Mercurial > hg > truffle
diff src/share/vm/gc_implementation/parNew/asParNewGeneration.cpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | 183f41cf8bfe |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/gc_implementation/parNew/asParNewGeneration.cpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,630 @@ +/* + * 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