Mercurial > hg > truffle
diff src/share/vm/gc_implementation/parallelScavenge/asPSYoungGen.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/parallelScavenge/asPSYoungGen.cpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,469 @@ +/* + * Copyright 2003-2006 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/_asPSYoungGen.cpp.incl" + +ASPSYoungGen::ASPSYoungGen(size_t init_byte_size, + size_t minimum_byte_size, + size_t byte_size_limit) : + PSYoungGen(init_byte_size, minimum_byte_size, byte_size_limit), + _gen_size_limit(byte_size_limit) { +} + + +ASPSYoungGen::ASPSYoungGen(PSVirtualSpace* vs, + size_t init_byte_size, + size_t minimum_byte_size, + size_t byte_size_limit) : + //PSYoungGen(init_byte_size, minimum_byte_size, byte_size_limit), + PSYoungGen(vs->committed_size(), minimum_byte_size, byte_size_limit), + _gen_size_limit(byte_size_limit) { + + assert(vs->committed_size() == init_byte_size, "Cannot replace with"); + + _virtual_space = vs; +} + +void ASPSYoungGen::initialize_virtual_space(ReservedSpace rs, + size_t alignment) { + assert(_init_gen_size != 0, "Should have a finite size"); + _virtual_space = new PSVirtualSpaceHighToLow(rs, alignment); + if (!_virtual_space->expand_by(_init_gen_size)) { + vm_exit_during_initialization("Could not reserve enough space for " + "object heap"); + } +} + +void ASPSYoungGen::initialize(ReservedSpace rs, size_t alignment) { + initialize_virtual_space(rs, alignment); + initialize_work(); +} + +size_t ASPSYoungGen::available_for_expansion() { + + size_t current_committed_size = virtual_space()->committed_size(); + assert((gen_size_limit() >= current_committed_size), + "generation size limit is wrong"); + ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); + size_t result = gen_size_limit() - current_committed_size; + size_t result_aligned = align_size_down(result, heap->young_gen_alignment()); + return result_aligned; +} + +// Return the number of bytes the young gen is willing give up. +// +// Future implementations could check the survivors and if to_space is in the +// right place (below from_space), take a chunk from to_space. +size_t ASPSYoungGen::available_for_contraction() { + + size_t uncommitted_bytes = virtual_space()->uncommitted_size(); + if (uncommitted_bytes != 0) { + return uncommitted_bytes; + } + + if (eden_space()->is_empty()) { + // Respect the minimum size for eden and for the young gen as a whole. + ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); + const size_t eden_alignment = heap->intra_generation_alignment(); + const size_t gen_alignment = heap->young_gen_alignment(); + + assert(eden_space()->capacity_in_bytes() >= eden_alignment, + "Alignment is wrong"); + size_t eden_avail = eden_space()->capacity_in_bytes() - eden_alignment; + eden_avail = align_size_down(eden_avail, gen_alignment); + + assert(virtual_space()->committed_size() >= min_gen_size(), + "minimum gen size is wrong"); + size_t gen_avail = virtual_space()->committed_size() - min_gen_size(); + assert(virtual_space()->is_aligned(gen_avail), "not aligned"); + + const size_t max_contraction = MIN2(eden_avail, gen_avail); + // See comment for ASPSOldGen::available_for_contraction() + // for reasons the "increment" fraction is used. + PSAdaptiveSizePolicy* policy = heap->size_policy(); + size_t result = policy->eden_increment_aligned_down(max_contraction); + size_t result_aligned = align_size_down(result, gen_alignment); + if (PrintAdaptiveSizePolicy && Verbose) { + gclog_or_tty->print_cr("ASPSYoungGen::available_for_contraction: %d K", + result_aligned/K); + gclog_or_tty->print_cr(" max_contraction %d K", max_contraction/K); + gclog_or_tty->print_cr(" eden_avail %d K", eden_avail/K); + gclog_or_tty->print_cr(" gen_avail %d K", gen_avail/K); + } + return result_aligned; + + } + + return 0; +} + +// The current implementation only considers to the end of eden. +// If to_space is below from_space, to_space is not considered. +// to_space can be. +size_t ASPSYoungGen::available_to_live() { + ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); + const size_t alignment = heap->intra_generation_alignment(); + + // Include any space that is committed but is not in eden. + size_t available = pointer_delta(eden_space()->bottom(), + virtual_space()->low(), + sizeof(char)); + + const size_t eden_capacity = eden_space()->capacity_in_bytes(); + if (eden_space()->is_empty() && eden_capacity > alignment) { + available += eden_capacity - alignment; + } + return available; +} + +// Similar to PSYoungGen::resize_generation() but +// allows sum of eden_size and 2 * survivor_size to exceed _max_gen_size +// expands at the low end of the virtual space +// moves the boundary between the generations in order to expand +// some additional diagnostics +// If no additional changes are required, this can be deleted +// and the changes factored back into PSYoungGen::resize_generation(). +bool ASPSYoungGen::resize_generation(size_t eden_size, size_t survivor_size) { + const size_t alignment = virtual_space()->alignment(); + size_t orig_size = virtual_space()->committed_size(); + bool size_changed = false; + + // There used to be a guarantee here that + // (eden_size + 2*survivor_size) <= _max_gen_size + // This requirement is enforced by the calculation of desired_size + // below. It may not be true on entry since the size of the + // eden_size is no bounded by the generation size. + + assert(max_size() == reserved().byte_size(), "max gen size problem?"); + assert(min_gen_size() <= orig_size && orig_size <= max_size(), + "just checking"); + + // Adjust new generation size + const size_t eden_plus_survivors = + align_size_up(eden_size + 2 * survivor_size, alignment); + size_t desired_size = MAX2(MIN2(eden_plus_survivors, gen_size_limit()), + min_gen_size()); + assert(desired_size <= gen_size_limit(), "just checking"); + + if (desired_size > orig_size) { + // Grow the generation + size_t change = desired_size - orig_size; + if (!virtual_space()->expand_by(change)) { + return false; + } + size_changed = true; + } else if (desired_size < orig_size) { + size_t desired_change = orig_size - desired_size; + + // How much is available for shrinking. + size_t available_bytes = limit_gen_shrink(desired_change); + size_t change = MIN2(desired_change, available_bytes); + virtual_space()->shrink_by(change); + size_changed = true; + } else { + if (Verbose && PrintGC) { + if (orig_size == gen_size_limit()) { + gclog_or_tty->print_cr("ASPSYoung generation size at maximum: " + SIZE_FORMAT "K", orig_size/K); + } else if (orig_size == min_gen_size()) { + gclog_or_tty->print_cr("ASPSYoung generation size at minium: " + SIZE_FORMAT "K", orig_size/K); + } + } + } + + if (size_changed) { + reset_after_change(); + if (Verbose && PrintGC) { + size_t current_size = virtual_space()->committed_size(); + gclog_or_tty->print_cr("ASPSYoung generation size changed: " + SIZE_FORMAT "K->" SIZE_FORMAT "K", + orig_size/K, current_size/K); + } + } + + guarantee(eden_plus_survivors <= virtual_space()->committed_size() || + virtual_space()->committed_size() == max_size(), "Sanity"); + + return true; +} + +// Similar to PSYoungGen::resize_spaces() but +// eden always starts at the low end of the committed virtual space +// current implementation does not allow holes between the spaces +// _young_generation_boundary has to be reset because it changes. +// so additional verification +void ASPSYoungGen::resize_spaces(size_t requested_eden_size, + size_t requested_survivor_size) { + assert(requested_eden_size > 0 && requested_survivor_size > 0, + "just checking"); + + space_invariants(); + + // We require eden and to space to be empty + if ((!eden_space()->is_empty()) || (!to_space()->is_empty())) { + return; + } + + if (PrintAdaptiveSizePolicy && Verbose) { + gclog_or_tty->print_cr("PSYoungGen::resize_spaces(requested_eden_size: " + SIZE_FORMAT + ", requested_survivor_size: " SIZE_FORMAT ")", + requested_eden_size, requested_survivor_size); + gclog_or_tty->print_cr(" eden: [" PTR_FORMAT ".." PTR_FORMAT ") " + SIZE_FORMAT, + eden_space()->bottom(), + eden_space()->end(), + pointer_delta(eden_space()->end(), + eden_space()->bottom(), + sizeof(char))); + gclog_or_tty->print_cr(" from: [" PTR_FORMAT ".." PTR_FORMAT ") " + SIZE_FORMAT, + from_space()->bottom(), + from_space()->end(), + pointer_delta(from_space()->end(), + from_space()->bottom(), + sizeof(char))); + gclog_or_tty->print_cr(" to: [" PTR_FORMAT ".." PTR_FORMAT ") " + SIZE_FORMAT, + to_space()->bottom(), + to_space()->end(), + pointer_delta( to_space()->end(), + to_space()->bottom(), + sizeof(char))); + } + + // There's nothing to do if the new sizes are the same as the current + if (requested_survivor_size == to_space()->capacity_in_bytes() && + requested_survivor_size == from_space()->capacity_in_bytes() && + requested_eden_size == eden_space()->capacity_in_bytes()) { + if (PrintAdaptiveSizePolicy && Verbose) { + gclog_or_tty->print_cr(" capacities are the right sizes, returning"); + } + return; + } + + char* eden_start = (char*)virtual_space()->low(); + char* eden_end = (char*)eden_space()->end(); + char* from_start = (char*)from_space()->bottom(); + char* from_end = (char*)from_space()->end(); + char* to_start = (char*)to_space()->bottom(); + char* to_end = (char*)to_space()->end(); + + assert(eden_start < from_start, "Cannot push into from_space"); + + ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); + const size_t alignment = heap->intra_generation_alignment(); + + // 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 + // Compute how big eden can be, then adjust end. + // See comment in PSYoungGen::resize_spaces() on + // calculating eden_end. + const size_t eden_size = MIN2(requested_eden_size, + pointer_delta(from_start, + eden_start, + sizeof(char))); + eden_end = eden_start + eden_size; + assert(eden_end >= eden_start, "addition overflowed") + + // To may resize into from space as long as it is clear of live data. + // From space must remain page aligned, though, so we need to do some + // extra calculations. + + // First calculate an optimal to-space + to_end = (char*)virtual_space()->high(); + to_start = (char*)pointer_delta(to_end, + (char*)requested_survivor_size, + sizeof(char)); + + // Does the optimal to-space overlap from-space? + if (to_start < (char*)from_space()->end()) { + assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); + + // Calculate the minimum offset possible for from_end + size_t from_size = + pointer_delta(from_space()->top(), from_start, sizeof(char)); + + // Should we be in this method if from_space is empty? Why not the set_space method? FIX ME! + if (from_size == 0) { + from_size = alignment; + } else { + from_size = align_size_up(from_size, alignment); + } + + from_end = from_start + from_size; + assert(from_end > from_start, "addition overflow or from_size problem"); + + guarantee(from_end <= (char*)from_space()->end(), + "from_end moved to the right"); + + // Now update to_start with the new from_end + to_start = MAX2(from_end, to_start); + } + + guarantee(to_start != to_end, "to space is zero sized"); + + if (PrintAdaptiveSizePolicy && Verbose) { + gclog_or_tty->print_cr(" [eden_start .. eden_end): " + "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, + 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:"); + } + + // 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 comment in PSYoungGen::resize_spaces() on + // calculating eden_end. + const size_t eden_size = MIN2(requested_eden_size, + pointer_delta(to_start, + eden_start, + sizeof(char))); + eden_end = eden_start + eden_size; + assert(eden_end >= eden_start, "addition overflowed") + + // Don't let eden shrink down to 0 or less. + eden_end = MAX2(eden_end, eden_start + alignment); + to_start = MAX2(to_start, eden_end); + + if (PrintAdaptiveSizePolicy && Verbose) { + gclog_or_tty->print_cr(" [eden_start .. eden_end): " + "[" PTR_FORMAT " .. " PTR_FORMAT ") " SIZE_FORMAT, + 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_space()->bottom(), + "from start moved to the right"); + guarantee((HeapWord*)from_end >= from_space()->top(), + "from end moved into live data"); + assert(is_object_aligned((intptr_t)eden_start), "checking alignment"); + assert(is_object_aligned((intptr_t)from_start), "checking alignment"); + assert(is_object_aligned((intptr_t)to_start), "checking alignment"); + + MemRegion edenMR((HeapWord*)eden_start, (HeapWord*)eden_end); + MemRegion toMR ((HeapWord*)to_start, (HeapWord*)to_end); + MemRegion fromMR((HeapWord*)from_start, (HeapWord*)from_end); + + // Let's make sure the call to initialize doesn't reset "top"! + DEBUG_ONLY(HeapWord* old_from_top = from_space()->top();) + + // For PrintAdaptiveSizePolicy block below + size_t old_from = from_space()->capacity_in_bytes(); + size_t old_to = to_space()->capacity_in_bytes(); + + eden_space()->initialize(edenMR, true); + to_space()->initialize(toMR , true); + from_space()->initialize(fromMR, false); // Note, not cleared! + PSScavenge::set_young_generation_boundary(eden_space()->bottom()); + + assert(from_space()->top() == old_from_top, "from top changed!"); + + if (PrintAdaptiveSizePolicy) { + ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); + assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); + + gclog_or_tty->print("AdaptiveSizePolicy::survivor space sizes: " + "collection: %d " + "(" SIZE_FORMAT ", " SIZE_FORMAT ") -> " + "(" SIZE_FORMAT ", " SIZE_FORMAT ") ", + heap->total_collections(), + old_from, old_to, + from_space()->capacity_in_bytes(), + to_space()->capacity_in_bytes()); + gclog_or_tty->cr(); + } + space_invariants(); +} + +void ASPSYoungGen::reset_after_change() { + assert_locked_or_safepoint(Heap_lock); + + _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(), + (HeapWord*)virtual_space()->high_boundary()); + PSScavenge::reference_processor()->set_span(_reserved); + + HeapWord* new_eden_bottom = (HeapWord*)virtual_space()->low(); + HeapWord* eden_bottom = eden_space()->bottom(); + if (new_eden_bottom != eden_bottom) { + MemRegion eden_mr(new_eden_bottom, eden_space()->end()); + eden_space()->initialize(eden_mr, true); + PSScavenge::set_young_generation_boundary(eden_space()->bottom()); + } + MemRegion cmr((HeapWord*)virtual_space()->low(), + (HeapWord*)virtual_space()->high()); + Universe::heap()->barrier_set()->resize_covered_region(cmr); + + space_invariants(); +}