jdk-sandbox: comparison hotspot/src/share/vm/gc_implementation/parNew/asParNewGeneration.cpp

equal deleted inserted replaced

-:fd16c54261b3
+:489c9b5090e2
+/*
+* Copyright 2005-2006 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/_asParNewGeneration.cpp.incl"
+ASParNewGeneration::ASParNewGeneration(ReservedSpace rs,
+size_t initial_byte_size,
+size_t min_byte_size,
+int level) :
+ParNewGeneration(rs, initial_byte_size, level),
+_min_gen_size(min_byte_size) {}
+const char* ASParNewGeneration::name() const {
+return "adaptive size par new generation";
+}
+void ASParNewGeneration::adjust_desired_tenuring_threshold() {
+assert(UseAdaptiveSizePolicy,
+"Should only be used with UseAdaptiveSizePolicy");
+}
+void ASParNewGeneration::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();
+if (PrintAdaptiveSizePolicy && Verbose) {
+gclog_or_tty->print_cr("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(), capacity(),
+max_gen_size(), min_gen_size());
+}
+}
+}
+size_t ASParNewGeneration::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 ASParNewGeneration::available_to_live() const {
+#undef SHRINKS_AT_END_OF_EDEN
+#ifdef SHRINKS_AT_END_OF_EDEN
+size_t delta_in_survivor = 0;
+ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
+const size_t space_alignment = heap->intra_generation_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_size_down(delta_in_bytes, gen_alignment);
+return delta_in_bytes;
+#else
+// The only space available for shrinking is in to-space if it
+// is above from-space.
+if (to()->bottom() > from()->bottom()) {
+const size_t alignment = os::vm_page_size();
+if (to()->capacity() < alignment) {
+return 0;
+} else {
+return to()->capacity() - alignment;
+}
+} else {
+return 0;
+}
+#endif
+}
+// 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 ASParNewGeneration::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_size_down(bytes, os::vm_page_size());
+}
+// Note that the the alignment used is the OS page size as
+// opposed to an alignment associated with the virtual space
+// (as is done in the ASPSYoungGen/ASPSOldGen)
+bool ASParNewGeneration::resize_generation(size_t eden_size,
+size_t survivor_size) {
+const size_t alignment = os::vm_page_size();
+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 disired survivor sizes are desired goals and may
+// exceed the total generation size.
+assert(min_gen_size() <= orig_size && orig_size <= max_gen_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, max_gen_size()),
+min_gen_size());
+assert(desired_size <= max_gen_size(), "just checking");
+if (desired_size > orig_size) {
+// Grow the generation
+size_t change = desired_size - orig_size;
+assert(change % alignment == 0, "just checking");
+if (!virtual_space()->expand_by(change)) {
+return false; // Error if we fail to resize!
+}
+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 (Verbose && PrintGC) {
+if (orig_size == max_gen_size()) {
+gclog_or_tty->print_cr("ASParNew generation size at maximum: "
+SIZE_FORMAT "K", orig_size/K);
+} else if (orig_size == min_gen_size()) {
+gclog_or_tty->print_cr("ASParNew generation size at minium: "
+SIZE_FORMAT "K", orig_size/K);
+}
+}
+}
+if (size_changed) {
+MemRegion cmr((HeapWord*)virtual_space()->low(),
+(HeapWord*)virtual_space()->high());
+GenCollectedHeap::heap()->barrier_set()->resize_covered_region(cmr);
+if (Verbose && PrintGC) {
+size_t current_size  = virtual_space()->committed_size();
+gclog_or_tty->print_cr("ASParNew 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_gen_size(), "Sanity");
+return true;
+}
+void ASParNewGeneration::reset_survivors_after_shrink() {
+GenCollectedHeap* gch = GenCollectedHeap::heap();
+HeapWord* new_end = (HeapWord*)virtual_space()->high();
+if (from()->end() > to()->end()) {
+assert(new_end >= from()->end(), "Shrinking past from-space");
+} else {
+assert(new_end >= to()->bottom(), "Shrink was too large");
+// Was there a shrink of the survivor space?
+if (new_end < to()->end()) {
+MemRegion mr(to()->bottom(), new_end);
+to()->initialize(mr, false /* clear */);
+}
+}
+}
+void ASParNewGeneration::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");
+CollectedHeap* heap = Universe::heap();
+assert(heap->kind() == CollectedHeap::GenCollectedHeap, "Sanity");
+// We require eden and to space to be empty
+if ((!eden()->is_empty()) || (!to()->is_empty())) {
+return;
+}
+size_t cur_eden_size = eden()->capacity();
+if (PrintAdaptiveSizePolicy && Verbose) {
+gclog_or_tty->print_cr("ASParNew::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()->bottom(),
+eden()->end(),
+pointer_delta(eden()->end(),
+eden()->bottom(),
+sizeof(char)));
+gclog_or_tty->print_cr("    from: [" PTR_FORMAT ".." PTR_FORMAT ") "
+SIZE_FORMAT,
+from()->bottom(),
+from()->end(),
+pointer_delta(from()->end(),
+from()->bottom(),
+sizeof(char)));
+gclog_or_tty->print_cr("      to: [" PTR_FORMAT ".." PTR_FORMAT ") "
+SIZE_FORMAT,
+to()->bottom(),
+to()->end(),
+pointer_delta(  to()->end(),
+to()->bottom(),
+sizeof(char)));
+}
+// There's nothing to do if the new sizes are the same as the current
+if (requested_survivor_size == to()->capacity() &&
+requested_survivor_size == from()->capacity() &&
+requested_eden_size == eden()->capacity()) {
+if (PrintAdaptiveSizePolicy && Verbose) {
+gclog_or_tty->print_cr("    capacities are the right sizes, returning");
+}
+return;
+}
+char* eden_start = (char*)eden()->bottom();
+char* eden_end   = (char*)eden()->end();
+char* from_start = (char*)from()->bottom();
+char* from_end   = (char*)from()->end();
+char* to_start   = (char*)to()->bottom();
+char* to_end     = (char*)to()->end();
+const size_t alignment = os::vm_page_size();
+const bool maintain_minimum =
+(requested_eden_size + 2 * requested_survivor_size) <= min_gen_size();
+// 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
+// "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)));
+}
+// tty->print_cr("eden_size before: " SIZE_FORMAT, eden_size);
+eden_size = align_size_down(eden_size, alignment);
+// tty->print_cr("eden_size after: " SIZE_FORMAT, eden_size);
+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()->end()) {
+// Calculate the minimum offset possible for from_end
+size_t from_size = pointer_delta(from()->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()->end(), "from_end moved to the right");
+// Now update to_start with the new from_end
+to_start = MAX2(from_end, to_start);
+} else {
+// If shrinking, move to-space down to abut the end of from-space
+// so that shrinking will move to-space down.  If not shrinking
+// to-space is moving up to allow for growth on the next expansion.
+if (requested_eden_size <= cur_eden_size) {
+to_start = from_end;
+if (to_start + requested_survivor_size > to_start) {
+to_end = to_start + requested_survivor_size;
+}
+}
+// else leave to_end pointing to the high end of the virtual space.
+}
+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:");
+}
+// Calculate the to-space boundaries based on
+// the start of from-space.
+to_end = from_start;
+to_start = (char*)pointer_delta(from_start,
+(char*)requested_survivor_size,
+sizeof(char));
+// Calculate the ideal eden boundaries.
+// eden_end is already at the bottom of the generation
+assert(eden_start == virtual_space()->low(),
+"Eden is not starting at the low end of the virtual space");
+if (eden_start + requested_eden_size >= eden_start) {
+eden_end = eden_start + requested_eden_size;
+} else {
+eden_end = to_start;
+}
+// Does eden intrude into to-space?  to-space
+// gets priority but eden is not allowed to shrink
+// to 0.
+if (eden_end > to_start) {
+eden_end = to_start;
+}
+// Don't let eden shrink down to 0 or less.
+eden_end = MAX2(eden_end, eden_start + alignment);
+assert(eden_start + alignment >= eden_start, "Overflow");
+size_t eden_size;
+if (maintain_minimum) {
+// Use all the space available.
+eden_end = MAX2(eden_end, to_start);
+eden_size = pointer_delta(eden_end, eden_start, sizeof(char));
+eden_size = MIN2(eden_size, cur_eden_size);
+} else {
+eden_size = pointer_delta(eden_end, eden_start, sizeof(char));
+}
+eden_size = align_size_down(eden_size, alignment);
+assert(maintain_minimum || eden_size <= requested_eden_size,
+"Eden size is too large");
+assert(eden_size >= alignment, "Eden size is too small");
+eden_end = eden_start + eden_size;
+// Move to-space down to eden.
+if (requested_eden_size < cur_eden_size) {
+to_start = eden_end;
+if (to_start + requested_survivor_size > to_start) {
+to_end = MIN2(from_start, to_start + requested_survivor_size);
+} else {
+to_end = from_start;
+}
+}
+// eden_end may have moved so again make sure
+// the to-space and eden don't overlap.
+to_start = MAX2(eden_end, to_start);
+// from-space
+size_t from_used = from()->used();
+if (requested_survivor_size > from_used) {
+if (from_start + requested_survivor_size >= from_start) {
+from_end = from_start + requested_survivor_size;
+}
+if (from_end > virtual_space()->high()) {
+from_end = virtual_space()->high();
+}
+}
+assert(to_start >= eden_end, "to-space should be above eden");
+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()->bottom(),
+"from start moved to the right");
+guarantee((HeapWord*)from_end >= from()->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"!
+HeapWord* old_from_top = from()->top();
+// For PrintAdaptiveSizePolicy block  below
+size_t old_from = from()->capacity();
+size_t old_to   = to()->capacity();
+// The call to initialize NULL's the next compaction space
+eden()->initialize(edenMR, true);
+eden()->set_next_compaction_space(from());
+to()->initialize(toMR  , true);
+from()->initialize(fromMR, false);     // Note, not cleared!
+assert(from()->top() == old_from_top, "from top changed!");
+if (PrintAdaptiveSizePolicy) {
+GenCollectedHeap* gch = GenCollectedHeap::heap();
+assert(gch->kind() == CollectedHeap::GenCollectedHeap, "Sanity");
+gclog_or_tty->print("AdaptiveSizePolicy::survivor space sizes: "
+"collection: %d "
+"(" SIZE_FORMAT ", " SIZE_FORMAT ") -> "
+"(" SIZE_FORMAT ", " SIZE_FORMAT ") ",
+gch->total_collections(),
+old_from, old_to,
+from()->capacity(),
+to()->capacity());
+gclog_or_tty->cr();
+}
+}
+void ASParNewGeneration::compute_new_size() {
+GenCollectedHeap* gch = GenCollectedHeap::heap();
+assert(gch->kind() == CollectedHeap::GenCollectedHeap,
+"not a CMS generational heap");
+CMSAdaptiveSizePolicy* size_policy =
+(CMSAdaptiveSizePolicy*)gch->gen_policy()->size_policy();
+assert(size_policy->is_gc_cms_adaptive_size_policy(),
+"Wrong type of size policy");
+size_t survived = from()->used();
+if (!survivor_overflow()) {
+// Keep running averages on how much survived
+size_policy->avg_survived()->sample(survived);
+} else {
+size_t promoted =
+(size_t) next_gen()->gc_stats()->avg_promoted()->last_sample();
+assert(promoted < gch->capacity(), "Conversion problem?");
+size_t survived_guess = survived + promoted;
+size_policy->avg_survived()->sample(survived_guess);
+}
+size_t survivor_limit = max_survivor_size();
+_tenuring_threshold =
+size_policy->compute_survivor_space_size_and_threshold(
+_survivor_overflow,
+_tenuring_threshold,
+survivor_limit);
+size_policy->avg_young_live()->sample(used());
+size_policy->avg_eden_live()->sample(eden()->used());
+size_policy->compute_young_generation_free_space(eden()->capacity(),
+max_gen_size());
+resize(size_policy->calculated_eden_size_in_bytes(),
+size_policy->calculated_survivor_size_in_bytes());
+if (UsePerfData) {
+CMSGCAdaptivePolicyCounters* counters =
+(CMSGCAdaptivePolicyCounters*) gch->collector_policy()->counters();
+assert(counters->kind() ==
+GCPolicyCounters::CMSGCAdaptivePolicyCountersKind,
+"Wrong kind of counters");
+counters->update_tenuring_threshold(_tenuring_threshold);
+counters->update_survivor_overflowed(_survivor_overflow);
+counters->update_young_capacity(capacity());
+}
+}
+#ifndef PRODUCT
+// Changes from PSYoungGen version
+//      value of "alignment"
+void ASParNewGeneration::space_invariants() {
+const size_t alignment = os::vm_page_size();
+// Currently, our eden size cannot shrink to zero
+guarantee(eden()->capacity() >= alignment, "eden too small");
+guarantee(from()->capacity() >= alignment, "from too small");
+guarantee(to()->capacity() >= alignment, "to too small");
+// Relationship of spaces to each other
+char* eden_start = (char*)eden()->bottom();
+char* eden_end   = (char*)eden()->end();
+char* from_start = (char*)from()->bottom();
+char* from_end   = (char*)from()->end();
+char* to_start   = (char*)to()->bottom();
+char* to_end     = (char*)to()->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()->capacity() +
+to()->capacity() +
+from()->capacity()), "Committed size is inconsistent");
+assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),
+"Space invariant");
+char* eden_top = (char*)eden()->top();
+char* from_top = (char*)from()->top();
+char* to_top = (char*)to()->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");
+}
+#endif

changeset 1	489c9b5090e2
child 186	32e6c95f8d9b