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

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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
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27
hotspot/src/share/vm/runtime/virtualspace.cpp
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@ -109,6 +109,7 @@ ReservedSpace::ReservedSpace(const size_t prefix_size,
const size_t prefix_align,
const size_t suffix_size,
const size_t suffix_align,
char* requested_address,
const size_t noaccess_prefix)
{
assert(prefix_size != 0, "sanity");
@ -131,7 +132,7 @@ ReservedSpace::ReservedSpace(const size_t prefix_size,
const bool try_reserve_special = UseLargePages &&
prefix_align == os::large_page_size();
if (!os::can_commit_large_page_memory() && try_reserve_special) {
initialize(size, prefix_align, true, NULL, noaccess_prefix);
initialize(size, prefix_align, true, requested_address, noaccess_prefix);
return;
}
@ -146,7 +147,13 @@ ReservedSpace::ReservedSpace(const size_t prefix_size,
noaccess_prefix == prefix_align, "noaccess prefix wrong");
// Optimistically try to reserve the exact size needed.
char* addr = os::reserve_memory(size, NULL, prefix_align);
char* addr;
if (requested_address != 0) {
addr = os::attempt_reserve_memory_at(size,
requested_address-noaccess_prefix);
} else {
addr = os::reserve_memory(size, NULL, prefix_align);
}
if (addr == NULL) return;
// Check whether the result has the needed alignment (unlikely unless
@ -206,12 +213,8 @@ void ReservedSpace::initialize(size_t size, size_t alignment, bool large,
char* base = NULL;
if (special) {
// It's not hard to implement reserve_memory_special() such that it can
// allocate at fixed address, but there seems no use of this feature
// for now, so it's not implemented.
assert(requested_address == NULL, "not implemented");
base = os::reserve_memory_special(size);
base = os::reserve_memory_special(size, requested_address);
if (base != NULL) {
// Check alignment constraints
@ -372,7 +375,8 @@ ReservedHeapSpace::ReservedHeapSpace(size_t size, size_t alignment,
bool large, char* requested_address) :
ReservedSpace(size, alignment, large,
requested_address,
UseCompressedOops && UseImplicitNullCheckForNarrowOop ?
(UseCompressedOops && (Universe::narrow_oop_base() != NULL) &&
Universe::narrow_oop_use_implicit_null_checks()) ?
lcm(os::vm_page_size(), alignment) : 0) {
// Only reserved space for the java heap should have a noaccess_prefix
// if using compressed oops.
@ -382,9 +386,12 @@ ReservedHeapSpace::ReservedHeapSpace(size_t size, size_t alignment,
ReservedHeapSpace::ReservedHeapSpace(const size_t prefix_size,
const size_t prefix_align,
const size_t suffix_size,
const size_t suffix_align) :
const size_t suffix_align,
char* requested_address) :
ReservedSpace(prefix_size, prefix_align, suffix_size, suffix_align,
UseCompressedOops && UseImplicitNullCheckForNarrowOop ?
requested_address,
(UseCompressedOops && (Universe::narrow_oop_base() != NULL) &&
Universe::narrow_oop_use_implicit_null_checks()) ?
lcm(os::vm_page_size(), prefix_align) : 0) {
protect_noaccess_prefix(prefix_size+suffix_size);
}