Mercurial > hg > graal-jvmci-8
diff src/share/vm/memory/space.hpp @ 263:12eea04c8b06
6672698: mangle_unused_area() should not remangle the entire heap at each collection.
Summary: Maintain a high water mark for the allocations in a space and mangle only up to that high water mark.
Reviewed-by: ysr, apetrusenko
author | jmasa |
---|---|
date | Wed, 09 Jul 2008 15:08:55 -0700 |
parents | ba764ed4b6f2 |
children | 850fdf70db2b |
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--- a/src/share/vm/memory/space.hpp Fri Jun 27 19:12:11 2008 -0700 +++ b/src/share/vm/memory/space.hpp Wed Jul 09 15:08:55 2008 -0700 @@ -131,15 +131,17 @@ return MemRegion(bottom(), saved_mark_word()); } - // Initialization - virtual void initialize(MemRegion mr, bool clear_space); - virtual void clear(); + // Initialization. These may be run to reset an existing + // Space. + virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); + 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 @@ -354,7 +356,7 @@ CompactibleSpace* _next_compaction_space; public: - virtual void initialize(MemRegion mr, bool clear_space); + virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); // Used temporarily during a compaction phase to hold the value // top should have when compaction is complete. @@ -724,12 +726,14 @@ /* continuously, but those that weren't need to have their thresholds */ \ /* re-initialized. Also mangles unused area for debugging. */ \ if (is_empty()) { \ - clear(); \ + 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 { @@ -738,13 +742,21 @@ 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: - virtual void initialize(MemRegion mr, bool clear_space); + + ContiguousSpace(); + ~ContiguousSpace(); + + virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); // Accessors HeapWord* top() const { return _top; } @@ -753,15 +765,34 @@ void set_saved_mark() { _saved_mark_word = top(); } void reset_saved_mark() { _saved_mark_word = bottom(); } - virtual void clear(); + virtual void clear(bool mangle_space); 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(); } - void mangle_unused_area(); - void mangle_region(MemRegion mr); + // 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()); } @@ -956,7 +987,7 @@ void set_soft_end(HeapWord* value) { _soft_end = value; } // Override. - void clear(); + void clear(bool mangle_space); // Set both the 'hard' and 'soft' limits (_end and _soft_end). void set_end(HeapWord* value) { @@ -1000,7 +1031,7 @@ void set_bottom(HeapWord* value); void set_end(HeapWord* value); - void clear(); + void clear(bool mangle_space); inline HeapWord* block_start(const void* p) const;