diff src/hotspot/share/gc/epsilon/epsilonCollectedHeap.hpp @ 55767:8e22715afabc

Initial import of Epsilon sources from jdk10/sandbox
author shade
date Mon, 06 Nov 2017 18:53:38 +0100
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+++ b/src/hotspot/share/gc/epsilon/epsilonCollectedHeap.hpp	Mon Nov 06 18:53:38 2017 +0100
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+/*
+ * Copyright (c) 2017, Red Hat, Inc. and/or its affiliates.
+ *
+ * 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.
+ *
+ */
+
+#ifndef SHARE_VM_GC_EPSILON_COLLECTEDHEAP_HPP
+#define SHARE_VM_GC_EPSILON_COLLECTEDHEAP_HPP
+
+#include "gc/shared/collectedHeap.hpp"
+#include "gc/shared/space.hpp"
+#include "gc/epsilon/epsilonCollectorPolicy.hpp"
+#include "gc/epsilon/epsilonMonitoringSupport.hpp"
+#include "gc/epsilon/epsilonBarrierSet.hpp"
+#include "gc/epsilon/epsilon_globals.hpp"
+
+class EpsilonCollectedHeap : public CollectedHeap {
+private:
+  EpsilonCollectorPolicy* _policy;
+  EpsilonMonitoringSupport* _monitoring_support;
+  ContiguousSpace* _space;
+  VirtualSpace _virtual_space;
+  size_t _max_tlab_size;
+  size_t _last_counter_update;
+public:
+  EpsilonCollectedHeap(EpsilonCollectorPolicy* p) : _policy(p) {};
+
+  virtual Name kind() const {
+    return CollectedHeap::EpsilonCollectedHeap;
+  }
+
+  virtual const char *name() const {
+    return "Epsilon GC";
+  }
+
+  virtual jint initialize();
+
+  virtual void post_initialize() {}
+
+  static EpsilonCollectedHeap* heap();
+
+  virtual size_t capacity()     const { return _virtual_space.committed_size(); }
+  virtual size_t used()         const { return _space->used(); }
+  virtual size_t max_capacity() const { return _virtual_space.reserved_size(); }
+
+  virtual bool is_maximal_no_gc() const {
+    // No GC is going to happen, unless we are at capacity.
+    // At which point we will fail anyway.
+    return used() == capacity();
+  }
+
+  virtual bool is_in(const void *p) const { return _space->is_in(p); }
+
+  virtual bool is_scavengable(oop obj) {
+    // Epsilon does not move objects, no objects are scavengable.
+    return false;
+  }
+
+  HeapWord* allocate_work(size_t size);
+  virtual HeapWord* mem_allocate(size_t size, bool *gc_overhead_limit_was_exceeded);
+  virtual HeapWord* allocate_new_tlab(size_t size);
+
+  // TLAB allocations
+  virtual bool supports_tlab_allocation()           const { return UseTLAB; }
+  virtual size_t tlab_capacity(Thread *thr)         const { return capacity(); }
+  virtual size_t tlab_used(Thread *thr)             const { return used(); }
+  virtual size_t max_tlab_size()                    const { return _max_tlab_size; }
+  virtual size_t unsafe_max_tlab_alloc(Thread *thr) const;
+
+  virtual bool can_elide_tlab_store_barriers() const {
+    // No store barriers for Epsilon, allow elision
+    return true;
+  }
+
+  virtual bool can_elide_initializing_store_barrier(oop new_obj) {
+    // No card marks for Epsilon, can elide them all.
+    return true;
+  }
+
+  virtual bool card_mark_must_follow_store() const {
+    // No card marks for Epsilon.
+    return false;
+  }
+
+  virtual void collect(GCCause::Cause cause);
+  virtual void do_full_collection(bool clear_all_soft_refs);
+
+  virtual AdaptiveSizePolicy *size_policy() {
+    // No such thing for Epsilon
+    return NULL;
+  }
+
+  virtual CollectorPolicy *collector_policy() const {
+    return _policy;
+  }
+
+  virtual void object_iterate(ObjectClosure *cl) {
+    safe_object_iterate(cl);
+  }
+
+  virtual void safe_object_iterate(ObjectClosure *cl);
+
+  virtual HeapWord* block_start(const void *addr) const {
+    // Epsilon does not support block parsing.
+    return NULL;
+  }
+
+  virtual size_t block_size(const HeapWord *addr) const {
+    // Epsilon does not support block parsing.
+    return 0;
+  }
+
+  virtual bool block_is_obj(const HeapWord *addr) const {
+    // Epsilon does not support block parsing.
+    return false;
+  }
+
+  virtual jlong millis_since_last_gc() {
+    // Report time since the VM start
+    return os::elapsed_counter() / NANOSECS_PER_MILLISEC;
+  }
+
+  virtual void prepare_for_verify() {
+    // No heap verification.
+  }
+
+  virtual void print_gc_threads_on(outputStream *st) const {
+    // No GC threads.
+  }
+
+  virtual void gc_threads_do(ThreadClosure *tc) const {
+    // No GC threads.
+  }
+
+  virtual void print_on(outputStream *st) const;
+  virtual void print_tracing_info() const;
+
+  virtual void verify(VerifyOption option) {
+    // No heap verification for Epsilon.
+  }
+
+};
+
+#endif // SHARE_VM_GC_EPSILON_COLLECTEDHEAP_HPP