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-rw-r--r--src/shared/mempool.c94
1 files changed, 94 insertions, 0 deletions
diff --git a/src/shared/mempool.c b/src/shared/mempool.c
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+/*-*- 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_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