8069367: Eagerly reclaimed humongous objects left on mark stack
Summary: Prevent eager reclaim of objects that might be on mark stack.
Reviewed-by: brutisso, tschatzl
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#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTG1REFINE_HPP
#define SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTG1REFINE_HPP
#include "gc_implementation/g1/g1HotCardCache.hpp"
#include "memory/allocation.hpp"
#include "runtime/thread.hpp"
#include "utilities/globalDefinitions.hpp"
// Forward decl
class ConcurrentG1RefineThread;
class G1CollectedHeap;
class G1HotCardCache;
class G1RegionToSpaceMapper;
class G1RemSet;
class DirtyCardQueue;
class ConcurrentG1Refine: public CHeapObj<mtGC> {
ConcurrentG1RefineThread** _threads;
uint _n_threads;
uint _n_worker_threads;
/*
* The value of the update buffer queue length falls into one of 3 zones:
* green, yellow, red. If the value is in [0, green) nothing is
* done, the buffers are left unprocessed to enable the caching effect of the
* dirtied cards. In the yellow zone [green, yellow) the concurrent refinement
* threads are gradually activated. In [yellow, red) all threads are
* running. If the length becomes red (max queue length) the mutators start
* processing the buffers.
*
* There are some interesting cases (when G1UseAdaptiveConcRefinement
* is turned off):
* 1) green = yellow = red = 0. In this case the mutator will process all
* buffers. Except for those that are created by the deferred updates
* machinery during a collection.
* 2) green = 0. Means no caching. Can be a good way to minimize the
* amount of time spent updating rsets during a collection.
*/
int _green_zone;
int _yellow_zone;
int _red_zone;
int _thread_threshold_step;
// We delay the refinement of 'hot' cards using the hot card cache.
G1HotCardCache _hot_card_cache;
// Reset the threshold step value based of the current zone boundaries.
void reset_threshold_step();
public:
ConcurrentG1Refine(G1CollectedHeap* g1h, CardTableEntryClosure* refine_closure);
~ConcurrentG1Refine();
void init(G1RegionToSpaceMapper* card_counts_storage);
void stop();
void reinitialize_threads();
// Iterate over all concurrent refinement threads
void threads_do(ThreadClosure *tc);
// Iterate over all worker refinement threads
void worker_threads_do(ThreadClosure * tc);
// The RS sampling thread
ConcurrentG1RefineThread * sampling_thread() const;
static uint thread_num();
void print_worker_threads_on(outputStream* st) const;
void set_green_zone(int x) { _green_zone = x; }
void set_yellow_zone(int x) { _yellow_zone = x; }
void set_red_zone(int x) { _red_zone = x; }
int green_zone() const { return _green_zone; }
int yellow_zone() const { return _yellow_zone; }
int red_zone() const { return _red_zone; }
uint total_thread_num() const { return _n_threads; }
uint worker_thread_num() const { return _n_worker_threads; }
int thread_threshold_step() const { return _thread_threshold_step; }
G1HotCardCache* hot_card_cache() { return &_hot_card_cache; }
};
#endif // SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTG1REFINE_HPP