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authorStephan Uphoff <ups@FreeBSD.org>2007-11-08 14:47:55 +0000
committerStephan Uphoff <ups@FreeBSD.org>2007-11-08 14:47:55 +0000
commitf53d15fe1b8a7a7df972f253b38c698f6ca45b71 (patch)
treee657852bc96f8f77553f7abb0596889a6b8d5e00 /sys/sys/_rmlock.h
parent0559b904bc69c95a21b7b5a286242091064aa485 (diff)
downloadsrc-f53d15fe1b8a7a7df972f253b38c698f6ca45b71.tar.gz
src-f53d15fe1b8a7a7df972f253b38c698f6ca45b71.zip
Initial checkin for rmlock (read mostly lock) a multi reader single writer
lock optimized for almost exclusive reader access. (see also rmlock.9) TODO: Convert to per cpu variables linkerset as soon as it is available. Optimize UP (single processor) case.
Notes
Notes: svn path=/head/; revision=173444
Diffstat (limited to 'sys/sys/_rmlock.h')
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+/*-
+ * Copyright (c) 2007 Stephan Uphoff <ups@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the author nor the names of any co-contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef _SYS__RMLOCK_H_
+#define _SYS__RMLOCK_H_
+
+/*
+ * XXXUPS remove as soon as we have per cpu variable
+ * linker sets and can define rm_queue in _rm_lock.h
+*/
+#include <sys/pcpu.h>
+/*
+ * Mostly reader/occasional writer lock.
+ */
+
+LIST_HEAD(rmpriolist,rm_priotracker);
+
+struct rmlock {
+ struct lock_object lock_object;
+ volatile int rm_noreadtoken;
+ LIST_HEAD(,rm_priotracker) rm_activeReaders;
+ struct mtx rm_lock;
+
+};
+
+struct rm_priotracker {
+ struct rm_queue rmp_cpuQueue; /* Must be first */
+ struct rmlock *rmp_rmlock;
+ struct thread *rmp_thread;
+ int rmp_flags;
+ LIST_ENTRY(rm_priotracker) rmp_qentry;
+};
+
+#endif /* !_SYS__RMLOCK_H_ */