2 * Copyright 2000, International Business Machines Corporation and others.
5 * This software has been released under the terms of the IBM Public
6 * License. For details, see the LICENSE file in the top-level source
7 * directory or online at http://www.openafs.org/dl/license10.html
11 * osi_alloc.c - Linux memory allocation routines.
14 #include <afsconfig.h>
15 #include "afs/param.h"
18 #include "afs/sysincludes.h"
19 #include "afsincludes.h"
23 #include "afs_atomlist.h"
24 #include "afs_lhash.h"
26 #define MAX_KMALLOC_SIZE PAGE_SIZE /* Max we should alloc with kmalloc */
27 #define MAX_BUCKET_LEN 30 /* max. no. of entries per buckets we expect to see */
28 #define STAT_INTERVAL 8192 /* we collect stats once every STAT_INTERVAL allocs */
31 #define KM_TYPE 1 /* kmalloc */
32 #define VM_TYPE 2 /* vmalloc */
34 struct osi_linux_mem {
38 /* These assume 32-bit pointers */
39 #define MEMTYPE(A) (((unsigned long)A) & 0x3)
40 #define MEMADDR(A) (void *)((unsigned long)(A) & (~0x3))
43 afs_atomlist *al_mem_pool; /* pool of osi_linux_mem structures */
44 afs_lhash *lh_mem_htab; /* mem hash table */
45 unsigned int allocator_init = 0; /* has the allocator been initialized? */
46 unsigned int afs_linux_cur_allocs = 0;
47 unsigned int afs_linux_total_allocs = 0;
48 unsigned int afs_linux_hash_verify_count = 0; /* used by hash_verify */
49 struct afs_lhash_stat afs_linux_lsb; /* hash table statistics */
50 unsigned int afs_linux_hash_bucket_dist[MAX_BUCKET_LEN]; /* bucket population distribution in our hash table */
52 #if defined(AFS_LINUX24_ENV)
53 #include "h/vmalloc.h"
55 /* externs : can we do this in a better way. Including vmalloc.h causes other
57 extern void vfree(void *addr);
58 extern void *vmalloc(unsigned long size);
61 /* Allocator support functions (static) */
64 hash_equal(const void *a, const void *b)
66 return (MEMADDR(((struct osi_linux_mem *)a)->chunk) ==
67 MEMADDR(((struct osi_linux_mem *)b)->chunk));
71 /* linux_alloc : Allocates memory from the linux kernel. It uses
72 * kmalloc if possible. Otherwise, we use vmalloc.
74 * asize - size of memory required in bytes
76 * returns NULL if we failed to allocate memory.
77 * or pointer to memory if we succeeded.
80 linux_alloc(unsigned int asize, int drop_glock)
84 int haveGlock = ISAFS_GLOCK();
86 /* if we can use kmalloc use it to allocate the required memory. */
87 while (!new && max_retry) {
88 if (asize <= MAX_KMALLOC_SIZE) {
89 new = (void *)(unsigned long)kmalloc(asize,
96 if (new) /* piggy back alloc type */
97 new = (void *)(KM_TYPE | (unsigned long)new);
99 osi_Assert(drop_glock || !haveGlock);
100 if (drop_glock && haveGlock)
102 new = (void *)vmalloc(asize);
103 if (drop_glock && haveGlock)
105 if (new) /* piggy back alloc type */
106 new = (void *)(VM_TYPE | (unsigned long)new);
110 #ifdef set_current_state
111 set_current_state(TASK_INTERRUPTIBLE);
113 current->state = TASK_INTERRUPTIBLE;
115 if (drop_glock && haveGlock)
117 schedule_timeout(HZ);
118 if (drop_glock && haveGlock)
120 #ifdef set_current_state
121 set_current_state(TASK_RUNNING);
123 current->state = TASK_RUNNING;
129 memset(MEMADDR(new), 0, asize);
138 /* mask out the type information from the pointer and
139 * use the appropriate free routine to free the chunk.
141 switch (MEMTYPE(p)) {
149 printf("afs_osi_Free: Asked to free unknown type %d at 0x%lx\n",
150 (int)MEMTYPE(p), (unsigned long)MEMADDR(p));
156 /* hash_chunk() receives a pointer to a chunk and hashes it to produce a
157 * key that the hashtable can use. The key is obtained by
158 * right shifting out the 2 LSBs and then multiplying the
159 * result by a constant no. and dividing it with a large prime.
161 #define HASH_CONST 32786
162 #define HASH_PRIME 79367
168 key = (unsigned int)(long)p >> 2;
169 key = (key * HASH_CONST) % HASH_PRIME;
174 /* hash_free() : Invoked by osi_linux_free_afs_memory(), thru
175 * afs_lhash_iter(), this function is called by the lhash
176 * module for every entry in the hash table. hash_free
177 * frees the memory associated with the entry as well
178 * as returning the osi_linux_mem struct to its pool.
181 hash_free(size_t index, unsigned key, void *data)
183 linux_free(((struct osi_linux_mem *)data)->chunk);
184 afs_atomlist_put(al_mem_pool, data);
187 /* hash_verify() is invoked by osi_linux_verify_alloced_memory() thru
188 * afs_lhash_iter() and is called by the lhash module for every element
190 * hash_verify() verifies (within limits) that the memory passed to it is
194 hash_verify(size_t index, unsigned key, void *data)
196 struct osi_linux_mem *lmp = (struct osi_linux_mem *)data;
199 memtype = MEMTYPE(lmp->chunk);
200 if (memtype != KM_TYPE && memtype != VM_TYPE) {
202 ("osi_linux_verify_alloced_memory: unknown type %d at 0x%lx, index=%lu\n",
203 (int)memtype, (unsigned long)lmp->chunk, (unsigned long)index);
205 afs_linux_hash_verify_count++;
209 /* local_free() : wrapper for vfree(), to deal with incompatible protoypes */
211 local_free(void *p, size_t n)
216 /* linux_alloc_init(): Initializes the kernel memory allocator. As part
217 * of this process, it also initializes a pool of osi_linux_mem
218 * structures as well as the hash table itself.
224 linux_alloc_init(void)
226 /* initiate our pool of osi_linux_mem structs */
228 afs_atomlist_create(sizeof(struct osi_linux_mem), sizeof(long) * 1024,
229 (void *)vmalloc, local_free);
231 printf("afs_osi_Alloc: Error in initialization(atomlist_create)\n");
235 /* initialize the hash table to hold references to alloc'ed chunks */
236 lh_mem_htab = afs_lhash_create(hash_equal, (void *)vmalloc, local_free);
238 printf("afs_osi_Alloc: Error in initialization(lhash_create)\n");
246 /* hash_bucket_stat() : Counts the no. of elements in each bucket and
247 * stores results in our bucket stats vector.
249 static unsigned int cur_bucket, cur_bucket_len;
251 hash_bucket_stat(size_t index, unsigned key, void *data)
253 if (index == cur_bucket) {
254 /* while still on the same bucket, inc len & return */
257 } else { /* if we're on the next bucket, store the distribution */
258 if (cur_bucket_len < MAX_BUCKET_LEN)
259 afs_linux_hash_bucket_dist[cur_bucket_len]++;
262 ("afs_get_hash_stats: Warning! exceeded max bucket len %d\n",
269 /* get_hash_stats() : get hash table statistics */
275 afs_lhash_stat(lh_mem_htab, &afs_linux_lsb);
277 /* clear out the bucket stat vector */
278 for (i = 0; i < MAX_BUCKET_LEN; i++)
279 afs_linux_hash_bucket_dist[i] = 0;
280 cur_bucket = cur_bucket_len = 00;
282 /* populate the bucket stat vector */
283 afs_lhash_iter(lh_mem_htab, hash_bucket_stat);
286 /************** Linux memory allocator interface functions **********/
288 #if defined(AFS_LINUX24_ENV)
289 DECLARE_MUTEX(afs_linux_alloc_sem);
291 struct semaphore afs_linux_alloc_sem = MUTEX;
295 osi_linux_alloc(unsigned int asize, int drop_glock)
298 struct osi_linux_mem *lmem;
300 new = linux_alloc(asize, drop_glock); /* get a chunk of memory of size asize */
303 printf("afs_osi_Alloc: Can't vmalloc %d bytes.\n", asize);
307 down(&afs_linux_alloc_sem);
309 /* allocator hasn't been initialized yet */
310 if (allocator_init == 0) {
311 if (linux_alloc_init() == 0) {
314 allocator_init = 1; /* initialization complete */
317 /* get an atom to store the pointer to the chunk */
318 lmem = (struct osi_linux_mem *)afs_atomlist_get(al_mem_pool);
320 printf("afs_osi_Alloc: atomlist_get() failed.");
323 /* store the chunk reference */
326 /* hash in the chunk */
327 if (afs_lhash_enter(lh_mem_htab, hash_chunk(new), lmem) != 0) {
328 printf("afs_osi_Alloc: lhash_enter failed\n");
331 afs_linux_cur_allocs++; /* no. of current allocations */
332 afs_linux_total_allocs++; /* total no. of allocations done so far */
333 if ((afs_linux_cur_allocs % STAT_INTERVAL) == 0) {
337 up(&afs_linux_alloc_sem);
350 /* osi_linux_free() - free chunk of memory passed to us.
353 osi_linux_free(void *addr)
355 struct osi_linux_mem lmem, *lmp;
357 down(&afs_linux_alloc_sem);
360 /* remove this chunk from our hash table */
362 (struct osi_linux_mem *)afs_lhash_remove(lh_mem_htab,
363 hash_chunk(addr), &lmem))) {
364 linux_free(lmp->chunk); /* this contains the piggybacked type info */
365 afs_atomlist_put(al_mem_pool, lmp); /* return osi_linux_mem struct to pool */
366 afs_linux_cur_allocs--;
368 printf("osi_linux_free: failed to remove chunk from hashtable\n");
372 up(&afs_linux_alloc_sem);
375 /* osi_linux_free_afs_memory() - free all chunks of memory allocated.
378 osi_linux_free_afs_memory(void)
380 down(&afs_linux_alloc_sem);
382 if (allocator_init) {
383 /* iterate through all elements in the hash table and free both
384 * the chunk and the atom associated with it.
386 afs_lhash_iter(lh_mem_htab, hash_free);
388 /* free the atomlist. */
389 afs_atomlist_destroy(al_mem_pool);
391 /* free the hashlist. */
392 afs_lhash_destroy(lh_mem_htab);
394 /* change the state so that the allocator is now uninitialized. */
397 up(&afs_linux_alloc_sem);
400 /* osi_linux_verify_alloced_memory(): verify all chunks of alloced memory in
404 osi_linux_verify_alloced_memory()
406 down(&afs_linux_alloc_sem);
408 /* count of times hash_verify was called. reset it to 0 before iteration */
409 afs_linux_hash_verify_count = 0;
411 /* iterate thru elements in the hash table */
412 afs_lhash_iter(lh_mem_htab, hash_verify);
414 if (afs_linux_hash_verify_count != afs_linux_cur_allocs) {
415 /* hmm, some pieces of memory are missing. */
417 ("osi_linux_verify_alloced_memory: %d chunks of memory are not accounted for during verify!\n",
418 afs_linux_hash_verify_count - afs_linux_cur_allocs);
421 up(&afs_linux_alloc_sem);