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src/hotspot/share/memory/virtualspace.cpp
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@@ -1,7 +1,7 @@
/*
- * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2017, 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.
@@ -33,14 +33,14 @@
// ReservedSpace
// Dummy constructor
ReservedSpace::ReservedSpace() : _base(NULL), _size(0), _noaccess_prefix(0),
- _alignment(0), _special(false), _executable(false) {
+ _alignment(0), _special(false), _executable(false), _fd_for_heap(-1) {
}
-ReservedSpace::ReservedSpace(size_t size, size_t preferred_page_size) {
+ReservedSpace::ReservedSpace(size_t size, size_t preferred_page_size) : _fd_for_heap(-1) {
bool has_preferred_page_size = preferred_page_size != 0;
// Want to use large pages where possible and pad with small pages.
size_t page_size = has_preferred_page_size ? preferred_page_size : os::page_size_for_region_unaligned(size, 1);
bool large_pages = page_size != (size_t)os::vm_page_size();
size_t alignment;
@@ -57,23 +57,34 @@
initialize(size, alignment, large_pages, NULL, false);
}
ReservedSpace::ReservedSpace(size_t size, size_t alignment,
bool large,
- char* requested_address) {
+ char* requested_address) : _fd_for_heap(-1) {
initialize(size, alignment, large, requested_address, false);
}
ReservedSpace::ReservedSpace(size_t size, size_t alignment,
bool large,
- bool executable) {
+ bool executable) : _fd_for_heap(-1) {
initialize(size, alignment, large, NULL, executable);
}
+// Helper method
+static void unmap_or_release_memory(char* base, size_t size, bool is_file_mapped) {
+ if (is_file_mapped) {
+ if (!os::unmap_memory(base, size)) {
+ fatal("os::unmap_memory failed");
+ }
+ } else if (!os::release_memory(base, size)) {
+ fatal("os::release_memory failed");
+ }
+}
+
// Helper method.
static bool failed_to_reserve_as_requested(char* base, char* requested_address,
- const size_t size, bool special)
+ const size_t size, bool special, bool is_file_mapped = false)
{
if (base == requested_address || requested_address == NULL)
return false; // did not fail
if (base != NULL) {
@@ -85,13 +96,11 @@
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");
- }
+ unmap_or_release_memory(base, size, is_file_mapped);
}
}
return true;
}
@@ -118,11 +127,22 @@
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.
+ // If there is a backing file directory for this space then whether
+ // large pages are allocated is up to the filesystem of the backing file.
+ // So we ignore the UseLargePages flag in this case.
bool special = large && !os::can_commit_large_page_memory();
+ if (special && _fd_for_heap != -1) {
+ special = false;
+ if (UseLargePages && (!FLAG_IS_DEFAULT(UseLargePages) ||
+ !FLAG_IS_DEFAULT(LargePageSizeInBytes))) {
+ log_debug(gc, heap)("Ignoring UseLargePages since large page support is up to the file system of the backing file for Java heap");
+ }
+ }
+
char* base = NULL;
if (special) {
base = os::reserve_memory_special(size, alignment, requested_address, executable);
@@ -155,31 +175,32 @@
// 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)) {
+ base = os::attempt_reserve_memory_at(size, requested_address, _fd_for_heap);
+ if (failed_to_reserve_as_requested(base, requested_address, size, false, _fd_for_heap != -1)) {
// OS ignored requested address. Try different address.
base = NULL;
}
} else {
- base = os::reserve_memory(size, NULL, alignment);
+ base = os::reserve_memory(size, NULL, alignment, _fd_for_heap);
}
if (base == NULL) return;
// Check alignment constraints
if ((((size_t)base) & (alignment - 1)) != 0) {
// Base not aligned, retry
- if (!os::release_memory(base, size)) fatal("os::release_memory failed");
+ unmap_or_release_memory(base, size, _fd_for_heap != -1 /*is_file_mapped*/);
+
// Make sure that size is aligned
size = align_up(size, alignment);
- base = os::reserve_memory_aligned(size, alignment);
+ base = os::reserve_memory_aligned(size, alignment, _fd_for_heap);
if (requested_address != 0 &&
- failed_to_reserve_as_requested(base, requested_address, size, false)) {
+ failed_to_reserve_as_requested(base, requested_address, size, false, _fd_for_heap != -1)) {
// 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;
@@ -188,10 +209,14 @@
}
// Done
_base = base;
_size = size;
_alignment = alignment;
+ // If heap is reserved with a backing file, the entire space has been committed. So set the _special flag to true
+ if (_fd_for_heap != -1) {
+ _special = true;
+ }
}
ReservedSpace::ReservedSpace(char* base, size_t size, size_t alignment,
bool special, bool executable) {
@@ -250,11 +275,15 @@
void ReservedSpace::release() {
if (is_reserved()) {
char *real_base = _base - _noaccess_prefix;
const size_t real_size = _size + _noaccess_prefix;
if (special()) {
+ if (_fd_for_heap != -1) {
+ os::unmap_memory(real_base, real_size);
+ } else {
os::release_memory_special(real_base, real_size);
+ }
} else{
os::release_memory(real_base, real_size);
}
_base = NULL;
_size = 0;
@@ -311,11 +340,21 @@
release();
}
// 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.
+ // If there is a backing file directory for this space then whether
+ // large pages are allocated is up to the filesystem of the backing file.
+ // So we ignore the UseLargePages flag in this case.
bool special = large && !os::can_commit_large_page_memory();
+ if (special && _fd_for_heap != -1) {
+ special = false;
+ if (UseLargePages && (!FLAG_IS_DEFAULT(UseLargePages) ||
+ !FLAG_IS_DEFAULT(LargePageSizeInBytes))) {
+ log_debug(gc, heap)("Cannot allocate large pages for Java Heap when AllocateHeapAt option is set.");
+ }
+ }
char* base = NULL;
log_trace(gc, heap, coops)("Trying to allocate at address " PTR_FORMAT
" heap of size " SIZE_FORMAT_HEX,
p2i(requested_address),
@@ -348,22 +387,27 @@
// 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);
+ base = os::attempt_reserve_memory_at(size, requested_address, _fd_for_heap);
} else {
- base = os::reserve_memory(size, NULL, alignment);
+ base = os::reserve_memory(size, NULL, alignment, _fd_for_heap);
}
}
if (base == NULL) { return; }
// Done
_base = base;
_size = size;
_alignment = alignment;
+ // If heap is reserved with a backing file, the entire space has been committed. So set the _special flag to true
+ if (_fd_for_heap != -1) {
+ _special = true;
+ }
+
// Check alignment constraints
if ((((size_t)base) & (alignment - 1)) != 0) {
// Base not aligned, retry.
release();
}
@@ -554,16 +598,24 @@
initialize(size + noaccess_prefix, alignment, large, NULL, false);
}
}
}
-ReservedHeapSpace::ReservedHeapSpace(size_t size, size_t alignment, bool large) : ReservedSpace() {
+ReservedHeapSpace::ReservedHeapSpace(size_t size, size_t alignment, bool large, const char* heap_allocation_directory) : ReservedSpace() {
if (size == 0) {
return;
}
+ if (heap_allocation_directory != NULL) {
+ _fd_for_heap = os::create_file_for_heap(heap_allocation_directory);
+ if (_fd_for_heap == -1) {
+ vm_exit_during_initialization(
+ err_msg("Could not create file for Heap at location %s", heap_allocation_directory));
+ }
+ }
+
// Heap size should be aligned to alignment, too.
guarantee(is_aligned(size, alignment), "set by caller");
if (UseCompressedOops) {
initialize_compressed_heap(size, alignment, large);
@@ -583,10 +635,14 @@
"area must be distinguishable from marks for mark-sweep");
if (base() != NULL) {
MemTracker::record_virtual_memory_type((address)base(), mtJavaHeap);
}
+
+ if (_fd_for_heap != -1) {
+ os::close(_fd_for_heap);
+ }
}
// Reserve space for code segment. Same as Java heap only we mark this as
// executable.
ReservedCodeSpace::ReservedCodeSpace(size_t r_size,
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