8025852: Remove unnecessary setters in collector policy classes
Summary: Use instance variables directly within the collector policy classes and remove unused setters.
Reviewed-by: tschatzl, jcoomes
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#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCREGION_HPP
#define SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCREGION_HPP
#include "gc_implementation/g1/heapRegion.hpp"
class G1CollectedHeap;
// 0 -> no tracing, 1 -> basic tracing, 2 -> basic + allocation tracing
#define G1_ALLOC_REGION_TRACING 0
class ar_ext_msg;
// A class that holds a region that is active in satisfying allocation
// requests, potentially issued in parallel. When the active region is
// full it will be retired and replaced with a new one. The
// implementation assumes that fast-path allocations will be lock-free
// and a lock will need to be taken when the active region needs to be
// replaced.
class G1AllocRegion VALUE_OBJ_CLASS_SPEC {
friend class ar_ext_msg;
private:
// The active allocating region we are currently allocating out
// of. The invariant is that if this object is initialized (i.e.,
// init() has been called and release() has not) then _alloc_region
// is either an active allocating region or the dummy region (i.e.,
// it can never be NULL) and this object can be used to satisfy
// allocation requests. If this object is not initialized
// (i.e. init() has not been called or release() has been called)
// then _alloc_region is NULL and this object should not be used to
// satisfy allocation requests (it was done this way to force the
// correct use of init() and release()).
HeapRegion* _alloc_region;
// It keeps track of the distinct number of regions that are used
// for allocation in the active interval of this object, i.e.,
// between a call to init() and a call to release(). The count
// mostly includes regions that are freshly allocated, as well as
// the region that is re-used using the set() method. This count can
// be used in any heuristics that might want to bound how many
// distinct regions this object can used during an active interval.
uint _count;
// When we set up a new active region we save its used bytes in this
// field so that, when we retire it, we can calculate how much space
// we allocated in it.
size_t _used_bytes_before;
// When true, indicates that allocate calls should do BOT updates.
const bool _bot_updates;
// Useful for debugging and tracing.
const char* _name;
// A dummy region (i.e., it's been allocated specially for this
// purpose and it is not part of the heap) that is full (i.e., top()
// == end()). When we don't have a valid active region we make
// _alloc_region point to this. This allows us to skip checking
// whether the _alloc_region is NULL or not.
static HeapRegion* _dummy_region;
// Some of the methods below take a bot_updates parameter. Its value
// should be the same as the _bot_updates field. The idea is that
// the parameter will be a constant for a particular alloc region
// and, given that these methods will be hopefully inlined, the
// compiler should compile out the test.
// Perform a non-MT-safe allocation out of the given region.
static inline HeapWord* allocate(HeapRegion* alloc_region,
size_t word_size,
bool bot_updates);
// Perform a MT-safe allocation out of the given region.
static inline HeapWord* par_allocate(HeapRegion* alloc_region,
size_t word_size,
bool bot_updates);
// Ensure that the region passed as a parameter has been filled up
// so that noone else can allocate out of it any more.
static void fill_up_remaining_space(HeapRegion* alloc_region,
bool bot_updates);
// Retire the active allocating region. If fill_up is true then make
// sure that the region is full before we retire it so that noone
// else can allocate out of it.
void retire(bool fill_up);
// Allocate a new active region and use it to perform a word_size
// allocation. The force parameter will be passed on to
// G1CollectedHeap::allocate_new_alloc_region() and tells it to try
// to allocate a new region even if the max has been reached.
HeapWord* new_alloc_region_and_allocate(size_t word_size, bool force);
void fill_in_ext_msg(ar_ext_msg* msg, const char* message);
protected:
// For convenience as subclasses use it.
static G1CollectedHeap* _g1h;
virtual HeapRegion* allocate_new_region(size_t word_size, bool force) = 0;
virtual void retire_region(HeapRegion* alloc_region,
size_t allocated_bytes) = 0;
G1AllocRegion(const char* name, bool bot_updates);
public:
static void setup(G1CollectedHeap* g1h, HeapRegion* dummy_region);
HeapRegion* get() const {
// Make sure that the dummy region does not escape this class.
return (_alloc_region == _dummy_region) ? NULL : _alloc_region;
}
uint count() { return _count; }
// The following two are the building blocks for the allocation method.
// First-level allocation: Should be called without holding a
// lock. It will try to allocate lock-free out of the active region,
// or return NULL if it was unable to.
inline HeapWord* attempt_allocation(size_t word_size, bool bot_updates);
// Second-level allocation: Should be called while holding a
// lock. It will try to first allocate lock-free out of the active
// region or, if it's unable to, it will try to replace the active
// alloc region with a new one. We require that the caller takes the
// appropriate lock before calling this so that it is easier to make
// it conform to its locking protocol.
inline HeapWord* attempt_allocation_locked(size_t word_size,
bool bot_updates);
// Should be called to allocate a new region even if the max of this
// type of regions has been reached. Should only be called if other
// allocation attempts have failed and we are not holding a valid
// active region.
inline HeapWord* attempt_allocation_force(size_t word_size,
bool bot_updates);
// Should be called before we start using this object.
void init();
// This can be used to set the active region to a specific
// region. (Use Example: we try to retain the last old GC alloc
// region that we've used during a GC and we can use set() to
// re-instate it at the beginning of the next GC.)
void set(HeapRegion* alloc_region);
// Should be called when we want to release the active region which
// is returned after it's been retired.
HeapRegion* release();
#if G1_ALLOC_REGION_TRACING
void trace(const char* str, size_t word_size = 0, HeapWord* result = NULL);
#else // G1_ALLOC_REGION_TRACING
void trace(const char* str, size_t word_size = 0, HeapWord* result = NULL) { }
#endif // G1_ALLOC_REGION_TRACING
};
class ar_ext_msg : public err_msg {
public:
ar_ext_msg(G1AllocRegion* alloc_region, const char *message) : err_msg("") {
alloc_region->fill_in_ext_msg(this, message);
}
};
#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1ALLOCREGION_HPP