IOBUF support (to be used by transports and fuse)

Signed-off-by: Anand V. Avati <avati@amp.gluster.com>

1 files changed, 97 insertions, 0 deletions

diff --git a/libglusterfs/src/iobuf.h b/libglusterfs/src/iobuf.h
new file mode 100644
index 000000000..8a854db8f
--- /dev/null
+++ b/libglusterfs/src/iobuf.h
@@ -0,0 +1,97 @@
+/*
+   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_ */