/* * Copyright (c) 2005, 2013, 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_implementation/concurrentMarkSweep/cmsAdaptiveSizePolicy.hpp" #include "gc_implementation/concurrentMarkSweep/cmsGCAdaptivePolicyCounters.hpp" #include "gc_implementation/parNew/asParNewGeneration.hpp" #include "gc_implementation/parNew/parNewGeneration.hpp" #include "gc_implementation/shared/markSweep.inline.hpp" #include "gc_implementation/shared/spaceDecorator.hpp" #include "memory/defNewGeneration.inline.hpp" #include "memory/referencePolicy.hpp" #include "oops/markOop.inline.hpp" #include "oops/oop.pcgc.inline.hpp" 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_heap_alignment(); const size_t gen_alignment = heap->object_heap_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 desired 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 (expand(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, SpaceDecorator::DontClear, SpaceDecorator::DontMangle); } } } 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))); } eden_size = align_size_down(eden_size, alignment); 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(); // If not clearing the spaces, do some checking to verify that // the spaces are already mangled. // Must check mangling before the spaces are reshaped. Otherwise, // the bottom or end of one space may have moved into another // a failure of the check may not correctly indicate which space // is not properly mangled. if (ZapUnusedHeapArea) { HeapWord* limit = (HeapWord*) virtual_space()->high(); eden()->check_mangled_unused_area(limit); from()->check_mangled_unused_area(limit); to()->check_mangled_unused_area(limit); } // The call to initialize NULL's the next compaction space eden()->initialize(edenMR, SpaceDecorator::Clear, SpaceDecorator::DontMangle); eden()->set_next_compaction_space(from()); to()->initialize(toMR , SpaceDecorator::Clear, SpaceDecorator::DontMangle); from()->initialize(fromMR, SpaceDecorator::DontClear, SpaceDecorator::DontMangle); 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_eden_space_size(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