Mercurial > hg > graal-compiler
view src/share/vm/memory/space.hpp @ 7235:a6bd253a770f
expanded LOG_PRINTF stub to handle up to 3 arguments in addition to the format string
author | Doug Simon <doug.simon@oracle.com> |
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date | Mon, 17 Dec 2012 11:12:01 +0100 |
parents | da91efe96a93 |
children | b735136e0d82 |
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/* * Copyright (c) 1997, 2012, 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. * */ #ifndef SHARE_VM_MEMORY_SPACE_HPP #define SHARE_VM_MEMORY_SPACE_HPP #include "memory/allocation.hpp" #include "memory/blockOffsetTable.hpp" #include "memory/cardTableModRefBS.hpp" #include "memory/iterator.hpp" #include "memory/memRegion.hpp" #include "memory/watermark.hpp" #include "oops/markOop.hpp" #include "runtime/mutexLocker.hpp" #include "runtime/prefetch.hpp" #include "utilities/workgroup.hpp" #ifdef TARGET_OS_FAMILY_linux # include "os_linux.inline.hpp" #endif #ifdef TARGET_OS_FAMILY_solaris # include "os_solaris.inline.hpp" #endif #ifdef TARGET_OS_FAMILY_windows # include "os_windows.inline.hpp" #endif #ifdef TARGET_OS_FAMILY_bsd # include "os_bsd.inline.hpp" #endif // A space is an abstraction for the "storage units" backing // up the generation abstraction. It includes specific // implementations for keeping track of free and used space, // for iterating over objects and free blocks, etc. // Here's the Space hierarchy: // // - Space -- an asbtract base class describing a heap area // - CompactibleSpace -- a space supporting compaction // - CompactibleFreeListSpace -- (used for CMS generation) // - ContiguousSpace -- a compactible space in which all free space // is contiguous // - EdenSpace -- contiguous space used as nursery // - ConcEdenSpace -- contiguous space with a 'soft end safe' allocation // - OffsetTableContigSpace -- contiguous space with a block offset array // that allows "fast" block_start calls // - TenuredSpace -- (used for TenuredGeneration) // Forward decls. class Space; class BlockOffsetArray; class BlockOffsetArrayContigSpace; class Generation; class CompactibleSpace; class BlockOffsetTable; class GenRemSet; class CardTableRS; class DirtyCardToOopClosure; // An oop closure that is circumscribed by a filtering memory region. class SpaceMemRegionOopsIterClosure: public ExtendedOopClosure { private: ExtendedOopClosure* _cl; MemRegion _mr; protected: template <class T> void do_oop_work(T* p) { if (_mr.contains(p)) { _cl->do_oop(p); } } public: SpaceMemRegionOopsIterClosure(ExtendedOopClosure* cl, MemRegion mr): _cl(cl), _mr(mr) {} virtual void do_oop(oop* p); virtual void do_oop(narrowOop* p); virtual bool do_metadata() { // _cl is of type ExtendedOopClosure instead of OopClosure, so that we can check this. assert(!_cl->do_metadata(), "I've checked all call paths, this shouldn't happen."); return false; } virtual void do_klass(Klass* k) { ShouldNotReachHere(); } virtual void do_class_loader_data(ClassLoaderData* cld) { ShouldNotReachHere(); } }; // A Space describes a heap area. Class Space is an abstract // base class. // // Space supports allocation, size computation and GC support is provided. // // Invariant: bottom() and end() are on page_size boundaries and // bottom() <= top() <= end() // top() is inclusive and end() is exclusive. class Space: public CHeapObj<mtGC> { friend class VMStructs; protected: HeapWord* _bottom; HeapWord* _end; // Used in support of save_marks() HeapWord* _saved_mark_word; MemRegionClosure* _preconsumptionDirtyCardClosure; // A sequential tasks done structure. This supports // parallel GC, where we have threads dynamically // claiming sub-tasks from a larger parallel task. SequentialSubTasksDone _par_seq_tasks; Space(): _bottom(NULL), _end(NULL), _preconsumptionDirtyCardClosure(NULL) { } public: // Accessors HeapWord* bottom() const { return _bottom; } HeapWord* end() const { return _end; } virtual void set_bottom(HeapWord* value) { _bottom = value; } virtual void set_end(HeapWord* value) { _end = value; } virtual HeapWord* saved_mark_word() const { return _saved_mark_word; } void set_saved_mark_word(HeapWord* p) { _saved_mark_word = p; } MemRegionClosure* preconsumptionDirtyCardClosure() const { return _preconsumptionDirtyCardClosure; } void setPreconsumptionDirtyCardClosure(MemRegionClosure* cl) { _preconsumptionDirtyCardClosure = cl; } // Returns a subregion of the space containing all the objects in // the space. virtual MemRegion used_region() const { return MemRegion(bottom(), end()); } // Returns a region that is guaranteed to contain (at least) all objects // allocated at the time of the last call to "save_marks". If the space // initializes its DirtyCardToOopClosure's specifying the "contig" option // (that is, if the space is contiguous), then this region must contain only // such objects: the memregion will be from the bottom of the region to the // saved mark. Otherwise, the "obj_allocated_since_save_marks" method of // the space must distiguish between objects in the region allocated before // and after the call to save marks. virtual MemRegion used_region_at_save_marks() const { return MemRegion(bottom(), saved_mark_word()); } // Initialization. // "initialize" should be called once on a space, before it is used for // any purpose. The "mr" arguments gives the bounds of the space, and // the "clear_space" argument should be true unless the memory in "mr" is // known to be zeroed. virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); // The "clear" method must be called on a region that may have // had allocation performed in it, but is now to be considered empty. virtual void clear(bool mangle_space); // For detecting GC bugs. Should only be called at GC boundaries, since // some unused space may be used as scratch space during GC's. // Default implementation does nothing. We also call this when expanding // a space to satisfy an allocation request. See bug #4668531 virtual void mangle_unused_area() {} virtual void mangle_unused_area_complete() {} virtual void mangle_region(MemRegion mr) {} // Testers bool is_empty() const { return used() == 0; } bool not_empty() const { return used() > 0; } // Returns true iff the given the space contains the // given address as part of an allocated object. For // ceratin kinds of spaces, this might be a potentially // expensive operation. To prevent performance problems // on account of its inadvertent use in product jvm's, // we restrict its use to assertion checks only. virtual bool is_in(const void* p) const = 0; // Returns true iff the given reserved memory of the space contains the // given address. bool is_in_reserved(const void* p) const { return _bottom <= p && p < _end; } // Returns true iff the given block is not allocated. virtual bool is_free_block(const HeapWord* p) const = 0; // Test whether p is double-aligned static bool is_aligned(void* p) { return ((intptr_t)p & (sizeof(double)-1)) == 0; } // Size computations. Sizes are in bytes. size_t capacity() const { return byte_size(bottom(), end()); } virtual size_t used() const = 0; virtual size_t free() const = 0; // Iterate over all the ref-containing fields of all objects in the // space, calling "cl.do_oop" on each. Fields in objects allocated by // applications of the closure are not included in the iteration. virtual void oop_iterate(ExtendedOopClosure* cl); // Same as above, restricted to the intersection of a memory region and // the space. Fields in objects allocated by applications of the closure // are not included in the iteration. virtual void oop_iterate(MemRegion mr, ExtendedOopClosure* cl) = 0; // Iterate over all objects in the space, calling "cl.do_object" on // each. Objects allocated by applications of the closure are not // included in the iteration. virtual void object_iterate(ObjectClosure* blk) = 0; // Similar to object_iterate() except only iterates over // objects whose internal references point to objects in the space. virtual void safe_object_iterate(ObjectClosure* blk) = 0; // Iterate over all objects that intersect with mr, calling "cl->do_object" // on each. There is an exception to this: if this closure has already // been invoked on an object, it may skip such objects in some cases. This is // Most likely to happen in an "upwards" (ascending address) iteration of // MemRegions. virtual void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl); // Iterate over as many initialized objects in the space as possible, // calling "cl.do_object_careful" on each. Return NULL if all objects // in the space (at the start of the iteration) were iterated over. // Return an address indicating the extent of the iteration in the // event that the iteration had to return because of finding an // uninitialized object in the space, or if the closure "cl" // signalled early termination. virtual HeapWord* object_iterate_careful(ObjectClosureCareful* cl); virtual HeapWord* object_iterate_careful_m(MemRegion mr, ObjectClosureCareful* cl); // Create and return a new dirty card to oop closure. Can be // overriden to return the appropriate type of closure // depending on the type of space in which the closure will // operate. ResourceArea allocated. virtual DirtyCardToOopClosure* new_dcto_cl(ExtendedOopClosure* cl, CardTableModRefBS::PrecisionStyle precision, HeapWord* boundary = NULL); // If "p" is in the space, returns the address of the start of the // "block" that contains "p". We say "block" instead of "object" since // some heaps may not pack objects densely; a chunk may either be an // object or a non-object. If "p" is not in the space, return NULL. virtual HeapWord* block_start_const(const void* p) const = 0; // The non-const version may have benevolent side effects on the data // structure supporting these calls, possibly speeding up future calls. // The default implementation, however, is simply to call the const // version. inline virtual HeapWord* block_start(const void* p); // Requires "addr" to be the start of a chunk, and returns its size. // "addr + size" is required to be the start of a new chunk, or the end // of the active area of the heap. virtual size_t block_size(const HeapWord* addr) const = 0; // Requires "addr" to be the start of a block, and returns "TRUE" iff // the block is an object. virtual bool block_is_obj(const HeapWord* addr) const = 0; // Requires "addr" to be the start of a block, and returns "TRUE" iff // the block is an object and the object is alive. virtual bool obj_is_alive(const HeapWord* addr) const; // Allocation (return NULL if full). Assumes the caller has established // mutually exclusive access to the space. virtual HeapWord* allocate(size_t word_size) = 0; // Allocation (return NULL if full). Enforces mutual exclusion internally. virtual HeapWord* par_allocate(size_t word_size) = 0; // Returns true if this object has been allocated since a // generation's "save_marks" call. virtual bool obj_allocated_since_save_marks(const oop obj) const = 0; // Mark-sweep-compact support: all spaces can update pointers to objects // moving as a part of compaction. virtual void adjust_pointers(); // PrintHeapAtGC support virtual void print() const; virtual void print_on(outputStream* st) const; virtual void print_short() const; virtual void print_short_on(outputStream* st) const; // Accessor for parallel sequential tasks. SequentialSubTasksDone* par_seq_tasks() { return &_par_seq_tasks; } // IF "this" is a ContiguousSpace, return it, else return NULL. virtual ContiguousSpace* toContiguousSpace() { return NULL; } // Debugging virtual void verify() const = 0; }; // A MemRegionClosure (ResourceObj) whose "do_MemRegion" function applies an // OopClosure to (the addresses of) all the ref-containing fields that could // be modified by virtue of the given MemRegion being dirty. (Note that // because of the imprecise nature of the write barrier, this may iterate // over oops beyond the region.) // This base type for dirty card to oop closures handles memory regions // in non-contiguous spaces with no boundaries, and should be sub-classed // to support other space types. See ContiguousDCTOC for a sub-class // that works with ContiguousSpaces. class DirtyCardToOopClosure: public MemRegionClosureRO { protected: ExtendedOopClosure* _cl; Space* _sp; CardTableModRefBS::PrecisionStyle _precision; HeapWord* _boundary; // If non-NULL, process only non-NULL oops // pointing below boundary. HeapWord* _min_done; // ObjHeadPreciseArray precision requires // a downwards traversal; this is the // lowest location already done (or, // alternatively, the lowest address that // shouldn't be done again. NULL means infinity.) NOT_PRODUCT(HeapWord* _last_bottom;) NOT_PRODUCT(HeapWord* _last_explicit_min_done;) // Get the actual top of the area on which the closure will // operate, given where the top is assumed to be (the end of the // memory region passed to do_MemRegion) and where the object // at the top is assumed to start. For example, an object may // start at the top but actually extend past the assumed top, // in which case the top becomes the end of the object. virtual HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj); // Walk the given memory region from bottom to (actual) top // looking for objects and applying the oop closure (_cl) to // them. The base implementation of this treats the area as // blocks, where a block may or may not be an object. Sub- // classes should override this to provide more accurate // or possibly more efficient walking. virtual void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top); public: DirtyCardToOopClosure(Space* sp, ExtendedOopClosure* cl, CardTableModRefBS::PrecisionStyle precision, HeapWord* boundary) : _sp(sp), _cl(cl), _precision(precision), _boundary(boundary), _min_done(NULL) { NOT_PRODUCT(_last_bottom = NULL); NOT_PRODUCT(_last_explicit_min_done = NULL); } void do_MemRegion(MemRegion mr); void set_min_done(HeapWord* min_done) { _min_done = min_done; NOT_PRODUCT(_last_explicit_min_done = _min_done); } #ifndef PRODUCT void set_last_bottom(HeapWord* last_bottom) { _last_bottom = last_bottom; } #endif }; // A structure to represent a point at which objects are being copied // during compaction. class CompactPoint : public StackObj { public: Generation* gen; CompactibleSpace* space; HeapWord* threshold; CompactPoint(Generation* _gen, CompactibleSpace* _space, HeapWord* _threshold) : gen(_gen), space(_space), threshold(_threshold) {} }; // A space that supports compaction operations. This is usually, but not // necessarily, a space that is normally contiguous. But, for example, a // free-list-based space whose normal collection is a mark-sweep without // compaction could still support compaction in full GC's. class CompactibleSpace: public Space { friend class VMStructs; friend class CompactibleFreeListSpace; private: HeapWord* _compaction_top; CompactibleSpace* _next_compaction_space; public: CompactibleSpace() : _compaction_top(NULL), _next_compaction_space(NULL) {} virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); virtual void clear(bool mangle_space); // Used temporarily during a compaction phase to hold the value // top should have when compaction is complete. HeapWord* compaction_top() const { return _compaction_top; } void set_compaction_top(HeapWord* value) { assert(value == NULL || (value >= bottom() && value <= end()), "should point inside space"); _compaction_top = value; } // Perform operations on the space needed after a compaction // has been performed. virtual void reset_after_compaction() {} // Returns the next space (in the current generation) to be compacted in // the global compaction order. Also is used to select the next // space into which to compact. virtual CompactibleSpace* next_compaction_space() const { return _next_compaction_space; } void set_next_compaction_space(CompactibleSpace* csp) { _next_compaction_space = csp; } // MarkSweep support phase2 // Start the process of compaction of the current space: compute // post-compaction addresses, and insert forwarding pointers. The fields // "cp->gen" and "cp->compaction_space" are the generation and space into // which we are currently compacting. This call updates "cp" as necessary, // and leaves the "compaction_top" of the final value of // "cp->compaction_space" up-to-date. Offset tables may be updated in // this phase as if the final copy had occurred; if so, "cp->threshold" // indicates when the next such action should be taken. virtual void prepare_for_compaction(CompactPoint* cp); // MarkSweep support phase3 virtual void adjust_pointers(); // MarkSweep support phase4 virtual void compact(); // The maximum percentage of objects that can be dead in the compacted // live part of a compacted space ("deadwood" support.) virtual size_t allowed_dead_ratio() const { return 0; }; // Some contiguous spaces may maintain some data structures that should // be updated whenever an allocation crosses a boundary. This function // returns the first such boundary. // (The default implementation returns the end of the space, so the // boundary is never crossed.) virtual HeapWord* initialize_threshold() { return end(); } // "q" is an object of the given "size" that should be forwarded; // "cp" names the generation ("gen") and containing "this" (which must // also equal "cp->space"). "compact_top" is where in "this" the // next object should be forwarded to. If there is room in "this" for // the object, insert an appropriate forwarding pointer in "q". // If not, go to the next compaction space (there must // be one, since compaction must succeed -- we go to the first space of // the previous generation if necessary, updating "cp"), reset compact_top // and then forward. In either case, returns the new value of "compact_top". // If the forwarding crosses "cp->threshold", invokes the "cross_threhold" // function of the then-current compaction space, and updates "cp->threshold // accordingly". virtual HeapWord* forward(oop q, size_t size, CompactPoint* cp, HeapWord* compact_top); // Return a size with adjusments as required of the space. virtual size_t adjust_object_size_v(size_t size) const { return size; } protected: // Used during compaction. HeapWord* _first_dead; HeapWord* _end_of_live; // Minimum size of a free block. virtual size_t minimum_free_block_size() const = 0; // This the function is invoked when an allocation of an object covering // "start" to "end occurs crosses the threshold; returns the next // threshold. (The default implementation does nothing.) virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* the_end) { return end(); } // Requires "allowed_deadspace_words > 0", that "q" is the start of a // free block of the given "word_len", and that "q", were it an object, // would not move if forwared. If the size allows, fill the free // block with an object, to prevent excessive compaction. Returns "true" // iff the free region was made deadspace, and modifies // "allowed_deadspace_words" to reflect the number of available deadspace // words remaining after this operation. bool insert_deadspace(size_t& allowed_deadspace_words, HeapWord* q, size_t word_len); }; #define SCAN_AND_FORWARD(cp,scan_limit,block_is_obj,block_size) { \ /* Compute the new addresses for the live objects and store it in the mark \ * Used by universe::mark_sweep_phase2() \ */ \ HeapWord* compact_top; /* This is where we are currently compacting to. */ \ \ /* We're sure to be here before any objects are compacted into this \ * space, so this is a good time to initialize this: \ */ \ set_compaction_top(bottom()); \ \ if (cp->space == NULL) { \ assert(cp->gen != NULL, "need a generation"); \ assert(cp->threshold == NULL, "just checking"); \ assert(cp->gen->first_compaction_space() == this, "just checking"); \ cp->space = cp->gen->first_compaction_space(); \ compact_top = cp->space->bottom(); \ cp->space->set_compaction_top(compact_top); \ cp->threshold = cp->space->initialize_threshold(); \ } else { \ compact_top = cp->space->compaction_top(); \ } \ \ /* We allow some amount of garbage towards the bottom of the space, so \ * we don't start compacting before there is a significant gain to be made.\ * Occasionally, we want to ensure a full compaction, which is determined \ * by the MarkSweepAlwaysCompactCount parameter. \ */ \ int invocations = MarkSweep::total_invocations(); \ bool skip_dead = (MarkSweepAlwaysCompactCount < 1) \ ||((invocations % MarkSweepAlwaysCompactCount) != 0); \ \ size_t allowed_deadspace = 0; \ if (skip_dead) { \ const size_t ratio = allowed_dead_ratio(); \ allowed_deadspace = (capacity() * ratio / 100) / HeapWordSize; \ } \ \ HeapWord* q = bottom(); \ HeapWord* t = scan_limit(); \ \ HeapWord* end_of_live= q; /* One byte beyond the last byte of the last \ live object. */ \ HeapWord* first_dead = end();/* The first dead object. */ \ LiveRange* liveRange = NULL; /* The current live range, recorded in the \ first header of preceding free area. */ \ _first_dead = first_dead; \ \ const intx interval = PrefetchScanIntervalInBytes; \ \ while (q < t) { \ assert(!block_is_obj(q) || \ oop(q)->mark()->is_marked() || oop(q)->mark()->is_unlocked() || \ oop(q)->mark()->has_bias_pattern(), \ "these are the only valid states during a mark sweep"); \ if (block_is_obj(q) && oop(q)->is_gc_marked()) { \ /* prefetch beyond q */ \ Prefetch::write(q, interval); \ size_t size = block_size(q); \ compact_top = cp->space->forward(oop(q), size, cp, compact_top); \ q += size; \ end_of_live = q; \ } else { \ /* run over all the contiguous dead objects */ \ HeapWord* end = q; \ do { \ /* prefetch beyond end */ \ Prefetch::write(end, interval); \ end += block_size(end); \ } while (end < t && (!block_is_obj(end) || !oop(end)->is_gc_marked()));\ \ /* see if we might want to pretend this object is alive so that \ * we don't have to compact quite as often. \ */ \ if (allowed_deadspace > 0 && q == compact_top) { \ size_t sz = pointer_delta(end, q); \ if (insert_deadspace(allowed_deadspace, q, sz)) { \ compact_top = cp->space->forward(oop(q), sz, cp, compact_top); \ q = end; \ end_of_live = end; \ continue; \ } \ } \ \ /* otherwise, it really is a free region. */ \ \ /* for the previous LiveRange, record the end of the live objects. */ \ if (liveRange) { \ liveRange->set_end(q); \ } \ \ /* record the current LiveRange object. \ * liveRange->start() is overlaid on the mark word. \ */ \ liveRange = (LiveRange*)q; \ liveRange->set_start(end); \ liveRange->set_end(end); \ \ /* see if this is the first dead region. */ \ if (q < first_dead) { \ first_dead = q; \ } \ \ /* move on to the next object */ \ q = end; \ } \ } \ \ assert(q == t, "just checking"); \ if (liveRange != NULL) { \ liveRange->set_end(q); \ } \ _end_of_live = end_of_live; \ if (end_of_live < first_dead) { \ first_dead = end_of_live; \ } \ _first_dead = first_dead; \ \ /* save the compaction_top of the compaction space. */ \ cp->space->set_compaction_top(compact_top); \ } #define SCAN_AND_ADJUST_POINTERS(adjust_obj_size) { \ /* adjust all the interior pointers to point at the new locations of objects \ * Used by MarkSweep::mark_sweep_phase3() */ \ \ HeapWord* q = bottom(); \ HeapWord* t = _end_of_live; /* Established by "prepare_for_compaction". */ \ \ assert(_first_dead <= _end_of_live, "Stands to reason, no?"); \ \ if (q < t && _first_dead > q && \ !oop(q)->is_gc_marked()) { \ /* we have a chunk of the space which hasn't moved and we've \ * reinitialized the mark word during the previous pass, so we can't \ * use is_gc_marked for the traversal. */ \ HeapWord* end = _first_dead; \ \ while (q < end) { \ /* I originally tried to conjoin "block_start(q) == q" to the \ * assertion below, but that doesn't work, because you can't \ * accurately traverse previous objects to get to the current one \ * after their pointers have been \ * updated, until the actual compaction is done. dld, 4/00 */ \ assert(block_is_obj(q), \ "should be at block boundaries, and should be looking at objs"); \ \ VALIDATE_MARK_SWEEP_ONLY(MarkSweep::track_interior_pointers(oop(q))); \ \ /* point all the oops to the new location */ \ size_t size = oop(q)->adjust_pointers(); \ size = adjust_obj_size(size); \ \ VALIDATE_MARK_SWEEP_ONLY(MarkSweep::check_interior_pointers()); \ \ VALIDATE_MARK_SWEEP_ONLY(MarkSweep::validate_live_oop(oop(q), size)); \ \ q += size; \ } \ \ if (_first_dead == t) { \ q = t; \ } else { \ /* $$$ This is funky. Using this to read the previously written \ * LiveRange. See also use below. */ \ q = (HeapWord*)oop(_first_dead)->mark()->decode_pointer(); \ } \ } \ \ const intx interval = PrefetchScanIntervalInBytes; \ \ debug_only(HeapWord* prev_q = NULL); \ while (q < t) { \ /* prefetch beyond q */ \ Prefetch::write(q, interval); \ if (oop(q)->is_gc_marked()) { \ /* q is alive */ \ VALIDATE_MARK_SWEEP_ONLY(MarkSweep::track_interior_pointers(oop(q))); \ /* point all the oops to the new location */ \ size_t size = oop(q)->adjust_pointers(); \ size = adjust_obj_size(size); \ VALIDATE_MARK_SWEEP_ONLY(MarkSweep::check_interior_pointers()); \ VALIDATE_MARK_SWEEP_ONLY(MarkSweep::validate_live_oop(oop(q), size)); \ debug_only(prev_q = q); \ q += size; \ } else { \ /* q is not a live object, so its mark should point at the next \ * live object */ \ debug_only(prev_q = q); \ q = (HeapWord*) oop(q)->mark()->decode_pointer(); \ assert(q > prev_q, "we should be moving forward through memory"); \ } \ } \ \ assert(q == t, "just checking"); \ } #define SCAN_AND_COMPACT(obj_size) { \ /* Copy all live objects to their new location \ * Used by MarkSweep::mark_sweep_phase4() */ \ \ HeapWord* q = bottom(); \ HeapWord* const t = _end_of_live; \ debug_only(HeapWord* prev_q = NULL); \ \ if (q < t && _first_dead > q && \ !oop(q)->is_gc_marked()) { \ debug_only( \ /* we have a chunk of the space which hasn't moved and we've reinitialized \ * the mark word during the previous pass, so we can't use is_gc_marked for \ * the traversal. */ \ HeapWord* const end = _first_dead; \ \ while (q < end) { \ size_t size = obj_size(q); \ assert(!oop(q)->is_gc_marked(), \ "should be unmarked (special dense prefix handling)"); \ VALIDATE_MARK_SWEEP_ONLY(MarkSweep::live_oop_moved_to(q, size, q)); \ debug_only(prev_q = q); \ q += size; \ } \ ) /* debug_only */ \ \ if (_first_dead == t) { \ q = t; \ } else { \ /* $$$ Funky */ \ q = (HeapWord*) oop(_first_dead)->mark()->decode_pointer(); \ } \ } \ \ const intx scan_interval = PrefetchScanIntervalInBytes; \ const intx copy_interval = PrefetchCopyIntervalInBytes; \ while (q < t) { \ if (!oop(q)->is_gc_marked()) { \ /* mark is pointer to next marked oop */ \ debug_only(prev_q = q); \ q = (HeapWord*) oop(q)->mark()->decode_pointer(); \ assert(q > prev_q, "we should be moving forward through memory"); \ } else { \ /* prefetch beyond q */ \ Prefetch::read(q, scan_interval); \ \ /* size and destination */ \ size_t size = obj_size(q); \ HeapWord* compaction_top = (HeapWord*)oop(q)->forwardee(); \ \ /* prefetch beyond compaction_top */ \ Prefetch::write(compaction_top, copy_interval); \ \ /* copy object and reinit its mark */ \ VALIDATE_MARK_SWEEP_ONLY(MarkSweep::live_oop_moved_to(q, size, \ compaction_top)); \ assert(q != compaction_top, "everything in this pass should be moving"); \ Copy::aligned_conjoint_words(q, compaction_top, size); \ oop(compaction_top)->init_mark(); \ assert(oop(compaction_top)->klass() != NULL, "should have a class"); \ \ debug_only(prev_q = q); \ q += size; \ } \ } \ \ /* Let's remember if we were empty before we did the compaction. */ \ bool was_empty = used_region().is_empty(); \ /* Reset space after compaction is complete */ \ reset_after_compaction(); \ /* We do this clear, below, since it has overloaded meanings for some */ \ /* space subtypes. For example, OffsetTableContigSpace's that were */ \ /* compacted into will have had their offset table thresholds updated */ \ /* continuously, but those that weren't need to have their thresholds */ \ /* re-initialized. Also mangles unused area for debugging. */ \ if (used_region().is_empty()) { \ if (!was_empty) clear(SpaceDecorator::Mangle); \ } else { \ if (ZapUnusedHeapArea) mangle_unused_area(); \ } \ } class GenSpaceMangler; // A space in which the free area is contiguous. It therefore supports // faster allocation, and compaction. class ContiguousSpace: public CompactibleSpace { friend class OneContigSpaceCardGeneration; friend class VMStructs; protected: HeapWord* _top; HeapWord* _concurrent_iteration_safe_limit; // A helper for mangling the unused area of the space in debug builds. GenSpaceMangler* _mangler; GenSpaceMangler* mangler() { return _mangler; } // Allocation helpers (return NULL if full). inline HeapWord* allocate_impl(size_t word_size, HeapWord* end_value); inline HeapWord* par_allocate_impl(size_t word_size, HeapWord* end_value); public: ContiguousSpace(); ~ContiguousSpace(); virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); virtual void clear(bool mangle_space); // Accessors HeapWord* top() const { return _top; } void set_top(HeapWord* value) { _top = value; } virtual void set_saved_mark() { _saved_mark_word = top(); } void reset_saved_mark() { _saved_mark_word = bottom(); } WaterMark bottom_mark() { return WaterMark(this, bottom()); } WaterMark top_mark() { return WaterMark(this, top()); } WaterMark saved_mark() { return WaterMark(this, saved_mark_word()); } bool saved_mark_at_top() const { return saved_mark_word() == top(); } // In debug mode mangle (write it with a particular bit // pattern) the unused part of a space. // Used to save the an address in a space for later use during mangling. void set_top_for_allocations(HeapWord* v) PRODUCT_RETURN; // Used to save the space's current top for later use during mangling. void set_top_for_allocations() PRODUCT_RETURN; // Mangle regions in the space from the current top up to the // previously mangled part of the space. void mangle_unused_area() PRODUCT_RETURN; // Mangle [top, end) void mangle_unused_area_complete() PRODUCT_RETURN; // Mangle the given MemRegion. void mangle_region(MemRegion mr) PRODUCT_RETURN; // Do some sparse checking on the area that should have been mangled. void check_mangled_unused_area(HeapWord* limit) PRODUCT_RETURN; // Check the complete area that should have been mangled. // This code may be NULL depending on the macro DEBUG_MANGLING. void check_mangled_unused_area_complete() PRODUCT_RETURN; // Size computations: sizes in bytes. size_t capacity() const { return byte_size(bottom(), end()); } size_t used() const { return byte_size(bottom(), top()); } size_t free() const { return byte_size(top(), end()); } // Override from space. bool is_in(const void* p) const; virtual bool is_free_block(const HeapWord* p) const; // In a contiguous space we have a more obvious bound on what parts // contain objects. MemRegion used_region() const { return MemRegion(bottom(), top()); } MemRegion used_region_at_save_marks() const { return MemRegion(bottom(), saved_mark_word()); } // Allocation (return NULL if full) virtual HeapWord* allocate(size_t word_size); virtual HeapWord* par_allocate(size_t word_size); virtual bool obj_allocated_since_save_marks(const oop obj) const { return (HeapWord*)obj >= saved_mark_word(); } // Iteration void oop_iterate(ExtendedOopClosure* cl); void oop_iterate(MemRegion mr, ExtendedOopClosure* cl); void object_iterate(ObjectClosure* blk); // For contiguous spaces this method will iterate safely over objects // in the space (i.e., between bottom and top) when at a safepoint. void safe_object_iterate(ObjectClosure* blk); void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl); // iterates on objects up to the safe limit HeapWord* object_iterate_careful(ObjectClosureCareful* cl); HeapWord* concurrent_iteration_safe_limit() { assert(_concurrent_iteration_safe_limit <= top(), "_concurrent_iteration_safe_limit update missed"); return _concurrent_iteration_safe_limit; } // changes the safe limit, all objects from bottom() to the new // limit should be properly initialized void set_concurrent_iteration_safe_limit(HeapWord* new_limit) { assert(new_limit <= top(), "uninitialized objects in the safe range"); _concurrent_iteration_safe_limit = new_limit; } #ifndef SERIALGC // In support of parallel oop_iterate. #define ContigSpace_PAR_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ void par_oop_iterate(MemRegion mr, OopClosureType* blk); ALL_PAR_OOP_ITERATE_CLOSURES(ContigSpace_PAR_OOP_ITERATE_DECL) #undef ContigSpace_PAR_OOP_ITERATE_DECL #endif // SERIALGC // Compaction support virtual void reset_after_compaction() { assert(compaction_top() >= bottom() && compaction_top() <= end(), "should point inside space"); set_top(compaction_top()); // set new iteration safe limit set_concurrent_iteration_safe_limit(compaction_top()); } virtual size_t minimum_free_block_size() const { return 0; } // Override. DirtyCardToOopClosure* new_dcto_cl(ExtendedOopClosure* cl, CardTableModRefBS::PrecisionStyle precision, HeapWord* boundary = NULL); // Apply "blk->do_oop" to the addresses of all reference fields in objects // starting with the _saved_mark_word, which was noted during a generation's // save_marks and is required to denote the head of an object. // Fields in objects allocated by applications of the closure // *are* included in the iteration. // Updates _saved_mark_word to point to just after the last object // iterated over. #define ContigSpace_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ void oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk); ALL_SINCE_SAVE_MARKS_CLOSURES(ContigSpace_OOP_SINCE_SAVE_MARKS_DECL) #undef ContigSpace_OOP_SINCE_SAVE_MARKS_DECL // Same as object_iterate, but starting from "mark", which is required // to denote the start of an object. Objects allocated by // applications of the closure *are* included in the iteration. virtual void object_iterate_from(WaterMark mark, ObjectClosure* blk); // Very inefficient implementation. virtual HeapWord* block_start_const(const void* p) const; size_t block_size(const HeapWord* p) const; // If a block is in the allocated area, it is an object. bool block_is_obj(const HeapWord* p) const { return p < top(); } // Addresses for inlined allocation HeapWord** top_addr() { return &_top; } HeapWord** end_addr() { return &_end; } // Overrides for more efficient compaction support. void prepare_for_compaction(CompactPoint* cp); // PrintHeapAtGC support. virtual void print_on(outputStream* st) const; // Checked dynamic downcasts. virtual ContiguousSpace* toContiguousSpace() { return this; } // Debugging virtual void verify() const; // Used to increase collection frequency. "factor" of 0 means entire // space. void allocate_temporary_filler(int factor); }; // A dirty card to oop closure that does filtering. // It knows how to filter out objects that are outside of the _boundary. class Filtering_DCTOC : public DirtyCardToOopClosure { protected: // Override. void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top); // Walk the given memory region, from bottom to top, applying // the given oop closure to (possibly) all objects found. The // given oop closure may or may not be the same as the oop // closure with which this closure was created, as it may // be a filtering closure which makes use of the _boundary. // We offer two signatures, so the FilteringClosure static type is // apparent. virtual void walk_mem_region_with_cl(MemRegion mr, HeapWord* bottom, HeapWord* top, ExtendedOopClosure* cl) = 0; virtual void walk_mem_region_with_cl(MemRegion mr, HeapWord* bottom, HeapWord* top, FilteringClosure* cl) = 0; public: Filtering_DCTOC(Space* sp, ExtendedOopClosure* cl, CardTableModRefBS::PrecisionStyle precision, HeapWord* boundary) : DirtyCardToOopClosure(sp, cl, precision, boundary) {} }; // A dirty card to oop closure for contiguous spaces // (ContiguousSpace and sub-classes). // It is a FilteringClosure, as defined above, and it knows: // // 1. That the actual top of any area in a memory region // contained by the space is bounded by the end of the contiguous // region of the space. // 2. That the space is really made up of objects and not just // blocks. class ContiguousSpaceDCTOC : public Filtering_DCTOC { protected: // Overrides. HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj); virtual void walk_mem_region_with_cl(MemRegion mr, HeapWord* bottom, HeapWord* top, ExtendedOopClosure* cl); virtual void walk_mem_region_with_cl(MemRegion mr, HeapWord* bottom, HeapWord* top, FilteringClosure* cl); public: ContiguousSpaceDCTOC(ContiguousSpace* sp, ExtendedOopClosure* cl, CardTableModRefBS::PrecisionStyle precision, HeapWord* boundary) : Filtering_DCTOC(sp, cl, precision, boundary) {} }; // Class EdenSpace describes eden-space in new generation. class DefNewGeneration; class EdenSpace : public ContiguousSpace { friend class VMStructs; private: DefNewGeneration* _gen; // _soft_end is used as a soft limit on allocation. As soft limits are // reached, the slow-path allocation code can invoke other actions and then // adjust _soft_end up to a new soft limit or to end(). HeapWord* _soft_end; public: EdenSpace(DefNewGeneration* gen) : _gen(gen), _soft_end(NULL) {} // Get/set just the 'soft' limit. HeapWord* soft_end() { return _soft_end; } HeapWord** soft_end_addr() { return &_soft_end; } void set_soft_end(HeapWord* value) { _soft_end = value; } // Override. void clear(bool mangle_space); // Set both the 'hard' and 'soft' limits (_end and _soft_end). void set_end(HeapWord* value) { set_soft_end(value); ContiguousSpace::set_end(value); } // Allocation (return NULL if full) HeapWord* allocate(size_t word_size); HeapWord* par_allocate(size_t word_size); }; // Class ConcEdenSpace extends EdenSpace for the sake of safe // allocation while soft-end is being modified concurrently class ConcEdenSpace : public EdenSpace { public: ConcEdenSpace(DefNewGeneration* gen) : EdenSpace(gen) { } // Allocation (return NULL if full) HeapWord* par_allocate(size_t word_size); }; // A ContigSpace that Supports an efficient "block_start" operation via // a BlockOffsetArray (whose BlockOffsetSharedArray may be shared with // other spaces.) This is the abstract base class for old generation // (tenured) spaces. class OffsetTableContigSpace: public ContiguousSpace { friend class VMStructs; protected: BlockOffsetArrayContigSpace _offsets; Mutex _par_alloc_lock; public: // Constructor OffsetTableContigSpace(BlockOffsetSharedArray* sharedOffsetArray, MemRegion mr); void set_bottom(HeapWord* value); void set_end(HeapWord* value); void clear(bool mangle_space); inline HeapWord* block_start_const(const void* p) const; // Add offset table update. virtual inline HeapWord* allocate(size_t word_size); inline HeapWord* par_allocate(size_t word_size); // MarkSweep support phase3 virtual HeapWord* initialize_threshold(); virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end); virtual void print_on(outputStream* st) const; // Debugging void verify() const; }; // Class TenuredSpace is used by TenuredGeneration class TenuredSpace: public OffsetTableContigSpace { friend class VMStructs; protected: // Mark sweep support size_t allowed_dead_ratio() const; public: // Constructor TenuredSpace(BlockOffsetSharedArray* sharedOffsetArray, MemRegion mr) : OffsetTableContigSpace(sharedOffsetArray, mr) {} }; #endif // SHARE_VM_MEMORY_SPACE_HPP