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
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
|
/* Copyright (c) 2003-2007 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program 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 for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA */
#define DBTUP_C
#define DBTUP_PAG_MAN_CPP
#include "Dbtup.hpp"
#include <RefConvert.hpp>
#include <ndb_limits.h>
#include <pc.hpp>
/* ---------------------------------------------------------------- */
// 4) Page Memory Manager (buddy algorithm)
//
// The following data structures in Dbtup is used by the Page Memory
// Manager.
//
// cfreepageList[16]
// Pages with a header
//
// The cfreepageList is 16 free lists. Free list 0 contains chunks of
// pages with 2^0 (=1) pages in each chunk. Free list 1 chunks of 2^1
// (=2) pages in each chunk and so forth upto free list 15 which
// contains chunks of 2^15 (=32768) pages in each chunk.
// The cfreepageList array contains the pointer to the first chunk
// in each of those lists. The lists are doubly linked where the
// first page in each chunk contains the next and previous references
// in position ZPAGE_NEXT_CLUST_POS and ZPAGE_PREV_CLUST_POS in the
// page header.
// In addition the leading page and the last page in each chunk is marked
// with a state (=ZFREE_COMMON) in position ZPAGE_STATE_POS in page
// header. This state indicates that the page is the leading or last page
// in a chunk of free pages. Furthermore the leading and last page is
// also marked with a reference to the leading (=ZPAGE_FIRST_CLUST_POS)
// and the last page (=ZPAGE_LAST_CLUST_POS) in the chunk.
//
// The aim of these data structures is to enable a free area handling of
// free pages based on a buddy algorithm. When allocating pages it is
// performed in chunks of pages and the algorithm tries to make the
// chunks as large as possible.
// This manager is invoked when fragments lack internal page space to
// accomodate all the data they are requested to store. It is also
// invoked when fragments deallocate page space back to the free area.
//
// The following routines are part of the external interface:
// void
// allocConsPages(Uint32 noOfPagesToAllocate, #In
// Uint32& noOfPagesAllocated, #Out
// Uint32& retPageRef) #Out
// void
// returnCommonArea(Uint32 retPageRef, #In
// Uint32 retNoPages) #In
//
// allocConsPages tries to allocate noOfPagesToAllocate pages in one chunk.
// If this fails it delivers a chunk as large as possible. It returns the
// i-value of the first page in the chunk delivered, if zero pages returned
// this i-value is undefined. It also returns the size of the chunk actually
// delivered.
//
// returnCommonArea is used when somebody is returning pages to the free area.
// It is used both from internal routines and external routines.
//
// The following routines are private routines used to support the
// above external interface:
// removeCommonArea()
// insertCommonArea()
// findFreeLeftNeighbours()
// findFreeRightNeighbours()
// Uint32
// nextHigherTwoLog(Uint32 input)
//
// nextHigherTwoLog is a support routine which is a mathematical function with
// an integer as input and an integer as output. It calculates the 2-log of
// (input + 1). If the 2-log of (input + 1) is larger than 15 then the routine
// will return 15. It is part of the external interface since it is also used
// by other similar memory management algorithms.
//
// External dependencies:
// None.
//
// Side Effects:
// Apart from the above mentioned data structures there are no more
// side effects other than through the subroutine parameters in the
// external interface.
//
/* ---------------------------------------------------------------- */
/* ---------------------------------------------------------------- */
/* CALCULATE THE 2-LOG + 1 OF TMP AND PUT RESULT INTO TBITS */
/* ---------------------------------------------------------------- */
Uint32 Dbtup::nextHigherTwoLog(Uint32 input)
{
input = input | (input >> 8);
input = input | (input >> 4);
input = input | (input >> 2);
input = input | (input >> 1);
Uint32 output = (input & 0x5555) + ((input >> 1) & 0x5555);
output = (output & 0x3333) + ((output >> 2) & 0x3333);
output = output + (output >> 4);
output = (output & 0xf) + ((output >> 8) & 0xf);
return output;
}//nextHigherTwoLog()
void Dbtup::initializePage()
{
for (Uint32 i = 0; i < 16; i++) {
cfreepageList[i] = RNIL;
}//for
PagePtr pagePtr;
for (pagePtr.i = 0; pagePtr.i < c_page_pool.getSize(); pagePtr.i++) {
jam();
refresh_watch_dog();
c_page_pool.getPtr(pagePtr);
pagePtr.p->physical_page_id= RNIL;
pagePtr.p->next_page = pagePtr.i + 1;
pagePtr.p->first_cluster_page = RNIL;
pagePtr.p->next_cluster_page = RNIL;
pagePtr.p->last_cluster_page = RNIL;
pagePtr.p->prev_page = RNIL;
pagePtr.p->page_state = ZFREE_COMMON;
}//for
pagePtr.p->next_page = RNIL;
/**
* Page 0 cant be part of buddy as
* it will scan left right when searching for bigger blocks,
* if 0 is part of arrat, it can search to -1...which is not good
*/
pagePtr.i = 0;
c_page_pool.getPtr(pagePtr);
pagePtr.p->page_state = ~ZFREE_COMMON;
Uint32 tmp = 1;
returnCommonArea(tmp, c_page_pool.getSize() - tmp);
cnoOfAllocatedPages = tmp; // Is updated by returnCommonArea
}//Dbtup::initializePage()
#ifdef VM_TRACE
Uint32 fc_left, fc_right, fc_remove;
#endif
void Dbtup::allocConsPages(Uint32 noOfPagesToAllocate,
Uint32& noOfPagesAllocated,
Uint32& allocPageRef)
{
#ifdef VM_TRACE
fc_left = fc_right = fc_remove = 0;
#endif
if (noOfPagesToAllocate == 0){
jam();
noOfPagesAllocated = 0;
return;
}//if
Uint32 firstListToCheck = nextHigherTwoLog(noOfPagesToAllocate - 1);
for (Uint32 i = firstListToCheck; i < 16; i++) {
jam();
if (cfreepageList[i] != RNIL) {
jam();
/* ---------------------------------------------------------------- */
/* PROPER AMOUNT OF PAGES WERE FOUND. NOW SPLIT THE FOUND */
/* AREA AND RETURN THE PART NOT NEEDED. */
/* ---------------------------------------------------------------- */
noOfPagesAllocated = noOfPagesToAllocate;
allocPageRef = cfreepageList[i];
removeCommonArea(allocPageRef, i);
Uint32 retNo = (1 << i) - noOfPagesToAllocate;
Uint32 retPageRef = allocPageRef + noOfPagesToAllocate;
returnCommonArea(retPageRef, retNo);
return;
}//if
}//for
/* ---------------------------------------------------------------- */
/* PROPER AMOUNT OF PAGES WERE NOT FOUND. FIND AS MUCH AS */
/* POSSIBLE. */
/* ---------------------------------------------------------------- */
if (firstListToCheck)
{
jam();
for (Uint32 j = firstListToCheck - 1; (Uint32)~j; j--) {
jam();
if (cfreepageList[j] != RNIL) {
jam();
/* ---------------------------------------------------------------- */
/* SOME AREA WAS FOUND, ALLOCATE ALL OF IT. */
/* ---------------------------------------------------------------- */
allocPageRef = cfreepageList[j];
removeCommonArea(allocPageRef, j);
noOfPagesAllocated = 1 << j;
findFreeLeftNeighbours(allocPageRef, noOfPagesAllocated,
noOfPagesToAllocate);
findFreeRightNeighbours(allocPageRef, noOfPagesAllocated,
noOfPagesToAllocate);
return;
}//if
}//for
}
/* ---------------------------------------------------------------- */
/* NO FREE AREA AT ALL EXISTED. RETURN ZERO PAGES */
/* ---------------------------------------------------------------- */
noOfPagesAllocated = 0;
return;
}//allocConsPages()
void Dbtup::returnCommonArea(Uint32 retPageRef, Uint32 retNo)
{
do {
jam();
if (retNo == 0) {
jam();
return;
}//if
Uint32 list = nextHigherTwoLog(retNo) - 1;
retNo -= (1 << list);
insertCommonArea(retPageRef, list);
retPageRef += (1 << list);
} while (1);
}//Dbtup::returnCommonArea()
void Dbtup::findFreeLeftNeighbours(Uint32& allocPageRef,
Uint32& noPagesAllocated,
Uint32 noOfPagesToAllocate)
{
PagePtr pageFirstPtr, pageLastPtr;
Uint32 remainAllocate = noOfPagesToAllocate - noPagesAllocated;
Uint32 loop = 0;
while (allocPageRef > 0 &&
++loop < 16)
{
jam();
pageLastPtr.i = allocPageRef - 1;
c_page_pool.getPtr(pageLastPtr);
if (pageLastPtr.p->page_state != ZFREE_COMMON) {
jam();
return;
} else {
jam();
pageFirstPtr.i = pageLastPtr.p->first_cluster_page;
ndbrequire(pageFirstPtr.i != RNIL);
Uint32 list = nextHigherTwoLog(pageLastPtr.i - pageFirstPtr.i);
removeCommonArea(pageFirstPtr.i, list);
Uint32 listSize = 1 << list;
if (listSize > remainAllocate) {
jam();
Uint32 retNo = listSize - remainAllocate;
returnCommonArea(pageFirstPtr.i, retNo);
allocPageRef = pageFirstPtr.i + retNo;
noPagesAllocated = noOfPagesToAllocate;
return;
} else {
jam();
allocPageRef = pageFirstPtr.i;
noPagesAllocated += listSize;
remainAllocate -= listSize;
}//if
}//if
#ifdef VM_TRACE
fc_left++;
#endif
}//while
}//Dbtup::findFreeLeftNeighbours()
void Dbtup::findFreeRightNeighbours(Uint32& allocPageRef,
Uint32& noPagesAllocated,
Uint32 noOfPagesToAllocate)
{
PagePtr pageFirstPtr, pageLastPtr;
Uint32 remainAllocate = noOfPagesToAllocate - noPagesAllocated;
if (remainAllocate == 0) {
jam();
return;
}//if
Uint32 loop = 0;
while ((allocPageRef + noPagesAllocated) < c_page_pool.getSize() &&
++loop < 16)
{
jam();
pageFirstPtr.i = allocPageRef + noPagesAllocated;
c_page_pool.getPtr(pageFirstPtr);
if (pageFirstPtr.p->page_state != ZFREE_COMMON) {
jam();
return;
} else {
jam();
pageLastPtr.i = pageFirstPtr.p->last_cluster_page;
ndbrequire(pageLastPtr.i != RNIL);
Uint32 list = nextHigherTwoLog(pageLastPtr.i - pageFirstPtr.i);
removeCommonArea(pageFirstPtr.i, list);
Uint32 listSize = 1 << list;
if (listSize > remainAllocate) {
jam();
Uint32 retPageRef = pageFirstPtr.i + remainAllocate;
Uint32 retNo = listSize - remainAllocate;
returnCommonArea(retPageRef, retNo);
noPagesAllocated += remainAllocate;
return;
} else {
jam();
noPagesAllocated += listSize;
remainAllocate -= listSize;
}//if
}//if
#ifdef VM_TRACE
fc_right++;
#endif
}//while
}//Dbtup::findFreeRightNeighbours()
void Dbtup::insertCommonArea(Uint32 insPageRef, Uint32 insList)
{
cnoOfAllocatedPages -= (1 << insList);
PagePtr pageLastPtr, pageInsPtr, pageHeadPtr;
pageHeadPtr.i = cfreepageList[insList];
c_page_pool.getPtr(pageInsPtr, insPageRef);
ndbrequire(insList < 16);
pageLastPtr.i = (pageInsPtr.i + (1 << insList)) - 1;
pageInsPtr.p->page_state = ZFREE_COMMON;
pageInsPtr.p->next_cluster_page = pageHeadPtr.i;
pageInsPtr.p->prev_cluster_page = RNIL;
pageInsPtr.p->last_cluster_page = pageLastPtr.i;
cfreepageList[insList] = pageInsPtr.i;
if (pageHeadPtr.i != RNIL)
{
jam();
c_page_pool.getPtr(pageHeadPtr);
pageHeadPtr.p->prev_cluster_page = pageInsPtr.i;
}
c_page_pool.getPtr(pageLastPtr);
pageLastPtr.p->page_state = ZFREE_COMMON;
pageLastPtr.p->first_cluster_page = pageInsPtr.i;
pageLastPtr.p->next_page = RNIL;
}//Dbtup::insertCommonArea()
void Dbtup::removeCommonArea(Uint32 remPageRef, Uint32 list)
{
cnoOfAllocatedPages += (1 << list);
PagePtr pagePrevPtr, pageNextPtr, pageLastPtr, remPagePtr;
c_page_pool.getPtr(remPagePtr, remPageRef);
ndbrequire(list < 16);
if (cfreepageList[list] == remPagePtr.i) {
jam();
ndbassert(remPagePtr.p->prev_cluster_page == RNIL);
cfreepageList[list] = remPagePtr.p->next_cluster_page;
pageNextPtr.i = cfreepageList[list];
if (pageNextPtr.i != RNIL) {
jam();
c_page_pool.getPtr(pageNextPtr);
pageNextPtr.p->prev_cluster_page = RNIL;
}//if
} else {
pagePrevPtr.i = remPagePtr.p->prev_cluster_page;
pageNextPtr.i = remPagePtr.p->next_cluster_page;
c_page_pool.getPtr(pagePrevPtr);
pagePrevPtr.p->next_cluster_page = pageNextPtr.i;
if (pageNextPtr.i != RNIL)
{
jam();
c_page_pool.getPtr(pageNextPtr);
pageNextPtr.p->prev_cluster_page = pagePrevPtr.i;
}
}//if
remPagePtr.p->next_cluster_page= RNIL;
remPagePtr.p->last_cluster_page= RNIL;
remPagePtr.p->prev_cluster_page= RNIL;
remPagePtr.p->page_state = ~ZFREE_COMMON;
pageLastPtr.i = (remPagePtr.i + (1 << list)) - 1;
c_page_pool.getPtr(pageLastPtr);
pageLastPtr.p->first_cluster_page= RNIL;
pageLastPtr.p->page_state = ~ZFREE_COMMON;
}//Dbtup::removeCommonArea()
|