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.

5 files changed, 195 insertions, 0 deletions

diff --git a/sys/sys/_rmlock.h b/sys/sys/_rmlock.h
new file mode 100644
index 000000000000..e5c68d54732d
--- /dev/null
+++ b/sys/sys/_rmlock.h
@@ -0,0 +1,62 @@
+/*-
+ * 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_ */
diff --git a/sys/sys/lock.h b/sys/sys/lock.h
index 6d35ce58be32..2a9c4aa7ddd2 100644
--- a/sys/sys/lock.h
+++ b/sys/sys/lock.h
@@ -222,6 +222,7 @@ extern struct lock_class lock_class_mtx_sleep;
 extern struct lock_class lock_class_mtx_spin;
 extern struct lock_class lock_class_sx;
 extern struct lock_class lock_class_rw;
+extern struct lock_class lock_class_rm;
 extern struct lock_class lock_class_lockmgr;
 
 extern struct lock_class *lock_classes[];
diff --git a/sys/sys/pcpu.h b/sys/sys/pcpu.h
index b2fd6281a6fe..8757fe63968b 100644
--- a/sys/sys/pcpu.h
+++ b/sys/sys/pcpu.h
@@ -48,6 +48,15 @@
 struct pcb;
 struct thread;
 
+/* 
+ * XXXUPS remove as soon as we have per cpu variable
+ * linker sets and  can define rm_queue in _rm_lock.h
+*/
+struct rm_queue {
+	struct rm_queue* volatile rmq_next;
+	struct rm_queue* volatile rmq_prev;
+};
+
 /*
  * This structure maps out the global data that needs to be kept on a
  * per-cpu basis.  The members are accessed via the PCPU_GET/SET/PTR
@@ -74,6 +83,15 @@ struct pcpu {
 	PCPU_MD_FIELDS;
 	struct vmmeter	pc_cnt;			/* VM stats counters */
 	struct device	*pc_device;
+
+	/* 
+	 * Stuff for read mostly lock
+	 * 
+	 * XXXUPS remove as soon as we have per cpu variable
+	 * linker sets.
+	 */
+	struct rm_queue  pc_rm_queue; 
+
 };
 
 SLIST_HEAD(cpuhead, pcpu);
@@ -92,6 +110,10 @@ extern struct cpuhead cpuhead;
  * db_show_mdpcpu() is responsible for handling machine dependent
  * fields for the DDB 'show pcpu' command.
  */
+
+extern struct pcpu *cpuid_to_pcpu[MAXCPU];
+
+
 void	cpu_pcpu_init(struct pcpu *pcpu, int cpuid, size_t size);
 void	db_show_mdpcpu(struct pcpu *pcpu);
 
diff --git a/sys/sys/rmlock.h b/sys/sys/rmlock.h
new file mode 100644
index 000000000000..04ccb3820e6b
--- /dev/null
+++ b/sys/sys/rmlock.h
@@ -0,0 +1,109 @@
+/*-
+ * 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_
+
+#include <sys/mutex.h>
+
+#include <sys/_lock.h>
+#include <sys/_rmlock.h>
+
+#ifdef _KERNEL
+
+
+void	rm_init(struct rmlock *rm, const char *name, int opts);
+void	rm_destroy(struct rmlock *rm);
+void	rm_sysinit(void *arg);
+
+
+void	_rm_wlock_debug(struct rmlock *rm, const char *file, int line);
+void	_rm_wunlock_debug(struct rmlock *rm, const char *file, int line);
+void	_rm_rlock_debug(struct rmlock *rm, struct rm_priotracker *tracker,
+    const char *file, int line);
+void	_rm_runlock_debug(struct rmlock *rm,  struct rm_priotracker *tracker,
+    const char *file, int line);
+
+
+void	_rm_wlock(struct rmlock *rm);
+void	_rm_wunlock(struct rmlock *rm);
+void	_rm_rlock(struct rmlock *rm, struct rm_priotracker *tracker);
+void	_rm_runlock(struct rmlock *rm,  struct rm_priotracker *tracker);
+
+/*
+ * Public interface for lock operations.
+ *
+ */
+
+#ifndef LOCK_DEBUG
+#error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/rmlock.h>
+#endif
+
+#if LOCK_DEBUG > 0
+
+#define	rm_wlock(rm)	_rm_wlock_debug((rm), LOCK_FILE, LOCK_LINE)
+#define	rm_wunlock(rm)	_rm_wunlock_debug((rm), LOCK_FILE, LOCK_LINE)
+#define	rm_rlock(rm,tracker)  \
+    _rm_rlock_debug((rm),(tracker), LOCK_FILE, LOCK_LINE )
+#define	rm_runlock(rm,tracker)	\
+    _rm_runlock_debug((rm), (tracker), LOCK_FILE, LOCK_LINE )
+
+#else
+
+#define	rm_wlock(rm)		_rm_wlock((rm))
+#define	rm_wunlock(rm)		_rm_wunlock((rm))
+#define	rm_rlock(rm,tracker)   	_rm_rlock((rm),(tracker))
+#define	rm_runlock(rm,tracker)	_rm_runlock((rm), (tracker))
+
+#endif
+
+#define	rm_initialized(rm)	lock_initalized(&(rm)->lock_object)
+
+struct rm_args {
+	struct rmlock	*ra_rm;
+	const char 	*ra_desc;
+	int		ra_opts;
+};
+
+#define	RM_SYSINIT(name, rm, desc, opts)       				\
+	static struct rm_args name##_args = {				\
+		(rm),							\
+		(desc),							\
+                (opts),							\
+	};								\
+	SYSINIT(name##_rm_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE,	\
+	    rm_sysinit, &name##_args);					\
+	SYSUNINIT(name##_rm_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE,	\
+	    rm_destroy, (rm))
+
+
+#endif /* _KERNEL */
+#endif /* !_SYS_RMLOCK_H_ */
diff --git a/sys/sys/smp.h b/sys/sys/smp.h
index f2b2f523213f..7c79bb9eb2e0 100644
--- a/sys/sys/smp.h
+++ b/sys/sys/smp.h
@@ -100,6 +100,7 @@ void	forward_roundrobin(void);
 int	restart_cpus(cpumask_t);
 int	stop_cpus(cpumask_t);
 void	smp_rendezvous_action(void);
+void   smp_no_rendevous_barrier(void *);
 extern	struct mtx smp_ipi_mtx;
 
 #endif /* SMP */