xref: /illumos-gate/usr/src/uts/common/os/memlist_new.c (revision 581cede61ac9c14d8d4ea452562a567189eead78)
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 2008 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
27 
28 #include <sys/types.h>
29 #include <sys/cmn_err.h>
30 #include <sys/mutex.h>
31 #include <sys/param.h>		/* for NULL */
32 #include <sys/debug.h>
33 #include <sys/memlist.h>
34 #include <sys/memlist_impl.h>
35 
36 static struct memlist *memlist_freelist;
37 static uint_t memlist_freelist_count;
38 static kmutex_t memlist_freelist_mutex;
39 
40 /*
41  * Caller must test for NULL return.
42  */
43 struct memlist *
44 memlist_get_one(void)
45 {
46 	struct memlist *mlp;
47 
48 	mutex_enter(&memlist_freelist_mutex);
49 	mlp = memlist_freelist;
50 	if (mlp != NULL) {
51 		memlist_freelist = mlp->next;
52 		memlist_freelist_count--;
53 	}
54 	mutex_exit(&memlist_freelist_mutex);
55 
56 	return (mlp);
57 }
58 
59 void
60 memlist_free_one(struct memlist *mlp)
61 {
62 	ASSERT(mlp != NULL);
63 
64 	mutex_enter(&memlist_freelist_mutex);
65 	mlp->next = memlist_freelist;
66 	memlist_freelist = mlp;
67 	memlist_freelist_count++;
68 	mutex_exit(&memlist_freelist_mutex);
69 }
70 
71 void
72 memlist_free_list(struct memlist *mlp)
73 {
74 	struct memlist *mlendp;
75 	uint_t count;
76 
77 	if (mlp == NULL) {
78 		return;
79 	}
80 
81 	count = 1;
82 	for (mlendp = mlp; mlendp->next != NULL; mlendp = mlendp->next)
83 		count++;
84 	mutex_enter(&memlist_freelist_mutex);
85 	mlendp->next = memlist_freelist;
86 	memlist_freelist = mlp;
87 	memlist_freelist_count += count;
88 	mutex_exit(&memlist_freelist_mutex);
89 }
90 
91 void
92 memlist_free_block(caddr_t base, size_t bytes)
93 {
94 	struct memlist *mlp, *mlendp;
95 	uint_t count;
96 
97 	count = bytes / sizeof (struct memlist);
98 	if (count == 0)
99 		return;
100 
101 	mlp = (struct memlist *)base;
102 	mlendp = &mlp[count - 1];
103 	for (; mlp != mlendp; mlp++)
104 		mlp->next = mlp + 1;
105 	mlendp->next = NULL;
106 	mlp = (struct memlist *)base;
107 	mutex_enter(&memlist_freelist_mutex);
108 	mlendp->next = memlist_freelist;
109 	memlist_freelist = mlp;
110 	memlist_freelist_count += count;
111 	mutex_exit(&memlist_freelist_mutex);
112 }
113 
114 /*
115  * Insert into a sorted memory list.
116  * new = new element to insert
117  * curmemlistp = memory list to which to add segment.
118  */
119 void
120 memlist_insert(
121 	struct memlist *new,
122 	struct memlist **curmemlistp)
123 {
124 	struct memlist *cur, *last;
125 	uint64_t start, end;
126 
127 	start = new->address;
128 	end = start + new->size;
129 	last = NULL;
130 	for (cur = *curmemlistp; cur; cur = cur->next) {
131 		last = cur;
132 		if (cur->address >= end) {
133 			new->next = cur;
134 			new->prev = cur->prev;
135 			cur->prev = new;
136 			if (cur == *curmemlistp)
137 				*curmemlistp = new;
138 			else
139 				new->prev->next = new;
140 			return;
141 		}
142 		if (cur->address + cur->size > start)
143 			panic("munged memory list = 0x%p\n",
144 			    (void *)curmemlistp);
145 	}
146 	new->next = NULL;
147 	new->prev = last;
148 	if (last != NULL)
149 		last->next = new;
150 }
151 
152 void
153 memlist_del(struct memlist *memlistp,
154 	struct memlist **curmemlistp)
155 {
156 #ifdef DEBUG
157 	/*
158 	 * Check that the memlist is on the list.
159 	 */
160 	struct memlist *mlp;
161 
162 	for (mlp = *curmemlistp; mlp != NULL; mlp = mlp->next)
163 		if (mlp == memlistp)
164 			break;
165 	ASSERT(mlp == memlistp);
166 #endif /* DEBUG */
167 	if (*curmemlistp == memlistp) {
168 		ASSERT(memlistp->prev == NULL);
169 		*curmemlistp = memlistp->next;
170 	}
171 	if (memlistp->prev != NULL) {
172 		ASSERT(memlistp->prev->next == memlistp);
173 		memlistp->prev->next = memlistp->next;
174 	}
175 	if (memlistp->next != NULL) {
176 		ASSERT(memlistp->next->prev == memlistp);
177 		memlistp->next->prev = memlistp->prev;
178 	}
179 }
180 
181 struct memlist *
182 memlist_find(struct memlist *mlp, uint64_t address)
183 {
184 	for (; mlp != NULL; mlp = mlp->next)
185 		if (address >= mlp->address &&
186 		    address < (mlp->address + mlp->size))
187 			break;
188 	return (mlp);
189 }
190 
191 /*
192  * Add a span to a memlist.
193  * Return:
194  * MEML_SPANOP_OK if OK.
195  * MEML_SPANOP_ESPAN if part or all of span already exists
196  * MEML_SPANOP_EALLOC for allocation failure
197  */
198 int
199 memlist_add_span(
200 	uint64_t address,
201 	uint64_t bytes,
202 	struct memlist **curmemlistp)
203 {
204 	struct memlist *dst;
205 	struct memlist *prev, *next;
206 
207 	/*
208 	 * allocate a new struct memlist
209 	 */
210 
211 	dst = memlist_get_one();
212 
213 	if (dst == NULL) {
214 		return (MEML_SPANOP_EALLOC);
215 	}
216 
217 	dst->address = address;
218 	dst->size = bytes;
219 
220 	/*
221 	 * First insert.
222 	 */
223 	if (*curmemlistp == NULL) {
224 		dst->prev = NULL;
225 		dst->next = NULL;
226 		*curmemlistp = dst;
227 		return (MEML_SPANOP_OK);
228 	}
229 
230 	/*
231 	 * Insert into sorted list.
232 	 */
233 	for (prev = NULL, next = *curmemlistp; next != NULL;
234 	    prev = next, next = next->next) {
235 		if (address > (next->address + next->size))
236 			continue;
237 
238 		/*
239 		 * Else insert here.
240 		 */
241 
242 		/*
243 		 * Prepend to next.
244 		 */
245 		if ((address + bytes) == next->address) {
246 			memlist_free_one(dst);
247 
248 			next->address = address;
249 			next->size += bytes;
250 
251 			return (MEML_SPANOP_OK);
252 		}
253 
254 		/*
255 		 * Append to next.
256 		 */
257 		if (address == (next->address + next->size)) {
258 			memlist_free_one(dst);
259 
260 			if (next->next) {
261 				/*
262 				 * don't overlap with next->next
263 				 */
264 				if ((address + bytes) > next->next->address) {
265 					return (MEML_SPANOP_ESPAN);
266 				}
267 				/*
268 				 * Concatenate next and next->next
269 				 */
270 				if ((address + bytes) == next->next->address) {
271 					struct memlist *mlp = next->next;
272 
273 					if (next == *curmemlistp)
274 						*curmemlistp = next->next;
275 
276 					mlp->address = next->address;
277 					mlp->size += next->size;
278 					mlp->size += bytes;
279 
280 					if (next->prev)
281 						next->prev->next = mlp;
282 					mlp->prev = next->prev;
283 
284 					memlist_free_one(next);
285 					return (MEML_SPANOP_OK);
286 				}
287 			}
288 
289 			next->size += bytes;
290 
291 			return (MEML_SPANOP_OK);
292 		}
293 
294 		/* don't overlap with next */
295 		if ((address + bytes) > next->address) {
296 			memlist_free_one(dst);
297 			return (MEML_SPANOP_ESPAN);
298 		}
299 
300 		/*
301 		 * Insert before next.
302 		 */
303 		dst->prev = prev;
304 		dst->next = next;
305 		next->prev = dst;
306 		if (prev == NULL) {
307 			*curmemlistp = dst;
308 		} else {
309 			prev->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->next = dst;
318 	dst->prev = prev;
319 	dst->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->next) {
343 		if ((address >= next->address) &&
344 		    (address < next->address + next->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->address + next->size) {
359 		return (MEML_SPANOP_ESPAN);
360 	}
361 
362 	/*
363 	 * Span at beginning of struct memlist.
364 	 */
365 	if (address == next->address) {
366 		/*
367 		 * If start & size match, delete from list.
368 		 */
369 		if (bytes == next->size) {
370 			if (next == *curmemlistp)
371 				*curmemlistp = next->next;
372 			if (next->prev != NULL)
373 				next->prev->next = next->next;
374 			if (next->next != NULL)
375 				next->next->prev = next->prev;
376 
377 			memlist_free_one(next);
378 		} else {
379 			/*
380 			 * Increment start address by bytes.
381 			 */
382 			next->address += bytes;
383 			next->size -= bytes;
384 		}
385 		return (MEML_SPANOP_OK);
386 	}
387 
388 	/*
389 	 * Span at end of struct memlist.
390 	 */
391 	if (address + bytes == next->address + next->size) {
392 		/*
393 		 * decrement size by bytes
394 		 */
395 		next->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->address = address + bytes;
417 		dst->size = (next->address + next->size) - dst->address;
418 		next->size = address - next->address;
419 
420 		/*
421 		 * New struct memlist gets address starting
422 		 * after span, until end.
423 		 */
424 
425 		/*
426 		 * link in new memlist after old
427 		 */
428 		dst->next = next->next;
429 		dst->prev = next;
430 
431 		if (next->next != NULL)
432 			next->next->prev = dst;
433 		next->next = dst;
434 	}
435 	return (MEML_SPANOP_OK);
436 }
437