8204210: Implementation: JEP 333: ZGC: A Scalable Low-Latency Garbage Collector (Experimental)
Reviewed-by: pliden, stefank, eosterlund, ehelin, sjohanss, rbackman, coleenp, ihse, jgeorge, lmesnik, rkennke
Contributed-by: per.liden@oracle.com, stefan.karlsson@oracle.com, erik.osterlund@oracle.com, mikael.gerdin@oracle.com, kim.barrett@oracle.com, nils.eliasson@oracle.com, rickard.backman@oracle.com, rwestrel@redhat.com, coleen.phillimore@oracle.com, robbin.ehn@oracle.com, gerard.ziemski@oracle.com, hugh.wilkinson@intel.com, sandhya.viswanathan@intel.com, bill.npo.wheeler@intel.com, vinay.k.awasthi@intel.com, yasuenag@gmail.com
/*
* Copyright (c) 2016, 2017, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
#include "precompiled.hpp"
#include "gc/z/zPage.inline.hpp"
#include "gc/z/zPhysicalMemory.inline.hpp"
#include "gc/z/zPreMappedMemory.inline.hpp"
#include "gc/z/zVirtualMemory.inline.hpp"
#include "logging/log.hpp"
ZPreMappedMemory::ZPreMappedMemory(ZVirtualMemoryManager &vmm, ZPhysicalMemoryManager &pmm, size_t size) :
_vmem(),
_pmem(),
_initialized(false) {
if (!vmm.is_initialized() || !pmm.is_initialized()) {
// Not initialized
return;
}
// Pre-mapping and pre-touching memory can take a long time. Log a message
// to help the user understand why the JVM might seem slow to start.
log_info(gc, init)("Pre-touching: %s", AlwaysPreTouch ? "Enabled" : "Disabled");
log_info(gc, init)("Pre-mapping: " SIZE_FORMAT "M", size / M);
_pmem = pmm.alloc(size);
if (_pmem.is_null()) {
// Out of memory
return;
}
_vmem = vmm.alloc(size, true /* alloc_from_front */);
if (_vmem.is_null()) {
// Out of address space
pmm.free(_pmem);
return;
}
// Map physical memory
pmm.map(_pmem, _vmem.start());
_initialized = true;
}
ZPage* ZPreMappedMemory::alloc_page(uint8_t type, size_t size) {
if (size > available()) {
// Not enough pre-mapped memory
return NULL;
}
// Take a chunk of the pre-mapped memory
const ZPhysicalMemory pmem = _pmem.split(size);
const ZVirtualMemory vmem = _vmem.split(size);
ZPage* const page = new ZPage(type, vmem, pmem);
page->set_pre_mapped();
return page;
}
void ZPreMappedMemory::clear() {
assert(_pmem.is_null(), "Should be detached");
_vmem.clear();
}