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 /*

  * Copyright (c) 2003, 2014, 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/parallelScavenge/asPSYoungGen.hpp"

 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"

 #include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp"

 #include "gc_implementation/parallelScavenge/psScavenge.hpp"

 #include "gc_implementation/parallelScavenge/psYoungGen.hpp"

 #include "gc_implementation/shared/gcUtil.hpp"

 #include "gc_implementation/shared/spaceDecorator.hpp"

 #include "oops/oop.inline.hpp"

 #include "runtime/java.hpp"

 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->generation_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->space_alignment();

     const size_t gen_alignment = heap->generation_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: " SIZE_FORMAT " K",

         result_aligned/K);

       gclog_or_tty->print_cr("  max_contraction " SIZE_FORMAT " K", max_contraction/K);

       gclog_or_tty->print_cr("  eden_avail " SIZE_FORMAT " K", eden_avail/K);

       gclog_or_tty->print_cr("  gen_avail " SIZE_FORMAT " 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->space_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;

     HeapWord* prev_low = (HeapWord*) virtual_space()->low();

     if (!virtual_space()->expand_by(change)) {

       return false;

     }

     if (ZapUnusedHeapArea) {

       // Mangle newly committed space immediately because it

       // can be done here more simply that after the new

       // spaces have been computed.

       HeapWord* new_low = (HeapWord*) virtual_space()->low();

       assert(new_low < prev_low, "Did not grow");

       MemRegion mangle_region(new_low, prev_low);

       SpaceMangler::mangle_region(mangle_region);

     }

     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(UseAdaptiveSizePolicy, "sanity check");

   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,

                   p2i(eden_space()->bottom()),

                   p2i(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,

                   p2i(from_space()->bottom()),

                   p2i(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,

                   p2i(to_space()->bottom()),

                   p2i(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->space_alignment();

   const bool maintain_minimum =

     (requested_eden_size + 2 * requested_survivor_size) <= min_gen_size();

   bool eden_from_to_order = from_start < to_start;

   // Check whether from space is below to space

   if (eden_from_to_order) {

     // Eden, from, to

     if (PrintAdaptiveSizePolicy && Verbose) {

       gclog_or_tty->print_cr("  Eden, from, to:");

     }

     // Set eden

     // "requested_eden_size" is a goal for the size of eden

     // and may not be attainable.  "eden_size" below is

     // calculated based on the location of from-space and

     // the goal for the size of eden.  from-space is

     // fixed in place because it contains live data.

     // The calculation is done this way to avoid 32bit

     // overflow (i.e., eden_start + requested_eden_size

     // may too large for representation in 32bits).

     size_t eden_size;

     if (maintain_minimum) {

       // Only make eden larger than the requested size if

       // the minimum size of the generation has to be maintained.

       // This could be done in general but policy at a higher

       // level is determining a requested size for eden and that

       // should be honored unless there is a fundamental reason.

       eden_size = pointer_delta(from_start,

                                 eden_start,

                                 sizeof(char));

     } else {

       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,

                     p2i(eden_start),

                     p2i(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,

                     p2i(from_start),

                     p2i(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,

                     p2i(to_start),

                     p2i(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  comments above on calculating eden_end.

     size_t eden_size;

     if (maintain_minimum) {

       eden_size = pointer_delta(to_start, eden_start, sizeof(char));

     } else {

       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,

                     p2i(eden_start),

                     p2i(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,

                     p2i(to_start),

                     p2i(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,

                     p2i(from_start),

                     p2i(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();

   if (ZapUnusedHeapArea) {

     // NUMA is a special case because a numa space is not mangled

     // in order to not prematurely bind its address to memory to

     // the wrong memory (i.e., don't want the GC thread to first

     // touch the memory).  The survivor spaces are not numa

     // spaces and are mangled.

     if (UseNUMA) {

       if (eden_from_to_order) {

         mangle_survivors(from_space(), fromMR, to_space(), toMR);

       } else {

         mangle_survivors(to_space(), toMR, from_space(), fromMR);

       }

     }

     // If not mangling the spaces, do some checking to verify that

     // the spaces are already mangled.

     // The spaces should be correctly mangled at this point so

     // do some checking here. Note that they are not being mangled

     // in the calls to initialize().

     // Must check mangling before the spaces are reshaped.  Otherwise,

     // the bottom or end of one space may have moved into an area

     // covered by another space and a failure of the check may

     // not correctly indicate which space is not properly mangled.

     HeapWord* limit = (HeapWord*) virtual_space()->high();

     eden_space()->check_mangled_unused_area(limit);

     from_space()->check_mangled_unused_area(limit);

       to_space()->check_mangled_unused_area(limit);

   }

   // When an existing space is being initialized, it is not

   // mangled because the space has been previously mangled.

   eden_space()->initialize(edenMR,

                            SpaceDecorator::Clear,

                            SpaceDecorator::DontMangle);

     to_space()->initialize(toMR,

                            SpaceDecorator::Clear,

                            SpaceDecorator::DontMangle);

   from_space()->initialize(fromMR,

                            SpaceDecorator::DontClear,

                            SpaceDecorator::DontMangle);

   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,

                              SpaceDecorator::Clear,

                              SpaceDecorator::Mangle);

     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();

 }