--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/gc_implementation/parallelScavenge/asPSYoungGen.cpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,469 @@
+/*
+ * Copyright 2003-2006 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/_asPSYoungGen.cpp.incl"
+
+ASPSYoungGen::ASPSYoungGen(size_t init_byte_size,
+                           size_t minimum_byte_size,
+                           size_t byte_size_limit) :
+  PSYoungGen(init_byte_size, minimum_byte_size, byte_size_limit),
+  _gen_size_limit(byte_size_limit) {
+}
+
+
+ASPSYoungGen::ASPSYoungGen(PSVirtualSpace* vs,
+                           size_t init_byte_size,
+                           size_t minimum_byte_size,
+                           size_t byte_size_limit) :
+  //PSYoungGen(init_byte_size, minimum_byte_size, byte_size_limit),
+  PSYoungGen(vs->committed_size(), minimum_byte_size, byte_size_limit),
+  _gen_size_limit(byte_size_limit) {
+
+  assert(vs->committed_size() == init_byte_size, "Cannot replace with");
+
+  _virtual_space = vs;
+}
+
+void ASPSYoungGen::initialize_virtual_space(ReservedSpace rs,
+                                            size_t alignment) {
+  assert(_init_gen_size != 0, "Should have a finite size");
+  _virtual_space = new PSVirtualSpaceHighToLow(rs, alignment);
+  if (!_virtual_space->expand_by(_init_gen_size)) {
+    vm_exit_during_initialization("Could not reserve enough space for "
+                                  "object heap");
+  }
+}
+
+void ASPSYoungGen::initialize(ReservedSpace rs, size_t alignment) {
+  initialize_virtual_space(rs, alignment);
+  initialize_work();
+}
+
+size_t ASPSYoungGen::available_for_expansion() {
+
+  size_t current_committed_size = virtual_space()->committed_size();
+  assert((gen_size_limit() >= current_committed_size),
+    "generation size limit is wrong");
+  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
+  size_t result =  gen_size_limit() - current_committed_size;
+  size_t result_aligned = align_size_down(result, heap->young_gen_alignment());
+  return result_aligned;
+}
+
+// Return the number of bytes the young gen is willing give up.
+//
+// Future implementations could check the survivors and if to_space is in the
+// right place (below from_space), take a chunk from to_space.
+size_t ASPSYoungGen::available_for_contraction() {
+
+  size_t uncommitted_bytes = virtual_space()->uncommitted_size();
+  if (uncommitted_bytes != 0) {
+    return uncommitted_bytes;
+  }
+
+  if (eden_space()->is_empty()) {
+    // Respect the minimum size for eden and for the young gen as a whole.
+    ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
+    const size_t eden_alignment = heap->intra_generation_alignment();
+    const size_t gen_alignment = heap->young_gen_alignment();
+
+    assert(eden_space()->capacity_in_bytes() >= eden_alignment,
+      "Alignment is wrong");
+    size_t eden_avail = eden_space()->capacity_in_bytes() - eden_alignment;
+    eden_avail = align_size_down(eden_avail, gen_alignment);
+
+    assert(virtual_space()->committed_size() >= min_gen_size(),
+      "minimum gen size is wrong");
+    size_t gen_avail = virtual_space()->committed_size() - min_gen_size();
+    assert(virtual_space()->is_aligned(gen_avail), "not aligned");
+
+    const size_t max_contraction = MIN2(eden_avail, gen_avail);
+    // See comment for ASPSOldGen::available_for_contraction()
+    // for reasons the "increment" fraction is used.
+    PSAdaptiveSizePolicy* policy = heap->size_policy();
+    size_t result = policy->eden_increment_aligned_down(max_contraction);
+    size_t result_aligned = align_size_down(result, gen_alignment);
+    if (PrintAdaptiveSizePolicy && Verbose) {
+      gclog_or_tty->print_cr("ASPSYoungGen::available_for_contraction: %d K",
+        result_aligned/K);
+      gclog_or_tty->print_cr("  max_contraction %d K", max_contraction/K);
+      gclog_or_tty->print_cr("  eden_avail %d K", eden_avail/K);
+      gclog_or_tty->print_cr("  gen_avail %d K", gen_avail/K);
+    }
+    return result_aligned;
+
+  }
+
+  return 0;
+}
+
+// The current implementation only considers to the end of eden.
+// If to_space is below from_space, to_space is not considered.
+// to_space can be.
+size_t ASPSYoungGen::available_to_live() {
+  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
+  const size_t alignment = heap->intra_generation_alignment();
+
+  // Include any space that is committed but is not in eden.
+  size_t available = pointer_delta(eden_space()->bottom(),
+                                   virtual_space()->low(),
+                                   sizeof(char));
+
+  const size_t eden_capacity = eden_space()->capacity_in_bytes();
+  if (eden_space()->is_empty() && eden_capacity > alignment) {
+    available += eden_capacity - alignment;
+  }
+  return available;
+}
+
+// Similar to PSYoungGen::resize_generation() but
+//  allows sum of eden_size and 2 * survivor_size to exceed _max_gen_size
+//  expands at the low end of the virtual space
+//  moves the boundary between the generations in order to expand
+//  some additional diagnostics
+// If no additional changes are required, this can be deleted
+// and the changes factored back into PSYoungGen::resize_generation().
+bool ASPSYoungGen::resize_generation(size_t eden_size, size_t survivor_size) {
+  const size_t alignment = virtual_space()->alignment();
+  size_t orig_size = virtual_space()->committed_size();
+  bool size_changed = false;
+
+  // There used to be a guarantee here that
+  //   (eden_size + 2*survivor_size)  <= _max_gen_size
+  // This requirement is enforced by the calculation of desired_size
+  // below.  It may not be true on entry since the size of the
+  // eden_size is no bounded by the generation size.
+
+  assert(max_size() == reserved().byte_size(), "max gen size problem?");
+  assert(min_gen_size() <= orig_size && orig_size <= max_size(),
+         "just checking");
+
+  // Adjust new generation size
+  const size_t eden_plus_survivors =
+    align_size_up(eden_size + 2 * survivor_size, alignment);
+  size_t desired_size = MAX2(MIN2(eden_plus_survivors, gen_size_limit()),
+                             min_gen_size());
+  assert(desired_size <= gen_size_limit(), "just checking");
+
+  if (desired_size > orig_size) {
+    // Grow the generation
+    size_t change = desired_size - orig_size;
+    if (!virtual_space()->expand_by(change)) {
+      return false;
+    }
+    size_changed = true;
+  } else if (desired_size < orig_size) {
+    size_t desired_change = orig_size - desired_size;
+
+    // How much is available for shrinking.
+    size_t available_bytes = limit_gen_shrink(desired_change);
+    size_t change = MIN2(desired_change, available_bytes);
+    virtual_space()->shrink_by(change);
+    size_changed = true;
+  } else {
+    if (Verbose && PrintGC) {
+      if (orig_size == gen_size_limit()) {
+        gclog_or_tty->print_cr("ASPSYoung generation size at maximum: "
+          SIZE_FORMAT "K", orig_size/K);
+      } else if (orig_size == min_gen_size()) {
+        gclog_or_tty->print_cr("ASPSYoung generation size at minium: "
+          SIZE_FORMAT "K", orig_size/K);
+      }
+    }
+  }
+
+  if (size_changed) {
+    reset_after_change();
+    if (Verbose && PrintGC) {
+      size_t current_size  = virtual_space()->committed_size();
+      gclog_or_tty->print_cr("ASPSYoung generation size changed: "
+        SIZE_FORMAT "K->" SIZE_FORMAT "K",
+        orig_size/K, current_size/K);
+    }
+  }
+
+  guarantee(eden_plus_survivors <= virtual_space()->committed_size() ||
+            virtual_space()->committed_size() == max_size(), "Sanity");
+
+  return true;
+}
+
+// Similar to PSYoungGen::resize_spaces() but
+//  eden always starts at the low end of the committed virtual space
+//  current implementation does not allow holes between the spaces
+//  _young_generation_boundary has to be reset because it changes.
+//  so additional verification
+void ASPSYoungGen::resize_spaces(size_t requested_eden_size,
+                                 size_t requested_survivor_size) {
+  assert(requested_eden_size > 0 && requested_survivor_size > 0,
+         "just checking");
+
+  space_invariants();
+
+  // We require eden and to space to be empty
+  if ((!eden_space()->is_empty()) || (!to_space()->is_empty())) {
+    return;
+  }
+
+  if (PrintAdaptiveSizePolicy && Verbose) {
+    gclog_or_tty->print_cr("PSYoungGen::resize_spaces(requested_eden_size: "
+                  SIZE_FORMAT
+                  ", requested_survivor_size: " SIZE_FORMAT ")",
+                  requested_eden_size, requested_survivor_size);
+    gclog_or_tty->print_cr("    eden: [" PTR_FORMAT ".." PTR_FORMAT ") "
+                  SIZE_FORMAT,
+                  eden_space()->bottom(),
+                  eden_space()->end(),
+                  pointer_delta(eden_space()->end(),
+                                eden_space()->bottom(),
+                                sizeof(char)));
+    gclog_or_tty->print_cr("    from: [" PTR_FORMAT ".." PTR_FORMAT ") "
+                  SIZE_FORMAT,
+                  from_space()->bottom(),
+                  from_space()->end(),
+                  pointer_delta(from_space()->end(),
+                                from_space()->bottom(),
+                                sizeof(char)));
+    gclog_or_tty->print_cr("      to: [" PTR_FORMAT ".." PTR_FORMAT ") "
+                  SIZE_FORMAT,
+                  to_space()->bottom(),
+                  to_space()->end(),
+                  pointer_delta(  to_space()->end(),
+                                  to_space()->bottom(),
+                                  sizeof(char)));
+  }
+
+  // There's nothing to do if the new sizes are the same as the current
+  if (requested_survivor_size == to_space()->capacity_in_bytes() &&
+      requested_survivor_size == from_space()->capacity_in_bytes() &&
+      requested_eden_size == eden_space()->capacity_in_bytes()) {
+    if (PrintAdaptiveSizePolicy && Verbose) {
+      gclog_or_tty->print_cr("    capacities are the right sizes, returning");
+    }
+    return;
+  }
+
+  char* eden_start = (char*)virtual_space()->low();
+  char* eden_end   = (char*)eden_space()->end();
+  char* from_start = (char*)from_space()->bottom();
+  char* from_end   = (char*)from_space()->end();
+  char* to_start   = (char*)to_space()->bottom();
+  char* to_end     = (char*)to_space()->end();
+
+  assert(eden_start < from_start, "Cannot push into from_space");
+
+  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
+  const size_t alignment = heap->intra_generation_alignment();
+
+  // Check whether from space is below to space
+  if (from_start < to_start) {
+    // Eden, from, to
+    if (PrintAdaptiveSizePolicy && Verbose) {
+      gclog_or_tty->print_cr("  Eden, from, to:");
+    }
+
+    // Set eden
+    // Compute how big eden can be, then adjust end.
+    // See comment in PSYoungGen::resize_spaces() on
+    // calculating eden_end.
+    const size_t eden_size = MIN2(requested_eden_size,
+                                  pointer_delta(from_start,
+                                                eden_start,
+                                                sizeof(char)));
+    eden_end = eden_start + eden_size;
+    assert(eden_end >= eden_start, "addition overflowed")
+
+    // To may resize into from space as long as it is clear of live data.
+    // From space must remain page aligned, though, so we need to do some
+    // extra calculations.
+
+    // First calculate an optimal to-space
+    to_end   = (char*)virtual_space()->high();
+    to_start = (char*)pointer_delta(to_end,
+                                    (char*)requested_survivor_size,
+                                    sizeof(char));
+
+    // Does the optimal to-space overlap from-space?
+    if (to_start < (char*)from_space()->end()) {
+      assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
+
+      // Calculate the minimum offset possible for from_end
+      size_t from_size =
+        pointer_delta(from_space()->top(), from_start, sizeof(char));
+
+      // Should we be in this method if from_space is empty? Why not the set_space method? FIX ME!
+      if (from_size == 0) {
+        from_size = alignment;
+      } else {
+        from_size = align_size_up(from_size, alignment);
+      }
+
+      from_end = from_start + from_size;
+      assert(from_end > from_start, "addition overflow or from_size problem");
+
+      guarantee(from_end <= (char*)from_space()->end(),
+        "from_end moved to the right");
+
+      // Now update to_start with the new from_end
+      to_start = MAX2(from_end, to_start);
+    }
+
+    guarantee(to_start != to_end, "to space is zero sized");
+
+    if (PrintAdaptiveSizePolicy && Verbose) {
+      gclog_or_tty->print_cr("    [eden_start .. eden_end): "
+                    "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
+                    eden_start,
+                    eden_end,
+                    pointer_delta(eden_end, eden_start, sizeof(char)));
+      gclog_or_tty->print_cr("    [from_start .. from_end): "
+                    "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
+                    from_start,
+                    from_end,
+                    pointer_delta(from_end, from_start, sizeof(char)));
+      gclog_or_tty->print_cr("    [  to_start ..   to_end): "
+                    "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
+                    to_start,
+                    to_end,
+                    pointer_delta(  to_end,   to_start, sizeof(char)));
+    }
+  } else {
+    // Eden, to, from
+    if (PrintAdaptiveSizePolicy && Verbose) {
+      gclog_or_tty->print_cr("  Eden, to, from:");
+    }
+
+    // To space gets priority over eden resizing. Note that we position
+    // to space as if we were able to resize from space, even though from
+    // space is not modified.
+    // Giving eden priority was tried and gave poorer performance.
+    to_end   = (char*)pointer_delta(virtual_space()->high(),
+                                    (char*)requested_survivor_size,
+                                    sizeof(char));
+    to_end   = MIN2(to_end, from_start);
+    to_start = (char*)pointer_delta(to_end, (char*)requested_survivor_size,
+                                    sizeof(char));
+    // if the space sizes are to be increased by several times then
+    // 'to_start' will point beyond the young generation. In this case
+    // 'to_start' should be adjusted.
+    to_start = MAX2(to_start, eden_start + alignment);
+
+    // Compute how big eden can be, then adjust end.
+    // See comment in PSYoungGen::resize_spaces() on
+    // calculating eden_end.
+    const size_t eden_size = MIN2(requested_eden_size,
+                                  pointer_delta(to_start,
+                                                eden_start,
+                                                sizeof(char)));
+    eden_end = eden_start + eden_size;
+    assert(eden_end >= eden_start, "addition overflowed")
+
+    // Don't let eden shrink down to 0 or less.
+    eden_end = MAX2(eden_end, eden_start + alignment);
+    to_start = MAX2(to_start, eden_end);
+
+    if (PrintAdaptiveSizePolicy && Verbose) {
+      gclog_or_tty->print_cr("    [eden_start .. eden_end): "
+                    "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
+                    eden_start,
+                    eden_end,
+                    pointer_delta(eden_end, eden_start, sizeof(char)));
+      gclog_or_tty->print_cr("    [  to_start ..   to_end): "
+                    "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
+                    to_start,
+                    to_end,
+                    pointer_delta(  to_end,   to_start, sizeof(char)));
+      gclog_or_tty->print_cr("    [from_start .. from_end): "
+                    "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
+                    from_start,
+                    from_end,
+                    pointer_delta(from_end, from_start, sizeof(char)));
+    }
+  }
+
+
+  guarantee((HeapWord*)from_start <= from_space()->bottom(),
+            "from start moved to the right");
+  guarantee((HeapWord*)from_end >= from_space()->top(),
+            "from end moved into live data");
+  assert(is_object_aligned((intptr_t)eden_start), "checking alignment");
+  assert(is_object_aligned((intptr_t)from_start), "checking alignment");
+  assert(is_object_aligned((intptr_t)to_start), "checking alignment");
+
+  MemRegion edenMR((HeapWord*)eden_start, (HeapWord*)eden_end);
+  MemRegion toMR  ((HeapWord*)to_start,   (HeapWord*)to_end);
+  MemRegion fromMR((HeapWord*)from_start, (HeapWord*)from_end);
+
+  // Let's make sure the call to initialize doesn't reset "top"!
+  DEBUG_ONLY(HeapWord* old_from_top = from_space()->top();)
+
+  // For PrintAdaptiveSizePolicy block  below
+  size_t old_from = from_space()->capacity_in_bytes();
+  size_t old_to   = to_space()->capacity_in_bytes();
+
+  eden_space()->initialize(edenMR, true);
+    to_space()->initialize(toMR  , true);
+  from_space()->initialize(fromMR, false);     // Note, not cleared!
+  PSScavenge::set_young_generation_boundary(eden_space()->bottom());
+
+  assert(from_space()->top() == old_from_top, "from top changed!");
+
+  if (PrintAdaptiveSizePolicy) {
+    ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
+    assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
+
+    gclog_or_tty->print("AdaptiveSizePolicy::survivor space sizes: "
+                  "collection: %d "
+                  "(" SIZE_FORMAT ", " SIZE_FORMAT ") -> "
+                  "(" SIZE_FORMAT ", " SIZE_FORMAT ") ",
+                  heap->total_collections(),
+                  old_from, old_to,
+                  from_space()->capacity_in_bytes(),
+                  to_space()->capacity_in_bytes());
+    gclog_or_tty->cr();
+  }
+  space_invariants();
+}
+
+void ASPSYoungGen::reset_after_change() {
+  assert_locked_or_safepoint(Heap_lock);
+
+  _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
+                        (HeapWord*)virtual_space()->high_boundary());
+  PSScavenge::reference_processor()->set_span(_reserved);
+
+  HeapWord* new_eden_bottom = (HeapWord*)virtual_space()->low();
+  HeapWord* eden_bottom = eden_space()->bottom();
+  if (new_eden_bottom != eden_bottom) {
+    MemRegion eden_mr(new_eden_bottom, eden_space()->end());
+    eden_space()->initialize(eden_mr, true);
+    PSScavenge::set_young_generation_boundary(eden_space()->bottom());
+  }
+  MemRegion cmr((HeapWord*)virtual_space()->low(),
+                (HeapWord*)virtual_space()->high());
+  Universe::heap()->barrier_set()->resize_covered_region(cmr);
+
+  space_invariants();
+}