/usr/share/systemtap/runtime/mempool.c is in systemtap-common 2.3-1ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 | /* -*- linux-c -*-
* Preallocated memory pools
* Copyright (C) 2008-2009 Red Hat Inc.
*
* This file is part of systemtap, and is free software. You can
* redistribute it and/or modify it under the terms of the GNU General
* Public License (GPL); either version 2, or (at your option) any
* later version.
*/
#ifndef _STP_MEMPOOL_C_
#define _STP_MEMPOOL_C_
/* An opaque struct identifying the memory pool. */
typedef struct {
struct list_head free_list;
unsigned num;
unsigned size;
spinlock_t lock;
} _stp_mempool_t;
/* for internal use only */
struct _stp_mem_buffer {
struct list_head list;
_stp_mempool_t *pool;
void *buf;
};
/* Delete a memory pool */
static void _stp_mempool_destroy(_stp_mempool_t *pool)
{
struct list_head *p, *tmp;
if (pool) {
list_for_each_safe(p, tmp, &pool->free_list) {
list_del(p);
_stp_kfree(p);
}
_stp_kfree(pool);
}
}
/* Create a new memory pool */
static _stp_mempool_t *_stp_mempool_init(size_t size, size_t num)
{
int i, alloc_size;
struct _stp_mem_buffer *m;
_stp_mempool_t *pool = (_stp_mempool_t *)_stp_kmalloc(sizeof(_stp_mempool_t));
if (unlikely(pool == NULL)) {
errk("Memory allocation failed.\n");
return NULL;
}
INIT_LIST_HEAD(&pool->free_list);
spin_lock_init(&pool->lock);
alloc_size = size + sizeof(struct _stp_mem_buffer) - sizeof(void *);
for (i = 0; i < num; i++) {
m = (struct _stp_mem_buffer *)_stp_kmalloc(alloc_size);
if (unlikely(m == NULL))
goto err;
m->pool = pool;
list_add((struct list_head *)m, &pool->free_list);
}
pool->num = num;
pool->size = alloc_size;
return pool;
err:
_stp_mempool_destroy(pool);
return NULL;
}
/* allocate a buffer from a memory pool */
static void *_stp_mempool_alloc(_stp_mempool_t *pool)
{
unsigned long flags;
struct _stp_mem_buffer *ptr = NULL;
/* PR14804: tolerate accidental early call, before pool is
actually initialized. */
if (pool == NULL)
return NULL;
spin_lock_irqsave(&pool->lock, flags);
if (likely(!list_empty(&pool->free_list))) {
ptr = (struct _stp_mem_buffer *)pool->free_list.next;
list_del_init(&ptr->list);
spin_unlock_irqrestore(&pool->lock, flags);
return &ptr->buf;
}
spin_unlock_irqrestore(&pool->lock, flags);
return NULL;
}
/* return a buffer to its memory pool */
static void _stp_mempool_free(void *buf)
{
unsigned long flags;
struct _stp_mem_buffer *m = container_of(buf, struct _stp_mem_buffer, buf);
spin_lock_irqsave(&m->pool->lock, flags);
list_add(&m->list, &m->pool->free_list);
spin_unlock_irqrestore(&m->pool->lock, flags);
}
#endif /* _STP_MEMPOOL_C_ */
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