1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
|
/* IBM_PROLOG_BEGIN_TAG */
/* This is an automatically generated prolog. */
/* */
/* $Source: src/include/kernel/heapmgr.H $ */
/* */
/* IBM CONFIDENTIAL */
/* */
/* COPYRIGHT International Business Machines Corp. 2010,2013 */
/* */
/* p1 */
/* */
/* Object Code Only (OCO) source materials */
/* Licensed Internal Code Source Materials */
/* IBM HostBoot Licensed Internal Code */
/* */
/* The source code for this program is not published or otherwise */
/* divested of its trade secrets, irrespective of what has been */
/* deposited with the U.S. Copyright Office. */
/* */
/* Origin: 30 */
/* */
/* IBM_PROLOG_END_TAG */
#ifndef __KERNEL_HEAPMGR_H
#define __KERNEL_HEAPMGR_H
#include <stdint.h>
#include <util/lockfree/stack.H>
#include <builtins.h>
extern "C"
void kernel_execute_decrementer();
/**
* A class to manage the dynamic memory allocation heap.
* <p>There is a small allocation heap and a large heap.
* The Small allocation heap is a Fibonacci buddy system divided into the
* following bucket sizes: 16,32,48,80,128,208,336,544,880,1424,2304,3728.
* Eight bytes is used for overhead in each allocation making the effective
* bucket sizes 8,24,40,72,120,200,328,536,872,1416,2296, and 3720.
* The small heap increases one page at a time as allocations are needed.
* A 4k pages is initially divided into buckes of size 3728,336, and 32.
* Pages can't be recovered once assinged to the small heap.</p>
*
* <p>Anthing larger than 3720 goes into the large allocation heap.
* Memory in the large allocation heap are assigned as integral pages.
* When memory is released from the large allocation heap, it is returned
* to the system page manager.</p>
*/
class HeapManager
{
public:
enum
{
BUCKETS = 12, //!< number of buckets
MIN_BUCKET_SIZE = 16, //!< Smallest bucket size
FIB_START_INCR = 16, //!< Seed for the Fibonacci series
BUCKET_SIZE0 = MIN_BUCKET_SIZE,
BUCKET_SIZE1 = BUCKET_SIZE0 + FIB_START_INCR,
BUCKET_SIZE2 = BUCKET_SIZE1 + BUCKET_SIZE0,
BUCKET_SIZE3 = BUCKET_SIZE2 + BUCKET_SIZE1,
BUCKET_SIZE4 = BUCKET_SIZE3 + BUCKET_SIZE2,
BUCKET_SIZE5 = BUCKET_SIZE4 + BUCKET_SIZE3,
BUCKET_SIZE6 = BUCKET_SIZE5 + BUCKET_SIZE4,
BUCKET_SIZE7 = BUCKET_SIZE6 + BUCKET_SIZE5,
BUCKET_SIZE8 = BUCKET_SIZE7 + BUCKET_SIZE6,
BUCKET_SIZE9 = BUCKET_SIZE8 + BUCKET_SIZE7,
BUCKET_SIZE10 = BUCKET_SIZE9 + BUCKET_SIZE8,
BUCKET_SIZE11 = BUCKET_SIZE10 + BUCKET_SIZE9,
MAX_SMALL_ALLOC_SIZE = BUCKET_SIZE11 - 8,// last bucket size-8
};
friend class CpuManager;
friend void kernel_execute_decrementer();
/**
* Initalize the HeapManager
*/
static void init();
/**
* Reqest an allocation of heap memory
* @param[in] i_sz requested memory size in bytes
* @return a pointer to allocated memory
*/
static void* allocate(size_t i_sz);
/**
* Request a change in allocation size
* @param[in] i_ptr The memory allocation
* @param[in] i_sz The new size
* @return a pointer to allocated memory
* @post Memory may have been moved
*/
static void* realloc(void * i_ptr, size_t i_sz);
/**
* Return an allocation to the heap.
* @param[in] The allocation
*/
static void free(void * i_ptr);
protected:
/**
* ctor
*/
HeapManager() {};
/**
* dtor
*/
~HeapManager() {};
/**
* Coalesce unallocated memory chucks
* @pre This function can only be called from kernel space and
* requires that all other processes are quiesced
*/
static void coalesce( void );
/**
* Print some stats to printkd
* @pre system quiesced, This function can only be called from
* kernel space.
* @post coalesce() called
*/
static void stats( void );
private:
struct chunk_t
{
struct
{
bool free:1; //!< Is chunk free
bool coalesce:1; //!< Is chunk being coalesced
uint64_t bucket:62; //!< Which bucket this chunk belongs to
} PACKED;
chunk_t* next; //!< Next chunk (for unallocated chunks only)
};
/**
* big chunk directory entry
*/
struct big_chunk_t
{
void * addr; //!< Allocated address
size_t page_count; //!< Number of pages used
big_chunk_t * next; //!< Next allocation
big_chunk_t(void * i_ptr, size_t i_pages)
: addr(i_ptr), page_count(i_pages), next(NULL) {}
};
void* _allocate(size_t); //!< see allocate
void* _allocateBig(size_t); //!< see allocate
void* _realloc(void*,size_t); //!< see realloc
void* _reallocBig(void*,size_t);//!< see realloc
void _free(void*); //!< see free
bool _freeBig(void*); //!< see free
void _coalesce(void); //!< see coalesce
/**
* Get a chunk of free memory from the given bucket
* @param[in] The bucket index
* @return a chunk
*/
chunk_t* pop_bucket(size_t);
/**
* Push a free chunk onto the free bucket stack
* @param[in] the chunk
* @param[in] the bucket index
*/
void push_bucket(chunk_t*, size_t);
/**
* Get a new page from the page manager, set it up, and addit it to the
* free pool
*/
void newPage();
/**
* Get the bytesize of the given bucket
* @param[in] The bucket index
* @return the bytesize of the bucket
*/
ALWAYS_INLINE
size_t bucketByteSize(size_t i_bucketIndex)
{
return cv_chunk_size[i_bucketIndex];
}
/**
* Get the bucket index for a given size
* @param[in] The bytesize
* @return the smallest bucket index that the given size will fit into
*/
size_t bucketIndex(size_t i_sz);
/**
* Walk through all the allocated pages and verify coherency
*/
void test_pages();
private: // data
Util::Lockfree::Stack<chunk_t> first_chunk[BUCKETS]; //!< free pool
Util::Lockfree::Stack<big_chunk_t> big_chunk_stack; //!< big chunk dir
static const size_t cv_chunk_size[BUCKETS];//!< The bucket sizes
static uint32_t cv_coalesce_count; //!< coalesced chunk count
static uint32_t cv_free_bytes; //!< Only valid after coalesce()
static uint32_t cv_free_chunks; //!< Only valid after coalesce()
static uint32_t cv_smallheap_page_count; //!< # of pages being used
static uint32_t cv_largeheap_page_count; //!< # of pages being used
static uint32_t cv_largeheap_page_max; //!< Max # of pages used
};
#endif
|
