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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <stdint.h>
#include <stdlib.h>
#include "format-util.h"
#include "macro.h"
#include "memory-util.h"
#include "mempool.h"
struct pool {
struct pool *next;
size_t n_tiles;
size_t n_used;
};
static void* pool_ptr(struct pool *p) {
return ((uint8_t*) ASSERT_PTR(p)) + ALIGN(sizeof(struct pool));
}
void* mempool_alloc_tile(struct mempool *mp) {
size_t i;
/* When a tile is released we add it to the list and simply
* place the next pointer at its offset 0. */
assert(mp);
assert(mp->tile_size >= sizeof(void*));
assert(mp->at_least > 0);
if (mp->freelist) {
void *t;
t = mp->freelist;
mp->freelist = *(void**) mp->freelist;
return t;
}
if (_unlikely_(!mp->first_pool) ||
_unlikely_(mp->first_pool->n_used >= mp->first_pool->n_tiles)) {
size_t size, n;
struct pool *p;
n = mp->first_pool ? mp->first_pool->n_tiles : 0;
n = MAX(mp->at_least, n * 2);
size = PAGE_ALIGN(ALIGN(sizeof(struct pool)) + n*mp->tile_size);
n = (size - ALIGN(sizeof(struct pool))) / mp->tile_size;
p = malloc(size);
if (!p)
return NULL;
p->next = mp->first_pool;
p->n_tiles = n;
p->n_used = 0;
mp->first_pool = p;
}
i = mp->first_pool->n_used++;
return (uint8_t*) pool_ptr(mp->first_pool) + i*mp->tile_size;
}
void* mempool_alloc0_tile(struct mempool *mp) {
void *p;
p = mempool_alloc_tile(mp);
if (p)
memzero(p, mp->tile_size);
return p;
}
void* mempool_free_tile(struct mempool *mp, void *p) {
assert(mp);
if (!p)
return NULL;
*(void**) p = mp->freelist;
mp->freelist = p;
return NULL;
}
static bool pool_contains(struct mempool *mp, struct pool *p, void *ptr) {
size_t off;
void *a;
assert(mp);
assert(p);
if (!ptr)
return false;
a = pool_ptr(p);
if ((uint8_t*) ptr < (uint8_t*) a)
return false;
off = (uint8_t*) ptr - (uint8_t*) a;
if (off >= mp->tile_size * p->n_tiles)
return false;
assert(off % mp->tile_size == 0);
return true;
}
static bool pool_is_unused(struct mempool *mp, struct pool *p) {
assert(mp);
assert(p);
if (p->n_used == 0)
return true;
/* Check if all tiles in this specific pool are in the freelist. */
size_t n = 0;
void *i = mp->freelist;
while (i) {
if (pool_contains(mp, p, i))
n++;
i = *(void**) i;
}
assert(n <= p->n_used);
return n == p->n_used;
}
static void pool_unlink(struct mempool *mp, struct pool *p) {
size_t m = 0;
assert(mp);
assert(p);
if (p->n_used == 0)
return;
void **i = &mp->freelist;
while (*i) {
void *d = *i;
if (pool_contains(mp, p, d)) {
*i = *(void**) d;
m++;
if (m == p->n_used)
break;
} else
i = (void**) d;
}
}
void mempool_trim(struct mempool *mp) {
size_t trimmed = 0, left = 0;
assert(mp);
struct pool **p = &mp->first_pool;
while (*p) {
struct pool *d = *p;
if (pool_is_unused(mp, d)) {
trimmed += d->n_tiles * mp->tile_size;
pool_unlink(mp, d);
*p = d->next;
free(d);
} else {
left += d->n_tiles * mp->tile_size;
p = &d->next;
}
}
log_debug("Trimmed %s from memory pool %p. (%s left)", FORMAT_BYTES(trimmed), mp, FORMAT_BYTES(left));
}
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