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/*
* PgBouncer - Lightweight connection pooler for PostgreSQL.
*
* Copyright (c) 2007-2009 Marko Kreen, Skype Technologies OÜ
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* Primitive slab allocator.
*
* - On each alloc initializer is called.
* - if init func is not given, memset() is done
*/
#include <sys/param.h>
#include "bouncer.h"
#define CUSTOM_ALIGN(x, a) (((unsigned long)(x) + ((a) - 1)) & ~((a) - 1))
#ifndef ALIGN
#define ALIGN(x) CUSTOM_ALIGN(x, sizeof(long))
#endif
/*
* Store for pre-initialized objects of one type.
*/
struct ObjectCache {
List head;
StatList freelist;
StatList slablist;
char name[32];
unsigned final_size;
unsigned total_count;
obj_init_fn init_func;
};
/*
* Header for each slab.
*/
struct Slab {
List head;
};
/* keep track of all caches */
static STATLIST(objcache_list);
/* cache for cache headers */
static ObjectCache *objcache_cache = NULL;
/* fill struct contents */
static void init_objcache(ObjectCache *cache,
const char *name,
unsigned obj_size,
unsigned align,
obj_init_fn init_func)
{
list_init(&cache->head);
statlist_init(&cache->freelist, name);
statlist_init(&cache->slablist, name);
safe_strcpy(cache->name, name, sizeof(cache->name));
cache->total_count = 0;
cache->init_func = init_func;
statlist_append(&cache->head, &objcache_list);
if (align == 0)
cache->final_size = ALIGN(obj_size);
else
cache->final_size = CUSTOM_ALIGN(obj_size, align);
log_noise("new cache: %s, size=%u", name, cache->final_size);
}
/* make new cache */
ObjectCache * objcache_create(const char *name,
unsigned obj_size,
unsigned align,
obj_init_fn init_func)
{
ObjectCache *cache;
/* main cache */
if (!objcache_cache) {
objcache_cache = malloc(sizeof(ObjectCache));
if (!objcache_cache)
return NULL;
init_objcache(objcache_cache, "objcache_cache",
sizeof(ObjectCache), 0, NULL);
}
/* new cache object */
cache = obj_alloc(objcache_cache);
if (cache)
init_objcache(cache, name, obj_size, align, init_func);
return cache;
}
/* free all storage associated by cache */
void objcache_destroy(ObjectCache *cache)
{
List *item, *tmp;
struct Slab *slab;
statlist_for_each_safe(item, &cache->slablist, tmp) {
slab = container_of(item, struct Slab, head);
free(slab);
}
statlist_remove(&cache->head, &objcache_list);
memset(cache, 0, sizeof(*cache));
obj_free(objcache_cache, cache);
}
/* add new block of objects to cache */
static void grow(ObjectCache *cache)
{
unsigned count, i, size;
char *area;
struct Slab *slab;
/* calc new slab size */
count = cache->total_count;
if (count < 50)
count = 16 * 1024 / cache->final_size;
if (count < 50)
count = 50;
size = count * cache->final_size;
/* allocate & init */
slab = malloc(size + sizeof(struct Slab));
if (!slab)
return;
list_init(&slab->head);
area = (char *)slab + sizeof(struct Slab);
memset(area, 0, size);
/* init objects */
for (i = 0; i < count; i++) {
void *obj = area + i * cache->final_size;
List *head = (List *)obj;
list_init(head);
statlist_append(head, &cache->freelist);
}
/* register to cache */
cache->total_count += count;
statlist_append(&slab->head, &cache->slablist);
}
/* get free object from cache */
void *obj_alloc(ObjectCache *cache)
{
List *item = statlist_pop(&cache->freelist);
if (!item) {
grow(cache);
item = statlist_pop(&cache->freelist);
}
if (item) {
if (cache->init_func)
cache->init_func(item);
else
memset(item, 0, cache->final_size);
}
return item;
}
/* put object back to cache */
void obj_free(ObjectCache *cache, void *obj)
{
List *item = obj;
list_init(item);
statlist_prepend(item, &cache->freelist);
}
/* total number of objects allocated from cache */
int objcache_total_count(const ObjectCache *cache)
{
return cache->total_count;
}
/* free objects in cache */
int objcache_free_count(const ObjectCache *cache)
{
return statlist_count(&cache->freelist);
}
/* number of objects in use */
int objcache_active_count(const ObjectCache *cache)
{
return objcache_total_count(cache) - objcache_free_count(cache);
}
static void run_slab_stats(ObjectCache *cache, slab_stat_fn fn, void *arg)
{
unsigned free = statlist_count(&cache->freelist);
fn(arg, cache->name, cache->final_size, free, cache->total_count);
}
void objcache_stats(slab_stat_fn fn, void *arg)
{
ObjectCache *cache;
List *item;
statlist_for_each(item, &objcache_list) {
cache = container_of(item, ObjectCache, head);
run_slab_stats(cache, fn, arg);
}
}
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