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/*
* Copyright (c) 2014, 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.
*
*/
#ifndef SHARE_VM_SERVICES_MALLOC_SITE_TABLE_HPP
#define SHARE_VM_SERVICES_MALLOC_SITE_TABLE_HPP
#if INCLUDE_NMT
#include "memory/allocation.hpp"
#include "runtime/atomic.hpp"
#include "services/allocationSite.hpp"
#include "services/mallocTracker.hpp"
#include "services/nmtCommon.hpp"
#include "utilities/nativeCallStack.hpp"
// MallocSite represents a code path that eventually calls
// os::malloc() to allocate memory
class MallocSite : public AllocationSite<MemoryCounter> {
public:
MallocSite() :
AllocationSite<MemoryCounter>(NativeCallStack::EMPTY_STACK) { }
MallocSite(const NativeCallStack& stack) :
AllocationSite<MemoryCounter>(stack) { }
void allocate(size_t size) { data()->allocate(size); }
void deallocate(size_t size) { data()->deallocate(size); }
// Memory allocated from this code path
size_t size() const { return peek()->size(); }
// The number of calls were made
size_t count() const { return peek()->count(); }
};
// Malloc site hashtable entry
class MallocSiteHashtableEntry : public CHeapObj<mtNMT> {
private:
MallocSite _malloc_site;
MallocSiteHashtableEntry* _next;
public:
MallocSiteHashtableEntry() : _next(NULL) { }
MallocSiteHashtableEntry(NativeCallStack stack):
_malloc_site(stack), _next(NULL) { }
inline const MallocSiteHashtableEntry* next() const {
return _next;
}
// Insert an entry atomically.
// Return true if the entry is inserted successfully.
// The operation can be failed due to contention from other thread.
bool atomic_insert(const MallocSiteHashtableEntry* entry) {
return (Atomic::cmpxchg_ptr((void*)entry, (volatile void*)&_next,
NULL) == NULL);
}
void set_callsite(const MallocSite& site) {
_malloc_site = site;
}
inline const MallocSite* peek() const { return &_malloc_site; }
inline MallocSite* data() { return &_malloc_site; }
inline long hash() const { return _malloc_site.hash(); }
inline bool equals(const NativeCallStack& stack) const {
return _malloc_site.equals(stack);
}
// Allocation/deallocation on this allocation site
inline void allocate(size_t size) { _malloc_site.allocate(size); }
inline void deallocate(size_t size) { _malloc_site.deallocate(size); }
// Memory counters
inline size_t size() const { return _malloc_site.size(); }
inline size_t count() const { return _malloc_site.count(); }
};
// The walker walks every entry on MallocSiteTable
class MallocSiteWalker : public StackObj {
public:
virtual bool do_malloc_site(const MallocSite* e) { return false; }
};
/*
* Native memory tracking call site table.
* The table is only needed when detail tracking is enabled.
*/
class MallocSiteTable : AllStatic {
private:
// The number of hash bucket in this hashtable. The number should
// be tuned if malloc activities changed significantly.
// The statistics data can be obtained via Jcmd
// jcmd <pid> VM.native_memory statistics.
// Currently, (number of buckets / number of entires) ratio is
// about 1 / 6
enum {
table_base_size = 128, // The base size is calculated from statistics to give
// table ratio around 1:6
table_size = (table_base_size * NMT_TrackingStackDepth - 1)
};
// This is a very special lock, that allows multiple shared accesses (sharedLock), but
// once exclusive access (exclusiveLock) is requested, all shared accesses are
// rejected forever.
class AccessLock : public StackObj {
enum LockState {
NoLock,
SharedLock,
ExclusiveLock
};
private:
// A very large negative number. The only possibility to "overflow"
// this number is when there are more than -min_jint threads in
// this process, which is not going to happen in foreseeable future.
const static int _MAGIC_ = min_jint;
LockState _lock_state;
volatile int* _lock;
public:
AccessLock(volatile int* lock) :
_lock(lock), _lock_state(NoLock) {
}
~AccessLock() {
if (_lock_state == SharedLock) {
Atomic::dec((volatile jint*)_lock);
}
}
// Acquire shared lock.
// Return true if shared access is granted.
inline bool sharedLock() {
jint res = Atomic::add(1, _lock);
if (res < 0) {
Atomic::add(-1, _lock);
return false;
}
_lock_state = SharedLock;
return true;
}
// Acquire exclusive lock
void exclusiveLock();
};
public:
static bool initialize();
static void shutdown();
NOT_PRODUCT(static int access_peak_count() { return _peak_count; })
// Number of hash buckets
static inline int hash_buckets() { return (int)table_size; }
// Access and copy a call stack from this table. Shared lock should be
// acquired before access the entry.
static inline bool access_stack(NativeCallStack& stack, size_t bucket_idx,
size_t pos_idx) {
AccessLock locker(&_access_count);
if (locker.sharedLock()) {
NOT_PRODUCT(_peak_count = MAX2(_peak_count, _access_count);)
MallocSite* site = malloc_site(bucket_idx, pos_idx);
if (site != NULL) {
stack = *site->call_stack();
return true;
}
}
return false;
}
// Record a new allocation from specified call path.
// Return true if the allocation is recorded successfully, bucket_idx
// and pos_idx are also updated to indicate the entry where the allocation
// information was recorded.
// Return false only occurs under rare scenarios:
// 1. out of memory
// 2. overflow hash bucket
static inline bool allocation_at(const NativeCallStack& stack, size_t size,
size_t* bucket_idx, size_t* pos_idx) {
AccessLock locker(&_access_count);
if (locker.sharedLock()) {
NOT_PRODUCT(_peak_count = MAX2(_peak_count, _access_count);)
MallocSite* site = lookup_or_add(stack, bucket_idx, pos_idx);
if (site != NULL) site->allocate(size);
return site != NULL;
}
return false;
}
// Record memory deallocation. bucket_idx and pos_idx indicate where the allocation
// information was recorded.
static inline bool deallocation_at(size_t size, size_t bucket_idx, size_t pos_idx) {
AccessLock locker(&_access_count);
if (locker.sharedLock()) {
NOT_PRODUCT(_peak_count = MAX2(_peak_count, _access_count);)
MallocSite* site = malloc_site(bucket_idx, pos_idx);
if (site != NULL) {
site->deallocate(size);
return true;
}
}
return false;
}
// Walk this table.
static bool walk_malloc_site(MallocSiteWalker* walker);
private:
static MallocSiteHashtableEntry* new_entry(const NativeCallStack& key);
static void reset();
// Delete a bucket linked list
static void delete_linked_list(MallocSiteHashtableEntry* head);
static MallocSite* lookup_or_add(const NativeCallStack& key, size_t* bucket_idx, size_t* pos_idx);
static MallocSite* malloc_site(size_t bucket_idx, size_t pos_idx);
static bool walk(MallocSiteWalker* walker);
static inline int hash_to_index(int hash) {
hash = (hash > 0) ? hash : (-hash);
return (hash % table_size);
}
static inline const NativeCallStack* hash_entry_allocation_stack() {
return (NativeCallStack*)_hash_entry_allocation_stack;
}
private:
// Counter for counting concurrent access
static volatile int _access_count;
// The callsite hashtable. It has to be a static table,
// since malloc call can come from C runtime linker.
static MallocSiteHashtableEntry* _table[table_size];
// Reserve enough memory for placing the objects
// The memory for hashtable entry allocation stack object
static size_t _hash_entry_allocation_stack[CALC_OBJ_SIZE_IN_TYPE(NativeCallStack, size_t)];
// The memory for hashtable entry allocation callsite object
static size_t _hash_entry_allocation_site[CALC_OBJ_SIZE_IN_TYPE(MallocSiteHashtableEntry, size_t)];
NOT_PRODUCT(static int _peak_count;)
};
#endif // INCLUDE_NMT
#endif // SHARE_VM_SERVICES_MALLOC_SITE_TABLE_HPP