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
|
/* Hack replacement for Linux's kmem_cache_t allocator
Copyright (C) 2000 Free Software Foundation, Inc.
This file is part of the GNU Hurd.
The GNU Hurd is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2, or (at
your option) any later version.
The GNU Hurd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */
/* Hack replacement for Linux's kmem_cache_t allocator, using plain malloc
and cthreads locking. The locking here is probably unnecessary. */
#include <pthread.h>
#include <linux/malloc.h>
struct kmem_cache_s
{
pthread_mutex_t lock;
void *freelist;
size_t item_size;
void (*ctor) (void *, kmem_cache_t *, unsigned long);
void (*dtor) (void *, kmem_cache_t *, unsigned long);
};
kmem_cache_t *
kmem_cache_create (const char *name, size_t item_size,
size_t something, unsigned long flags,
void (*ctor) (void *, kmem_cache_t *, unsigned long),
void (*dtor) (void *, kmem_cache_t *, unsigned long))
{
kmem_cache_t *new = malloc (sizeof *new);
if (!new)
return 0;
pthread_mutex_init (&new->lock, NULL);
new->freelist = 0;
new->item_size = item_size;
new->ctor = ctor;
new->dtor = dtor;
return new;
}
void *
kmem_cache_alloc (kmem_cache_t *cache, int flags)
{
void *p;
pthread_mutex_lock (&cache->lock);
p = cache->freelist;
if (p != 0) {
cache->freelist = *(void **)(p + cache->item_size);
pthread_mutex_unlock (&cache->lock);
return p;
}
pthread_mutex_unlock (&cache->lock);
p = malloc (cache->item_size + sizeof (void *));
if (p && cache->ctor)
(*cache->ctor) (p, cache, flags);
return p;
}
void
kmem_cache_free (kmem_cache_t *cache, void *p)
{
void **const nextp = (void **) (p + cache->item_size);
pthread_mutex_lock (&cache->lock);
*nextp = cache->freelist;
cache->freelist = p;
pthread_mutex_unlock (&cache->lock);
/* XXX eventually destroy some... */
}
|
