[systemd-devel] [PATCH 12/26] shared: split mempool implementation from hashmaps
Michal Schmidt
mschmidt at redhat.com
Thu Oct 16 00:50:50 PDT 2014
---
Makefile.am | 2 +
src/shared/hashmap.c | 101 ++++++++++-----------------------------------------
src/shared/mempool.c | 94 +++++++++++++++++++++++++++++++++++++++++++++++
src/shared/mempool.h | 55 ++++++++++++++++++++++++++++
4 files changed, 171 insertions(+), 81 deletions(-)
create mode 100644 src/shared/mempool.c
create mode 100644 src/shared/mempool.h
diff --git a/Makefile.am b/Makefile.am
index 275e793..dfad63b 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -769,6 +769,8 @@ libsystemd_shared_la_SOURCES = \
src/shared/time-util.h \
src/shared/locale-util.c \
src/shared/locale-util.h \
+ src/shared/mempool.c \
+ src/shared/mempool.h \
src/shared/hashmap.c \
src/shared/hashmap.h \
src/shared/siphash24.c \
diff --git a/src/shared/hashmap.c b/src/shared/hashmap.c
index 8225b8e..1ae3602 100644
--- a/src/shared/hashmap.c
+++ b/src/shared/hashmap.c
@@ -28,6 +28,7 @@
#include "hashmap.h"
#include "macro.h"
#include "siphash24.h"
+#include "mempool.h"
#define INITIAL_N_BUCKETS 31
@@ -50,82 +51,21 @@ struct Hashmap {
bool from_pool:1;
};
-struct pool {
- struct pool *next;
- unsigned n_tiles;
- unsigned n_used;
+struct hashmap_tile {
+ Hashmap h;
+ struct hashmap_entry *initial_buckets[INITIAL_N_BUCKETS];
};
-static struct pool *first_hashmap_pool = NULL;
-static void *first_hashmap_tile = NULL;
-
-static struct pool *first_entry_pool = NULL;
-static void *first_entry_tile = NULL;
-
-static void* allocate_tile(struct pool **first_pool, void **first_tile, size_t tile_size, unsigned at_least) {
- unsigned i;
-
- /* When a tile is released we add it to the list and simply
- * place the next pointer at its offset 0. */
-
- assert(tile_size >= sizeof(void*));
- assert(at_least > 0);
-
- if (*first_tile) {
- void *r;
-
- r = *first_tile;
- *first_tile = * (void**) (*first_tile);
- return r;
- }
-
- if (_unlikely_(!*first_pool) || _unlikely_((*first_pool)->n_used >= (*first_pool)->n_tiles)) {
- unsigned n;
- size_t size;
- struct pool *p;
-
- n = *first_pool ? (*first_pool)->n_tiles : 0;
- n = MAX(at_least, n * 2);
- size = PAGE_ALIGN(ALIGN(sizeof(struct pool)) + n*tile_size);
- n = (size - ALIGN(sizeof(struct pool))) / tile_size;
-
- p = malloc(size);
- if (!p)
- return NULL;
-
- p->next = *first_pool;
- p->n_tiles = n;
- p->n_used = 0;
-
- *first_pool = p;
- }
-
- i = (*first_pool)->n_used++;
-
- return ((uint8_t*) (*first_pool)) + ALIGN(sizeof(struct pool)) + i*tile_size;
-}
-
-static void deallocate_tile(void **first_tile, void *p) {
- * (void**) p = *first_tile;
- *first_tile = p;
-}
+static DEFINE_MEMPOOL(hashmap_pool, struct hashmap_tile, 8);
+static DEFINE_MEMPOOL(hashmap_entry_pool, struct hashmap_entry, 64);
#ifdef VALGRIND
-static void drop_pool(struct pool *p) {
- while (p) {
- struct pool *n;
- n = p->next;
- free(p);
- p = n;
- }
-}
-
-__attribute__((destructor)) static void cleanup_pool(void) {
+__attribute__((destructor)) static void cleanup_pools(void) {
/* Be nice to valgrind */
- drop_pool(first_hashmap_pool);
- drop_pool(first_entry_pool);
+ mempool_drop(&hashmap_entry_pool);
+ mempool_drop(&hashmap_pool);
}
#endif
@@ -223,33 +163,32 @@ static void get_hash_key(uint8_t hash_key[HASH_KEY_SIZE], bool reuse_is_ok) {
Hashmap *hashmap_new(const struct hash_ops *hash_ops) {
bool b;
+ struct hashmap_tile *ht;
Hashmap *h;
- size_t size;
b = is_main_thread();
- size = ALIGN(sizeof(Hashmap)) + INITIAL_N_BUCKETS * sizeof(struct hashmap_entry*);
-
if (b) {
- h = allocate_tile(&first_hashmap_pool, &first_hashmap_tile, size, 8);
- if (!h)
+ ht = hashmap_pool_alloc_tile();
+ if (!ht)
return NULL;
- memzero(h, size);
+ memzero(ht, sizeof(struct hashmap_tile));
} else {
- h = malloc0(size);
+ ht = malloc0(sizeof(struct hashmap_tile));
- if (!h)
+ if (!ht)
return NULL;
}
+ h = &ht->h;
h->hash_ops = hash_ops ? hash_ops : &trivial_hash_ops;
h->n_buckets = INITIAL_N_BUCKETS;
h->n_entries = 0;
h->iterate_list_head = h->iterate_list_tail = NULL;
- h->buckets = (struct hashmap_entry**) ((uint8_t*) h + ALIGN(sizeof(Hashmap)));
+ h->buckets = ht->initial_buckets;
h->from_pool = b;
@@ -339,7 +278,7 @@ static void remove_entry(Hashmap *h, struct hashmap_entry *e) {
unlink_entry(h, e, hash);
if (h->from_pool)
- deallocate_tile(&first_entry_tile, e);
+ hashmap_entry_pool_free_tile(e);
else
free(e);
}
@@ -357,7 +296,7 @@ void hashmap_free(Hashmap*h) {
free(h->buckets);
if (h->from_pool)
- deallocate_tile(&first_hashmap_tile, h);
+ hashmap_pool_free_tile(container_of(h, struct hashmap_tile, h));
else
free(h);
}
@@ -497,7 +436,7 @@ static int __hashmap_put(Hashmap *h, const void *key, void *value, unsigned hash
hash = bucket_hash(h, key);
if (h->from_pool)
- e = allocate_tile(&first_entry_pool, &first_entry_tile, sizeof(struct hashmap_entry), 64U);
+ e = hashmap_entry_pool_alloc_tile();
else
e = new(struct hashmap_entry, 1);
diff --git a/src/shared/mempool.c b/src/shared/mempool.c
new file mode 100644
index 0000000..b1655ea
--- /dev/null
+++ b/src/shared/mempool.c
@@ -0,0 +1,94 @@
+/*-*- 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
diff --git a/src/shared/mempool.h b/src/shared/mempool.h
new file mode 100644
index 0000000..7f8bb98
--- /dev/null
+++ b/src/shared/mempool.h
@@ -0,0 +1,55 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+ This file is part of systemd.
+
+ Copyright 2011-2014 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 <stddef.h>
+
+struct pool;
+
+struct mempool {
+ struct pool *first_pool;
+ void *freelist;
+ size_t tile_size;
+ unsigned at_least;
+};
+
+void* __mempool_alloc_tile(struct mempool *mp);
+void __mempool_free_tile(struct mempool *mp, void *p);
+
+#define DEFINE_MEMPOOL(pool_name, tile_type, alloc_at_least) \
+struct mempool pool_name = { \
+ .tile_size = sizeof(tile_type), \
+ .at_least = alloc_at_least, \
+}; \
+static inline tile_type* pool_name##_alloc_tile(void) { \
+ return __mempool_alloc_tile(&pool_name); \
+} \
+static inline void pool_name##_free_tile(tile_type *p) { \
+ __mempool_free_tile(&pool_name, p); \
+} \
+struct __useless_struct_to_allow_trailing_semicolon__
+
+
+#ifdef VALGRIND
+void mempool_drop(struct mempool *mp);
+#endif
--
2.1.0
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