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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-10 20:49:52 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-10 20:49:52 +0000
commit55944e5e40b1be2afc4855d8d2baf4b73d1876b5 (patch)
tree33f869f55a1b149e9b7c2b7e201867ca5dd52992 /src/basic/mempool.c
parentInitial commit. (diff)
downloadsystemd-55944e5e40b1be2afc4855d8d2baf4b73d1876b5.tar.xz
systemd-55944e5e40b1be2afc4855d8d2baf4b73d1876b5.zip
Adding upstream version 255.4.upstream/255.4
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/basic/mempool.c')
-rw-r--r--src/basic/mempool.c175
1 files changed, 175 insertions, 0 deletions
diff --git a/src/basic/mempool.c b/src/basic/mempool.c
new file mode 100644
index 0000000..391f29b
--- /dev/null
+++ b/src/basic/mempool.c
@@ -0,0 +1,175 @@
+/* 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));
+}