bool PSVirtualSpace::expand_by(size_t bytes, bool pre_touch) {
assert(is_aligned(bytes), "arg not aligned");
DEBUG_ONLY(PSVirtualSpaceVerifier this_verifier(this));
if (uncommitted_size() < bytes) {
return false;
}
char* const base_addr = committed_high_addr();
bool result=os::commit_memory(_account,base_addr,bytes,alignment(),Modules::ParGC_PSVirtualSpace);
if (result) {
_committed_high_addr += bytes;
}
if (pre_touch || AlwaysPreTouch) {
for (char* curr = base_addr;
curr < _committed_high_addr;
curr += os::vm_page_size()) {
char tmp = *curr;
*curr = 0;
}
}
return result;
}
size_t PSVirtualSpaceHighToLow::expand_into(PSVirtualSpace* other_space,
size_t bytes) {
assert(is_aligned(bytes), "arg not aligned");
assert(grows_down(), "this space must grow down");
assert(other_space->grows_up(), "other space must grow up");
assert(reserved_low_addr() == other_space->reserved_high_addr(),
"spaces not contiguous");
assert(special() == other_space->special(), "one space is special in memory, the other is not");
DEBUG_ONLY(PSVirtualSpaceVerifier this_verifier(this));
DEBUG_ONLY(PSVirtualSpaceVerifier other_verifier(other_space));
size_t bytes_needed = bytes;
// First use the uncommitted region in this space.
size_t tmp_bytes = MIN2(uncommitted_size(), bytes_needed);
if (tmp_bytes > 0) {
if (expand_by(tmp_bytes)) {
bytes_needed -= tmp_bytes;
} else {
return 0;
}
}
// Next take from the uncommitted region in the other space, and commit it.
tmp_bytes = MIN2(other_space->uncommitted_size(), bytes_needed);
if (tmp_bytes > 0) {
char* const commit_base = committed_low_addr() - tmp_bytes;
if (other_space->special() ||
os::commit_memory(commit_base, tmp_bytes, alignment(), !ExecMem)) {
// Reduce the reserved region in the other space.
other_space->set_reserved(other_space->reserved_low_addr(),
other_space->reserved_high_addr() - tmp_bytes,
other_space->special());
// Grow both reserved and committed in this space.
_reserved_low_addr -= tmp_bytes;
_committed_low_addr -= tmp_bytes;
bytes_needed -= tmp_bytes;
} else {
return bytes - bytes_needed;
}
}
// Finally take from the already committed region in the other space.
tmp_bytes = bytes_needed;
if (tmp_bytes > 0) {
// Reduce both committed and reserved in the other space.
other_space->set_committed(other_space->committed_low_addr(),
other_space->committed_high_addr() - tmp_bytes);
other_space->set_reserved(other_space->reserved_low_addr(),
other_space->reserved_high_addr() - tmp_bytes,
other_space->special());
// Grow both reserved and committed in this space.
_reserved_low_addr -= tmp_bytes;
_committed_low_addr -= tmp_bytes;
}
return bytes;
}
void PSVirtualSpace::release() {
DEBUG_ONLY(PSVirtualSpaceVerifier this_verifier(this));
// This may not release memory it didn't reserve.
// Use rs.release() to release the underlying memory instead.
_reserved_low_addr = _reserved_high_addr = NULL;
_committed_low_addr = _committed_high_addr = NULL;
_special = false;
}
void PSVirtualSpace::release() {
DEBUG_ONLY(PSVirtualSpaceVerifier this_verifier(this));
if (reserved_low_addr() != NULL) {
os::release_memory(reserved_low_addr(),reserved_size());
}
_reserved_low_addr = _reserved_high_addr = NULL;
_committed_low_addr = _committed_high_addr = NULL;
}
bool PSVirtualSpaceHighToLow::shrink_by(size_t bytes) {
assert(is_aligned(bytes), "arg not aligned");
DEBUG_ONLY(PSVirtualSpaceVerifier this_verifier(this));
if (committed_size() < bytes) {
return false;
}
char* const base_addr = committed_low_addr();
os::uncommit_memory(base_addr,bytes,Modules::ParGC_PSVirtualSpace);
return true;
}
bool PSVirtualSpaceHighToLow::shrink_by(size_t bytes) {
assert(is_aligned(bytes), "arg not aligned");
DEBUG_ONLY(PSVirtualSpaceVerifier this_verifier(this));
if (committed_size() < bytes) {
return false;
}
char* const base_addr = committed_low_addr();
bool result = special() || os::uncommit_memory(base_addr, bytes);
if (result) {
_committed_low_addr += bytes;
}
return result;
}
bool PSVirtualSpace::expand_by(size_t bytes) {
assert(is_aligned(bytes), "arg not aligned");
DEBUG_ONLY(PSVirtualSpaceVerifier this_verifier(this));
if (uncommitted_size() < bytes) {
return false;
}
char* const base_addr = committed_high_addr();
bool result = os::commit_memory(base_addr, bytes, alignment());
if (result) {
_committed_high_addr += bytes;
}
return result;
}
bool PSVirtualSpaceHighToLow::expand_by(size_t bytes) {
assert(is_aligned(bytes), "arg not aligned");
DEBUG_ONLY(PSVirtualSpaceVerifier this_verifier(this));
if (uncommitted_size() < bytes) {
return false;
}
char* const base_addr = committed_low_addr() - bytes;
bool result = special() ||
os::commit_memory(base_addr, bytes, alignment(), !ExecMem);
if (result) {
_committed_low_addr -= bytes;
}
return result;
}