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-rw-r--r--libglusterfs/src/iobuf.h97
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diff --git a/libglusterfs/src/iobuf.h b/libglusterfs/src/iobuf.h
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+/*
+ Copyright (c) 2009 Z RESEARCH, Inc. <http://www.zresearch.com>
+ This file is part of GlusterFS.
+
+ GlusterFS is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published
+ by the Free Software Foundation; either version 3 of the License,
+ or (at your option) any later version.
+
+ GlusterFS 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
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see
+ <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef _IOBUF_H_
+#define _IOBUF_H_
+
+#include "list.h"
+#include "common-utils.h"
+#include <pthread.h>
+#include <sys/mman.h>
+
+/* one allocatable unit for the consumers of the IOBUF API */
+/* each unit hosts @page_size bytes of memory */
+struct iobuf;
+
+/* one region of memory MMAPed from the operating system */
+/* each region MMAPs @arena_size bytes of memory */
+/* each arena hosts @arena_size / @page_size IOBUFs */
+struct iobuf_arena;
+
+/* expandable and contractable pool of memory, internally broken into arenas */
+struct iobuf_pool;
+
+
+struct iobuf {
+ union {
+ struct list_head list;
+ struct {
+ struct iobuf *next;
+ struct iobuf *prev;
+ };
+ };
+ struct iobuf_arena *iobuf_arena;
+
+ gf_lock_t lock; /* for ->ptr and ->ref */
+ int ref; /* 0 == passive, >0 == active */
+
+ void *ptr; /* usable memory region by the consumer */
+};
+
+
+struct iobuf_arena {
+ union {
+ struct list_head list;
+ struct {
+ struct iobuf_arena *next;
+ struct iobuf_arena *prev;
+ };
+ };
+ struct iobuf_pool *iobuf_pool;
+
+ void *mem_base;
+ struct iobuf *iobufs; /* allocated iobufs list */
+
+ int active_cnt;
+ struct iobuf active; /* head node iobuf
+ (unused by itself) */
+ int passive_cnt;
+ struct iobuf passive; /* head node iobuf
+ (unused by itself) */
+};
+
+
+struct iobuf_pool {
+ pthread_mutex_t mutex;
+ size_t page_size; /* size of all iobufs in this pool */
+ size_t arena_size; /* size of memory region in arena */
+
+ int arena_cnt;
+ struct iobuf_arena arenas; /* head node arena
+ (unused by itself) */
+};
+
+
+
+
+struct iobuf_pool *iobuf_pool_new (size_t arena_size, size_t page_size);
+struct iobuf *iobuf_get (struct iobuf_pool *iobuf_pool);
+void iobuf_unref (struct iobuf *iobuf);
+
+#endif /* !_IOBUF_H_ */