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
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head><meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
<title>Xenomai API: Dynamic memory allocation services.</title>
<link href="doxygen.css" rel="stylesheet" type="text/css">
<link href="tabs.css" rel="stylesheet" type="text/css">
</head><body>
<!-- Generated by Doxygen 1.5.5 -->
<div class="navigation" id="top">
<div class="tabs">
<ul>
<li><a href="main.html"><span>Main Page</span></a></li>
<li><a href="pages.html"><span>Related Pages</span></a></li>
<li><a href="modules.html"><span>Modules</span></a></li>
<li><a href="annotated.html"><span>Data Structures</span></a></li>
<li><a href="files.html"><span>Files</span></a></li>
<li><a href="examples.html"><span>Examples</span></a></li>
<li>
<form action="search.php" method="get">
<table cellspacing="0" cellpadding="0" border="0">
<tr>
<td><label> <u>S</u>earch for </label></td>
<td><input type="text" name="query" value="" size="20" accesskey="s"/></td>
</tr>
</table>
</form>
</li>
</ul>
</div>
</div>
<div class="contents">
<h1>Dynamic memory allocation services.<br>
<small>
[<a class="el" href="group__nucleus.html">Xenomai nucleus.</a>]</small>
</h1>
<p>
<div class="dynheader">
Collaboration diagram for Dynamic memory allocation services.:</div>
<div class="dynsection">
<center><table><tr><td><img src="group__heap.png" border="0" alt="" usemap="#group____heap_map">
<map name="group____heap_map">
<area shape="rect" href="group__nucleus.html" title="Xenomai nucleus." alt="" coords="5,6,131,30"></map></td></tr></table></center>
</div>
<hr><a name="_details"></a><h2>Detailed Description</h2>
Dynamic memory allocation services.<p>
The implementation of the memory allocator follows the algorithm described in a USENIX 1988 paper called "Design of a General Purpose Memory Allocator for the 4.3BSD Unix Kernel" by Marshall K. McKusick and Michael J. Karels. You can find it at various locations on the net, including <a href="http://docs.FreeBSD.org/44doc/papers/kernmalloc.pdf.">http://docs.FreeBSD.org/44doc/papers/kernmalloc.pdf.</a> A minor variation allows this implementation to have 'extendable' heaps when needed, with multiple memory extents providing autonomous page address spaces.<p>
The data structures hierarchy is as follows:<p>
<code> <div class="fragment"><pre class="fragment">
HEAP {
block_buckets[]
extent_queue -------+
} |
V
EXTENT #1 {
{static header}
page_map[npages]
page_array[npages][pagesize]
} -+
|
|
V
EXTENT #n {
{static header}
page_map[npages]
page_array[npages][pagesize]
}
</pre></div> </code>
<p>
<table border="0" cellpadding="0" cellspacing="0">
<tr><td></td></tr>
<tr><td colspan="2"><br><h2>Files</h2></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">file </td><td class="memItemRight" valign="bottom"><a class="el" href="ksrc_2nucleus_2heap_8c.html">heap.c</a></td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Dynamic memory allocation services. <br></td></tr>
<p>
<tr><td colspan="2"><br><h2>Functions</h2></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__heap.html#gd65beaf18754ad1f85c479eaf9219042">xnheap_init</a> (xnheap_t *heap, void *heapaddr, u_long heapsize, u_long pagesize)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Initialize a memory heap. <a href="#gd65beaf18754ad1f85c479eaf9219042"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__heap.html#g7ab506f024eda1d9030e1bf9494c0781">xnheap_destroy</a> (xnheap_t *heap, void(*flushfn)(xnheap_t *heap, void *extaddr, u_long extsize, void *cookie), void *cookie)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Destroys a memory heap. <a href="#g7ab506f024eda1d9030e1bf9494c0781"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">void * </td><td class="memItemRight" valign="bottom"><a class="el" href="group__heap.html#gaa8ae99881c9e6a4f8b56aa79f983bdb">xnheap_alloc</a> (xnheap_t *heap, u_long size)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Allocate a memory block from a memory heap. <a href="#gaa8ae99881c9e6a4f8b56aa79f983bdb"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__heap.html#gcb0151aaff9d56134c7c217bfa67c816">xnheap_test_and_free</a> (xnheap_t *heap, void *block, int(*ckfn)(void *block))</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Test and release a memory block to a memory heap. <a href="#gcb0151aaff9d56134c7c217bfa67c816"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__heap.html#g5dc4305113cd272cfed62e20e2a12ae6">xnheap_free</a> (xnheap_t *heap, void *block)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Release a memory block to a memory heap. <a href="#g5dc4305113cd272cfed62e20e2a12ae6"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__heap.html#g4842cb75faa41b2cc3ce8e44cf0beade">xnheap_extend</a> (xnheap_t *heap, void *extaddr, u_long extsize)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Extend a memory heap. <a href="#g4842cb75faa41b2cc3ce8e44cf0beade"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="group__heap.html#g548f69835e12bf259b6d417b11338a11">xnheap_schedule_free</a> (xnheap_t *heap, void *block, xnholder_t *link)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Schedule a memory block for release. <a href="#g548f69835e12bf259b6d417b11338a11"></a><br></td></tr>
</table>
<hr><h2>Function Documentation</h2>
<a class="anchor" name="gaa8ae99881c9e6a4f8b56aa79f983bdb"></a><!-- doxytag: member="heap.c::xnheap_alloc" ref="gaa8ae99881c9e6a4f8b56aa79f983bdb" args="(xnheap_t *heap, u_long size)" -->
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">void* xnheap_alloc </td>
<td>(</td>
<td class="paramtype">xnheap_t * </td>
<td class="paramname"> <em>heap</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">u_long </td>
<td class="paramname"> <em>size</em></td><td> </td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td><td width="100%"></td>
</tr>
</table>
</div>
<div class="memdoc">
<p>
Allocate a memory block from a memory heap.
<p>
Allocates a contiguous region of memory from an active memory heap. Such allocation is guaranteed to be time-bounded.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>heap</em> </td><td>The descriptor address of the heap to get memory from.</td></tr>
<tr><td valign="top"></td><td valign="top"><em>size</em> </td><td>The size in bytes of the requested block. Sizes lower or equal to the page size are rounded either to the minimum allocation size if lower than this value, or to the minimum alignment size if greater or equal to this value. In the current implementation, with MINALLOC = 8 and MINALIGN = 16, a 7 bytes request will be rounded to 8 bytes, and a 17 bytes request will be rounded to 32.</td></tr>
</table>
</dl>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>The address of the allocated region upon success, or NULL if no memory is available from the specified heap.</dd></dl>
Environments:<p>
This service can be called from:<p>
<ul>
<li>Kernel module initialization/cleanup code</li><li>Interrupt service routine</li><li>Kernel-based task</li><li>User-space task</li></ul>
<p>
Rescheduling: never.
<p>Referenced by <a class="el" href="shm_8c-source.html#l00473">ftruncate()</a>, <a class="el" href="ksrc_2skins_2native_2heap_8c-source.html#l00503">rt_heap_alloc()</a>, <a class="el" href="ksrc_2skins_2native_2heap_8c-source.html#l00622">rt_heap_free()</a>, <a class="el" href="ksrc_2skins_2native_2pipe_8c-source.html#l00942">rt_pipe_alloc()</a>, <a class="el" href="ksrc_2skins_2native_2pipe_8c-source.html#l00210">rt_pipe_create()</a>, and <a class="el" href="ksrc_2skins_2native_2queue_8c-source.html#l00423">rt_queue_alloc()</a>.</p>
</div>
</div><p>
<a class="anchor" name="g7ab506f024eda1d9030e1bf9494c0781"></a><!-- doxytag: member="heap.c::xnheap_destroy" ref="g7ab506f024eda1d9030e1bf9494c0781" args="(xnheap_t *heap, void(*flushfn)(xnheap_t *heap, void *extaddr, u_long extsize, void *cookie), void *cookie)" -->
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">int xnheap_destroy </td>
<td>(</td>
<td class="paramtype">xnheap_t * </td>
<td class="paramname"> <em>heap</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">void(*)(xnheap_t *heap, void *extaddr, u_long extsize, void *cookie) </td>
<td class="paramname"> <em>flushfn</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">void * </td>
<td class="paramname"> <em>cookie</em></td><td> </td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td><td width="100%"></td>
</tr>
</table>
</div>
<div class="memdoc">
<p>
Destroys a memory heap.
<p>
Destroys a memory heap.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>heap</em> </td><td>The descriptor address of the destroyed heap.</td></tr>
<tr><td valign="top"></td><td valign="top"><em>flushfn</em> </td><td>If non-NULL, the address of a flush routine which will be called for each extent attached to the heap. This routine can be used by the calling code to further release the heap memory.</td></tr>
<tr><td valign="top"></td><td valign="top"><em>cookie</em> </td><td>If <em>flushfn</em> is non-NULL, <em>cookie</em> is an opaque pointer which will be passed unmodified to <em>flushfn</em>.</td></tr>
</table>
</dl>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>0 is returned on success, or -EBUSY if external mappings are still pending on the heap memory.</dd></dl>
Environments:<p>
This service can be called from:<p>
<ul>
<li>Kernel module initialization/cleanup code</li><li>Kernel-based task</li><li>User-space task</li></ul>
<p>
Rescheduling: never.
<p>Referenced by <a class="el" href="shm_8c-source.html#l00473">ftruncate()</a>, <a class="el" href="ksrc_2skins_2native_2heap_8c-source.html#l00363">rt_heap_delete()</a>, <a class="el" href="ksrc_2skins_2native_2pipe_8c-source.html#l00210">rt_pipe_create()</a>, <a class="el" href="ksrc_2skins_2native_2pipe_8c-source.html#l00356">rt_pipe_delete()</a>, <a class="el" href="ksrc_2skins_2native_2queue_8c-source.html#l00331">rt_queue_delete()</a>, and <a class="el" href="pod_8c-source.html#l00449">xnpod_shutdown()</a>.</p>
</div>
</div><p>
<a class="anchor" name="g4842cb75faa41b2cc3ce8e44cf0beade"></a><!-- doxytag: member="heap.c::xnheap_extend" ref="g4842cb75faa41b2cc3ce8e44cf0beade" args="(xnheap_t *heap, void *extaddr, u_long extsize)" -->
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">int xnheap_extend </td>
<td>(</td>
<td class="paramtype">xnheap_t * </td>
<td class="paramname"> <em>heap</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">void * </td>
<td class="paramname"> <em>extaddr</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">u_long </td>
<td class="paramname"> <em>extsize</em></td><td> </td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td><td width="100%"></td>
</tr>
</table>
</div>
<div class="memdoc">
<p>
Extend a memory heap.
<p>
Add a new extent to an existing memory heap.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>heap</em> </td><td>The descriptor address of the heap to add an extent to.</td></tr>
<tr><td valign="top"></td><td valign="top"><em>extaddr</em> </td><td>The address of the extent memory.</td></tr>
<tr><td valign="top"></td><td valign="top"><em>extsize</em> </td><td>The size of the extent memory (in bytes). In the current implementation, this size must match the one of the initial extent passed to <a class="el" href="group__heap.html#gd65beaf18754ad1f85c479eaf9219042" title="Initialize a memory heap.">xnheap_init()</a>.</td></tr>
</table>
</dl>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>0 is returned upon success, or -EINVAL is returned if <em>extsize</em> differs from the initial extent's size.</dd></dl>
Environments:<p>
This service can be called from:<p>
<ul>
<li>Kernel module initialization/cleanup code</li><li>Interrupt service routine</li><li>Kernel-based task</li><li>User-space task</li></ul>
<p>
Rescheduling: never.
</div>
</div><p>
<a class="anchor" name="g5dc4305113cd272cfed62e20e2a12ae6"></a><!-- doxytag: member="heap.c::xnheap_free" ref="g5dc4305113cd272cfed62e20e2a12ae6" args="(xnheap_t *heap, void *block)" -->
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">int xnheap_free </td>
<td>(</td>
<td class="paramtype">xnheap_t * </td>
<td class="paramname"> <em>heap</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">void * </td>
<td class="paramname"> <em>block</em></td><td> </td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td><td width="100%"></td>
</tr>
</table>
</div>
<div class="memdoc">
<p>
Release a memory block to a memory heap.
<p>
Releases a memory region to the memory heap it was previously allocated from.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>heap</em> </td><td>The descriptor address of the heap to release memory to.</td></tr>
<tr><td valign="top"></td><td valign="top"><em>block</em> </td><td>The address of the region to be returned to the heap.</td></tr>
</table>
</dl>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>0 is returned upon success, or one of the following error codes:</dd></dl>
<ul>
<li>-EFAULT is returned whenever the memory address is outside the heap address space.</li></ul>
<p>
<ul>
<li>-EINVAL is returned whenever the memory address does not represent a valid block.</li></ul>
<p>
Environments:<p>
This service can be called from:<p>
<ul>
<li>Kernel module initialization/cleanup code</li><li>Interrupt service routine</li><li>Kernel-based task</li><li>User-space task</li></ul>
<p>
Rescheduling: never.
<p>References <a class="el" href="ksrc_2nucleus_2heap_8c-source.html#l00569">xnheap_test_and_free()</a>.</p>
<p>Referenced by <a class="el" href="shm_8c-source.html#l00473">ftruncate()</a>, <a class="el" href="ksrc_2skins_2native_2heap_8c-source.html#l00622">rt_heap_free()</a>, <a class="el" href="ksrc_2skins_2native_2pipe_8c-source.html#l00356">rt_pipe_delete()</a>, and <a class="el" href="ksrc_2skins_2native_2pipe_8c-source.html#l00982">rt_pipe_free()</a>.</p>
</div>
</div><p>
<a class="anchor" name="gd65beaf18754ad1f85c479eaf9219042"></a><!-- doxytag: member="heap.c::xnheap_init" ref="gd65beaf18754ad1f85c479eaf9219042" args="(xnheap_t *heap, void *heapaddr, u_long heapsize, u_long pagesize)" -->
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">int xnheap_init </td>
<td>(</td>
<td class="paramtype">xnheap_t * </td>
<td class="paramname"> <em>heap</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">void * </td>
<td class="paramname"> <em>heapaddr</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">u_long </td>
<td class="paramname"> <em>heapsize</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">u_long </td>
<td class="paramname"> <em>pagesize</em></td><td> </td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td><td width="100%"></td>
</tr>
</table>
</div>
<div class="memdoc">
<p>
Initialize a memory heap.
<p>
Initializes a memory heap suitable for time-bounded allocation requests of dynamic memory.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>heap</em> </td><td>The address of a heap descriptor which will be used to store the allocation data. This descriptor must always be valid while the heap is active therefore it must be allocated in permanent memory.</td></tr>
<tr><td valign="top"></td><td valign="top"><em>heapaddr</em> </td><td>The address of the heap storage area. All allocations will be made from the given area in time-bounded mode. Since additional extents can be added to a heap, this parameter is also known as the "initial extent".</td></tr>
<tr><td valign="top"></td><td valign="top"><em>heapsize</em> </td><td>The size in bytes of the initial extent pointed at by <em>heapaddr</em>. <em>heapsize</em> must be a multiple of pagesize and lower than 16 Mbytes. <em>heapsize</em> must be large enough to contain a dynamically-sized internal header. The following formula gives the size of this header:<br>
</td></tr>
</table>
</dl>
H = heapsize, P=pagesize, M=sizeof(struct pagemap), E=sizeof(xnextent_t)<br>
hdrsize = ((H - E) * M) / (M + 1)<br>
<p>
This value is then aligned on the next 16-byte boundary. The routine xnheap_overhead() computes the corrected heap size according to the previous formula.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>pagesize</em> </td><td>The size in bytes of the fundamental memory page which will be used to subdivide the heap internally. Choosing the right page size is important regarding performance and memory fragmentation issues, so it might be a good idea to take a look at <a href="http://docs.FreeBSD.org/44doc/papers/kernmalloc.pdf">http://docs.FreeBSD.org/44doc/papers/kernmalloc.pdf</a> to pick the best one for your needs. In the current implementation, pagesize must be a power of two in the range [ 8 .. 32768 ] inclusive.</td></tr>
</table>
</dl>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>0 is returned upon success, or one of the following error codes:</dd></dl>
<ul>
<li>-EINVAL is returned whenever a parameter is invalid.</li></ul>
<p>
Environments:<p>
This service can be called from:<p>
<ul>
<li>Kernel module initialization/cleanup code</li><li>Kernel-based task</li><li>User-space task</li></ul>
<p>
Rescheduling: never.
<p>Referenced by <a class="el" href="shm_8c-source.html#l00473">ftruncate()</a>, <a class="el" href="ksrc_2skins_2native_2heap_8c-source.html#l00237">rt_heap_create()</a>, <a class="el" href="ksrc_2skins_2native_2pipe_8c-source.html#l00210">rt_pipe_create()</a>, <a class="el" href="ksrc_2skins_2native_2queue_8c-source.html#l00209">rt_queue_create()</a>, and <a class="el" href="pod_8c-source.html#l00241">xnpod_init()</a>.</p>
</div>
</div><p>
<a class="anchor" name="g548f69835e12bf259b6d417b11338a11"></a><!-- doxytag: member="heap.c::xnheap_schedule_free" ref="g548f69835e12bf259b6d417b11338a11" args="(xnheap_t *heap, void *block, xnholder_t *link)" -->
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">void xnheap_schedule_free </td>
<td>(</td>
<td class="paramtype">xnheap_t * </td>
<td class="paramname"> <em>heap</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">void * </td>
<td class="paramname"> <em>block</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">xnholder_t * </td>
<td class="paramname"> <em>link</em></td><td> </td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td><td width="100%"></td>
</tr>
</table>
</div>
<div class="memdoc">
<p>
Schedule a memory block for release.
<p>
This routine records a block for later release by xnheap_finalize_free(). This service is useful to lazily free blocks of heap memory when immediate release is not an option, e.g. when active references are still pending on the object for a short time after the call. xnheap_finalize_free() is expected to be eventually called by the client code at some point in the future when actually freeing the idle objects is deemed safe.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>heap</em> </td><td>The descriptor address of the heap to release memory to.</td></tr>
<tr><td valign="top"></td><td valign="top"><em>block</em> </td><td>The address of the region to be returned to the heap.</td></tr>
<tr><td valign="top"></td><td valign="top"><em>link</em> </td><td>The address of a link member, likely but not necessarily within the released object, which will be used by the heap manager to hold the block in the queue of idle objects.</td></tr>
</table>
</dl>
Environments:<p>
This service can be called from:<p>
<ul>
<li>Kernel module initialization/cleanup code</li><li>Interrupt service routine</li><li>Kernel-based task</li><li>User-space task</li></ul>
<p>
Rescheduling: never.
</div>
</div><p>
<a class="anchor" name="gcb0151aaff9d56134c7c217bfa67c816"></a><!-- doxytag: member="heap.c::xnheap_test_and_free" ref="gcb0151aaff9d56134c7c217bfa67c816" args="(xnheap_t *heap, void *block, int(*ckfn)(void *block))" -->
<div class="memitem">
<div class="memproto">
<table class="memname">
<tr>
<td class="memname">int xnheap_test_and_free </td>
<td>(</td>
<td class="paramtype">xnheap_t * </td>
<td class="paramname"> <em>heap</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">void * </td>
<td class="paramname"> <em>block</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">int(*)(void *block) </td>
<td class="paramname"> <em>ckfn</em></td><td> </td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td><td width="100%"></td>
</tr>
</table>
</div>
<div class="memdoc">
<p>
Test and release a memory block to a memory heap.
<p>
Releases a memory region to the memory heap it was previously allocated from. Before the actual release is performed, an optional user-defined can be invoked to check for additional criteria with respect to the request consistency.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>heap</em> </td><td>The descriptor address of the heap to release memory to.</td></tr>
<tr><td valign="top"></td><td valign="top"><em>block</em> </td><td>The address of the region to be returned to the heap.</td></tr>
<tr><td valign="top"></td><td valign="top"><em>ckfn</em> </td><td>The address of a user-supplied verification routine which is to be called after the memory address specified by <em>block</em> has been checked for validity. The routine is expected to proceed to further consistency checks, and either return zero upon success, or non-zero upon error. In the latter case, the release process is aborted, and <em>ckfn's</em> return value is passed back to the caller of this service as its error return code. <em>ckfn</em> must not trigger the rescheduling procedure either directly or indirectly.</td></tr>
</table>
</dl>
<dl class="return" compact><dt><b>Returns:</b></dt><dd>0 is returned upon success, or -EINVAL is returned whenever the block is not a valid region of the specified heap. Additional return codes can also be defined locally by the <em>ckfn</em> routine.</dd></dl>
Environments:<p>
This service can be called from:<p>
<ul>
<li>Kernel module initialization/cleanup code</li><li>Interrupt service routine</li><li>Kernel-based task</li><li>User-space task</li></ul>
<p>
Rescheduling: never.
<p>Referenced by <a class="el" href="ksrc_2skins_2native_2queue_8c-source.html#l00498">rt_queue_free()</a>, and <a class="el" href="ksrc_2nucleus_2heap_8c-source.html#l00788">xnheap_free()</a>.</p>
</div>
</div><p>
</div>
<hr size="1"><address style="text-align: right;"><small>Generated on Sun Jun 8 18:08:50 2008 for Xenomai API by
<a href="http://www.doxygen.org/index.html">
<img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.5.5 </small></address>
</body>
</html>
|
