shared: split mempool implementation from hashmaps

Makefile.am

@@ -768,6 +768,8 @@ 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 \

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 = mempool_alloc_tile(&hashmap_pool);
+                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);
+                mempool_free_tile(&hashmap_entry_pool, 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);
+                mempool_free_tile(&hashmap_pool, 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 = mempool_alloc_tile(&hashmap_entry_pool);
         else
                 e = new(struct hashmap_entry, 1);
 

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

src/shared/mempool.h

@@ -0,0 +1,48 @@
+/*-*- 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, \
+}
+
+
+#ifdef VALGRIND
+void mempool_drop(struct mempool *mp);
+#endif