--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/parallel/psYoungGen.cpp Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,901 @@
+/*
+ * Copyright (c) 2001, 2015, 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 "gc/parallel/mutableNUMASpace.hpp"
+#include "gc/parallel/parallelScavengeHeap.hpp"
+#include "gc/parallel/psMarkSweepDecorator.hpp"
+#include "gc/parallel/psScavenge.hpp"
+#include "gc/parallel/psYoungGen.hpp"
+#include "gc/shared/gcUtil.hpp"
+#include "gc/shared/spaceDecorator.hpp"
+#include "logging/log.hpp"
+#include "oops/oop.inline.hpp"
+#include "runtime/java.hpp"
+#include "utilities/align.hpp"
+
+PSYoungGen::PSYoungGen(size_t initial_size,
+ size_t min_size,
+ size_t max_size) :
+ _init_gen_size(initial_size),
+ _min_gen_size(min_size),
+ _max_gen_size(max_size)
+{}
+
+void PSYoungGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) {
+ assert(_init_gen_size != 0, "Should have a finite size");
+ _virtual_space = new PSVirtualSpace(rs, alignment);
+ if (!virtual_space()->expand_by(_init_gen_size)) {
+ vm_exit_during_initialization("Could not reserve enough space for "
+ "object heap");
+ }
+}
+
+void PSYoungGen::initialize(ReservedSpace rs, size_t alignment) {
+ initialize_virtual_space(rs, alignment);
+ initialize_work();
+}
+
+void PSYoungGen::initialize_work() {
+
+ _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
+ (HeapWord*)virtual_space()->high_boundary());
+
+ MemRegion cmr((HeapWord*)virtual_space()->low(),
+ (HeapWord*)virtual_space()->high());
+ ParallelScavengeHeap::heap()->barrier_set()->resize_covered_region(cmr);
+
+ if (ZapUnusedHeapArea) {
+ // Mangle newly committed space immediately because it
+ // can be done here more simply that after the new
+ // spaces have been computed.
+ SpaceMangler::mangle_region(cmr);
+ }
+
+ if (UseNUMA) {
+ _eden_space = new MutableNUMASpace(virtual_space()->alignment());
+ } else {
+ _eden_space = new MutableSpace(virtual_space()->alignment());
+ }
+ _from_space = new MutableSpace(virtual_space()->alignment());
+ _to_space = new MutableSpace(virtual_space()->alignment());
+
+ if (_eden_space == NULL || _from_space == NULL || _to_space == NULL) {
+ vm_exit_during_initialization("Could not allocate a young gen space");
+ }
+
+ // Allocate the mark sweep views of spaces
+ _eden_mark_sweep =
+ new PSMarkSweepDecorator(_eden_space, NULL, MarkSweepDeadRatio);
+ _from_mark_sweep =
+ new PSMarkSweepDecorator(_from_space, NULL, MarkSweepDeadRatio);
+ _to_mark_sweep =
+ new PSMarkSweepDecorator(_to_space, NULL, MarkSweepDeadRatio);
+
+ if (_eden_mark_sweep == NULL ||
+ _from_mark_sweep == NULL ||
+ _to_mark_sweep == NULL) {
+ vm_exit_during_initialization("Could not complete allocation"
+ " of the young generation");
+ }
+
+ // Generation Counters - generation 0, 3 subspaces
+ _gen_counters = new PSGenerationCounters("new", 0, 3, _min_gen_size,
+ _max_gen_size, _virtual_space);
+
+ // Compute maximum space sizes for performance counters
+ ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
+ size_t alignment = heap->space_alignment();
+ size_t size = virtual_space()->reserved_size();
+
+ size_t max_survivor_size;
+ size_t max_eden_size;
+
+ if (UseAdaptiveSizePolicy) {
+ max_survivor_size = size / MinSurvivorRatio;
+
+ // round the survivor space size down to the nearest alignment
+ // and make sure its size is greater than 0.
+ max_survivor_size = align_down(max_survivor_size, alignment);
+ max_survivor_size = MAX2(max_survivor_size, alignment);
+
+ // set the maximum size of eden to be the size of the young gen
+ // less two times the minimum survivor size. The minimum survivor
+ // size for UseAdaptiveSizePolicy is one alignment.
+ max_eden_size = size - 2 * alignment;
+ } else {
+ max_survivor_size = size / InitialSurvivorRatio;
+
+ // round the survivor space size down to the nearest alignment
+ // and make sure its size is greater than 0.
+ max_survivor_size = align_down(max_survivor_size, alignment);
+ max_survivor_size = MAX2(max_survivor_size, alignment);
+
+ // set the maximum size of eden to be the size of the young gen
+ // less two times the survivor size when the generation is 100%
+ // committed. The minimum survivor size for -UseAdaptiveSizePolicy
+ // is dependent on the committed portion (current capacity) of the
+ // generation - the less space committed, the smaller the survivor
+ // space, possibly as small as an alignment. However, we are interested
+ // in the case where the young generation is 100% committed, as this
+ // is the point where eden reaches its maximum size. At this point,
+ // the size of a survivor space is max_survivor_size.
+ max_eden_size = size - 2 * max_survivor_size;
+ }
+
+ _eden_counters = new SpaceCounters("eden", 0, max_eden_size, _eden_space,
+ _gen_counters);
+ _from_counters = new SpaceCounters("s0", 1, max_survivor_size, _from_space,
+ _gen_counters);
+ _to_counters = new SpaceCounters("s1", 2, max_survivor_size, _to_space,
+ _gen_counters);
+
+ compute_initial_space_boundaries();
+}
+
+void PSYoungGen::compute_initial_space_boundaries() {
+ ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
+
+ // Compute sizes
+ size_t alignment = heap->space_alignment();
+ size_t size = virtual_space()->committed_size();
+ assert(size >= 3 * alignment, "Young space is not large enough for eden + 2 survivors");
+
+ size_t survivor_size = size / InitialSurvivorRatio;
+ survivor_size = align_down(survivor_size, alignment);
+ // ... but never less than an alignment
+ survivor_size = MAX2(survivor_size, alignment);
+
+ // Young generation is eden + 2 survivor spaces
+ size_t eden_size = size - (2 * survivor_size);
+
+ // Now go ahead and set 'em.
+ set_space_boundaries(eden_size, survivor_size);
+ space_invariants();
+
+ if (UsePerfData) {
+ _eden_counters->update_capacity();
+ _from_counters->update_capacity();
+ _to_counters->update_capacity();
+ }
+}
+
+void PSYoungGen::set_space_boundaries(size_t eden_size, size_t survivor_size) {
+ assert(eden_size < virtual_space()->committed_size(), "just checking");
+ assert(eden_size > 0 && survivor_size > 0, "just checking");
+
+ // Initial layout is Eden, to, from. After swapping survivor spaces,
+ // that leaves us with Eden, from, to, which is step one in our two
+ // step resize-with-live-data procedure.
+ char *eden_start = virtual_space()->low();
+ char *to_start = eden_start + eden_size;
+ char *from_start = to_start + survivor_size;
+ char *from_end = from_start + survivor_size;
+
+ assert(from_end == virtual_space()->high(), "just checking");
+ assert(is_object_aligned(eden_start), "checking alignment");
+ assert(is_object_aligned(to_start), "checking alignment");
+ assert(is_object_aligned(from_start), "checking alignment");
+
+ MemRegion eden_mr((HeapWord*)eden_start, (HeapWord*)to_start);
+ MemRegion to_mr ((HeapWord*)to_start, (HeapWord*)from_start);
+ MemRegion from_mr((HeapWord*)from_start, (HeapWord*)from_end);
+
+ eden_space()->initialize(eden_mr, true, ZapUnusedHeapArea);
+ to_space()->initialize(to_mr , true, ZapUnusedHeapArea);
+ from_space()->initialize(from_mr, true, ZapUnusedHeapArea);
+}
+
+#ifndef PRODUCT
+void PSYoungGen::space_invariants() {
+ ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
+ const size_t alignment = heap->space_alignment();
+
+ // Currently, our eden size cannot shrink to zero
+ guarantee(eden_space()->capacity_in_bytes() >= alignment, "eden too small");
+ guarantee(from_space()->capacity_in_bytes() >= alignment, "from too small");
+ guarantee(to_space()->capacity_in_bytes() >= alignment, "to too small");
+
+ // Relationship of spaces to each other
+ char* eden_start = (char*)eden_space()->bottom();
+ 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();
+
+ guarantee(eden_start >= virtual_space()->low(), "eden bottom");
+ guarantee(eden_start < eden_end, "eden space consistency");
+ guarantee(from_start < from_end, "from space consistency");
+ guarantee(to_start < to_end, "to space consistency");
+
+ // Check whether from space is below to space
+ if (from_start < to_start) {
+ // Eden, from, to
+ guarantee(eden_end <= from_start, "eden/from boundary");
+ guarantee(from_end <= to_start, "from/to boundary");
+ guarantee(to_end <= virtual_space()->high(), "to end");
+ } else {
+ // Eden, to, from
+ guarantee(eden_end <= to_start, "eden/to boundary");
+ guarantee(to_end <= from_start, "to/from boundary");
+ guarantee(from_end <= virtual_space()->high(), "from end");
+ }
+
+ // More checks that the virtual space is consistent with the spaces
+ assert(virtual_space()->committed_size() >=
+ (eden_space()->capacity_in_bytes() +
+ to_space()->capacity_in_bytes() +
+ from_space()->capacity_in_bytes()), "Committed size is inconsistent");
+ assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
+ "Space invariant");
+ char* eden_top = (char*)eden_space()->top();
+ char* from_top = (char*)from_space()->top();
+ char* to_top = (char*)to_space()->top();
+ assert(eden_top <= virtual_space()->high(), "eden top");
+ assert(from_top <= virtual_space()->high(), "from top");
+ assert(to_top <= virtual_space()->high(), "to top");
+
+ virtual_space()->verify();
+}
+#endif
+
+void PSYoungGen::resize(size_t eden_size, size_t survivor_size) {
+ // Resize the generation if needed. If the generation resize
+ // reports false, do not attempt to resize the spaces.
+ if (resize_generation(eden_size, survivor_size)) {
+ // Then we lay out the spaces inside the generation
+ resize_spaces(eden_size, survivor_size);
+
+ space_invariants();
+
+ log_trace(gc, ergo)("Young generation size: "
+ "desired eden: " SIZE_FORMAT " survivor: " SIZE_FORMAT
+ " used: " SIZE_FORMAT " capacity: " SIZE_FORMAT
+ " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,
+ eden_size, survivor_size, used_in_bytes(), capacity_in_bytes(),
+ _max_gen_size, min_gen_size());
+ }
+}
+
+
+bool PSYoungGen::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 this guarantee there.
+ // guarantee ((eden_size + 2*survivor_size) <= _max_gen_size, "incorrect input arguments");
+ // Code below forces this requirement. In addition the desired eden
+ // size and desired survivor sizes are desired goals and may
+ // exceed the total generation size.
+
+ assert(min_gen_size() <= orig_size && orig_size <= max_size(), "just checking");
+
+ // Adjust new generation size
+ const size_t eden_plus_survivors =
+ align_up(eden_size + 2 * survivor_size, alignment);
+ size_t desired_size = MAX2(MIN2(eden_plus_survivors, max_size()),
+ min_gen_size());
+ assert(desired_size <= max_size(), "just checking");
+
+ if (desired_size > orig_size) {
+ // Grow the generation
+ size_t change = desired_size - orig_size;
+ assert(change % alignment == 0, "just checking");
+ HeapWord* prev_high = (HeapWord*) virtual_space()->high();
+ if (!virtual_space()->expand_by(change)) {
+ return false; // Error if we fail to resize!
+ }
+ 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_high = (HeapWord*) virtual_space()->high();
+ MemRegion mangle_region(prev_high, new_high);
+ SpaceMangler::mangle_region(mangle_region);
+ }
+ size_changed = true;
+ } else if (desired_size < orig_size) {
+ size_t desired_change = orig_size - desired_size;
+ assert(desired_change % alignment == 0, "just checking");
+
+ desired_change = limit_gen_shrink(desired_change);
+
+ if (desired_change > 0) {
+ virtual_space()->shrink_by(desired_change);
+ reset_survivors_after_shrink();
+
+ size_changed = true;
+ }
+ } else {
+ if (orig_size == gen_size_limit()) {
+ log_trace(gc)("PSYoung generation size at maximum: " SIZE_FORMAT "K", orig_size/K);
+ } else if (orig_size == min_gen_size()) {
+ log_trace(gc)("PSYoung generation size at minium: " SIZE_FORMAT "K", orig_size/K);
+ }
+ }
+
+ if (size_changed) {
+ post_resize();
+ log_trace(gc)("PSYoung generation size changed: " SIZE_FORMAT "K->" SIZE_FORMAT "K",
+ orig_size/K, virtual_space()->committed_size()/K);
+ }
+
+ guarantee(eden_plus_survivors <= virtual_space()->committed_size() ||
+ virtual_space()->committed_size() == max_size(), "Sanity");
+
+ return true;
+}
+
+#ifndef PRODUCT
+// In the numa case eden is not mangled so a survivor space
+// moving into a region previously occupied by a survivor
+// may find an unmangled region. Also in the PS case eden
+// to-space and from-space may not touch (i.e., there may be
+// gaps between them due to movement while resizing the
+// spaces). Those gaps must be mangled.
+void PSYoungGen::mangle_survivors(MutableSpace* s1,
+ MemRegion s1MR,
+ MutableSpace* s2,
+ MemRegion s2MR) {
+ // Check eden and gap between eden and from-space, in deciding
+ // what to mangle in from-space. Check the gap between from-space
+ // and to-space when deciding what to mangle.
+ //
+ // +--------+ +----+ +---+
+ // | eden | |s1 | |s2 |
+ // +--------+ +----+ +---+
+ // +-------+ +-----+
+ // |s1MR | |s2MR |
+ // +-------+ +-----+
+ // All of survivor-space is properly mangled so find the
+ // upper bound on the mangling for any portion above current s1.
+ HeapWord* delta_end = MIN2(s1->bottom(), s1MR.end());
+ MemRegion delta1_left;
+ if (s1MR.start() < delta_end) {
+ delta1_left = MemRegion(s1MR.start(), delta_end);
+ s1->mangle_region(delta1_left);
+ }
+ // Find any portion to the right of the current s1.
+ HeapWord* delta_start = MAX2(s1->end(), s1MR.start());
+ MemRegion delta1_right;
+ if (delta_start < s1MR.end()) {
+ delta1_right = MemRegion(delta_start, s1MR.end());
+ s1->mangle_region(delta1_right);
+ }
+
+ // Similarly for the second survivor space except that
+ // any of the new region that overlaps with the current
+ // region of the first survivor space has already been
+ // mangled.
+ delta_end = MIN2(s2->bottom(), s2MR.end());
+ delta_start = MAX2(s2MR.start(), s1->end());
+ MemRegion delta2_left;
+ if (s2MR.start() < delta_end) {
+ delta2_left = MemRegion(s2MR.start(), delta_end);
+ s2->mangle_region(delta2_left);
+ }
+ delta_start = MAX2(s2->end(), s2MR.start());
+ MemRegion delta2_right;
+ if (delta_start < s2MR.end()) {
+ s2->mangle_region(delta2_right);
+ }
+
+ // s1
+ log_develop_trace(gc)("Current region: [" PTR_FORMAT ", " PTR_FORMAT ") "
+ "New region: [" PTR_FORMAT ", " PTR_FORMAT ")",
+ p2i(s1->bottom()), p2i(s1->end()),
+ p2i(s1MR.start()), p2i(s1MR.end()));
+ log_develop_trace(gc)(" Mangle before: [" PTR_FORMAT ", "
+ PTR_FORMAT ") Mangle after: [" PTR_FORMAT ", " PTR_FORMAT ")",
+ p2i(delta1_left.start()), p2i(delta1_left.end()),
+ p2i(delta1_right.start()), p2i(delta1_right.end()));
+
+ // s2
+ log_develop_trace(gc)("Current region: [" PTR_FORMAT ", " PTR_FORMAT ") "
+ "New region: [" PTR_FORMAT ", " PTR_FORMAT ")",
+ p2i(s2->bottom()), p2i(s2->end()),
+ p2i(s2MR.start()), p2i(s2MR.end()));
+ log_develop_trace(gc)(" Mangle before: [" PTR_FORMAT ", "
+ PTR_FORMAT ") Mangle after: [" PTR_FORMAT ", " PTR_FORMAT ")",
+ p2i(delta2_left.start()), p2i(delta2_left.end()),
+ p2i(delta2_right.start()), p2i(delta2_right.end()));
+}
+#endif // NOT PRODUCT
+
+void PSYoungGen::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");
+
+ // We require eden and to space to be empty
+ if ((!eden_space()->is_empty()) || (!to_space()->is_empty())) {
+ return;
+ }
+
+ log_trace(gc, ergo)("PSYoungGen::resize_spaces(requested_eden_size: " SIZE_FORMAT ", requested_survivor_size: " SIZE_FORMAT ")",
+ requested_eden_size, requested_survivor_size);
+ log_trace(gc, ergo)(" 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)));
+ log_trace(gc, ergo)(" 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)));
+ log_trace(gc, ergo)(" 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()) {
+ log_trace(gc, ergo)(" capacities are the right sizes, returning");
+ return;
+ }
+
+ char* eden_start = (char*)eden_space()->bottom();
+ 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();
+
+ ParallelScavengeHeap* heap = ParallelScavengeHeap::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
+ eden_from_to_order = true;
+ log_trace(gc, ergo)(" 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()) {
+ // 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_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");
+
+ log_trace(gc, ergo)(" [eden_start .. eden_end): [" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
+ p2i(eden_start),
+ p2i(eden_end),
+ pointer_delta(eden_end, eden_start, sizeof(char)));
+ log_trace(gc, ergo)(" [from_start .. from_end): [" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
+ p2i(from_start),
+ p2i(from_end),
+ pointer_delta(from_end, from_start, sizeof(char)));
+ log_trace(gc, ergo)(" [ 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
+ log_trace(gc, ergo)(" 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");
+
+ // Could choose to not let eden shrink
+ // to_start = MAX2(to_start, eden_end);
+
+ // 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);
+
+ log_trace(gc, ergo)(" [eden_start .. eden_end): [" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
+ p2i(eden_start),
+ p2i(eden_end),
+ pointer_delta(eden_end, eden_start, sizeof(char)));
+ log_trace(gc, ergo)(" [ to_start .. to_end): [" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT,
+ p2i(to_start),
+ p2i(to_end),
+ pointer_delta( to_end, to_start, sizeof(char)));
+ log_trace(gc, ergo)(" [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(eden_start), "checking alignment");
+ assert(is_object_aligned(from_start), "checking alignment");
+ assert(is_object_aligned(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"!
+ HeapWord* old_from_top = from_space()->top();
+
+ // For logging 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);
+
+ assert(from_space()->top() == old_from_top, "from top changed!");
+
+ log_trace(gc, ergo)("AdaptiveSizePolicy::survivor space sizes: collection: %d (" SIZE_FORMAT ", " SIZE_FORMAT ") -> (" SIZE_FORMAT ", " SIZE_FORMAT ") ",
+ ParallelScavengeHeap::heap()->total_collections(),
+ old_from, old_to,
+ from_space()->capacity_in_bytes(),
+ to_space()->capacity_in_bytes());
+}
+
+void PSYoungGen::swap_spaces() {
+ MutableSpace* s = from_space();
+ _from_space = to_space();
+ _to_space = s;
+
+ // Now update the decorators.
+ PSMarkSweepDecorator* md = from_mark_sweep();
+ _from_mark_sweep = to_mark_sweep();
+ _to_mark_sweep = md;
+
+ assert(from_mark_sweep()->space() == from_space(), "Sanity");
+ assert(to_mark_sweep()->space() == to_space(), "Sanity");
+}
+
+size_t PSYoungGen::capacity_in_bytes() const {
+ return eden_space()->capacity_in_bytes()
+ + from_space()->capacity_in_bytes(); // to_space() is only used during scavenge
+}
+
+
+size_t PSYoungGen::used_in_bytes() const {
+ return eden_space()->used_in_bytes()
+ + from_space()->used_in_bytes(); // to_space() is only used during scavenge
+}
+
+
+size_t PSYoungGen::free_in_bytes() const {
+ return eden_space()->free_in_bytes()
+ + from_space()->free_in_bytes(); // to_space() is only used during scavenge
+}
+
+size_t PSYoungGen::capacity_in_words() const {
+ return eden_space()->capacity_in_words()
+ + from_space()->capacity_in_words(); // to_space() is only used during scavenge
+}
+
+
+size_t PSYoungGen::used_in_words() const {
+ return eden_space()->used_in_words()
+ + from_space()->used_in_words(); // to_space() is only used during scavenge
+}
+
+
+size_t PSYoungGen::free_in_words() const {
+ return eden_space()->free_in_words()
+ + from_space()->free_in_words(); // to_space() is only used during scavenge
+}
+
+void PSYoungGen::object_iterate(ObjectClosure* blk) {
+ eden_space()->object_iterate(blk);
+ from_space()->object_iterate(blk);
+ to_space()->object_iterate(blk);
+}
+
+void PSYoungGen::precompact() {
+ eden_mark_sweep()->precompact();
+ from_mark_sweep()->precompact();
+ to_mark_sweep()->precompact();
+}
+
+void PSYoungGen::adjust_pointers() {
+ eden_mark_sweep()->adjust_pointers();
+ from_mark_sweep()->adjust_pointers();
+ to_mark_sweep()->adjust_pointers();
+}
+
+void PSYoungGen::compact() {
+ eden_mark_sweep()->compact(ZapUnusedHeapArea);
+ from_mark_sweep()->compact(ZapUnusedHeapArea);
+ // Mark sweep stores preserved markOops in to space, don't disturb!
+ to_mark_sweep()->compact(false);
+}
+
+void PSYoungGen::print() const { print_on(tty); }
+void PSYoungGen::print_on(outputStream* st) const {
+ st->print(" %-15s", "PSYoungGen");
+ st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
+ capacity_in_bytes()/K, used_in_bytes()/K);
+ virtual_space()->print_space_boundaries_on(st);
+ st->print(" eden"); eden_space()->print_on(st);
+ st->print(" from"); from_space()->print_on(st);
+ st->print(" to "); to_space()->print_on(st);
+}
+
+// Note that a space is not printed before the [NAME:
+void PSYoungGen::print_used_change(size_t prev_used) const {
+ log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)",
+ name(), prev_used / K, used_in_bytes() / K, capacity_in_bytes() / K);
+}
+
+size_t PSYoungGen::available_for_expansion() {
+ ShouldNotReachHere();
+ return 0;
+}
+
+size_t PSYoungGen::available_for_contraction() {
+ ShouldNotReachHere();
+ return 0;
+}
+
+size_t PSYoungGen::available_to_min_gen() {
+ assert(virtual_space()->committed_size() >= min_gen_size(), "Invariant");
+ return virtual_space()->committed_size() - min_gen_size();
+}
+
+// This method assumes that from-space has live data and that
+// any shrinkage of the young gen is limited by location of
+// from-space.
+size_t PSYoungGen::available_to_live() {
+ size_t delta_in_survivor = 0;
+ ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
+ const size_t space_alignment = heap->space_alignment();
+ const size_t gen_alignment = heap->generation_alignment();
+
+ MutableSpace* space_shrinking = NULL;
+ if (from_space()->end() > to_space()->end()) {
+ space_shrinking = from_space();
+ } else {
+ space_shrinking = to_space();
+ }
+
+ // Include any space that is committed but not included in
+ // the survivor spaces.
+ assert(((HeapWord*)virtual_space()->high()) >= space_shrinking->end(),
+ "Survivor space beyond high end");
+ size_t unused_committed = pointer_delta(virtual_space()->high(),
+ space_shrinking->end(), sizeof(char));
+
+ if (space_shrinking->is_empty()) {
+ // Don't let the space shrink to 0
+ assert(space_shrinking->capacity_in_bytes() >= space_alignment,
+ "Space is too small");
+ delta_in_survivor = space_shrinking->capacity_in_bytes() - space_alignment;
+ } else {
+ delta_in_survivor = pointer_delta(space_shrinking->end(),
+ space_shrinking->top(),
+ sizeof(char));
+ }
+
+ size_t delta_in_bytes = unused_committed + delta_in_survivor;
+ delta_in_bytes = align_down(delta_in_bytes, gen_alignment);
+ return delta_in_bytes;
+}
+
+// Return the number of bytes available for resizing down the young
+// generation. This is the minimum of
+// input "bytes"
+// bytes to the minimum young gen size
+// bytes to the size currently being used + some small extra
+size_t PSYoungGen::limit_gen_shrink(size_t bytes) {
+ // Allow shrinkage into the current eden but keep eden large enough
+ // to maintain the minimum young gen size
+ bytes = MIN3(bytes, available_to_min_gen(), available_to_live());
+ return align_down(bytes, virtual_space()->alignment());
+}
+
+void PSYoungGen::reset_after_change() {
+ ShouldNotReachHere();
+}
+
+void PSYoungGen::reset_survivors_after_shrink() {
+ _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
+ (HeapWord*)virtual_space()->high_boundary());
+ PSScavenge::reference_processor()->set_span(_reserved);
+
+ MutableSpace* space_shrinking = NULL;
+ if (from_space()->end() > to_space()->end()) {
+ space_shrinking = from_space();
+ } else {
+ space_shrinking = to_space();
+ }
+
+ HeapWord* new_end = (HeapWord*)virtual_space()->high();
+ assert(new_end >= space_shrinking->bottom(), "Shrink was too large");
+ // Was there a shrink of the survivor space?
+ if (new_end < space_shrinking->end()) {
+ MemRegion mr(space_shrinking->bottom(), new_end);
+ space_shrinking->initialize(mr,
+ SpaceDecorator::DontClear,
+ SpaceDecorator::Mangle);
+ }
+}
+
+// This method currently does not expect to expand into eden (i.e.,
+// the virtual space boundaries is expected to be consistent
+// with the eden boundaries..
+void PSYoungGen::post_resize() {
+ assert_locked_or_safepoint(Heap_lock);
+ assert((eden_space()->bottom() < to_space()->bottom()) &&
+ (eden_space()->bottom() < from_space()->bottom()),
+ "Eden is assumed to be below the survivor spaces");
+
+ MemRegion cmr((HeapWord*)virtual_space()->low(),
+ (HeapWord*)virtual_space()->high());
+ ParallelScavengeHeap::heap()->barrier_set()->resize_covered_region(cmr);
+ space_invariants();
+}
+
+
+
+void PSYoungGen::update_counters() {
+ if (UsePerfData) {
+ _eden_counters->update_all();
+ _from_counters->update_all();
+ _to_counters->update_all();
+ _gen_counters->update_all();
+ }
+}
+
+void PSYoungGen::verify() {
+ eden_space()->verify();
+ from_space()->verify();
+ to_space()->verify();
+}
+
+#ifndef PRODUCT
+void PSYoungGen::record_spaces_top() {
+ assert(ZapUnusedHeapArea, "Not mangling unused space");
+ eden_space()->set_top_for_allocations();
+ from_space()->set_top_for_allocations();
+ to_space()->set_top_for_allocations();
+}
+#endif