Add libtpool (thread pools)

OpenZFS provides a library called tpool which implements thread
pools for user space applications.  Porting this library means
the zpool utility no longer needs to borrow the kernel mutex and
taskq interfaces from libzpool.  This code was updated to use
the tpool library which behaves in a very similar fashion.

Porting libtpool was relatively straight forward and minimal
modifications were needed.  The core changes were:

* Fully convert the library to use pthreads.
* Updated signal handling.
* lmalloc/lfree converted to calloc/free
* Implemented portable pthread_attr_clone() function.

Finally, update the build system such that libzpool.so is no
longer linked in to zfs(8), zpool(8), etc.  All that is required
is libzfs to which the zcommon soures were added (which is the way
it always should have been).  Removing the libzpool dependency
resulted in several build issues which needed to be resolved.

* Moved zfeature support to module/zcommon/zfeature_common.c
* Moved ratelimiting to to module/zfs/zfs_ratelimit.c
* Moved get_system_hostid() to lib/libspl/gethostid.c
* Removed use of cmn_err() in zcommon source
* Removed dprintf_setup() call from zpool_main.c and zfs_main.c
* Removed highbit() and lowbit()
* Removed unnecessary library dependencies from Makefiles
* Removed fletcher-4 kstat in user space
* Added sha2 support explicitly to libzfs
* Added highbit64() and lowbit64() to zpool_util.c

Reviewed-by: Tony Hutter <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #6442 

1 files changed, 72 insertions, 0 deletions

diff --git a/include/thread_pool.h b/include/thread_pool.h
new file mode 100644
index 000000000..57266f11c
--- /dev/null
+++ b/include/thread_pool.h
@@ -0,0 +1,72 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#ifndef	_THREAD_POOL_H_
+#define	_THREAD_POOL_H_
+
+#include <sys/types.h>
+#include <thread.h>
+#include <pthread.h>
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+typedef	struct tpool tpool_t;	/* opaque thread pool descriptor */
+
+#if defined(__STDC__)
+
+extern	tpool_t	*tpool_create(uint_t min_threads, uint_t max_threads,
+			uint_t linger, pthread_attr_t *attr);
+extern	int	tpool_dispatch(tpool_t *tpool,
+			void (*func)(void *), void *arg);
+extern	void	tpool_destroy(tpool_t *tpool);
+extern	void	tpool_abandon(tpool_t *tpool);
+extern	void	tpool_wait(tpool_t *tpool);
+extern	void	tpool_suspend(tpool_t *tpool);
+extern	int	tpool_suspended(tpool_t *tpool);
+extern	void	tpool_resume(tpool_t *tpool);
+extern	int	tpool_member(tpool_t *tpool);
+
+#else	/* Non ANSI */
+
+extern	tpool_t	*tpool_create();
+extern	int	tpool_dispatch();
+extern	void	tpool_destroy();
+extern	void	tpool_abandon();
+extern	void	tpool_wait();
+extern	void	tpool_suspend();
+extern	int	tpool_suspended();
+extern	void	tpool_resume();
+extern	int	tpool_member();
+
+#endif	/* __STDC__ */
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif	/* _THREAD_POOL_H_ */