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systemd/src/shared/mempool.c
Michal Schmidt 52fc5ce38c mempool: add a zeroing alloc function
Add mempool_alloc0_tile(). It's like mempool_alloc_tile(), but it
initializes the allocated tile's memory to zero.
2014-10-30 19:50:50 +01:00

104 lines
2.8 KiB
C

/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010-2014 Lennart Poettering
Copyright 2014 Michal Schmidt
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include "mempool.h"
#include "macro.h"
#include "util.h"
struct pool {
struct pool *next;
unsigned n_tiles;
unsigned n_used;
};
void* mempool_alloc_tile(struct mempool *mp) {
unsigned i;
/* When a tile is released we add it to the list and simply
* place the next pointer at its offset 0. */
assert(mp->tile_size >= sizeof(void*));
assert(mp->at_least > 0);
if (mp->freelist) {
void *r;
r = mp->freelist;
mp->freelist = * (void**) mp->freelist;
return r;
}
if (_unlikely_(!mp->first_pool) ||
_unlikely_(mp->first_pool->n_used >= mp->first_pool->n_tiles)) {
unsigned n;
size_t size;
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*) mp->first_pool) + ALIGN(sizeof(struct 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) {
* (void**) p = mp->freelist;
mp->freelist = p;
}
#ifdef VALGRIND
void mempool_drop(struct mempool *mp) {
struct pool *p = mp->first_pool;
while (p) {
struct pool *n;
n = p->next;
free(p);
p = n;
}
}
#endif