linux.c

  1// SPDX-License-Identifier: GPL-2.0
  2#include <stdlib.h>
  3#include <string.h>
  4#include <malloc.h>
  5#include <pthread.h>
  6#include <unistd.h>
  7#include <assert.h>
  8
  9#include <linux/gfp.h>
 10#include <linux/poison.h>
 11#include <linux/slab.h>
 12#include <linux/radix-tree.h>
 13#include <urcu/uatomic.h>
 14
 15int nr_allocated;
 16int preempt_count;
 17int test_verbose;
 18
 19void kmem_cache_set_callback(struct kmem_cache *cachep, void (*callback)(void *))
 20{
 21	cachep->callback = callback;
 22}
 23
 24void kmem_cache_set_private(struct kmem_cache *cachep, void *private)
 25{
 26	cachep->private = private;
 27}
 28
 29void kmem_cache_set_non_kernel(struct kmem_cache *cachep, unsigned int val)
 30{
 31	cachep->non_kernel = val;
 32}
 33
 34unsigned long kmem_cache_get_alloc(struct kmem_cache *cachep)
 35{
 36	return cachep->size * cachep->nr_allocated;
 37}
 38
 39unsigned long kmem_cache_nr_allocated(struct kmem_cache *cachep)
 40{
 41	return cachep->nr_allocated;
 42}
 43
 44unsigned long kmem_cache_nr_tallocated(struct kmem_cache *cachep)
 45{
 46	return cachep->nr_tallocated;
 47}
 48
 49void kmem_cache_zero_nr_tallocated(struct kmem_cache *cachep)
 50{
 51	cachep->nr_tallocated = 0;
 52}
 53
 54void *kmem_cache_alloc_lru(struct kmem_cache *cachep, struct list_lru *lru,
 55		int gfp)
 56{
 57	void *p;
 58
 59	if (cachep->exec_callback) {
 60		if (cachep->callback)
 61			cachep->callback(cachep->private);
 62		cachep->exec_callback = false;
 63	}
 64
 65	if (!(gfp & __GFP_DIRECT_RECLAIM)) {
 66		if (!cachep->non_kernel) {
 67			if (cachep->callback)
 68				cachep->exec_callback = true;
 69			return NULL;
 70		}
 71
 72		cachep->non_kernel--;
 73	}
 74
 75	pthread_mutex_lock(&cachep->lock);
 76	if (cachep->nr_objs) {
 77		struct radix_tree_node *node = cachep->objs;
 78		cachep->nr_objs--;
 79		cachep->objs = node->parent;
 80		pthread_mutex_unlock(&cachep->lock);
 81		node->parent = NULL;
 82		p = node;
 83	} else {
 84		pthread_mutex_unlock(&cachep->lock);
 85		if (cachep->align) {
 86			if (posix_memalign(&p, cachep->align, cachep->size) < 0)
 87				return NULL;
 88		} else {
 89			p = malloc(cachep->size);
 90		}
 91
 92		if (cachep->ctor)
 93			cachep->ctor(p);
 94		else if (gfp & __GFP_ZERO)
 95			memset(p, 0, cachep->size);
 96	}
 97
 98	uatomic_inc(&cachep->nr_allocated);
 99	uatomic_inc(&nr_allocated);
100	uatomic_inc(&cachep->nr_tallocated);
101	if (kmalloc_verbose)
102		printf("Allocating %p from slab\n", p);
103	return p;
104}
105
106void __kmem_cache_free_locked(struct kmem_cache *cachep, void *objp)
107{
108	assert(objp);
109	if (cachep->nr_objs > 10 || cachep->align) {
110		memset(objp, POISON_FREE, cachep->size);
111		free(objp);
112	} else {
113		struct radix_tree_node *node = objp;
114		cachep->nr_objs++;
115		node->parent = cachep->objs;
116		cachep->objs = node;
117	}
118}
119
120void kmem_cache_free_locked(struct kmem_cache *cachep, void *objp)
121{
122	uatomic_dec(&nr_allocated);
123	uatomic_dec(&cachep->nr_allocated);
124	if (kmalloc_verbose)
125		printf("Freeing %p to slab\n", objp);
126	__kmem_cache_free_locked(cachep, objp);
127}
128
129void kmem_cache_free(struct kmem_cache *cachep, void *objp)
130{
131	pthread_mutex_lock(&cachep->lock);
132	kmem_cache_free_locked(cachep, objp);
133	pthread_mutex_unlock(&cachep->lock);
134}
135
136void kmem_cache_free_bulk(struct kmem_cache *cachep, size_t size, void **list)
137{
138	if (kmalloc_verbose)
139		pr_debug("Bulk free %p[0-%zu]\n", list, size - 1);
140
141	if (cachep->exec_callback) {
142		if (cachep->callback)
143			cachep->callback(cachep->private);
144		cachep->exec_callback = false;
145	}
146
147	pthread_mutex_lock(&cachep->lock);
148	for (int i = 0; i < size; i++)
149		kmem_cache_free_locked(cachep, list[i]);
150	pthread_mutex_unlock(&cachep->lock);
151}
152
153void kmem_cache_shrink(struct kmem_cache *cachep)
154{
155}
156
157int kmem_cache_alloc_bulk(struct kmem_cache *cachep, gfp_t gfp, size_t size,
158			  void **p)
159{
160	size_t i;
161
162	if (kmalloc_verbose)
163		pr_debug("Bulk alloc %zu\n", size);
164
165	pthread_mutex_lock(&cachep->lock);
166	if (cachep->nr_objs >= size) {
167		struct radix_tree_node *node;
168
169		for (i = 0; i < size; i++) {
170			if (!(gfp & __GFP_DIRECT_RECLAIM)) {
171				if (!cachep->non_kernel)
172					break;
173				cachep->non_kernel--;
174			}
175
176			node = cachep->objs;
177			cachep->nr_objs--;
178			cachep->objs = node->parent;
179			p[i] = node;
180			node->parent = NULL;
181		}
182		pthread_mutex_unlock(&cachep->lock);
183	} else {
184		pthread_mutex_unlock(&cachep->lock);
185		for (i = 0; i < size; i++) {
186			if (!(gfp & __GFP_DIRECT_RECLAIM)) {
187				if (!cachep->non_kernel)
188					break;
189				cachep->non_kernel--;
190			}
191
192			if (cachep->align) {
193				if (posix_memalign(&p[i], cachep->align,
194					       cachep->size) < 0)
195					break;
196			} else {
197				p[i] = malloc(cachep->size);
198				if (!p[i])
199					break;
200			}
201			if (cachep->ctor)
202				cachep->ctor(p[i]);
203			else if (gfp & __GFP_ZERO)
204				memset(p[i], 0, cachep->size);
205		}
206	}
207
208	if (i < size) {
209		size = i;
210		pthread_mutex_lock(&cachep->lock);
211		for (i = 0; i < size; i++)
212			__kmem_cache_free_locked(cachep, p[i]);
213		pthread_mutex_unlock(&cachep->lock);
214		if (cachep->callback)
215			cachep->exec_callback = true;
216		return 0;
217	}
218
219	for (i = 0; i < size; i++) {
220		uatomic_inc(&nr_allocated);
221		uatomic_inc(&cachep->nr_allocated);
222		uatomic_inc(&cachep->nr_tallocated);
223		if (kmalloc_verbose)
224			printf("Allocating %p from slab\n", p[i]);
225	}
226
227	return size;
228}
229
230struct kmem_cache *
231__kmem_cache_create_args(const char *name, unsigned int size,
232			  struct kmem_cache_args *args,
233			  unsigned int flags)
234{
235	struct kmem_cache *ret = malloc(sizeof(*ret));
236
237	pthread_mutex_init(&ret->lock, NULL);
238	ret->size = size;
239	ret->align = args->align;
240	ret->sheaf_capacity = args->sheaf_capacity;
241	ret->nr_objs = 0;
242	ret->nr_allocated = 0;
243	ret->nr_tallocated = 0;
244	ret->objs = NULL;
245	ret->ctor = args->ctor;
246	ret->non_kernel = 0;
247	ret->exec_callback = false;
248	ret->callback = NULL;
249	ret->private = NULL;
250
251	return ret;
252}
253
254struct slab_sheaf *
255kmem_cache_prefill_sheaf(struct kmem_cache *s, gfp_t gfp, unsigned int size)
256{
257	struct slab_sheaf *sheaf;
258	unsigned int capacity;
259
260	if (s->exec_callback) {
261		if (s->callback)
262			s->callback(s->private);
263		s->exec_callback = false;
264	}
265
266	capacity = max(size, s->sheaf_capacity);
267
268	sheaf = calloc(1, sizeof(*sheaf) + sizeof(void *) * capacity);
269	if (!sheaf)
270		return NULL;
271
272	sheaf->cache = s;
273	sheaf->capacity = capacity;
274	sheaf->size = kmem_cache_alloc_bulk(s, gfp, size, sheaf->objects);
275	if (!sheaf->size) {
276		free(sheaf);
277		return NULL;
278	}
279
280	return sheaf;
281}
282
283int kmem_cache_refill_sheaf(struct kmem_cache *s, gfp_t gfp,
284		 struct slab_sheaf **sheafp, unsigned int size)
285{
286	struct slab_sheaf *sheaf = *sheafp;
287	int refill;
288
289	if (sheaf->size >= size)
290		return 0;
291
292	if (size > sheaf->capacity) {
293		sheaf = kmem_cache_prefill_sheaf(s, gfp, size);
294		if (!sheaf)
295			return -ENOMEM;
296
297		kmem_cache_return_sheaf(s, gfp, *sheafp);
298		*sheafp = sheaf;
299		return 0;
300	}
301
302	refill = kmem_cache_alloc_bulk(s, gfp, size - sheaf->size,
303				       &sheaf->objects[sheaf->size]);
304	if (!refill)
305		return -ENOMEM;
306
307	sheaf->size += refill;
308	return 0;
309}
310
311void kmem_cache_return_sheaf(struct kmem_cache *s, gfp_t gfp,
312		 struct slab_sheaf *sheaf)
313{
314	if (sheaf->size)
315		kmem_cache_free_bulk(s, sheaf->size, &sheaf->objects[0]);
316
317	free(sheaf);
318}
319
320void *
321kmem_cache_alloc_from_sheaf(struct kmem_cache *s, gfp_t gfp,
322		struct slab_sheaf *sheaf)
323{
324	void *obj;
325
326	if (sheaf->size == 0) {
327		printf("Nothing left in sheaf!\n");
328		return NULL;
329	}
330
331	obj = sheaf->objects[--sheaf->size];
332	sheaf->objects[sheaf->size] = NULL;
333
334	return obj;
335}
336
337/*
338 * Test the test infrastructure for kem_cache_alloc/free and bulk counterparts.
339 */
340void test_kmem_cache_bulk(void)
341{
342	int i;
343	void *list[12];
344	static struct kmem_cache *test_cache, *test_cache2;
345
346	/*
347	 * Testing the bulk allocators without aligned kmem_cache to force the
348	 * bulk alloc/free to reuse
349	 */
350	test_cache = kmem_cache_create("test_cache", 256, 0, SLAB_PANIC, NULL);
351
352	for (i = 0; i < 5; i++)
353		list[i] = kmem_cache_alloc(test_cache, __GFP_DIRECT_RECLAIM);
354
355	for (i = 0; i < 5; i++)
356		kmem_cache_free(test_cache, list[i]);
357	assert(test_cache->nr_objs == 5);
358
359	kmem_cache_alloc_bulk(test_cache, __GFP_DIRECT_RECLAIM, 5, list);
360	kmem_cache_free_bulk(test_cache, 5, list);
361
362	for (i = 0; i < 12 ; i++)
363		list[i] = kmem_cache_alloc(test_cache, __GFP_DIRECT_RECLAIM);
364
365	for (i = 0; i < 12; i++)
366		kmem_cache_free(test_cache, list[i]);
367
368	/* The last free will not be kept around */
369	assert(test_cache->nr_objs == 11);
370
371	/* Aligned caches will immediately free */
372	test_cache2 = kmem_cache_create("test_cache2", 128, 128, SLAB_PANIC, NULL);
373
374	kmem_cache_alloc_bulk(test_cache2, __GFP_DIRECT_RECLAIM, 10, list);
375	kmem_cache_free_bulk(test_cache2, 10, list);
376	assert(!test_cache2->nr_objs);
377
378
379}