archive/jdk
1
0
Fork 0
mirror of https://github.com/openjdk/jdk.git synced 2025-09-21 11:34:38 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

6791178: Specialize for zero as the compressed oop vm heap base

Browse source 
Use zero based compressed oops if java heap is below 32gb and unscaled compressed oops if java heap is below 4gb.

Reviewed-by: never, twisti, jcoomes, coleenp
This commit is contained in:
Vladimir Kozlov 2009-03-12 10:37:46 -07:00
parent 66cecec230
commit 69f9ddee90
45 changed files with 1072 additions and 220 deletions
Download patch file Download diff file Expand all files Collapse all files

40
hotspot/src/share/vm/memory/universe.hpp
View file

@ -90,6 +90,19 @@ class LatestMethodOopCache : public CommonMethodOopCache {
methodOop get_methodOop();
};
// For UseCompressedOops.
struct NarrowOopStruct {
// Base address for oop-within-java-object materialization.
// NULL if using wide oops or zero based narrow oops.
address _base;
// Number of shift bits for encoding/decoding narrow oops.
// 0 if using wide oops or zero based unscaled narrow oops,
// LogMinObjAlignmentInBytes otherwise.
int _shift;
// Generate code with implicit null checks for narrow oops.
bool _use_implicit_null_checks;
};
class Universe: AllStatic {
// Ugh. Universe is much too friendly.
@ -181,9 +194,9 @@ class Universe: AllStatic {
// The particular choice of collected heap.
static CollectedHeap* _collectedHeap;
// Base address for oop-within-java-object materialization.
// NULL if using wide oops. Doubles as heap oop null value.
static address _heap_base;
// For UseCompressedOops.
static struct NarrowOopStruct _narrow_oop;
// array of dummy objects used with +FullGCAlot
debug_only(static objArrayOop _fullgc_alot_dummy_array;)
@ -328,8 +341,25 @@ class Universe: AllStatic {
static CollectedHeap* heap() { return _collectedHeap; }
// For UseCompressedOops
static address heap_base() { return _heap_base; }
static address* heap_base_addr() { return &_heap_base; }
static address* narrow_oop_base_addr() { return &_narrow_oop._base; }
static address narrow_oop_base() { return _narrow_oop._base; }
static int narrow_oop_shift() { return _narrow_oop._shift; }
static void set_narrow_oop_base(address base) { _narrow_oop._base = base; }
static void set_narrow_oop_shift(int shift) { _narrow_oop._shift = shift; }
static bool narrow_oop_use_implicit_null_checks() { return _narrow_oop._use_implicit_null_checks; }
static void set_narrow_oop_use_implicit_null_checks(bool use) { _narrow_oop._use_implicit_null_checks = use; }
// Narrow Oop encoding mode:
// 0 - Use 32-bits oops without encoding when
// NarrowOopHeapBaseMin + heap_size < 4Gb
// 1 - Use zero based compressed oops with encoding when
// NarrowOopHeapBaseMin + heap_size < 32Gb
// 2 - Use compressed oops with heap base + encoding.
enum NARROW_OOP_MODE {
UnscaledNarrowOop = 0,
ZeroBasedNarrowOop = 1,
HeapBasedNarrowOop = 2
};
static char* preferred_heap_base(size_t heap_size, NARROW_OOP_MODE mode);
// Historic gc information
static size_t get_heap_capacity_at_last_gc() { return _heap_capacity_at_last_gc; }