_new_high, upper_needs)) { |
| debug_only(warning("os::uncommit_memory failed")); |
| return; |
| } else { |
| _upper_high -= upper_needs; |
| } |
| } |
| if (middle_needs > 0) { |
| assert(lower_high_boundary() <= aligned_middle_new_high && |
| aligned_middle_new_high + middle_needs <= middle_high_boundary(), |
| "must not shrink beyond region"); |
| if (!os::uncommit_memory(aligned_middle_new_high, middle_needs)) { |
| debug_only(warning("os::uncommit_memory failed")); |
| return; |
| } else { |
| _middle_high -= middle_needs; |
| } |
| } |
| if (lower_needs > 0) { |
| assert(low_boundary() <= aligned_lower_new_high && |
| aligned_lower_new_high + lower_needs <= lower_high_boundary(), |
| "must not shrink beyond region"); |
| if (!os::uncommit_memory(aligned_lower_new_high, lower_needs)) { |
| debug_only(warning("os::uncommit_memory failed")); |
| return; |
| } else { |
| _lower_high -= lower_needs; |
| } |
| } |
| |
| _high -= size; |
| } |
| |
| #ifndef PRODUCT |
| void VirtualSpace::check_for_contiguity() { |
| // Check contiguity. |
| assert(low_boundary() <= lower_high() && |
| lower_high() <= lower_high_boundary(), |
| "high address must be contained within the region"); |
| assert(lower_high_boundary() <= middle_high() && |
| middle_high() <= middle_high_boundary(), |
| "high address must be contained within the region"); |
| assert(middle_high_boundary() <= upper_high() && |
| upper_high() <= upper_high_boundary(), |
| "high address must be contained within the region"); |
| assert(low() >= low_boundary(), "low"); |
| assert(low_boundary() <= lower_high_boundary(), "lower high boundary"); |
| assert(upper_high_boundary() <= high_boundary(), "upper high boundary"); |
| assert(high() <= upper_high(), "upper high"); |
| } |
| |
| void VirtualSpace::print() { |
| tty->print ("Virtual space:"); |
| if (special()) tty->print(" (pinned in memory)"); |
| tty->cr(); |
| tty->print_cr(" - committed: %ld", committed_size()); |
| tty->print_cr(" - reserved: %ld", reserved_size()); |
| tty->print_cr(" - [low, high]: [" INTPTR_FORMAT ", " INTPTR_FORMAT "]", low(), high()); |
| tty->print_cr(" - [low_b, high_b]: [" INTPTR_FORMAT ", " INTPTR_FORMAT "]", low_boundary(), high_boundary()); |
| } |
| |
| #endif |