--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/gc_implementation/parallelScavenge/adjoiningGenerations.cpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,278 @@
+/*
+ * Copyright 2003 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+# include "incls/_precompiled.incl"
+# include "incls/_adjoiningGenerations.cpp.incl"
+
+// If boundary moving is being used, create the young gen and old
+// gen with ASPSYoungGen and ASPSOldGen, respectively.  Revert to
+// the old behavior otherwise (with PSYoungGen and PSOldGen).
+
+AdjoiningGenerations::AdjoiningGenerations(ReservedSpace old_young_rs,
+                                           size_t init_low_byte_size,
+                                           size_t min_low_byte_size,
+                                           size_t max_low_byte_size,
+                                           size_t init_high_byte_size,
+                                           size_t min_high_byte_size,
+                                           size_t max_high_byte_size,
+                                           size_t alignment) :
+  _virtual_spaces(old_young_rs, min_low_byte_size,
+                  min_high_byte_size, alignment) {
+  assert(min_low_byte_size <= init_low_byte_size &&
+         init_low_byte_size <= max_low_byte_size, "Parameter check");
+  assert(min_high_byte_size <= init_high_byte_size &&
+         init_high_byte_size <= max_high_byte_size, "Parameter check");
+  // Create the generations differently based on the option to
+  // move the boundary.
+  if (UseAdaptiveGCBoundary) {
+    // Initialize the adjoining virtual spaces.  Then pass the
+    // a virtual to each generation for initialization of the
+    // generation.
+
+    // Does the actual creation of the virtual spaces
+    _virtual_spaces.initialize(max_low_byte_size,
+                               init_low_byte_size,
+                               init_high_byte_size);
+
+    // Place the young gen at the high end.  Passes in the virtual space.
+    _young_gen = new ASPSYoungGen(_virtual_spaces.high(),
+                                  _virtual_spaces.high()->committed_size(),
+                                  min_high_byte_size,
+                                  _virtual_spaces.high_byte_size_limit());
+
+    // Place the old gen at the low end. Passes in the virtual space.
+    _old_gen = new ASPSOldGen(_virtual_spaces.low(),
+                              _virtual_spaces.low()->committed_size(),
+                              min_low_byte_size,
+                              _virtual_spaces.low_byte_size_limit(),
+                              "old", 1);
+
+    young_gen()->initialize_work();
+    assert(young_gen()->reserved().byte_size() <= young_gen()->gen_size_limit(),
+     "Consistency check");
+    assert(old_young_rs.size() >= young_gen()->gen_size_limit(),
+     "Consistency check");
+
+    old_gen()->initialize_work("old", 1);
+    assert(old_gen()->reserved().byte_size() <= old_gen()->gen_size_limit(),
+     "Consistency check");
+    assert(old_young_rs.size() >= old_gen()->gen_size_limit(),
+     "Consistency check");
+  } else {
+
+    // Layout the reserved space for the generations.
+    ReservedSpace old_rs   =
+      virtual_spaces()->reserved_space().first_part(max_low_byte_size);
+    ReservedSpace heap_rs  =
+      virtual_spaces()->reserved_space().last_part(max_low_byte_size);
+    ReservedSpace young_rs = heap_rs.first_part(max_high_byte_size);
+    assert(young_rs.size() == heap_rs.size(), "Didn't reserve all of the heap");
+
+    // Create the generations.  Virtual spaces are not passed in.
+    _young_gen = new PSYoungGen(init_high_byte_size,
+                                min_high_byte_size,
+                                max_high_byte_size);
+    _old_gen = new PSOldGen(init_low_byte_size,
+                            min_low_byte_size,
+                            max_low_byte_size,
+                            "old", 1);
+
+    // The virtual spaces are created by the initialization of the gens.
+    _young_gen->initialize(young_rs, alignment);
+    assert(young_gen()->gen_size_limit() == young_rs.size(),
+      "Consistency check");
+    _old_gen->initialize(old_rs, alignment, "old", 1);
+    assert(old_gen()->gen_size_limit() == old_rs.size(), "Consistency check");
+  }
+}
+
+size_t AdjoiningGenerations::reserved_byte_size() {
+  return virtual_spaces()->reserved_space().size();
+}
+
+
+// Make checks on the current sizes of the generations and
+// the contraints on the sizes of the generations.  Push
+// up the boundary within the contraints.  A partial
+// push can occur.
+void AdjoiningGenerations::request_old_gen_expansion(size_t expand_in_bytes) {
+  assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
+
+  assert_lock_strong(ExpandHeap_lock);
+  assert_locked_or_safepoint(Heap_lock);
+
+  // These sizes limit the amount the boundaries can move.  Effectively,
+  // the generation says how much it is willing to yield to the other
+  // generation.
+  const size_t young_gen_available = young_gen()->available_for_contraction();
+  const size_t old_gen_available = old_gen()->available_for_expansion();
+  const size_t alignment = virtual_spaces()->alignment();
+  size_t change_in_bytes = MIN3(young_gen_available,
+                                old_gen_available,
+                                align_size_up_(expand_in_bytes, alignment));
+
+  if (change_in_bytes == 0) {
+    return;
+  }
+
+  if (TraceAdaptiveGCBoundary) {
+    gclog_or_tty->print_cr("Before expansion of old gen with boundary move");
+    gclog_or_tty->print_cr("  Requested change: 0x%x  Attempted change: 0x%x",
+      expand_in_bytes, change_in_bytes);
+    if (!PrintHeapAtGC) {
+      Universe::print_on(gclog_or_tty);
+    }
+    gclog_or_tty->print_cr("  PSOldGen max size: " SIZE_FORMAT "K",
+      old_gen()->max_gen_size()/K);
+  }
+
+  // Move the boundary between the generations up (smaller young gen).
+  if (virtual_spaces()->adjust_boundary_up(change_in_bytes)) {
+    young_gen()->reset_after_change();
+    old_gen()->reset_after_change();
+  }
+
+  // The total reserved for the generations should match the sum
+  // of the two even if the boundary is moving.
+  assert(reserved_byte_size() ==
+         old_gen()->max_gen_size() + young_gen()->max_size(),
+         "Space is missing");
+  young_gen()->space_invariants();
+  old_gen()->space_invariants();
+
+  if (TraceAdaptiveGCBoundary) {
+    gclog_or_tty->print_cr("After expansion of old gen with boundary move");
+    if (!PrintHeapAtGC) {
+      Universe::print_on(gclog_or_tty);
+    }
+    gclog_or_tty->print_cr("  PSOldGen max size: " SIZE_FORMAT "K",
+      old_gen()->max_gen_size()/K);
+  }
+}
+
+// See comments on request_old_gen_expansion()
+bool AdjoiningGenerations::request_young_gen_expansion(size_t expand_in_bytes) {
+  assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
+
+  // If eden is not empty, the boundary can be moved but no advantage
+  // can be made of the move since eden cannot be moved.
+  if (!young_gen()->eden_space()->is_empty()) {
+    return false;
+  }
+
+
+  bool result = false;
+  const size_t young_gen_available = young_gen()->available_for_expansion();
+  const size_t old_gen_available = old_gen()->available_for_contraction();
+  const size_t alignment = virtual_spaces()->alignment();
+  size_t change_in_bytes = MIN3(young_gen_available,
+                                old_gen_available,
+                                align_size_up_(expand_in_bytes, alignment));
+
+  if (change_in_bytes == 0) {
+    return false;
+  }
+
+  if (TraceAdaptiveGCBoundary) {
+    gclog_or_tty->print_cr("Before expansion of young gen with boundary move");
+    gclog_or_tty->print_cr("  Requested change: 0x%x  Attempted change: 0x%x",
+      expand_in_bytes, change_in_bytes);
+    if (!PrintHeapAtGC) {
+      Universe::print_on(gclog_or_tty);
+    }
+    gclog_or_tty->print_cr("  PSYoungGen max size: " SIZE_FORMAT "K",
+      young_gen()->max_size()/K);
+  }
+
+  // Move the boundary between the generations down (smaller old gen).
+  MutexLocker x(ExpandHeap_lock);
+  if (virtual_spaces()->adjust_boundary_down(change_in_bytes)) {
+    young_gen()->reset_after_change();
+    old_gen()->reset_after_change();
+    result = true;
+  }
+
+  // The total reserved for the generations should match the sum
+  // of the two even if the boundary is moving.
+  assert(reserved_byte_size() ==
+         old_gen()->max_gen_size() + young_gen()->max_size(),
+         "Space is missing");
+  young_gen()->space_invariants();
+  old_gen()->space_invariants();
+
+  if (TraceAdaptiveGCBoundary) {
+    gclog_or_tty->print_cr("After expansion of young gen with boundary move");
+    if (!PrintHeapAtGC) {
+      Universe::print_on(gclog_or_tty);
+    }
+    gclog_or_tty->print_cr("  PSYoungGen max size: " SIZE_FORMAT "K",
+      young_gen()->max_size()/K);
+  }
+
+  return result;
+}
+
+// Additional space is needed in the old generation.  Try to move the boundary
+// up to meet the need.  Moves boundary up only
+void AdjoiningGenerations::adjust_boundary_for_old_gen_needs(
+  size_t desired_free_space) {
+  assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
+
+  // Stress testing.
+  if (PSAdaptiveSizePolicyResizeVirtualSpaceAlot == 1) {
+    MutexLocker x(ExpandHeap_lock);
+    request_old_gen_expansion(virtual_spaces()->alignment() * 3 / 2);
+  }
+
+  // Expand only if the entire generation is already committed.
+  if (old_gen()->virtual_space()->uncommitted_size() == 0) {
+    if (old_gen()->free_in_bytes() < desired_free_space) {
+      MutexLocker x(ExpandHeap_lock);
+      request_old_gen_expansion(desired_free_space);
+    }
+  }
+}
+
+// See comment on adjust_boundary_for_old_gen_needss().
+// Adjust boundary down only.
+void AdjoiningGenerations::adjust_boundary_for_young_gen_needs(size_t eden_size,
+    size_t survivor_size) {
+
+  assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
+
+  // Stress testing.
+  if (PSAdaptiveSizePolicyResizeVirtualSpaceAlot == 0) {
+    request_young_gen_expansion(virtual_spaces()->alignment() * 3 / 2);
+    eden_size = young_gen()->eden_space()->capacity_in_bytes();
+  }
+
+  // Expand only if the entire generation is already committed.
+  if (young_gen()->virtual_space()->uncommitted_size() == 0) {
+    size_t desired_size = eden_size + 2 * survivor_size;
+    const size_t committed = young_gen()->virtual_space()->committed_size();
+    if (desired_size > committed) {
+      request_young_gen_expansion(desired_size - committed);
+    }
+  }
+}