xref: /illumos-gate/usr/src/uts/common/os/memlist_new.c (revision 56f33205c9ed776c3c909e07d52e94610a675740)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #include <sys/types.h>
27 #include <sys/cmn_err.h>
28 #include <sys/mutex.h>
29 #include <sys/param.h>		/* for NULL */
30 #include <sys/debug.h>
31 #include <sys/memlist.h>
32 #include <sys/memlist_impl.h>
33 
34 static struct memlist *memlist_freelist;
35 static uint_t memlist_freelist_count;
36 static kmutex_t memlist_freelist_mutex;
37 
38 /*
39  * Caller must test for NULL return.
40  */
41 struct memlist *
42 memlist_get_one(void)
43 {
44 	struct memlist *mlp;
45 
46 	mutex_enter(&memlist_freelist_mutex);
47 	mlp = memlist_freelist;
48 	if (mlp != NULL) {
49 		memlist_freelist = mlp->ml_next;
50 		memlist_freelist_count--;
51 	}
52 	mutex_exit(&memlist_freelist_mutex);
53 
54 	return (mlp);
55 }
56 
57 void
58 memlist_free_one(struct memlist *mlp)
59 {
60 	ASSERT(mlp != NULL);
61 
62 	mutex_enter(&memlist_freelist_mutex);
63 	mlp->ml_next = memlist_freelist;
64 	memlist_freelist = mlp;
65 	memlist_freelist_count++;
66 	mutex_exit(&memlist_freelist_mutex);
67 }
68 
69 void
70 memlist_free_list(struct memlist *mlp)
71 {
72 	struct memlist *mlendp;
73 	uint_t count;
74 
75 	if (mlp == NULL) {
76 		return;
77 	}
78 
79 	count = 1;
80 	for (mlendp = mlp; mlendp->ml_next != NULL; mlendp = mlendp->ml_next)
81 		count++;
82 	mutex_enter(&memlist_freelist_mutex);
83 	mlendp->ml_next = memlist_freelist;
84 	memlist_freelist = mlp;
85 	memlist_freelist_count += count;
86 	mutex_exit(&memlist_freelist_mutex);
87 }
88 
89 void
90 memlist_free_block(caddr_t base, size_t bytes)
91 {
92 	struct memlist *mlp, *mlendp;
93 	uint_t count;
94 
95 	count = bytes / sizeof (struct memlist);
96 	if (count == 0)
97 		return;
98 
99 	mlp = (struct memlist *)base;
100 	mlendp = &mlp[count - 1];
101 	for (; mlp != mlendp; mlp++)
102 		mlp->ml_next = mlp + 1;
103 	mlendp->ml_next = NULL;
104 	mlp = (struct memlist *)base;
105 	mutex_enter(&memlist_freelist_mutex);
106 	mlendp->ml_next = memlist_freelist;
107 	memlist_freelist = mlp;
108 	memlist_freelist_count += count;
109 	mutex_exit(&memlist_freelist_mutex);
110 }
111 
112 /*
113  * Insert into a sorted memory list.
114  * new = new element to insert
115  * curmemlistp = memory list to which to add segment.
116  */
117 void
118 memlist_insert(
119 	struct memlist *new,
120 	struct memlist **curmemlistp)
121 {
122 	struct memlist *cur, *last;
123 	uint64_t start, end;
124 
125 	start = new->ml_address;
126 	end = start + new->ml_size;
127 	last = NULL;
128 	for (cur = *curmemlistp; cur; cur = cur->ml_next) {
129 		last = cur;
130 		if (cur->ml_address >= end) {
131 			new->ml_next = cur;
132 			new->ml_prev = cur->ml_prev;
133 			cur->ml_prev = new;
134 			if (cur == *curmemlistp)
135 				*curmemlistp = new;
136 			else
137 				new->ml_prev->ml_next = new;
138 			return;
139 		}
140 		if (cur->ml_address + cur->ml_size > start)
141 			panic("munged memory list = 0x%p\n",
142 			    (void *)curmemlistp);
143 	}
144 	new->ml_next = NULL;
145 	new->ml_prev = last;
146 	if (last != NULL)
147 		last->ml_next = new;
148 }
149 
150 void
151 memlist_del(struct memlist *memlistp,
152 	struct memlist **curmemlistp)
153 {
154 #ifdef DEBUG
155 	/*
156 	 * Check that the memlist is on the list.
157 	 */
158 	struct memlist *mlp;
159 
160 	for (mlp = *curmemlistp; mlp != NULL; mlp = mlp->ml_next)
161 		if (mlp == memlistp)
162 			break;
163 	ASSERT(mlp == memlistp);
164 #endif /* DEBUG */
165 	if (*curmemlistp == memlistp) {
166 		ASSERT(memlistp->ml_prev == NULL);
167 		*curmemlistp = memlistp->ml_next;
168 	}
169 	if (memlistp->ml_prev != NULL) {
170 		ASSERT(memlistp->ml_prev->ml_next == memlistp);
171 		memlistp->ml_prev->ml_next = memlistp->ml_next;
172 	}
173 	if (memlistp->ml_next != NULL) {
174 		ASSERT(memlistp->ml_next->ml_prev == memlistp);
175 		memlistp->ml_next->ml_prev = memlistp->ml_prev;
176 	}
177 }
178 
179 struct memlist *
180 memlist_find(struct memlist *mlp, uint64_t address)
181 {
182 	for (; mlp != NULL; mlp = mlp->ml_next)
183 		if (address >= mlp->ml_address &&
184 		    address < (mlp->ml_address + mlp->ml_size))
185 			break;
186 	return (mlp);
187 }
188 
189 /*
190  * Add a span to a memlist.
191  * Return:
192  * MEML_SPANOP_OK if OK.
193  * MEML_SPANOP_ESPAN if part or all of span already exists
194  * MEML_SPANOP_EALLOC for allocation failure
195  */
196 int
197 memlist_add_span(
198 	uint64_t address,
199 	uint64_t bytes,
200 	struct memlist **curmemlistp)
201 {
202 	struct memlist *dst;
203 	struct memlist *prev, *next;
204 
205 	/*
206 	 * allocate a new struct memlist
207 	 */
208 
209 	dst = memlist_get_one();
210 
211 	if (dst == NULL) {
212 		return (MEML_SPANOP_EALLOC);
213 	}
214 
215 	dst->ml_address = address;
216 	dst->ml_size = bytes;
217 
218 	/*
219 	 * First insert.
220 	 */
221 	if (*curmemlistp == NULL) {
222 		dst->ml_prev = NULL;
223 		dst->ml_next = NULL;
224 		*curmemlistp = dst;
225 		return (MEML_SPANOP_OK);
226 	}
227 
228 	/*
229 	 * Insert into sorted list.
230 	 */
231 	for (prev = NULL, next = *curmemlistp; next != NULL;
232 	    prev = next, next = next->ml_next) {
233 		if (address > (next->ml_address + next->ml_size))
234 			continue;
235 
236 		/*
237 		 * Else insert here.
238 		 */
239 
240 		/*
241 		 * Prepend to next.
242 		 */
243 		if ((address + bytes) == next->ml_address) {
244 			memlist_free_one(dst);
245 
246 			next->ml_address = address;
247 			next->ml_size += bytes;
248 
249 			return (MEML_SPANOP_OK);
250 		}
251 
252 		/*
253 		 * Append to next.
254 		 */
255 		if (address == (next->ml_address + next->ml_size)) {
256 			memlist_free_one(dst);
257 
258 			if (next->ml_next) {
259 				/*
260 				 * don't overlap with next->ml_next
261 				 */
262 				if ((address + bytes) >
263 				    next->ml_next->ml_address) {
264 					return (MEML_SPANOP_ESPAN);
265 				}
266 				/*
267 				 * Concatenate next and next->ml_next
268 				 */
269 				if ((address + bytes) ==
270 				    next->ml_next->ml_address) {
271 					struct memlist *mlp = next->ml_next;
272 
273 					if (next == *curmemlistp)
274 						*curmemlistp = next->ml_next;
275 
276 					mlp->ml_address = next->ml_address;
277 					mlp->ml_size += next->ml_size;
278 					mlp->ml_size += bytes;
279 
280 					if (next->ml_prev)
281 						next->ml_prev->ml_next = mlp;
282 					mlp->ml_prev = next->ml_prev;
283 
284 					memlist_free_one(next);
285 					return (MEML_SPANOP_OK);
286 				}
287 			}
288 
289 			next->ml_size += bytes;
290 
291 			return (MEML_SPANOP_OK);
292 		}
293 
294 		/* don't overlap with next */
295 		if ((address + bytes) > next->ml_address) {
296 			memlist_free_one(dst);
297 			return (MEML_SPANOP_ESPAN);
298 		}
299 
300 		/*
301 		 * Insert before next.
302 		 */
303 		dst->ml_prev = prev;
304 		dst->ml_next = next;
305 		next->ml_prev = dst;
306 		if (prev == NULL) {
307 			*curmemlistp = dst;
308 		} else {
309 			prev->ml_next = dst;
310 		}
311 		return (MEML_SPANOP_OK);
312 	}
313 
314 	/*
315 	 * End of list, prev is valid and next is NULL.
316 	 */
317 	prev->ml_next = dst;
318 	dst->ml_prev = prev;
319 	dst->ml_next = NULL;
320 
321 	return (MEML_SPANOP_OK);
322 }
323 
324 /*
325  * Delete a span from a memlist.
326  * Return:
327  * MEML_SPANOP_OK if OK.
328  * MEML_SPANOP_ESPAN if part or all of span does not exist
329  * MEML_SPANOP_EALLOC for allocation failure
330  */
331 int
332 memlist_delete_span(
333 	uint64_t address,
334 	uint64_t bytes,
335 	struct memlist **curmemlistp)
336 {
337 	struct memlist *dst, *next;
338 
339 	/*
340 	 * Find element containing address.
341 	 */
342 	for (next = *curmemlistp; next != NULL; next = next->ml_next) {
343 		if ((address >= next->ml_address) &&
344 		    (address < next->ml_address + next->ml_size))
345 			break;
346 	}
347 
348 	/*
349 	 * If start address not in list.
350 	 */
351 	if (next == NULL) {
352 		return (MEML_SPANOP_ESPAN);
353 	}
354 
355 	/*
356 	 * Error if size goes off end of this struct memlist.
357 	 */
358 	if (address + bytes > next->ml_address + next->ml_size) {
359 		return (MEML_SPANOP_ESPAN);
360 	}
361 
362 	/*
363 	 * Span at beginning of struct memlist.
364 	 */
365 	if (address == next->ml_address) {
366 		/*
367 		 * If start & size match, delete from list.
368 		 */
369 		if (bytes == next->ml_size) {
370 			if (next == *curmemlistp)
371 				*curmemlistp = next->ml_next;
372 			if (next->ml_prev != NULL)
373 				next->ml_prev->ml_next = next->ml_next;
374 			if (next->ml_next != NULL)
375 				next->ml_next->ml_prev = next->ml_prev;
376 
377 			memlist_free_one(next);
378 		} else {
379 			/*
380 			 * Increment start address by bytes.
381 			 */
382 			next->ml_address += bytes;
383 			next->ml_size -= bytes;
384 		}
385 		return (MEML_SPANOP_OK);
386 	}
387 
388 	/*
389 	 * Span at end of struct memlist.
390 	 */
391 	if (address + bytes == next->ml_address + next->ml_size) {
392 		/*
393 		 * decrement size by bytes
394 		 */
395 		next->ml_size -= bytes;
396 		return (MEML_SPANOP_OK);
397 	}
398 
399 	/*
400 	 * Delete a span in the middle of the struct memlist.
401 	 */
402 	{
403 		/*
404 		 * create a new struct memlist
405 		 */
406 		dst = memlist_get_one();
407 
408 		if (dst == NULL) {
409 			return (MEML_SPANOP_EALLOC);
410 		}
411 
412 		/*
413 		 * Existing struct memlist gets address
414 		 * and size up to start of span.
415 		 */
416 		dst->ml_address = address + bytes;
417 		dst->ml_size =
418 		    (next->ml_address + next->ml_size) - dst->ml_address;
419 		next->ml_size = address - next->ml_address;
420 
421 		/*
422 		 * New struct memlist gets address starting
423 		 * after span, until end.
424 		 */
425 
426 		/*
427 		 * link in new memlist after old
428 		 */
429 		dst->ml_next = next->ml_next;
430 		dst->ml_prev = next;
431 
432 		if (next->ml_next != NULL)
433 			next->ml_next->ml_prev = dst;
434 		next->ml_next = dst;
435 	}
436 	return (MEML_SPANOP_OK);
437 }
438