tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
19struct kmem_cache {
20 pthread_mutex_t lock;
21 unsigned int size;
22 unsigned int align;
23 int nr_objs;
24 void *objs;
25 void (*ctor)(void *);
26};
27
28void *kmem_cache_alloc(struct kmem_cache *cachep, int gfp)
29{
30 void *p;
31
32 if (!(gfp & __GFP_DIRECT_RECLAIM))
33 return NULL;
34
35 pthread_mutex_lock(&cachep->lock);
36 if (cachep->nr_objs) {
37 struct radix_tree_node *node = cachep->objs;
38 cachep->nr_objs--;
39 cachep->objs = node->parent;
40 pthread_mutex_unlock(&cachep->lock);
41 node->parent = NULL;
42 p = node;
43 } else {
44 pthread_mutex_unlock(&cachep->lock);
45 if (cachep->align)
46 posix_memalign(&p, cachep->align, cachep->size);
47 else
48 p = malloc(cachep->size);
49 if (cachep->ctor)
50 cachep->ctor(p);
51 else if (gfp & __GFP_ZERO)
52 memset(p, 0, cachep->size);
53 }
54
55 uatomic_inc(&nr_allocated);
56 if (kmalloc_verbose)
57 printf("Allocating %p from slab\n", p);
58 return p;
59}
60
61void kmem_cache_free(struct kmem_cache *cachep, void *objp)
62{
63 assert(objp);
64 uatomic_dec(&nr_allocated);
65 if (kmalloc_verbose)
66 printf("Freeing %p to slab\n", objp);
67 pthread_mutex_lock(&cachep->lock);
68 if (cachep->nr_objs > 10 || cachep->align) {
69 memset(objp, POISON_FREE, cachep->size);
70 free(objp);
71 } else {
72 struct radix_tree_node *node = objp;
73 cachep->nr_objs++;
74 node->parent = cachep->objs;
75 cachep->objs = node;
76 }
77 pthread_mutex_unlock(&cachep->lock);
78}
79
80struct kmem_cache *
81kmem_cache_create(const char *name, unsigned int size, unsigned int align,
82 unsigned int flags, void (*ctor)(void *))
83{
84 struct kmem_cache *ret = malloc(sizeof(*ret));
85
86 pthread_mutex_init(&ret->lock, NULL);
87 ret->size = size;
88 ret->align = align;
89 ret->nr_objs = 0;
90 ret->objs = NULL;
91 ret->ctor = ctor;
92 return ret;
93}